20230505122 Supplemental Attachment A.pdf

Avista Utilities
Management
Program Review and
Recommendations
Rodney Pickett 9/20/2017
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Table of Contents
Executive Summary ........................................................................................................ 1
Purpose ........................................................................................................................... 2
Scope .............................................................................................................................. 3
Objectives, Assumptions, Constraints ............................................................................. 4
Objectives .................................................................................................................... 4
Assumptions ................................................................................................................ 4
Constraints ................................................................................................................ 11
Current Position ............................................................................................................ 12
Gaps in current Strategy and Objectives ................................................................... 25
Data Gaps ................................................................................................................. 26
Mitigation Plan for Gaps ............................................................................................ 26
Data Changes ............................................................................................................ 27
Future Position .............................................................................................................. 32
Future Performance Levels ....................................................................................... 33
Impacts of anticipated future demand, innovation, reliability, obsolescence, regulation,
and rising costs .......................................................................................................... 38
Justification for investing ............................................................................................ 41
Timing ........................................................................................................................ 41
Strategy Options ........................................................................................................... 44
Electric Distribution Wood Poles Scenarios ............................................................... 44
Run all Wood Pole and associated components to failure ..................................... 44
Inspect all Wood Poles on a 20 year cycle based on the Feeder ........................... 45
Inspect all Wood Poles on a 5 year cycle based on the Feeder ............................. 46
Inspect all Wood Poles on a 10 year cycle based on the Feeder ........................... 46
Inspect all Wood Poles on a 25 year cycle based on the Feeder ........................... 46
Inspect all Wood Poles on a 20 year cycle based on the Feeder and replace poles based on an age of 60 Years using the Grid Modernization Program .................... 46
Alternative Comparison ............................................................................................. 47
Strategy Selection ......................................................................................................... 55
Metrics ........................................................................................................................... 58
Bibliography .................................................................................................................. 60
Appendix A ...................................................................................................................... 0
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Appendix B - Model output reports for labor, spares, Lifecycle Cost summary, effects, and others as appropriate ............................................................................................... 0
Appendix C ...................................................................................................................... 0
Appendix D – Life Extension Impact Analysis of Reinforcing Electric Distribution Wood
Poles ............................................................................................................................... 0

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Executive Summary
Based on our analysis, Asset Management recommends continuing with our current 20
year cycle for the Wood Pole Management program. We examined several different alternatives and some do provide more a little more value but potentially require very
significant initial capital costs well beyond current levels.
Avista has between 233,000 and 244,000 wood poles in our Electric Distribution
system. These poles physically support most of the Electric Distribution infrastructure to
keep the conductors and other components a safe distance from the population and avoid injuries. We examine here the different strategies for maintaining our wood poles
and attached components to find the best strategy.
The Wood Pole Management program inspects and repairs or replaces distribution
wood poles, cross-arms, insulator pins, insulators, pole guying, cutouts, primary and
secondary connectors, lightning arresters, grounding, and Overhead Distribution transformers. This analysis covers distribution wood poles, cross-arms, insulator pins,
insulators, and pole guying. The Transformer Changeout Program analysis will cover
the primary and secondary connectors, secondary conductors, lightning arresters,
grounding, and Overhead Distribution transformers.
The Wood Pole Management program supports our Safe & Reliable Infrastructure strategy. Specifically, Wood Pole Management strives to invest in our infrastructure to
achieve optimum life-cycle performance – safely, reliably and at a fair price. The
program meets this objective by providing the best customer internal rate of return that
will fit within our capital and Operations and Maintenance budget constraints.
We selected continuing our 20 year inspection and maintenance cycle (see the table below) based on a good customer internal rate of return and alignment with our
historical budget limitation of around $22 million in Capital dollars for Wood Pole
Management and Grid Modernization.
We examined several alternatives that included a 5 year, 10 year, 20 year, and 25 year
inspection cycle time as well as the impact of Grid Modernization work on the related Wood Pole Management work. While the 5 year cycle did provide a better Customer
Internal Rate of Return of 8.85%, the 5 year cycle Operations and Maintenance costs
exceeded our historical spending constraint. The 20 year inspection cycle provided the
best Customer Internal Rate of Return for both the case that includes adding the
Transformer Changeout Program work of replacing all pre-1981 Overhead Transformers and our current practice of replacing transformers that functionally have
failed while meeting the Operating and Maintenance budget constraints. Any changes
to the Transformer Changeout Program are covered in a different document and
remains independent of this analysis.
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Alternative CIRR NPV of Life-
Cycle Costs Cost Ratio Reduction
6.03% $1,016,381,966 $509,538,239 0.804 -0.156
without Transformer
Changeout Program
8.00% $817,592,755 $351,165,376 1.243 0.194
WPM 20 Year Cycle with
TCOP
WPM 5 Year Cycle with
TCOP
WPM 10 Year Cycle with TCOP
WPM 25 Year Cycle with TCOP
WPM 20 Year Cycle with
TCOP and Grid Mod

Based on the analysis and selection of the 20 year inspection cycle, the table below
shows a projection for the Capital and O&M budgets required to support the program.

Budget Year 1 Year 2 Year 3 Year 4 Year 5
Capital
O&M

Any delays in implementing the Wood Pole Management program strategy as
envisioned will delay the immediate benefits and take 20 years based on the current
inspection cycle to recover the long range value of the strategy.
We recommend continuing the Wood Pole Management program on its 20 year
inspection cycle and follow-up work strategy. Any delays in the work will impact reliability and system performance. Ultimately, the Capital Planning Group makes the
final budget decisions and selects or modifies the strategy implemented based on
current budget constraints and Avista’s strategic initiatives.
Purpose
Asset Management maximizes the life-cycle value of Avista's physical assets. Our team
researches and collaborates to integrate knowledge, discover insight, and lead with
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intelligence in order to achieve Avista's strategic objectives. Avista invests in our infrastructure to achieve optimum life-cycle performance – safely, reliably and at a fair
price. We focus on sustaining safe systems that deliver energy effectively and
efficiently at all times.
Asset Management reviews programs periodically to ensure they accomplish their initial
objectives and bring them into alignment with current corporate strategic objectives. Tracy West analyzed the Wood Pole Management (WPM) program in 2012, so five
years have elapsed since the last review. Furthermore, our Vice-President, Heather
Rosentrator, requested Asset Management analyze and justify our current capital
spending on Electric Distribution assets.
Scope
The WPM inspects and repairs or replaces distribution wood poles, cross-arms, insulator pins, insulators, pole guying, cutouts, primary and secondary connectors,
lightning arresters, grounding, and Overhead Distribution transformers. This analysis
covers distribution wood poles, cross-arms, insulator pins, insulators, and pole guying.
The Transformer Changeout Program (TCOP) analysis covers cutouts, the primary and
secondary connectors, lightning arresters, grounding, and Overhead Distribution transformers. Primary conductor analysis was analyzed independent of the Wood Pole
Management program because WPM addresses very little primary conductor.
While WPM and Grid Modernization are related programs, this documented discusses
Grid Modernization as it relates to WPM and leaves its justification for another report.
Grid Modernization has several other drivers that are not associated with WPM such as road moves, Distribution automation, re-conductoring, TCOP, and other drivers.
Currently, the WPM program inspects all electric Distribution Wood Poles on a 20 year
cycle followed by the work identified to repair or replace components from the
inspection. The inspection covers all wood pole and all equipment attached to the pole.
Predominately, the inspection covers the wood pole, attached crossarms, insulator, insulator pins, Distribution overhead transformers, grounding, lightning arresters,
cutouts, and wildlife guards installed on transformers. The inspection includes a visual
inspection of the pole and attached components, boring and checking for internal rot as
well of external visual inspection of the pole checking. The specifics of the inspection
portion of WPM is outlined in the “Specification for the Inspection of Poles” (Specification S-622). The follow-up work to the inspections is covered specifically by
the following documents in the Distribution Feeder Management Plan (DFMP) –
Structure-Specific Programs found at Avista’s sharepoint site: DFMP – Structure-
Specific Programs – Design Criteria Manual - All Documents.
In order to align the assets better in the analysis, wood poles, attached crossarms, insulators, guying, and insulator pins were analyzed in the WPM models. The overhead
transformers, cutouts, grounding, lightning arresters, and wildlife guards were analyzed
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in different models for the Distribution transformer and combined in the final analysis to reflect the full WPM program budgets and impacts.
Duration of the strategy – 5 years
Objectives, Assumptions, Constraints
Objectives
From Avista’s Strategic Plan (Avista, 2017), the Wood Pole Management program
supports our Safe & Reliable Infrastructure strategy. Specifically, WPM strives to invest
in our infrastructure to achieve optimum life-cycle performance – safely, reliably and at a fair price. WPM meets this objective by providing the best customer internal rate of
return (CIRR) that will fit within our capital and Operations and Maintenance (O&M)
budget constraints.
Assumptions
Table 1 lists specific assumptions used in the analysis for WPM and the WPM portion of
the Grid Modernization program.
Table 1 Model Assumptions
Assumption Source of Assumption
Average Customer Impact Value per event = $24,431 value, average outage duration, and
insulator pins are the same age as the
are performed by contractors using the
contractors pricing
completed by contractors. Costs based
on weighted average price based on
number of units per contract price
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Assumption Source of Assumption
insulators, four insulator pins, and guying these assets is based on Wood Pole
Management inspection results using this
assumption so that the probability of
failure reflects the probability that the pole has a component and that component
has failed. This method is selected
because we don’t have an inventory for
insulators, insulator pins, and guying. So, except for the wood poles themselves, the MTTF’s for all components does not
reflect the components actual MTTF but
two different probabilities, i.e. probability
that the pole has the component and the
90% of the Distribution poles are cedar
time period between detection of a problem with a component’ failure is 20
years with a detection probability of
models, the time period between
detection of a problem with a component’
failure is 20 years with a detection probability of 100%. However, they only
replace the components that will fail

is the components that will fail before the the assumption directly above.
failed when it no longer has the required
strength to survive a one in 50 year
to have indication they no longer meet their functional requirements. an example, if an insulator shows signs of cracks or ultraviolet damage, they no longer have their full insulation
capabilities and are considered functional
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Assumption Source of Assumption

Input for the failure curves shown in Figure 1 through Figure 6 come from the Wood
Pole Management Inspection database (Pickett). In order to fully understand what is in
the Wood Pole Management Inspection database and how it is used, an Asset
Information Strategy is needed and is discussed below in the Gaps in current Strategy and Objectives section below. These failure curve provide the basis for predicting
future failures based on the age of an asset and shown the unreliability of the asset as a
function of age in hours. Some of the failure curves in Figure 1 through Figure 6 and
Table 2 through Table 7 were adjusted from their historical failure curve to represent
changes in policy that affect how the future failure curves will appear and the changes are noted for each table as appropriate. Table 2 through Table 7 summarize each of
the failure curves into the corresponding failure equations used in the model and the
Mean Time To Failure (MTTF) as a point of reference. The MTTF only allows you to
simply compare how the reliability of a component compares to a different component.
For better explanations of the failure curves and their associated equations, please see the “Training for New Employees - Weibull.pptx” located at: Training for New Employees
- Weibull.pptx. The specific equations for all failure curves can also be found in the
Availability Workbench Users Guide at AvailabilityWorkbench_Letter.pdf.

Figure 1 Cumulative Probability plot for Unreliability for Distribution Wood Pole Replacements from the AWB Models*
2016 Pole Cumulative Probability
432 5262 6.41E+04 7.808E+05
Time
0.1
0.2
0.3
0.5
1
2
3
5
10
20
30
50
70
90
99
99.9
Un
r
e
l
i
a
b
i
l
i
t
y
(%
)
Eta estimator
P0: 0%
B50: 6.934E+05
B20: 5.442E+05
B10: 4.615E+05
ε: 0.02628
γ2: 0
β2: 4.78
η2: 7.511Ε+05
γ1: 0
β1: 0.7738
η1: 2.428Ε+08
Median rank
Bi-Weibull
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*Note: Time is in Hours
Table 2 Failure Curve Values for Distribution Wood Pole Replacements
Bi-Weibull Failure Curve –
Wood Poles Replacement
- h 5190639 Years 85.74 Years
b 0.44 4.78
g 0 0
79 Years*
Wood Pole Management Inspection Data Inspection Data
*Note: These values were adjusted from a MTTF of 85 years to account for changes in WPM Policies that replaces pole in inaccessible areas instead of reinforcing them.

Figure 2 Cumulative Probability plot for Unreliability for Distribution Crossarms from the AWB Models*
*Note: Time is in Hours
Table 3 Failure Curve Values for Distribution Crossarms
Weibull Failure Curve – Crossarms Weibull Values
Characteristic Life - h 97 Years
2016Cross Arm Cumulative Probability
1.702E+04 6.422E+04 2.423E+05 9.146E+05
Time
0.1
0.2
0.3
0.5
1
2
3
5
10
20
30
50
70
90
99
99.9
Un
r
e
l
i
a
b
i
l
i
t
y
(%
)
Eta estimator
P0: 0.0005848%
B50: 6.84E+05
B20: 5.474E+05
B10: 4.7E+05
ε: 0.01904
γ: −1.16Ε+05
β: 6.05
η: 8.5Ε+05
Median rank
3-parameterWeibull
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Weibull Failure Curve – Crossarms Weibull Values
Shape Parameter - b
Offset - g
Mean Time To Failure (MTTF)
Source of Data
Inspection Data

Figure 3 Cumulative Probability plot for Unreliability for Distribution Pole Guying from the AWB Models*
*Note: Time is in Hours
Table 4 Failure Curve Values for Pole Guying
Weibull Failure Curve – Guying Weibull Values
Characteristic Life - h 126 Years
Shape Parameter - b 6.599
Offset - g -20 Years
Mean Time To Failure (MTTF) 98.25 Years
2016Guying Cumulative Probability
9720 4.486E+04 2.071E+05 9.556E+05
Time
0.1
0.2
0.3
0.5
1
2
3
5
10
20
30
50
70
90
99
99.9
Un
r
e
l
i
a
b
i
l
i
t
y
(
%
)
Eta estimator
P0: 0.0007237%
B50: 8.608E+05
B20: 6.96E+05
B10: 6.014E+05
ε: 0.006602
ρ: 0.9974
γ: −1.837Ε+05
β: 6.599
η: 1.104Ε+06
Median rank
3-parameterWeibull
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Weibull Failure Curve – Guying Weibull Values
Source of Data
Inspection Data

Figure 4 Cumulative Probability plot for Unreliability for Pin Insulators from the AWB Models*
*Note: Time is in Hours
Table 5 Failure Curve Values for Pin Insulators
Weibull Failure Curve – Insulator Weibull Values
Characteristic Life - h 91 Years
Shape Parameter - b 5.005
Offset - g 0 Years
Mean Time To Failure (MTTF) 84.6 Years
Source of Data Wood Pole Management
Inspection Data

ε: 0.02041
ρ: 0.9882
γ: 0
β: 5.005
η: 7.976Ε+05
Median rank
2-parameterWeibull
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Figure 5 Cumulative Probability plot for Unreliability for Insulator Pins from the AWB Models*
*Note: Time is in Hours
Table 6 Failure Curve Values for Insulator Pins
Weibull Failure Curve – Insulator Pins Weibull Values
Characteristic Life - h 90.3 Years
Shape Parameter - b 4.405
Offset - g 0 Years
Mean Time To Failure (MTTF) 83.1 Years
Source of Data Wood Pole Management
Inspection Data

ε: 0.0441
ρ: 0.9736
γ: 0
β: 4.405
η: 7.91Ε+05
Median rank
2-parameterWeibull
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Figure 6 Cumulative Probability plot for Unreliability for Distribution Wood Pole Reinforcements from the AWB Models*
*Note: Time is in Hours
Table 7 Failure Curve Values for Distribution Wood Pole Reinforcing
Weibull Failure Curve – Reinforce Poles Weibull Values
Characteristic Life - h 152 Years
Shape Parameter - b 2.852
Offset - g 0 Years
Mean Time To Failure (MTTF) 134 Years**
Source of Data Wood Pole Management
Inspection Data
**Note: These values were adjusted from a MTTF of 109 years to account for changes in WPM Policies that replaces pole in inaccessible areas instead of reinforcing them
with stubs.
Constraints
Budget constraints and decisions have generally limited the Capital spending on WPM
and Grid Modernization to about $22 million (see Table 9) in the past. These
constraints have limited the Grid Modernization the most and prevented the program of achieving the desired 60 year cycle. Based on 2012-2016 of 414 completed miles for
ε: 0.05082
γ: 0
β: 2.852
η: 1.335Ε+06
Median rank
2-parameterWeibull
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Grid Modernization, Avista is currently averaging ~ 84 year cycle time to complete all feeders instead of the desired 60 year cycle (see the file named “FW Grid
Modernization Approximate Cycle Time Based on Current Program Funding .msg” for
the calculation of current Grid Modernization cycle time).
Current Position
Avista estimates our system contains between 244,000 to 233,000 Distribution poles.
Currently our Maximo system documents just over 200,000 poles. Our ongoing 20 year inspection and inventory of our poles completes its first cycle in 2027 ideally when we
should have something that reflect a complete pole inventory of our electric distribution
system. Table 8 shows some key facts about the electric distribution system and the
WPM program. The quantity of poles in Table 8 is the high end estimate based on an
initial estimate from 2006 and the estimate of 233,000 poles comes from the average number of poles per mile multiplied by the number of Overhead Distribution mileage
listed in Table 8 (this method does ignore non-wood street and area light poles that are
not normally inspected). The Overhead Distribution mileage comes from a data pull of
Avista’s Facility Management (AFM) system that is performed periodically. The average
wood pole age comes from Maximo data for all poles with a known installation date (see Figure 8 below). The remaining data in Table 8 are standard values derived using the
processes outlined in the “Asset Management Standard Assumptions” by the Asset
Management group.
Table 8 Distribution Wood Pole Key Facts
Key Facts 2016 Values
Quantity 244,000 Poles (estimated)
Overhead Distribution Mileage 7,702 Miles
20 Year Cycle Time Mileage 385.1 Miles per Year
60 Year Cycle Time Mileage 128.4 Miles per Year
Average Wood Pole Age 31.73 Years
Mean Time To Failure (MTTF) – Wood Poles only 79 Years
5 Year OMT Average – Pole Rotten 43.8 Events per Year
Average Number of Customers Impacted per
Event
80.55 Customers
4.82 Hours
Most Critical)
2 for 2016

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Based on data extracted from Avista’s financial system, Table 9 shows our historical spending on WPM and Grid Modernization for the past 5 years (see AM - Capital
Spending Status - Summary - rev 1.xlsx for Capital Spending, see MAC 215 for
2016.xlsx for 2016 O&M Spending and see AM - MAC Budget Analysis - by Task.xlsx
for 2012-2016 O&M Spending in Asset Maintenance tab). Prior to 2012, the Grid
Modernization program had not been fully implemented, so we did not find as much value in going back in history beyond 2012. The O&M spending for WPM comes from
the same source and splits between WPM and Grid Modernization so that the WPM
stays on a 20 year inspection cycle. Historically, the 20 year cycle for WPM has come
from the miles completed by WPM and Grid Modernization. The two programs in the
past have used the same inspection results for planning and accomplishing the same work of the WPM program. Grid Modernization expands upon the WPM portion and
includes many more program drives and work scope beyond what we discuss in this
document. What this means is that as the miles of Grid Modernization is changed, the
miles of WPM work must change in the opposite direction so we maintain a 20 year
cycle. So if we do more miles of Grid Modernization work, we can reduce the number of miles WPM must perform by an equal amount.
Table 9 Historical Spending on Distribution WPM and Grid Modernization Programs
Program Year 2012 Year 2013 Year 2014 Year 2015 Year 2016 Average
Pole
Management
Capital Spending
$10,064,203 $9,258,713 $9,512,319 $9,111,453 $8,601,732 $9,309,684
Wood
Pole Managem
ent O&M Spending
$758,923 $564,222 $485,930 $455,991 $639,924 $580,998
Wood
Pole Managem
ent O&M Budgets
Not Provided $813,178 $818,778 $706,686 $789,631 $782,068
Grid
Modernization
Capital Spending
– ER 2470 Portion
Only
$7,362,925 $6,217,686 $8,683,159 $11,944,561 $9,476,167 $8,736,899

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The WPM O&M Budgets identified in Table 9 come from the file named, “Budget Requirements OM 4-21-2017.xlsx” and represents the budget needs to maintain the
program based on the current program according to Asset Maintenance. O&M budget
cuts reduced the available funding, so we modified the inspection scope to reduce the
costs by reducing the number of poles inspected and relied upon a backlog of work to
keep the program on the 20 year inspection cycle. Figure 7 shows this very fact. You see the number of poles inspected is directly related to the O&M budgets. Additional
O&M savings also came from a policy to not inspect poles on Grid Modernization
feeders 60 years old or greater since they will be replaced per the Grid Modernization
strategy. When you compare the WPM O&M spending to the O&M budget in Table 9,
you see the level of the budget cuts equaling an average of $200,000 per year below needed levels. For the past 8 years (2009 through 2016), Avista has inspected an
average of 12,370 poles per year which is near the planned number of 12,200 poles per
year for a 20 year cycle with a total population of 244,000 poles. In 2017, the backlog
will be gone and unless the O&M budget is restored to the WPM program, our cycle
time will begin to approach a 25 year cycle.

Figure 7 O&M Cost and Inspection Trends for WPM
Table 10 shows the structure types and material types for known poles from the same
data used to create the age profile in Figure 8. Cedar poles dominates the pole material
$408,386
$521,130 $547,860
$758,923
$564,222 $485,930 $455,991
$639,924
$29 $43 $41 $44 $47 $46 $56 $55 02000400060008000100001200014000160001800020000
$0$100,000$200,000$300,000$400,000$500,000$600,000$700,000$800,000
2009 2010 2011 2012 2013 2014 2015 2016
Nu
m
b
e
r

o
f

P
o
l
e
s

I
n
s
p
e
c
t
e
d
Ac
t
u
a
l

S
p
e
n
d
i
n
g

(
$
)
Year
Cost and Work Trends for Wood Pole ManagementO&M Spending O&M Cost per Pole Inspected Poles Inspected
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(>90% of the population) and supports the assumption of treating all poles with the same failure curves. Structure types are dominated by Distribution Pole and Service
Pole structure types (~ 78% combined of all structure types) and supports treating all
poles as the same structure type.
Table 10 Detailed Population by Structure Type and Pole Material
Structure Type Cedar Fir Laminated Larch Other Pine Steel Grand Total for Structure Type
1.714% 0.015% 0.000% 0.053% 0.000% 0.002% 0.030% 1.814%
0.003% 0.000% 0.000% 0.000% 0.000% 0.000% 0.000% 0.003%
0.007% 0.000% 0.000% 0.000% 0.000% 0.000% 0.000% 0.007%
0.008% 0.000% 0.000% 0.001% 0.000% 0.000% 0.000% 0.009%
68.909% 0.315% 0.014% 5.168% 0.034% 0.003% 0.087% 74.530%
1.314% 0.001% 0.001% 0.022% 0.000% 0.000% 0.003% 1.341%
0.000% 0.000% 0.000% 0.000% 0.003% 0.000% 0.000% 0.003%
1.867% 0.030% 0.001% 0.153% 0.001% 0.000% 0.001% 2.053%
0.003% 0.000% 0.000% 0.000% 0.000% 0.000% 0.000% 0.003%
0.695% 0.007% 0.000% 0.143% 0.000% 0.000% 0.002% 0.846%
0.022% 0.000% 0.000% 0.000% 0.000% 0.000% 0.000% 0.022%
0.015% 0.001% 0.000% 0.003% 0.003% 0.000% 0.000% 0.022%
0.012% 0.000% 0.000% 0.000% 0.000% 0.000% 0.000% 0.012%
0.089% 0.002% 0.000% 0.004% 0.000% 0.000% 0.000% 0.095%
9.990% 0.324% 0.000% 0.891% 0.002% 0.009% 0.018% 11.233%
4.552% 0.025% 0.000% 0.861% 0.000% 0.000% 0.286% 5.724%
1.978% 0.071% 0.001% 0.073% 0.024% 0.000% 0.135% 2.282%
0.001% 0.000% 0.000% 0.000% 0.000% 0.000% 0.000% 0.001%
Material 91.179% 0.790% 0.016% 7.372% 0.067% 0.014% 0.562% 100.000%

Figure 8 shows the model age profile based on poles with known ages from Distribution WPM database (see the following file for the data used: Health Index Work rev 1.xlsx).
The MTTF and the failure rates based on pole age come from the failure curves
developed and shown in Figure 1 and Table 2. Figure 8 shows the model population
age profile and demonstrates the changing number of poles approaching the MTTF and
entering the region of increasing failure rates. So the age profile shown illustrates that our population is largely younger than the MTTF. The MTTF represent the age at which
50% of the original population has failed. The failure rate begins to noticeable increase
after the age of 60 years as seen in Figure 8, so as a larger percentage of poles
approach the MTTF, we should see a larger number of pole failures compared to the
past. In fact, we do see indications of this in several data sources.
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Figure 8 Electric Distribution Wood Pole Population Distribution and Failure Rate based on Pole Age
Figure 11 shows a definite trend upwards in pole usage for Storms. We did see
unusual storms in 2014 and 2015 and we also saw an associated increasing trend in
the number of Major Event Days (MED) except for 2016. The number of MED
contributes to the trend upwards in quantity of material used for each year. However,
the year 2016 also used about the same number of poles as 2013 despite not having any MED to contribute to the storm damage. The potential trend of major storm events
poses a threat to the entire distribution system. An article titled “ClimateWise launches
two reports that warn of growing protection gap in insurance due to rising impact of
climate risks” published by the Cambridge Institute for Sustainability Leadership. The
article suggests major storm frequencies have increase by 6 fold and anticipates major storms occuring approximately once every 17 years (Cambridge Institute for
Sustainability Leadership, 2017). As antidotal evidence, Avista has experienced two
storms classified as one of the worst storms in history. The first storm was the 1996 Ice
Storm (NOAA National Centers for Environmental Information, 2017) which NOAA
identified as the worst ice storm in 60 years and the second storm was the 2015 November wind storm (Brunt, 2017) that broke the record for customer outages set by
the 1996 Ice Storm. Further analysis may be warranted in the future.
0.0%10.0%20.0%30.0%40.0%50.0%60.0%70.0%80.0%90.0%100.0%
05001,0001,5002,0002,5003,0003,5004,0004,500
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Figure 12 through Figure 15 continue to show trends upwards in the number of poles used in Grid Modernization and WPM (see Poles Crossarms Cutouts Replaced for
2012-2016 for ERs 2470 2055 2059 2060.xlsx and Stock 2012-2016 for ERs 2470 2054
2055 2060.xlsx for the associated data). Though, we may potentially see the number of
poles used in Grid Modernization to drop as future work potentially could include
feeders that have been inspected and maintained by WPM in the recent past.

Figure 9 WPM Related OMT Events (Includes Arresters, Crossarm-rotten, Cutout/Fuse, Insulator, Insulator Pin, Pole
Fire, Pole-rotten, Squirrel, Transformer - OH, and Wildlife Guard OMT Sub-Reasons)
The current trend in WPM related events in OMT continues to improve as seen in Figure 9 with each year’s work on WPM, Grid Modernization, TCOP, and other work.
The drivers for this improvement comes from improve trends in Overhead Transformer
failures associated with TCOP replacing many older transformers, Squirrel events
decreasing as more wildlife guards are installed on Overhead Transformers, and Cutout failures dropping with cutout replacements and better fuse coordination. However, the number of OMT events associated with Pole-rotten is growing a little each year as seen
in Figure 10 and Figure 16. The Pole-rotten trend remains small but noticeable and we
anticipate it to continue for the near future.
The data for Figure 9 and Figure 10 came from OMT Failure Data\Quarterly\Quarterly OMT Failure Data 2016.xlsx and Figure 16 comes from OMT Data for WPM subset.xlsx.
0200400600800100012001400160018002000
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Figure 10 WPM Related OMT Event Trends
When we examine the impacts WPM has had on Distribution Feeders, Figure 17 shows
the average number of WPM related Sustained Outages on Feeders prior to completing
the WPM work and the results after the work was completed (WPM related events
include Arrester, Crossarm-rotten, Cutout/Fuse, Insulator, Insulator Pin, Pole Fire, Pole-rotten, Squirrel, Transformer - OH, and Wildlife Guard OMT Sub-Reasons). The chart
in Figure 17 represents all of the feeders where WPM work has been completed. Year
0 represents the year the work was completed. Year -5 represents 5 years before the
WPM work was completed and Year 4 represents 4 years after WPM work was
completed. As an example, if the WPM work was completed in 2013, Year 0 represents 2013 for that feeder and Year -5 represents 2008 data for that particular feeders. The
number of events for each year is summed up by feeder and divided by the number of
miles in length for each feeder giving us the number of sustained outages per mile of
feeders. Using the number of outages per mile, normalizes the data so that the values
are not a function of feeder lengths that can change each year. The value of all the feeders is averaged in outages per mile and plotted in Figure 17 below.
01002003004005006007008009001000
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Outage Management Tool (OMT) Sub-Reasons Applicable Trends to Wood Pole Management200520062007200820092010201120122013 2014 2015 2016
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Figure 17 shows that the number of failures experienced by a feeder improves after WPM work is completed. Prior to WPM work, a feeder has about 0.18 outages per mile
each year related to WPM type of work. After the work is completed, the outages per
mile drop to 0.1 outage per mile. WPM work typically completed over one or two years
depending on the schedule and length of the feeder. For the data and development of
Figure 17 and Figure 23, see Events per Mile prior to and after WPM.xlsx.

Figure 11 ER 2059 - Electric Distribution Storm Related Material Issued for Poles, Crossarms, and Cutouts (Stubs not
used during storm events)

y = 77x + 21R² = 0.311
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Figure 12 ER 2055 - Electric Distribution Minor Blanket Material Issued for Poles, Stubs, Crossarms, and Cutouts

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Figure 13 ER 2060 and 2470 - WPM and Grid Modernization Material Issued for Poles, Stubs, Crossarms, and
Cutouts

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Figure 14 ER 2060 and 2470 - WPM and Grid Modernization Material Issued per Mile of Completed Work for Poles, Stubs, Crossarms, and Cutouts

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Figure 15 ER 2060 - WPM Material Issued per Mile of Completed Work for Poles, Stubs, Crossarms, and Cutouts
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Figure 16 OMT Trend for Crossarm-rotten, Cutout/Fuse, and Pole-rotten
y = 1.9091x + 30.091
R² = 0.4208
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Crossarm-rotten Cutout/Fuse Pole-rotten Linear (Pole-rotten)
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Figure 17 WPM Related Sustained Outages Events per Mile of Distribution Feeder Before and After WPM Work
Completed
Gaps in current Strategy and Objectives
The current strategy relies upon visual inspection and boring of poles to determine their
condition. Using health indices in the future may further enhance identifying components for replacement or repair by better predicting their future failure probability.
Industry is providing better and better tools for determining condition that may allow us
to better identify which components need to be replaced and which can stay in the
system as is.
The historic objective of the WPM program has been to maintain the current reliability but Avista has enjoyed definite improvement in reliability since the current version of the
WPM program was implemented. The objectives for reliability need to be identified to
help define what level of spending can be maintained and still keep or improve the
overall reliability to the desired level. If the Capital budgets of the future see further
constraints, it is likely that the WPM program could perform inspections and follow-up work on an even more non-optimal interval unless a specific reliability goal is established and budgets aligned. In other words, if we establish reliability goals and
0.000
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-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10WP
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align the budgets to support that specific goal, the economic optimization no longer drives the WPM cycle time but reliability goals.
Converting from Overhead to Underground Residential Districts may provide better
lifecycle costs and reliability when the costs of undergrounding is low enough. This
alternative should be analyzed and documented.
The Wood Pole Management Inspection Database requires an Asset Information Strategy document. A lot of work in the past and changes needed for the future require
a clear and documented strategy for collecting the data, metrics used in WPM, uses of
the data in decision processes, and more. We continually see that as new people enter
these fields, they don’t understand the why’s of data and its role in our processes, so
data gaps, errors, and processes changes occur that impact the overall quality and effectiveness of the data.
Data Gaps
The WPM Inspection database must be converted onto a new mobile platform due to
the end of life of the existing Trimble units. This is in progress and should be completed
in 2017. The data then needs to be imported and retained in Maximo for all future
inspections and follow-up work. Once the inspection portion of the data has been completed, the follow-up work planning and quality assurance inspection of completed work must be included in the process and data to properly maintain the data current
with current conditions.
The effective Ground Line Circumference (Effective GLC) is not recorded for all poles.
This will need to be calculated for each pole if we decide to implement a health index for Distribution wood poles.
Mitigation Plan for Gaps
Examine industry information and evaluate the use of a Health Index in the WPM
program. If justified, develop an implementation plan for collecting, analyzing, and
using a Health Index in the WPM program. This addresses potential changes in our
inspection methods and the Effective GLC issues.
For the reliability driver, this requires work outside of Asset Management, so no action is currently planned to address this gap. This addresses the question of using economic
optimization or reliability goals to drive WPM Cycle times.
Examine the lifecycle costs of keeping Overhead Distribution systems in rural areas as
compared to Underground Residential Districts (URD). This provides the analysis and documentation to answer the question discussed above.
Develop an Asset Information Strategy based on the “Asset Information – Asset
Information, Strategy, Standards and Data Management” Subject Specific Guidance
(SSG) from the Institute of Asset Management (IAM, 2015). This addresses the lack of
a current Asset Information Strategy for WPM and moves the implementation of moving the WPM Inspection database transition into Maximo for the repository of the information.
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Data Changes
For the WPM Related OMT Events and Outages shown in Figure 10, the data used should change going forward. When the WPM Related OMT Events metric was
created, the TCOP program did not exist and the equipment was only replaced based
on the WPM inspection. Going into the future, the TCOP will track OH – Transformer,
Squirrel, Arresters, and Cutout/Fuse OMT Events since they are more directly related to
that program now. WPM does drive a significant number of these replacements but many of the repairs and replacements are directly related to the replacement of the
overhead transformers.
The Pole Fire OMT events will also be removed since there is no correlation between
the WPM and the number of OMT events for a Pole Fire. The vast majority of Pole
Fires happen when we have had a long dry spell that causes dust to build up on the insulation followed by some light moisture. The added moisture allows for flashover that
causes the pole to ignite. These conditions are quite common in the third quarter near
the end of summer and you see this in Figure 18.

Figure 18 Pole Fire Events in OMT by Year and Quarter
We will also remove Wildlife Guards from the WPM related events since we see so very few wildlife guards causing a failure a seen in Figure 10.
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1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4
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With these changes, we revised Figure 9 that has been used in the past to the new revised WPM related events shown in Figure 19.

Figure 19 Revised WPM Related OMT Events (Includes Crossarm-rotten, Insulator, Insulator Pin, Pole-rotten OMT Sub-Reasons)
Looking at Figure 19 in more detail, the revised number of OMT Events related to WPM
work shows two different trends as illustrated in Figure 20. For 2008 – 2013, the
revised number of OMT events for WPM declined. Then for the past 4 years (2013-
2016) the trend changed and shows an upward trend. The driver for the upward trend
comes from Pole-rotten events. Figure 20 shows the individual contributions to the overall trend and the number of Pole-rotten events continues to rise from 33 events in
2006 to 55 events in 2016. For Figure 19 and Figure 20, see Detailed WPM OMT
Data.xlsx
020406080100120140160
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Figure 20 Revised WPM OMT Related Events with Trends
When we examine each Distribution Feeder individually, Figure 21 shows how the
feeders bundled by the Year WPM work was completed and shows the performance of
feeders without WPM work since 2006 for the worst feeders. Figure 22 shows all of the
feeders without WPM work since 2006. We may use data similar to this to help
prioritize and select the next feeders for WPM work. Simply using the number of OMT events to prioritize work on a feeder skews all work to the longest feeders because they
have the greatest exposure to Pole-rotten, Crossarm-rotten, and similar failures.
Normalizing the OMT data to events per mile removes this bias and allows us to
prioritize the work to where it will have the greatest impact per unit of work completed.
The final method for prioritizing WPM feeder work lies outside the scope of this analysis. An Asset Information Strategy for WPM includes developing the decision process and
outlines the data requirements needed to make the decisions.
See Appendix C for the data table for Figure 21 and Figure 22 and the file Pole-rotten
OMT Events rev 1.xlsx for the development of the graphs.
020406080100120140160
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General Downward Trend for Years 2008 -2013 General UpwardTrend for Years 2013 -2016
Overall Upward Trend driven by Pole-rotten Events
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Figure 21 Top Feeders for 2012-2016 WPM Related Events - Revised List
*Note: Many feeders that have had no WPM work completed were truncated from this
graph due its size. The full list in shown in Figure 22.
Using the revised list of WPM related event (Crossarm-rotten, Insulator, Insulator Pin,
and Pole-rotten), Figure 17 above becomes Figure 23 below. As you can see from the
dashed Linear (trend line) in Figure 23. WPM work still improves Distribution feeder outage performance but significantly less than in Figure 17.

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Figure 22 WPM OMT Events (Revised List) for 2012 - 2016 by Feeders without WPM Work Completed since 2006
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Figure 23 Revised WPM Related Sustained Outages Events per Mile of Distribution Feeder Before and After WPM
Work Completed
Future Position
We anticipate continuing the WPM program on a 20 year inspection cycle for reasons
we discuss in the Strategy Options section. The future position we describe here reflects a WPM program with a 20 year inspection cycle followed by work to address all
issues and does not include work performed as part of Grid Modernization. In actual
practice, the Grid Modernization can cover for the WPM program on feeders that have
not been inspected by WPM since 2006 and will change the WPM budget depending on
the amount of WPM work covered in the Grid Modernization work.
A model developed the future position based on the inputs and assumptions discussed
in other portions of this document. For these models, we loaded all of the data and
assumptions into Availability Workbench (AWB) from ISOGRAPH and created
Reliability Centered Maintenance models (RCMCost module in AWB) and then
converted the model results into Capital and O&M budget estimates and risk value estimates using the AWB Life Cycle Cost (LCC) module (LCC). The LCC output then
fed into a Revenue Resource Requirement model in an Excel spreadsheet and
0.0000.0050.0100.0150.0200.0250.030
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calculated the Customer Internal Rate of Return (CIRR), Return on Equity (ROE), Benefit Cost Ratio, and Risk Reduction Factor. For the Benefit Cost Ratio and Risk
Reduction Factor calculation methods, see the Asset Management Standard
Assumptions document. See the current Asset Management Manual for the current
model development process and discussion.
While we strive to create accurate models that effectively predict future performance, models have limitations and errors from multiple sources. Models intend to predict the
future performance based on the best available information we have today.
Unfortunately, current information has errors, missing data, provides a bias to past
methods, and a myriad of other sources causing error.
We strive to provide results that are within 80% of actual performance. Predictions also tend to show average values and don’t show annual variations we typically see in the
data. Models show the overall projected trends. We calibrate our model outputs by
comparing them to current values and trends to ensure they are consistent with today’s
values and help reduce error.
In order to further reduce error, we compare the differences between alternatives using incremental analysis inside the Revenue Resource Requirement model. This approach
eliminates common mode errors and helps select the alternative that provides the most
value.
As part of the process, we track our model’s results against actual results in the future
to ensure the models did provide a good picture and identify when models require revision.
Future Performance Levels
We established the current version of the WPM program to maintain the same level of
reliability and found it actually improved the system reliability. The work added to the
WPM to address Overhead Distribution Transformers, cutouts, missing grounds, and
adding wildlife guards helped improve the overall system reliability by reducing the number of associated OMT events each year. However, the underlying structural
performance of the poles and crossarms has not improved.
Table 11 and Table 12 show how each of the revised WPM related outages contributed
to the overall value of SAIFI and SAIDI. We calculated the average for each OMT
Subreason and combined them for an overall average impact to SAIFI of 0.02539 and to SAIDI of 0.08965 hours or 5.38 minutes. Based on a 20 Year Inspection and work
plan for all Distribution Feeders, the model projects the future average contribution to
SAIFI will be 0.04110 and to SAIDI will be 0.09112 hours or 5.47 minutes. Our analysis
indicates we expect these value to increase some over the next few years.
See the Detailed WPM OMT Data.xlsx file for the development of the historical values in Table 11 and Table 12 and Profiles - 20 Year Cycle - 5 year period.xlsx for the model
projections for both tables.
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Table 11 Annual Contribution to SAIFI by OMT Sub-Reason
Year SAIFI -
Crossarm-
rotten
Insulator Insulator Pin rotten
2012 0.00429 0.00166 0.00274 0.00084 0.00952
2013 0.00104 0.00988 0.00476 0.00197 0.01766
2014 0.01610 0.02123 0.00848 0.00790 0.05371
2015 0.00132 0.01199 0.00108 0.00022 0.01461
2016 0.01209 0.01310 0.00542 0.00084 0.03145
5 Year Average 0.00697 0.01157 0.00307 0.00419 0.02539
Projected Annual
Average
0.00801 0.02039 0.00942 0.00328 0.04110
*Note: Based on a model run for the next 5 years

Table 12 Annual Contribution to SAIDI (hours) by OMT Sub-Reason
Year SAIDI -
Crossarm-
rotten
Insulator Insulator Pin rotten
2012 0.00953 0.00648 0.00662 0.00421 0.02684
2013 0.00329 0.00662 0.01173 0.01004 0.06012
2014 0.05539 0.04634 0.02899 0.04171 0.17244
2015 0.00528 0.06202 0.00342 0.00064 0.07136
2016 0.04932 0.05297 0.01129 0.00392 0.11750
5 Year
Average
0.02456 0.04058 0.01241 0.01210 0.08965
Projected
Annual
Average
0.01550 0.04255 0.01663 0.01643 0.09112
*Note: Based on a model run for the next 5 years

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Figure 24 plots the historical number of OMT events by Subreason for 2012 through 2016 for Crossarm-rotten, Insulator, Insulator Pin, and Pole-rotten. Figure 24 also
shows the projections for the future number of OMT events by Subreason. This
projection comes from the 2016 Pole Failure Curves - 20 year cycle scaled up rev 7
model results included in Appendix B. The results show the number of OMT events
remaining fairly stable until about 2032. In 2032, enough of the population will reach end of life and be missed by the 20 year inspection cycle to cause the number of OMT
events to increase. While the number of poles replaced continues a steady rise as seen
in Figure 25, the remaining portion of the first round of inspections and early portion of
the second round reaches enough problem poles to contain the number of OMT events
until 2032. During our second round of inspections on the 20 year cycle, we begins to see replacement of all of the previously reinforced poles reaching their end of life and
the poles installed in the post-World War II building boom of the 1950’s reach the MTTF
age. This 1950’s age group represents a significant portion of the current population
profile shown in Figure 8 and drives a larger portions of our Distribution pole population
reaching their end of life.
For the data and chart development for Figure 24 through Figure 27, see WPM
Profiles.xlsx.

Figure 24 Actual and Projected Number of OMT Events for WPM Related OMT Events
0
20
40
60
80
100
120
2000 2010 2020 2030 2040 2050 2060 2070Nu
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OMT Trends and ProjectionsCrossarm-rotten Insulator Insulator Pin Pole-rottenProjected OMT EventsActualOMT Events
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Figure 25 shows the model projections for material usage along with the historical usage for Poles, Stubs (reinforcement), and Crossarms. The model projects these
numbers and shows the number of poles replaced or stubbed and crossarms replaced
rising with time. The age profile in Figure 8 supports the rising numbers of Poles
replaced or stubbed. As larger and larger portions of the current population approach
the MTTF point, a larger and larger portion will need to be replaced. The number will not stabilize until after 2060.

Figure 25 Actual and Projected Material Quantities for WPM Program
Given the trends of Figure 24 and Figure 25, the corresponding capital budget required
to maintain the program rises with time as seen in Figure 26 due to the increasing
number of components replaced and due to inflation assumed to be 2%. Figure 26 also shows the estimated budget for the Grid Modernization portion of work that ties to the
WPM work. The Grid Modernization portion of the budget shown in Figure 26 only
represents the amount of work of the program tied to inspecting, repairing and replacing
the same components as the WPM program. The WPM budget shown in Figure 26
represents all of the work required by WPM to maintain the system on a 20 year cycle. The actual budget needed by WPM depends upon how much WPM is given and
performed by the Grid Modernization on Feeders not inspected since 2006.
05001000150020002500300035004000
2000 2010 2020 2030 2040 2050 2060 2070
Qu
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Material Use and Material Use Projections for WPMPoles Issued Stubs Issued Crossarms IssuedProjected Material UsageActual MaterialUsed
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Figure 26 Capital Spending and Projections for Wood Pole Management and Grid Modernization Portion of the Work
if Completed on a 60 Year Cycle
*Note: The capital spending on Grid Modernization projected here only equates to the
same work scope as WPM and does not cover all aspects of Grid Modernization
Figure 27 shows our model projections for the O&M inspection costs as well as the
Asset Maintenance evaluation of budget requirements (see the file “Budget
Requirements OM 4-21-2017.xlsx”). Inflation is the sole reason for the rising trends in
this costs and we assume an inflation rate of 2%. Between 2013 and 2016, you see a
dip in the O&M inspection costs. This dip comes from the amount of the inspection assigned to Grid Modernization from the WPM work scope. Similar to the impacts on
the WPM budget caused by the Grid Modernization budget, we see a similar reduction
in the O&M costs based on how much of the WPM work gets assigned to Grid
Modernization. The values in Figure 27 show the costs assuming no Grid Modernization work covers WPM work scope and only represents the inspection costs associated with WPM.
$0
$20
$40
$60
$80
$100
$120
2000 2010 2020 2030 2040 2050 2060 2070
Ca
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Capital Spending and Projections for WPM and Equivalent Portion for Grid Modernization*2060 - Wood Pole Mgmt Grid Mod for 60 Year Cycle along with WPMProjected Capital SpendingActual CapitalSpending
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Figure 27 O&M Spending and Projections for Distribution Wood Pole Management for Inspection Costs Only
Impacts of anticipated future demand, innovation, reliability,
obsolescence, regulation, and rising costs
Overall, the anticipated future demand analysis is covered in Avista’s current Integrated Resource Plan and will not be discussed here. As for WPM, future demand generally
does not drive replacement of wood poles unless growth work requires a better class of
pole to deal with greater loading from added devices, larger conductor or clearance
issues. Since, WPM already deals with these impacts from growth, the program should
remain unaffected.
Impacts from innovation and obsolescence have had some small impacts to WPM for
the same reasons discussed above. Distribution line automation devices added to our
system added loads to a small percentage of poles that required replacing the poles
with stronger poles. This work falls within the new technology to address and not WPM.
One impact from new technology and innovation which could alter significantly the WPM and Vegetation Management programs is improvements in the installation of
underground cables for Underground Residential Districts (URD). If the cost of
undergrounding the electric distribution system reach low enough costs per mile values,
they could justify replacing the current Overhead Distribution system with a new URD
$0$500,000$1,000,000$1,500,000$2,000,000$2,500,000$3,000,000$3,500,000$4,000,000
2000 2010 2020 2030 2040 2050 2060 2070
O&
M

(
$
)
Year
O&M Spending and Projected Costs for Distribution WPMO&M for WPM Asset Maintenance Budget PlansProjected O&M SpendingActual O&MSpending
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system. Replacing Overhead Distribution with URD eliminates future Vegetation Management Cost and WPM costs and adds some Underground Equipment Inspection
costs.
While we plan to analysis when going from Overhead to Underground, no current
studies provide a definite system wide justification, but several localized analysis
performed as part of work planning has been completed. Installing URD cables in rural areas where they can plow in the cable have much lower installation costs and
potentially meet the cost thresholds today for undergrounding the electric Distribution
system while improving system reliability. Examining Figure 28 and Figure 29, you see
that 27% of the Electric Distribution system is underground but only contributes 2% to
the overall SAIDI value with Major Event Days (MED) excluded. While this is not conclusive proof we should underground the current Overhead system, it drives us to
evaluate this in the future. For the details and data behind Figure 28 see the file SAIFI
and SAIDI data for 2010 through 2015 excluding MED.xlsx and see the file Conductor
Ratio.xlsx for Figure 29.

Figure 28 Overhead Contribution to SAIDI Comparison between Underground and Overhead Distribution System
excluding MED
Overhead
Related Events
55%
Underground
Related Events
2%
Common
Events
43%
OVERHEAD CONTRIBUTION COMPARED TO
UNDERGROUND CONTRIBUTION TO SAIDI
EXCLUDING MED
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Figure 29 Percentages of the Electric Distribution System that in Underground and Overhead
Recently, the report “Reliability Targets for Washington’s Three Investor-Owned
Utilities” completed for the Washington Utilities and Transportation Commission
(WUTC) (Power System Engineers, 2017) provides what they believe is the appropriate
goals for SAIFI and SAIDI. If the WUTC decided to make these SAIFI and SAIDI goals
into performance requirements, the impact to WPM depends upon how the company chooses to meet the goals. Small changes to WPM funding don’t immediately show up
in the impacts to reliability or trends. Attempting to use WPM to help improve SAIFI and
SAIDI results will prove difficult given the amount of additional work required to see any
changes. WPM currently provides a stabilized contribution to SAIFI and SAIDI in the
short term but not in the long term as discussed above. Shortening the cycle time to around 5 years for WPM should improve SAIFI and SAIDI but could incur costs for the
first time through on this cycle that exceed current budget constraints. This is discussed
further below.

Overhead
Conductor
Segment Miles
73%
Underground
Conductor
Segment Miles
27%
ELECTRIC DISTRIBUTION RATIOS
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Justification for investing
The process for justifying the WPM involves examining several reasonable alternatives and using the Revenue Resource Requirement model to calculate the Customer
Internal Rate of Return (CIRR) between the different alternatives. The second criteria
constrains the O&M spending to historic levels or trends.
The alternative selected provides better value to customers when compared to a do
nothing case and yields a CIRR greater than 7%. A CIRR greater than 7% means that over the life of an asset, the customer’s rates will be lower overall even if the costs
increase for the early years of the project.
This document focuses on developing a strategy for Distribution Wood Poles and limits
the evaluation to different approaches to managing them. Comparing the selected
alternative for WPM against other projects and programs at Avista falls to the Capital Planning Group and their methods for ranking projects and programs.
Timing
One alternative examined below is a planned replacement of Wood Poles based on
their age. The “2016 Pole Failure Curves - Opt Grid mod 20 year cycle scaled up rev 9”
model analyzed the optimum age for replacing poles and found it to be 50 years as
shown in Figure 31 (438,000 hours = 50 Years). While the optimum age for replacing a
pole is 50 years, other strategies proved to provide more valuable to customers. Figure 31 illustrates the point, though, that if we wait too long to address wood poles that have
functionally failed, the costs begin to rise and reduce the value of the approach. The
graph in Figure 31 also shows if we do it too soon we lose value.
The optimum time to replace a pole or any other component is immediately before it
fails which is nearly impossible to do. Using models allows us to examine different strategies and balance all of the different variables to come up with an optimized
approach to the whole Electric Distribution system. You see the effects of delaying
work or speeding up work in the results of the different cycle times analyzed in the
sections below.
If we chose to suspend the WPM program for either 5 or 10 years for some reason, our capital costs would lower initially but increase our risk exposure due to failures. Table
13 shows how the CIRR, Net Present Value (NPV) of the Lifecycle Cost, NPV of Risk,
Benefit/Cost Ratios, and Risk Reduction Ratio’s compare between these alternatives
(see the Asset Management Standard Assumptions for the calculations methods used
(Avista's Asset Management, 2017)). Based on the results shown in Table 13, any pause in the current WPM program adds risk and costs that hurt the CIRR. Figure 30
shows graphically how delaying the WPM work impacts the projected number of OMT
events for each year. While delaying the work may provide some budget constraint
relief in the short run, the lost value will take 20 years (or one complete WPM cycle)
from restarting the work to reach the reliability projected for the current case. In other words, delaying WPM work adds costs in the future and reduces reliability that will
impact the results for 20 years.
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The calculations for Table 13 are in the file named 20 Year Cycle and delays Options 5-4-17.xlsx and is based on the following models: 2016 Pole Failure Curves - 20 year
cycle scaled up rev 7 - 5 year pause, 2016 Pole Failure Curves - 20 year cycle scaled
up rev 7 - 10 year pause, and 2016 Pole Failure Curves - 20 year cycle scaled up rev 7.
The data from the three models in Table 13 used in Figure 30 are found in file “WPM
Profiles.xlsx”.
Table 13 Comparison of Impacts of Continuing the 20 Year WPM Cycle, Pausing Program for 5 Years, and Pausing Program for 10 Years over a 50 Year Lifecycle
Alternative CIRR NPV of Life-Cycle Costs NPV of Risk Benefit/Cost Ratio Reduction
Ratio
Cycle Case 7.23% $489,167,584 $210,166,592 1.06 0.05
Cycle with 5
Year Delay
Case
6.73% $516,967,368 $234,082,522 0.95 -0.05
Cycle with 10
Year Delay
Case
6.55% $539,552,740 $253,240,357 0.91 -0.08

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Figure 30 Revised WPM Related Projected OMT Events Showing Impacts from Delaying Work
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Revised WPM Related Projected OMT Events Showing Impacts from Delaying WorkTotal Number of OMT Events for WPMTotal Number of OMT Events for WPM Delayed 5 YearsTotal Number of OMT Events for WPM Delayed 10 Years
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Figure 31 WPM Model Plot of Optimized Planned Replacement Age for a Wood Pole at 50 Years of Age
Strategy Options
The basis for the different WPM cycle time alternatives comes from the 2012 analysis.
We added to these alternatives a new alternative that examined Grid Modernization and
its impacts with and without WPM. In order to address questions on when and if WPM
should be paused for any reason, we added two scenarios showing the impacts of
suspending WPM inspections and the subsequence follow on work for 5 and 10 years to understand how this impacts the value of the work.
Electric Distribution Wood Poles Scenarios
Run all Wood Pole and associated components to failure
This alternative provides a base for comparison. While our intentions are not to do this,
we use this do nothing case to evaluate all the other alternatives against it. The base
case includes the following Components in Table 14.
Table 14 Components included by Program Models
Component WPM Models TCOP Models
Cutout Yes
Recommendation: Perform group task at 438000
Optimization plot for Planned Replacement
Cost
OperationalCriticality
Safety Criticality
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
Cri
t
i
c
a
l
i
t
y
2.5E+05 3E+05 3.5E+05 4E+05 4.5E+05 5E+05 5.5E+05 6E+05 6.5E+05 7E+05
Interval
9.6E+07
1.02E+08
1.08E+08
1.14E+08
1.2E+08
1.26E+08
1.32E+08
1.38E+08
1.44E+08
1.5E+08
1.56E+08
Co
s
t
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Secondary Connection
Primary Connection
Lightning Arrester
Grounds
Overhead Distribution
Transformer
Yes
Yes
Yes
Yes
Yes
Yes
Yes

This model consists of two files, 2016 Pole Failure Curves - Base Case scaled up rev 7
and 2016 TCOP Model for WPM - No Action Base Case 4-24-17. The results of both
models are combined in the Revenue Resource Requirement model in file Combined TCOP and WPM 4-24-17.xlsm. In Table 16, this alternative is called the “Base Case”.
In the case of evaluating Grid Modernization independent of WPM, only the 2016 Pole
Failure Curves - Base Case scaled up rev 7 model is used and is called “Base Case”
inTable 16.
Inspect all Wood Poles on a 20 year cycle based on the Feeder
In this alternative, we inspect the Electric Distribution system once every twenty years
and follow up the inspection with projects to replace or repair all identified components.
Within this alternative, we include four variations. The first variation represents our
current program and includes the structural components of the pole, crossarms, insulators, guying, and insulator pins (the model name is 2016 Pole Failure Curves - 20 year cycle scaled up rev 7) as well as the same components as the TCOP models
except the TCOP components are only replaced if they have functionally failed. In order
to reflect TCOP related components needing replacement identified by the WPM
inspection, the model, 2016 TCOP Model for WPM 20 Year Cycle No TCOP Case 4-21-17, was added to the WPM model results in file Combined TCOP and WPM 4-24-17.xlsm. In Table 16, this is called “WPM 20 Year Cycle without TCOP”.
The second variation adds TCOP work which includes cutouts, Overhead transformers,
wildlife guard installation, installation and replacement of missing grounds, and lightning
arresters that are replaced along with all pre-1981 transformers. This variation added the results of the 2016 TCOP Model for WPM 20 Year Cycle 4-24-17 for the TCOP components in the Revenue Resource Requirements model, Combined TCOP and
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WPM 4-24-17.xlsm. In Table 16, this alternative is called “WPM 20 Year Cycle with TCOP”.
The third and fourth variations uses the original, 2016 Pole Failure Curves - 20 year
cycle scaled up rev 7, model as the base case and then compares the same model with
a 5 or 10 year delay in performing the next round of inspections. The file, 2016 Pole
Failure Curves - 20 year cycle scaled up rev 7 - 5 year pause represents a 5 year delay in the WPM inspections and the file, 2016 Pole Failure Curves - 20 year cycle scaled up
rev 7 - 10 year pause, represents a 10 year delay in the WPM inspections. These two
variations excluded the TCOP related work since they are just used to show the impacts
of the delay shown only in Table 13.
Inspect all Wood Poles on a 5 year cycle based on the Feeder
This alternative represents the same model as the second variation of 20 year WPM but
with a 5 year inspection cycle and follow up work. The two models that make up this
alternative are 2016 Pole Failure Curves - 5 year cycle scaled up rev 7 and the 2016
TCOP Model for WPM 5 Year Cycle 4-24-17. The results of these two models are combined in the Revenue Resource Requirements model, Combined TCOP and WPM 4-24-17.xlsm. In Table 16, this alternative is called “WPM 5 Year Cycle with TCOP”.
Inspect all Wood Poles on a 10 year cycle based on the Feeder
This alternative represents the same model as the second variation of 20 year WPM but
with a 10 year inspection cycle and follow up work. The two models that make up this
alternative are 2016 Pole Failure Curves - 10 year cycle scaled up rev 7 and the 2016 TCOP Model for WPM 10 Year Cycle 4-24-17. The results of these two models are
combined in the Revenue Resource Requirements model, Combined TCOP and WPM
4-24-17.xlsm. In Table 16, this alternative is called “WPM 10 Year Cycle with TCOP”.
Inspect all Wood Poles on a 25 year cycle based on the Feeder
This alternative represents the same model as the second variation of 20 year WPM but with a 25 year inspection cycle and follow up work. The two models that make up this
alternative are 2016 Pole Failure Curves - 25 year cycle scaled up rev 7 and the 2016
TCOP Model for WPM 25 Year Cycle 4-24-17. The results of these two models are
combined in the Revenue Resource Requirements model, Combined TCOP and WPM 4-24-17.xlsm. In Table 16, this alternative is called “WPM 25 Year Cycle with TCOP”.
Inspect all Wood Poles on a 20 year cycle based on the Feeder and replace poles
based on an age of 60 Years using the Grid Modernization Program
This alternative represents the same inspection cycle as the 20 year WPM and
additionally replaces all poles that are 60 years or older. This model actually represents doing Grid Modernization once every 20 years instead of the programs goal of once every 60 years. This approach simplifies the analysis and ties the WPM and Grid
Modernization programs together as we do today, they both use the same inspection
cycle but 2/3 of the work goes to WPM and 1/3 should go to Grid Modernization. When
we combine the model results in the Revenue Resource Requirement model, we only
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use 1/3 of the models cost results to reflect the actual amount of work performed each year for the Grid Modernization and reflect the 60 year cycle intent and 2/3 of the WPM
Cost to reflect the remaining work completed by the normal WPM program.
The two models that make up this alternative are 2016 Pole Failure Curves - 60 Year
Grid mod 20 year cycle scaled up rev 7 and the 2016 TCOP Model for WPM 20 Year
Cycle 4-24-17. The same TCOP model as the normal 20 Year WPM cycle is used here because the scope of the TCOP is the same on the WPM portion of the work changes.
The results of these two models are combined in the Revenue Resource Requirements
model, Combined TCOP and WPM 4-24-17.xlsm. In Table 16, this alternative is called
“WPM 20 Year Cycle with TCOP and Grid Mod”.
The first variation of this model is the original option for Grid Modernization discussed above and uses a 20 year inspection and work cycle while replacing all poles based on
condition and replacing all poles 60 years or older. This uses the full output of the 2016
Pole Failure Curves - 60 Year Grid mod 20 year cycle scaled up rev 7 instead of 1/3. It
also includes the costs and risks associated with TCOP. This alternative is called
“TCOP and Grid Mod on 20 Year Cycle no WPM” in Table 16.
Three other variations of this model were used to only examine what it would look like if
WPM program was eliminated in favor of only performing Grid Modernization and then
compared to the WPM base case, 2016 Pole Failure Curves - Base Case scaled up rev
7. So the second variation is the same as Grid Modernization alternative discussed
above but performs the inspections on a 60 year cycle to coincide with the planned replacement age of 60 years for wood poles. This alternative is called “Grid Mod 60
Year Inspection Cycle 60 Year Old Replace” in Table 16.
The third variation of this model optimizes the replacement age shown in Figure 31 and
replaces all poles at 50 years or older on a 50 year cycle. This alternative model is
2016 Pole Failure Curves - Opt Grid mod 50 year cycle scaled up rev 9. In Table 16, this alternative is called “Grid Mod 50 Year Inspection Cycle 50 Year Old Replace”.
The fourth and final variation is the original option for Grid Modernization discussed
above and uses a 20 year inspection and work cycle while replacing all poles based on
condition and replacing all poles 60 years or older. This uses the full output of the 2016 Pole Failure Curves - 60 Year Grid mod 20 year cycle scaled up rev 7 instead of 1/3. In Table 16, this is called “Grid Mod 20 Year Inspection Cycle 60 Year Old Replace”.
Alternative Comparison
For the financial analysis and comparisons, we include the costs and risks associated
with both the WPM models and the TCOP models. This approach more accurately
reflects the budget requirements. For OMT projections and SAIDI contributions we
focused only on the WPM model outputs to accurately reflect the structural needs of the Electric Distribution system.
For comparing a WPM strategy verses a Grid Modernization strategy, we examined the
financial impacts of the three variations of the Grid Modernization alternative shown in
Table 15 (the 2016 Pole Failure Curves - 60 Year Grid mod 60 year cycle scaled up rev
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9, 2016 Pole Failure Curves - Opt Grid mod 50 year cycle scaled up rev 9, and 2016 Pole Failure Curves - 60 Year Grid mod 20 year cycle scaled up rev 7 models) against
the WPM do noting case (the 2016 Pole Failure Curves - Base Case scaled up rev 7
model). Table 15’s only functions is to compare Grid Modernization and WPM as a
direct replacement and not provide financial analysis of the Grid Modernization
program. Grid Modernization provides value in several areas not discussed here. In this comparison, we excluded the TCOP models for the comparison to simplify the
process. In order to add TCOP to Table 15 and Table 16 align the data with the data in
Table 16 would have required creating two additional TCOP models to align with all of
the alternatives in Table 15 that had no bearing on evaluating Distribution wood poles.
The alternatives “Grid Mod 20 Year Inspection Cycle 60 Year Old Replace” from Table 15 and “WPM 20 Year Cycle with TCOP and Grid Mod” from Table 16 represent the
same alternative. The only difference is that Table 16 includes TCOP related work for
the evaluation.
Table 15 Financial Comparison of Grid Modernization Alternative without WPM and excludes TCOP work
Alternatives CIRR NPV of Life-Cycle Costs fit/Co
st
Ratio
Reduc
tion
Ratio
10.21% $634,905,266 $333,324,749 1.72 -0.06
Inspection Cycle 60
Year Old Replace
4.35% $1,092,532,520 $292,376,730 0.58 0.04
Inspection Cycle 50 Year Old Replace
4.39% $1,071,808,146 $272,069,078 0.59 0.06
Inspection Cycle 60
Year Old Replace
5.15% $848,813,303 $172,184,635 0.75 0.19

Table 16 Financial Comparison of Alternatives
Alternative CIRR NPV of Life-Cycle Costs Cost
Ratio
Reducti
on Ratio
6.03% $1,016,381,966 $509,538,239 0.804 -0.156
without TCOP
8.00% $817,592,755 $351,165,376 1.243 0.194
with TCOP
7.94% $799,251,117 $304,232,511 1.272 0.257
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Alternative CIRR NPV of Life-
Cycle Costs Cost Ratio Reduction Ratio
with TCOP
8.85% $650,557,189 $104,155,317 1.562 0.623
with TCOP
7.85% $812,124,615 $279,737,157 1.252 0.283
with TCOP
7.46% $894,569,506 $389,231,116 1.136 0.134
with TCOP and Grid
Mod
7.10% $922,761,015 $481,637,684 1.101 0.030
on 20 Year Cycle no
WPM
5.85% $1,169,780,812 $261,237,753 0.869 0.212
Table 16 shows the 5 year WPM inspection and follow up provides the best value to
customers, because it has the highest CIRR. Unfortunately, it also has the highest
O&M Costs as shown in Figure 34. For the CIRR, the higher O&M costs associated
with more frequent inspections and follow up work is offset by the lower risk values (see Table 16, Figure 32, and Figure 36), lower material usage (Figure 33) and improve
reliability (Table 17). The increased inspection finds more problems and pending
failures before they actual cause an outage. A five year WPM inspection interval allows
the components to remain in the system longer by replacing them closer to their actual
point of failure. However, the TCOP portion of this alternative drives replacing all pre-1981 overhead transformers within a 5 year period and drives the capital costs up
significantly in the short run (see Figure 35). The results yield a better CIRR. This
alternative and the other shorter inspection cycle time alternatives face a significant risk
based on the assumption that only the components that will fail between the inspection
interval are replaced. Our inspection program may not be able to tell the difference between a component that will fail in the next one year from a component that will fail in
twenty years. The results could cause the initial capital costs to be four times the
current 20 year WPM inspection cycle without TCOP (see Figure 35). The CIRR is very
sensitive to this cost risk in the first inspection cycle, and the initial capital cost risk could
ultimately make it less attractive than our current program.

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Figure 32 OMT Projections for each Alternative WPM Inspection Cycle Time
Based on the results in Table 16, the next best alternative is our current WPM program,
the WPM 20 Year Cycle without TCOP alternative. Our current plans drive the WPM
program to replace all pre-1981 Overhead Distribution transformers as part of their
regular work starting in 2019. Including TCOP in WPM drives the CIRR down a little
(0.06%) when you examine the WPM 20 Year Cycle with TCOP alternative. The WPM 20 Year Cycle with TCOP alternative adds Capital costs to the program (see Figure 35)
but reduces the risk value (see Figure 36). The O&M cost increase in Figure 34 come
from TCOP component failures repaired or replaced on O&M.
Compared to the WPM 10 Year Cycle with TCOP alternative, the WPM 20 Year Cycle
with TCOP alternative appears about equivalent in Table 16, Table 17, Figure 32, Figure 33, and Figure 36. The 10 year and 20 year inspection cycle times appear to
trade benefits and costs between them in nearly equal proportions except for the O&M
costs shown in Figure 34. Given the 20 year inspection cycle alternatives for WPM are
within 1% of the 5 year inspection cycle alternative, it provides a very good CIRR and
alternative.
The WPM 10 Year Cycle with TCOP alternative’s CIRR of 7.85% is only 1% less than
the 5 year cycle time option. This alternative compares well with the two 20 year
0
50
100
150
200
250
2010 2020 2030 2040 2050 2060 2070
Nu
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Combined Pole-rotten, Crossarm-rotten, Insulator, and Insulator Pin OMT Projections for each Alternative Base Case WPM 20 Year Cycle with or without TCOPWPM 5 Year Cycle with TCOP WPM 10 Year Cycle with TCOPWPM 25 Year Cycle with TCOP
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inspection options as discussed above. The 10 year inspection cycle option improves the risk value in Table 16 Financial Comparison of Alternatives but less than the
negative impact of the increased O&M costs shown in Figure 34 that ultimately drive the
CIRR lower than the 5 year and both 20 year inspection options. The 10 year
inspection cycle alternatives drives the annual O&M and Capital costs down in the near
term similar to the 5 year inspection alternative, but the sensitivity of the analysis to the early years of the program reduces it CIRR. This alternative also faces the same initial
capital risk costs that could drive the first few year’s costs up to two times current 20
year WPM inspection cycle without TCOP (see Figure 35). Our inspection program
may not be able to tell the difference between a component that will fail in the next one
year from a component that will fail in twenty years.
The 25 year WPM inspection alternative shows a more significant change than
compared to the alternatives already discussed above. This option still provides value
to customers with a CIRR >7% (see Table 16). It reduces the initial and longer term
O&M costs as seen in Figure 34. However, the capital projections show higher
anticipated future costs than all other options except the Base Case alternative. This alternative provide lower reliability performance (Figure 32 and Table 17) which also
drives more material usage (Figure 33). Responding to failures uses more material in
general because a pole failure usually ends up replacing more components. For
example, we only need to stub a pole if its strength is restored by the stub, but if a pole
fails, the pole, crossarm, insulators, insulator pins, and other components attached to the pole generally must be replaced as well. This drives material usage up when
compared to planned repair and replacement. This option also provides the lowest risk
reduction of all the options when compared to the Base Case per Figure 36.
The base case or do nothing, i.e. no WPM, no TCOP, and no Grid Modernization,
defines the basis for comparing all of the other alternatives. The CIRR compared to the WPM 20 Year Cycle without TCOP alternative shows the second lowest CIRR. This
alternative performs worse than all other options in reliability (Figure 32 and Table 17),
material usage (Figure 33), and capital cost projects (Figure 35). The O&M cost
projections show an interesting behavior as it rises very significantly starting in the next few years and the declines significantly after about 2042. We attribute this O&M behavior to the bow wave of working coming from the TCOP related work as the
Overhead Distribution transformers and their associated equipment reach their end of
life and get replaced.

Staff_PR_122 Supplemental Attachment A Page 55 of 94

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Figure 33 Projected Material Usage for each Alternative

Table 17 Average Contribution to SAIFI and SAIDI for each Alternative over 50 Years due to Pole-rotten, Crossarm-Rotten, Insulator, and Insulator Pin

0.103 0.054 0.006 0.060 0.088
to SAIDI 0.226 0.119 0.013 0.138 0.203

2000400060008000100001200014000160001800020000
2010 2020 2030 2040 2050 2060 2070
Qu
a
n
t
i
t

o
f

M
a
t
e
r
i
a
l

U
s
e
d
Year
Projected Material Usage for Poles, Stubs, Guying, Insulators, and Insulator Pins for each AlternativeBase Case WPM 20 Year Cycle with or without TCOPWPM 5 Year Cycle with TCOP WPM 10 Year Cycle with TCOPWPM 25 Year Cycle with TCOP
Staff_PR_122 Supplemental Attachment A Page 56 of 94

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Figure 34 O&M Cost Projections for each Alternative
Table 16 includes two other alternatives not covered in Table 17 or in Figure 32 through
Figure 36. The WPM 20 Year Cycle with TCOP and Grid Mod alternative and the TCOP
and Grid Mod on 20 Year Cycle no WPM. These two options allow us to compare how
WPM and Grid Modernization interact and change the results. Grid Modernization
includes drives outside of the discussion in this report and we only include them to show how the two programs interact and compare.
Our current WPM program with a 20 year inspection cycle, the soon to be added TCOP
work for WPM, and the current related Grid Modernization work is covered by the WPM
20 Year Cycle with TCOP and Grid Mod alternative in Table 17. Table 17 shows that
the CIRR for this alternative still exceeds the 7% threshold and provides value to our customers.
The TCOP and Grid Mod on 20 Year Cycle no WPM alternative modifies the current
program by replacing all wood poles at 60 years or older and retains all other portions of
the WPM program. This alternative provide the second best reduction of risk (see Table
16) but at a very large costs which drives it to have the lowest CIRR of all alternatives examined.
$0$1,000,000$2,000,000$3,000,000$4,000,000$5,000,000$6,000,000$7,000,000$8,000,000
2010 2020 2030 2040 2050 2060 2070
O&
M

C
o
s
t
s
Year
O&M Cost Projections for each AlternativeBase Case O&M WPM 20 Year Cycle without TCOP O&MWPM 20 Year Cycle with TCOP O&M WPM 5 Year Cycle with TCOP O&MWPM 10 Year Cycle with TCOP O&M WPM 25 Year Cycle with TCOP O&M
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Figure 35 Capital Cost Projections for each Alternative
Table 15 takes a further look at Grid Modernization alternatives. These alternatives
exclude all work related to TCOP components and evaluates alternative Grid
Modernization approaches to replace WPM related work. The first alternative in Table
15 is the same Base Case as Table 16 minus the portion related to TCOP. The second
alternative represents our current approach with a 60 year Grid Modernization cycle and a strategy to replace all poles that are 50 years old or older. The second alternative
represents the Grid Modernization on a 50 year cycle and replacing all poles that are 50
years old or older. The final alternative represents the same alternative as the TCOP
and Grid Mod on 20 Year Cycle no WPM alternative in Table 16 minus the TCOP
related work. In all cases, the Base Case provides more value to our customers through the highest CIRR and demonstrates that the Grid Modernization program
should not replace the current WPM strategy without considering other factors outside
the current scope of WPM.
For more specifics and data details, see the fileCombined TCOP and WPM 4-24-
17.xlsm for the data supporting Table 16, Figure 36, Figure 34 and Figure 35. For Figure 32, Figure 33, and Table 17, see file Combined WPM Model Projections.xlsx.
The source data for both files is located in Appendix B.
$0
$20,000,000
$40,000,000
$60,000,000
$80,000,000
$100,000,000
$120,000,000
2010 2020 2030 2040 2050 2060 2070
Ca
p
i
t
a
l

C
o
s
t
s

(
$
)
Year
Capital Cost Projections for each AlternativeBase Case Capital WPM 20 Year Cycle without TCOP CapitalWPM 20 Year Cycle with TCOP Capital WPM 5 Year Cycle with TCOP CapitalWPM 10 Year Cycle with TCOP Capital WPM 25 Year Cycle with TCOP Capital
Staff_PR_122 Supplemental Attachment A Page 58 of 94

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Figure 36 Value of Risk Reduction by Year compared to the Base Case for Different WPM Options
Strategy Selection
Given the criteria of best CIRR while staying in line or below historic O&M program
costs, we selected to continue with the current 20 year inspection cycle for the WPM
program. This strategy provides the second best CIRR as shown in Table 16 and aligns
with historical spending as seen in Figure 34. The projected performance is discussed
in sections above.
The projected budget needs for ER 2060 and the program O&M Costs are shown in
Table 18. Table 18 shows the cost projections with and without the TCOP program
implemented. We provided both with and without TCOP so this report would not rely
upon the TCOP report outcomes. The decision whether to implement the next phase of
TCOP into WPM or take another alternative is outside the scope of this paper. Table 18 provides model based cost projections that we will monitor and report on as part of our
annual reviews, but detailed work planning, un-anticipated changes to costs and model
errors will drive the actual values to move from these specific values. We consider the
analysis successful if the actual costs for the projected work is within 20% of estimated
given the assumptions and error potential. The cost projections exclude the volume of
$0$20$40$60$80$100$120
2010 2020 2030 2040 2050 2060 2070Ri
s
k

V
a
l
u
e

D
i
f
f
e
r
e
n
c
e

(
$
)
Mi
l
l
i
o
n
s
Year
Value of Risk Reduction by Year compared to the Base Case for Different WPM OptionsDifference between Base Case and WPM 20 Year Cycle without TCOPDifference between Base Case and WPM 20 Year Cycle with TCOPDifference between Base Case and WPM 5 Year Cycle with TCOPDifference between Base Case and WPM 10 Year Cycle with TCOPDifference between Base Case and WPM 25 Year Cycle with TCOP
Staff_PR_122 Supplemental Attachment A Page 59 of 94

56 | P a g e

work associated with WPM assigned to Grid Modernization. The amount of work assigned to Grid Modernization will drive changes to the amount budgeted to WPM as
long as the number of miles actually completed meets the WPM objectives.
Table 18 Capital and O&M Budget Projections for WPM 20 Year Cycle with and without TCOP Work Scope
WPM 20 Year Cycle without
TCOP
$11,669,045 $803,810 $18,854,197 $1,194,173
$13,025,585 $803,810 $15,012,412 $1,194,173
$13,742,601 $833,885 $15,514,281 $1,231,681
$14,047,041 $847,704 $22,123,558 $1,197,474
$15,078,248 $880,576 $17,536,465 $1,232,031
$15,990,379 $593,203 $17,477,067 $973,800
$17,035,907 $961,525 $23,178,303 $1,257,104
$17,982,969 $985,914 $20,657,211 $1,301,619
$19,388,742 $1,026,983 $22,827,290 $1,285,068
$20,651,486 $1,066,738 $25,504,624 $1,247,586
$21,933,303 $1,102,010 $21,346,050 $1,286,464
$23,083,970 $1,145,501 $21,696,609 $1,409,309
$24,462,229 $1,194,949 $35,432,608 $1,167,284
$25,853,518 $1,226,307 $24,274,809 $1,163,392
$27,092,104 $1,279,239 $26,638,989 $1,144,464
$28,294,481 $1,338,443 $24,447,462 $1,171,457
$30,210,643 $1,398,744 $27,375,116 $1,190,335
$32,368,974 $1,483,989 $28,288,338 $1,221,174
$33,810,632 $1,499,797 $30,260,734 $1,219,065
$35,978,328 $1,574,987 $33,771,025 $1,181,509
$37,807,073 $1,623,520 $31,724,862 $1,219,246
$39,736,694 $1,671,033 $33,580,376 $1,266,123
$41,431,149 $1,728,080 $35,356,073 $1,329,740
$42,819,628 $1,732,325 $36,844,192 $1,362,974
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WPM 20 Year Cycle without
TCOP
$44,991,507 $1,766,328 $39,268,486 $1,416,535
$45,935,988 $1,320,934 $40,418,321 $984,371
$47,613,382 $1,898,959 $42,194,470 $1,574,716
$49,905,429 $1,989,480 $44,614,858 $1,662,442
$51,756,558 $2,050,291 $46,626,050 $1,749,100
$54,287,232 $2,113,936 $49,273,938 $1,815,657
$56,009,790 $2,165,167 $51,367,679 $1,892,150
$58,204,891 $2,254,576 $53,830,138 $1,991,977
$60,018,349 $2,318,425 $56,176,774 $2,109,047
$61,855,848 $2,338,516 $58,246,076 $2,154,559
$64,413,167 $2,417,055 $61,004,837 $2,270,341
$65,959,926 $2,474,064 $63,100,641 $2,366,721
$69,093,014 $2,580,155 $66,215,546 $2,496,157
$71,436,551 $2,694,404 $68,885,506 $2,696,692
$72,763,583 $2,758,003 $70,594,593 $2,784,684
$75,363,833 $2,846,480 $73,359,566 $2,893,595
$78,268,859 $2,891,708 $76,471,455 $2,975,904
$81,185,739 $2,988,557 $79,401,034 $3,136,331
$82,076,752 $2,986,840 $80,668,068 $3,188,476
$84,615,823 $2,990,264 $83,688,661 $3,285,170
$86,478,600 $3,044,214 $85,669,143 $3,392,886
$87,206,381 $2,389,762 $86,757,657 $2,832,616
$90,543,214 $3,234,023 $90,169,480 $3,780,636
$93,487,125 $3,396,688 $93,059,963 $3,972,833
$95,579,516 $3,470,648 $95,684,234 $4,215,587
$98,413,139 $3,638,373 $98,712,863 $4,507,533

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The analysis for this program should be reviewed annually in the annual Asset Management Plan Review and the analysis updated in 2022 or sooner if indicated by
the annual Asset Management Plan Review.
Metrics
The objective of metrics or key performance indicators is to ensure the right behavior is
in place and working, to ensure successful execution, to continually improve tools and
processes, and to ensure the systems operate as intended.
The goal is to provide a minimum of one leading and one lagging indicator. Lagging
indicators measures or monitors the past performance and leading indicators predict
future performance in order to avoid incidents and failures (IAM, 2015). The diagram in
Figure 37 helps illustrate this point.

Figure 37 Leading and Lagging Performance measurements for assets and the Asset Management System from IAM (IAM, 2015)
The following metrics in Table 19 are planned for the annual Asset Management Plan
Review. For the details on the data sources and calculations, see the Asset Information
Strategy for Wood Pole Management.
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Table 19 Metrics for Tracking WPM Performance
Metric Annual Goal Leading/Lagging
Indicator
follow up completed
(includes Grid
Modernization Miles if
they support the WPM
goal)
385.1 Miles Leading
by Year
Within 20% of projection Lagging
Year
Within 20% of projection Lagging
Related OMT Events
Within 20% of projection Lagging
Revised WPM related
OMT Events to SAIFI
0.054 Lagging
Revised WPM related
OMT Events to SAIDI
0.119 (hours) Lagging

Revisions, additions and removal of metrics may occur and be documented as part of the annual Asset Management Plan Review along with the justifications for the
changes.
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Bibliography
Avista. (2017, April 17). Strategies focus areas for 2017_final_widescreen_green.pptx. Retrieved from
http://sharepoint/departments/aboutavista/SitePages/Home.aspx?RootFolder=%
2Fdepartments%2Faboutavista%2FShared%20Documents%2FCompany%20Vis
ion%2C%20Purpose%2C%20Principles%2C%20Strategies%20and%20Focus%
20Areas%202017&FolderCTID=0x012000AEA2AE0E99911A4E8486
Avista's Asset Management. (2017). Asset Management Standard Assumptions.
IAM. (2015, May). Asset Information - Asset Information, Strategy, Standards and Data
Management. Institute of Asset Management.
IAM. (2015). Asset Management - an anatomy Version 3. The Institute of Asset
Management.
Maintenance, A. (n.d.). 2012-2015 UNITS TO RODNEY_9-25-2015.xlsx. Retrieved from
H:\A_Assets\Electric Distribution\Integrated Programs\Wood Pole
Management\Model\2017 Final
Pickett, R. (n.d.). Failure Curve Development rev 1.xlsx. Retrieved from
H:\A_Assets\Electric Distribution\Integrated Programs\Wood Pole Management\Model\2017 Final
Power System Engineers, I. (2017). Reliability Targets for Washington's Three Investor-
Owned Utilities.

Staff_PR_122 Supplemental Attachment A Page 64 of 94

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Appendix A
The Business Case template is currently under revision and not available for use.

Staff_PR_122 Supplemental Attachment A Page 65 of 94
Staff_PR_122 Supplemental Attachment A Page 66 of 94

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Appendix B - Model output reports for labor,
spares, Lifecycle Cost summary, effects, and
others as appropriate

Staff_PR_122 Supplemental Attachment A Page 67 of 94
Staff_PR_122 Supplemental Attachment A Page 68 of 94

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Due to the file sizes, a list of the files is provided here. Consult the files listed in Table 20 for all of the details.
Table 20 Model Output Files for Supporting Information
Model the Files Supports File Name
2016 Pole Failure Curves - 10 year
cycle scaled up rev 7
2016 Pole Failure Curves - 10 year cycle scaled up rev 7 -
Cause Cost Predictions.pdf
2016 Pole Failure Curves - 10 year
cycle scaled up rev 7
2016 Pole Failure Curves - 10 year cycle scaled up rev 7 - Cost
Nodes.pdf
2016 Pole Failure Curves - 10 year
cycle scaled up rev 7
2016 Pole Failure Curves - 10 year cycle scaled up rev 7 -
Effects Predictions by Time Interval.pdf
2016 Pole Failure Curves - 10 year
cycle scaled up rev 7
2016 Pole Failure Curves - 10 year cycle scaled up rev 7 -
Effects Predictions.pdf
2016 Pole Failure Curves - 10 year
cycle scaled up rev 7
2016 Pole Failure Curves - 10 year cycle scaled up rev 7 -
Equipment Predictions by Time Interval.pdf
2016 Pole Failure Curves - 10 year
cycle scaled up rev 7
2016 Pole Failure Curves - 10 year cycle scaled up rev 7 -
Equipment Predictions.pdf
2016 Pole Failure Curves - 10 year
cycle scaled up rev 7
2016 Pole Failure Curves - 10 year
cycle scaled up rev 7
2016 Pole Failure Curves - 10 year cycle scaled up rev 7 -
Labor Predictions.pdf
2016 Pole Failure Curves - 10 year
cycle scaled up rev 7
2016 Pole Failure Curves - 10 year cycle scaled up rev 7 -
Project Predictions by Time Interval.pdf
2016 Pole Failure Curves - 10 year
cycle scaled up rev 7
2016 Pole Failure Curves - 10 year cycle scaled up rev 7 -
Spares Predictions by Time Interval.pdf
2016 Pole Failure Curves - 10 year
cycle scaled up rev 7
2016 Pole Failure Curves - 10 year cycle scaled up rev 7 -
Spares Predictions.pdf
2016 Pole Failure Curves - 10 year
cycle scaled up rev 7
2016 Pole Failure Curves - 10 year cycle scaled up rev 7.awb
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year cycle scaled up rev 7 - 10
year pause - Cost Nodes.pdf
2016 Pole Failure Curves - 20 year
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year cycle scaled up rev 7 - 10
year pause.awb
2016 Pole Failure Curves - 20 year
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year cycle scaled up rev 7 - 5
year pause - Cost Nodes.pdf
2016 Pole Failure Curves - 20 year
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year cycle scaled up rev 7 - 5
year pause.awb
2016 Pole Failure Curves - 20 year
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year cycle scaled up rev 7 -
Cause Cost Predictions.pdf
2016 Pole Failure Curves - 20 year
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year cycle scaled up rev 7 - Cost
Nodes.pdf
2016 Pole Failure Curves - 20 year
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year cycle scaled up rev 7 -
Effects Predictions by Time Interval.pdf
2016 Pole Failure Curves - 20 year
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year cycle scaled up rev 7 -
Effects Predictions.pdf
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Model the Files Supports File Name
2016 Pole Failure Curves - 20 year
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year cycle scaled up rev 7 -
Equipment Predictions by Time Interval.pdf
2016 Pole Failure Curves - 20 year
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year cycle scaled up rev 7 -
Equipment Predictions.pdf
2016 Pole Failure Curves - 20 year
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year cycle scaled up rev 7 -
Labor Predictions by Time Interval.pdf
2016 Pole Failure Curves - 20 year
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year cycle scaled up rev 7 -
Project Predictions by Time Interval.pdf
2016 Pole Failure Curves - 20 year
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year cycle scaled up rev 7 -
Spares Predictions by Time Interval.pdf
2016 Pole Failure Curves - 20 year
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year
cycle scaled up rev 7
2016 Pole Failure Curves - 20 year cycle scaled up rev 7.awb
cycle scaled up rev 7
2016 Pole Failure Curves - 25 year cycle scaled up rev 7 -
Cause Cost Predictions.pdf
2016 Pole Failure Curves - 25 year
cycle scaled up rev 7
2016 Pole Failure Curves - 25 year cycle scaled up rev 7 - Cost
Nodes.pdf
2016 Pole Failure Curves - 25 year
cycle scaled up rev 7
2016 Pole Failure Curves - 25 year cycle scaled up rev 7 -
Effect Predictions by Time Interval.pdf
2016 Pole Failure Curves - 25 year
cycle scaled up rev 7
2016 Pole Failure Curves - 25 year cycle scaled up rev 7 -
Effect Predictions.pdf
2016 Pole Failure Curves - 25 year
cycle scaled up rev 7
2016 Pole Failure Curves - 25 year cycle scaled up rev 7 -
Equipment Predictions by Time Interval.pdf
2016 Pole Failure Curves - 25 year
cycle scaled up rev 7
2016 Pole Failure Curves - 25 year cycle scaled up rev 7 -
Equipment Predictions.pdf
2016 Pole Failure Curves - 25 year
cycle scaled up rev 7
2016 Pole Failure Curves - 25 year cycle scaled up rev 7 -
Labor Predictions by Time Interval.pdf
2016 Pole Failure Curves - 25 year
cycle scaled up rev 7
2016 Pole Failure Curves - 25 year cycle scaled up rev 7 -
Labor Predictions.pdf
2016 Pole Failure Curves - 25 year
cycle scaled up rev 7
2016 Pole Failure Curves - 25 year cycle scaled up rev 7 -
Project Predictions by Time Interval.pdf
2016 Pole Failure Curves - 25 year
cycle scaled up rev 7
2016 Pole Failure Curves - 25 year
cycle scaled up rev 7
2016 Pole Failure Curves - 25 year cycle scaled up rev 7 -
Spares Predictions.pdf
2016 Pole Failure Curves - 25 year
cycle scaled up rev 7
2016 Pole Failure Curves - 25 year cycle scaled up rev 7.awb
2016 Pole Failure Curves - 5 year cycle scaled up rev 7 -
Cause Cost Predictions.pdf
cycle scaled up rev 7
2016 Pole Failure Curves - 5 year cycle scaled up rev 7 - Cost
Nodes.pdf
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Model the Files Supports File Name
2016 Pole Failure Curves - 5 year
cycle scaled up rev 7
2016 Pole Failure Curves - 5 year cycle scaled up rev 7 -
Effects Predictions by Time Interval.pdf
2016 Pole Failure Curves - 5 year
cycle scaled up rev 7
2016 Pole Failure Curves - 5 year cycle scaled up rev 7 -
Effects Predictions.pdf
2016 Pole Failure Curves - 5 year
cycle scaled up rev 7
2016 Pole Failure Curves - 5 year cycle scaled up rev 7 -
Equipment Predictions by Time Interval.pdf
2016 Pole Failure Curves - 5 year
cycle scaled up rev 7
2016 Pole Failure Curves - 5 year
cycle scaled up rev 7
2016 Pole Failure Curves - 5 year cycle scaled up rev 7 - Labor
Predictions by Time Interval.pdf
2016 Pole Failure Curves - 5 year
cycle scaled up rev 7
2016 Pole Failure Curves - 5 year cycle scaled up rev 7 - Labor
Predictions.pdf
2016 Pole Failure Curves - 5 year
cycle scaled up rev 7
2016 Pole Failure Curves - 5 year
cycle scaled up rev 7
2016 Pole Failure Curves - 5 year cycle scaled up rev 7 -
Spares Predictions by Time Interval.pdf
2016 Pole Failure Curves - 5 year
cycle scaled up rev 7
2016 Pole Failure Curves - 5 year cycle scaled up rev 7 -
Spares Predictions.pdf
2016 Pole Failure Curves - 5 year
cycle scaled up rev 7
2016 Pole Failure Curves - 5 year cycle scaled up rev 7.awb
Grid mod 20 year cycle scaled up rev
2016 Pole Failure Curves - 60 Year Grid mod 20 year cycle
scaled up rev 7 - Cause Cost Predictions.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 20 year cycle scaled up rev
7
2016 Pole Failure Curves - 60 Year Grid mod 20 year cycle
scaled up rev 7 - Cost Nodes.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 20 year cycle scaled up rev
7
2016 Pole Failure Curves - 60 Year Grid mod 20 year cycle
scaled up rev 7 - Effects Predictions by Time Interval.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 20 year cycle scaled up rev
7
2016 Pole Failure Curves - 60 Year Grid mod 20 year cycle
scaled up rev 7 - Effects Predictions.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 20 year cycle scaled up rev
2016 Pole Failure Curves - 60 Year Grid mod 20 year cycle
scaled up rev 7 - Equipment Predictions by Time Interval.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 20 year cycle scaled up rev
7
2016 Pole Failure Curves - 60 Year Grid mod 20 year cycle
scaled up rev 7 - Equipment Predictions.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 20 year cycle scaled up rev
7
2016 Pole Failure Curves - 60 Year Grid mod 20 year cycle
scaled up rev 7 - Labor Predictions by Time Interval.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 20 year cycle scaled up rev
7
2016 Pole Failure Curves - 60 Year Grid mod 20 year cycle
scaled up rev 7 - Labor Predictions.pdf
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Model the Files Supports File Name
2016 Pole Failure Curves - 60 Year
Grid mod 20 year cycle scaled up rev
7
2016 Pole Failure Curves - 60 Year Grid mod 20 year cycle
scaled up rev 7 - Project Predictions by Time Interval.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 20 year cycle scaled up rev
7
2016 Pole Failure Curves - 60 Year Grid mod 20 year cycle
scaled up rev 7 - Spares Predictions by Time Interval.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 20 year cycle scaled up rev
2016 Pole Failure Curves - 60 Year Grid mod 20 year cycle
scaled up rev 7 - Spares Predictions.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 20 year cycle scaled up rev
7
2016 Pole Failure Curves - 60 Year Grid mod 20 year cycle
scaled up rev 7.awb
2016 Pole Failure Curves - 60 Year
Grid mod 60 year cycle scaled up rev
9
2016 Pole Failure Curves - 60 Year Grid mod 60 year cycle
scaled up rev 9 - Cause Cost Predictions.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 60 year cycle scaled up rev
9
2016 Pole Failure Curves - 60 Year Grid mod 60 year cycle
scaled up rev 9 - Cost Nodes.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 60 year cycle scaled up rev
2016 Pole Failure Curves - 60 Year Grid mod 60 year cycle
scaled up rev 9 - Effects Predictions by Time Interval.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 60 year cycle scaled up rev
9
2016 Pole Failure Curves - 60 Year Grid mod 60 year cycle
scaled up rev 9 - Effects Predictions.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 60 year cycle scaled up rev
9
2016 Pole Failure Curves - 60 Year Grid mod 60 year cycle
scaled up rev 9 - Equipment Predictions by Time Interval.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 60 year cycle scaled up rev
9
2016 Pole Failure Curves - 60 Year Grid mod 60 year cycle
scaled up rev 9 - Equipment Predictions.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 60 year cycle scaled up rev
9
2016 Pole Failure Curves - 60 Year Grid mod 60 year cycle
scaled up rev 9 - Labor Predictions by Time Interval.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 60 year cycle scaled up rev
2016 Pole Failure Curves - 60 Year Grid mod 60 year cycle
scaled up rev 9 - Labor Predictions.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 60 year cycle scaled up rev
9
2016 Pole Failure Curves - 60 Year Grid mod 60 year cycle
scaled up rev 9 - Project Predictions by Time Interval.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 60 year cycle scaled up rev
9
2016 Pole Failure Curves - 60 Year Grid mod 60 year cycle
scaled up rev 9 - Spares Predictions by Time Interval.pdf
Staff_PR_122 Supplemental Attachment A Page 72 of 94

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Model the Files Supports File Name
2016 Pole Failure Curves - 60 Year
Grid mod 60 year cycle scaled up rev
9
2016 Pole Failure Curves - 60 Year Grid mod 60 year cycle
scaled up rev 9 - Spares Predictions.pdf
2016 Pole Failure Curves - 60 Year
Grid mod 60 year cycle scaled up rev
9
2016 Pole Failure Curves - 60 Year Grid mod 60 year cycle
scaled up rev 9.awb
2016 Pole Failure Curves - Base Case
scaled up rev 7
2016 Pole Failure Curves - Base Case scaled up rev 7 - Cause
Cost Predictions.pdf
2016 Pole Failure Curves - Base Case
scaled up rev 7
2016 Pole Failure Curves - Base Case scaled up rev 7 - Cost
Nodes.pdf
2016 Pole Failure Curves - Base Case
scaled up rev 7
2016 Pole Failure Curves - Base Case scaled up rev 7 - Effects
Predictions by Time Interval.pdf
2016 Pole Failure Curves - Base Case
scaled up rev 7
2016 Pole Failure Curves - Base Case scaled up rev 7 - Effects
Predictions.pdf
2016 Pole Failure Curves - Base Case
scaled up rev 7
2016 Pole Failure Curves - Base Case
scaled up rev 7
2016 Pole Failure Curves - Base Case scaled up rev 7 -
Equipment Predictions.pdf
2016 Pole Failure Curves - Base Case
scaled up rev 7
2016 Pole Failure Curves - Base Case scaled up rev 7 - Labor
Predictions by Time Interval.pdf
2016 Pole Failure Curves - Base Case
scaled up rev 7
2016 Pole Failure Curves - Base Case
scaled up rev 7
2016 Pole Failure Curves - Base Case scaled up rev 7 - Project
Predictions by Time Interval.pdf
2016 Pole Failure Curves - Base Case
scaled up rev 7
2016 Pole Failure Curves - Base Case scaled up rev 7 - Spares
Predictions by Time Interval.pdf
2016 Pole Failure Curves - Base Case
scaled up rev 7
2016 Pole Failure Curves - Base Case
scaled up rev 7
2016 Pole Failure Curves - Base Case scaled up rev 7.awb
mod 50 year cycle scaled up rev 9
2016 Pole Failure Curves - Opt Grid mod 50 year cycle scaled
up rev 9 - Cause Cost Predictions.pdf
2016 Pole Failure Curves - Opt Grid
mod 50 year cycle scaled up rev 9
2016 Pole Failure Curves - Opt Grid mod 50 year cycle scaled
up rev 9 - Cost Nodes.pdf
2016 Pole Failure Curves - Opt Grid
mod 50 year cycle scaled up rev 9
2016 Pole Failure Curves - Opt Grid mod 50 year cycle scaled
up rev 9 - Effect Predictions by Time Interval.pdf
2016 Pole Failure Curves - Opt Grid
mod 50 year cycle scaled up rev 9
2016 Pole Failure Curves - Opt Grid mod 50 year cycle scaled
up rev 9 - Effect Predictions.pdf
2016 Pole Failure Curves - Opt Grid
mod 50 year cycle scaled up rev 9
2016 Pole Failure Curves - Opt Grid mod 50 year cycle scaled
up rev 9 - Equipment Predictions by Time Interval.pdf
2016 Pole Failure Curves - Opt Grid
mod 50 year cycle scaled up rev 9
2016 Pole Failure Curves - Opt Grid mod 50 year cycle scaled
up rev 9 - Equipment Predictions.pdf
2016 Pole Failure Curves - Opt Grid
mod 50 year cycle scaled up rev 9
2016 Pole Failure Curves - Opt Grid mod 50 year cycle scaled
up rev 9 - Labor Predictions by Time Interval.pdf
Staff_PR_122 Supplemental Attachment A Page 73 of 94

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Model the Files Supports File Name
2016 Pole Failure Curves - Opt Grid
mod 50 year cycle scaled up rev 9
2016 Pole Failure Curves - Opt Grid mod 50 year cycle scaled
up rev 9 - Labor Predictions.pdf
2016 Pole Failure Curves - Opt Grid
mod 50 year cycle scaled up rev 9
2016 Pole Failure Curves - Opt Grid mod 50 year cycle scaled
up rev 9 - Project Predictions by Time Interval.pdf
2016 Pole Failure Curves - Opt Grid
mod 50 year cycle scaled up rev 9
2016 Pole Failure Curves - Opt Grid mod 50 year cycle scaled
up rev 9 - Spares Predictions by Time Interval.pdf
2016 Pole Failure Curves - Opt Grid
mod 50 year cycle scaled up rev 9
2016 Pole Failure Curves - Opt Grid
mod 50 year cycle scaled up rev 9
2016 Pole Failure Curves - Opt Grid mod 50 year cycle scaled
up rev 9.awb
2016 TCOP Model for WPM - No
Action Base Case 4-24-17
2016 TCOP Model for WPM - No Action Base Case 4-24-17 -
Cause Cost Predictions.pdf
2016 TCOP Model for WPM - No
Action Base Case 4-24-17
2016 TCOP Model for WPM - No
Action Base Case 4-24-17
2016 TCOP Model for WPM - No Action Base Case 4-24-17 -
Effects Predictions by Time Interval.pdf
2016 TCOP Model for WPM - No
Action Base Case 4-24-17
2016 TCOP Model for WPM - No Action Base Case 4-24-17 -
Effects Predictions.pdf
2016 TCOP Model for WPM - No
Action Base Case 4-24-17
2016 TCOP Model for WPM - No Action Base Case 4-24-17 -
Equipment Predictions by Time Interval.pdf
2016 TCOP Model for WPM - No
Action Base Case 4-24-17
2016 TCOP Model for WPM - No Action Base Case 4-24-17 -
Equipment Predictions.pdf
2016 TCOP Model for WPM - No
Action Base Case 4-24-17
2016 TCOP Model for WPM - No Action Base Case 4-24-17 -
Labor Predictions by Time Interval.pdf
2016 TCOP Model for WPM - No
Action Base Case 4-24-17
2016 TCOP Model for WPM - No Action Base Case 4-24-17 -
Labor Predictions.pdf
2016 TCOP Model for WPM - No
Action Base Case 4-24-17
2016 TCOP Model for WPM - No Action Base Case 4-24-17 -
Project Predictions by Time Interval.pdf
2016 TCOP Model for WPM - No
Action Base Case 4-24-17
2016 TCOP Model for WPM - No Action Base Case 4-24-17 -
Spares Predictions by Time Interval.pdf
2016 TCOP Model for WPM - No
Action Base Case 4-24-17
2016 TCOP Model for WPM - No Action Base Case 4-24-17 -
Spares Predictions.pdf
2016 TCOP Model for WPM - No
Action Base Case 4-24-17
2016 TCOP Model for WPM - No Action Base Case 4-24-
17.awb
2016 TCOP Model for WPM 10 Year
Cycle 4-24-17
2016 TCOP Model for WPM 10 Year
Cycle 4-24-17
2016 TCOP Model for WPM 10 Year Cycle 4-24-17 - Cost
Nodes.pdf
2016 TCOP Model for WPM 10 Year
Cycle 4-24-17
2016 TCOP Model for WPM 10 Year Cycle 4-24-17 - Effects
Predictions by Time Interval.pdf
2016 TCOP Model for WPM 10 Year
Cycle 4-24-17
2016 TCOP Model for WPM 10 Year
Cycle 4-24-17
2016 TCOP Model for WPM 10 Year Cycle 4-24-17 -
Equipment Predictions by Time Interval.pdf
Staff_PR_122 Supplemental Attachment A Page 74 of 94

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Model the Files Supports File Name
2016 TCOP Model for WPM 10 Year
Cycle 4-24-17
2016 TCOP Model for WPM 10 Year Cycle 4-24-17 -
Equipment Predictions.pdf
2016 TCOP Model for WPM 10 Year
Cycle 4-24-17
2016 TCOP Model for WPM 10 Year Cycle 4-24-17 - Labor
Predictions by Time Interval.pdf
2016 TCOP Model for WPM 10 Year
Cycle 4-24-17
2016 TCOP Model for WPM 10 Year Cycle 4-24-17 - Labor
Predictions.pdf
2016 TCOP Model for WPM 10 Year
Cycle 4-24-17
2016 TCOP Model for WPM 10 Year
Cycle 4-24-17
2016 TCOP Model for WPM 10 Year Cycle 4-24-17 - Spares
Predictions by Time Interval.pdf
2016 TCOP Model for WPM 10 Year
Cycle 4-24-17
2016 TCOP Model for WPM 10 Year Cycle 4-24-17 - Spares
Predictions.pdf
2016 TCOP Model for WPM 10 Year
Cycle 4-24-17
2016 TCOP Model for WPM 20 Year
Cycle 4-24-17
2016 TCOP Model for WPM 20 Year Cycle 4-24-17 - Cause
Cost Predictions.pdf
2016 TCOP Model for WPM 20 Year
Cycle 4-24-17
2016 TCOP Model for WPM 20 Year Cycle 4-24-17 - Cost
Nodes.pdf
2016 TCOP Model for WPM 20 Year
Cycle 4-24-17
2016 TCOP Model for WPM 20 Year Cycle 4-24-17 - Effects
Predictions by Time Interval.pdf
2016 TCOP Model for WPM 20 Year
Cycle 4-24-17
2016 TCOP Model for WPM 20 Year Cycle 4-24-17 - Effects
Predictions.pdf
2016 TCOP Model for WPM 20 Year
Cycle 4-24-17
2016 TCOP Model for WPM 20 Year Cycle 4-24-17 -
Equipment Predictions by Time Interval.pdf
2016 TCOP Model for WPM 20 Year
Cycle 4-24-17
2016 TCOP Model for WPM 20 Year Cycle 4-24-17 -
Equipment Predictions.pdf
2016 TCOP Model for WPM 20 Year
Cycle 4-24-17
2016 TCOP Model for WPM 20 Year Cycle 4-24-17 - Labor
Predictions by Time Interval.pdf
2016 TCOP Model for WPM 20 Year
Cycle 4-24-17
2016 TCOP Model for WPM 20 Year Cycle 4-24-17 - Labor
Predictions.pdf
2016 TCOP Model for WPM 20 Year
Cycle 4-24-17
2016 TCOP Model for WPM 20 Year Cycle 4-24-17 - Project
Predictions by Time Interval.pdf
2016 TCOP Model for WPM 20 Year
Cycle 4-24-17
2016 TCOP Model for WPM 20 Year Cycle 4-24-17 - Spares
Predictions by Time Interval.pdf
2016 TCOP Model for WPM 20 Year
Cycle 4-24-17
2016 TCOP Model for WPM 20 Year
Cycle 4-24-17
2016 TCOP Model for WPM 20 Year Cycle 4-24-17.awb
Cycle No TCOP Case 4-21-17
2016 TCOP Model for WPM 20 Year Cycle No TCOP Case 4-
21-17 - Cause Cost Predictions.pdf
2016 TCOP Model for WPM 20 Year
Cycle No TCOP Case 4-21-17
2016 TCOP Model for WPM 20 Year
Cycle No TCOP Case 4-21-17
2016 TCOP Model for WPM 20 Year Cycle No TCOP Case 4-
21-17 - Effects Predictions by Time Interval.pdf
Staff_PR_122 Supplemental Attachment A Page 75 of 94

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Model the Files Supports File Name
2016 TCOP Model for WPM 20 Year
Cycle No TCOP Case 4-21-17
2016 TCOP Model for WPM 20 Year Cycle No TCOP Case 4-
21-17 - Effects Predictions.pdf
2016 TCOP Model for WPM 20 Year
Cycle No TCOP Case 4-21-17
2016 TCOP Model for WPM 20 Year Cycle No TCOP Case 4-
21-17 - Equipment Predictions by Time Interval.pdf
2016 TCOP Model for WPM 20 Year
Cycle No TCOP Case 4-21-17
2016 TCOP Model for WPM 20 Year Cycle No TCOP Case 4-
21-17 - Equipment Predictions.pdf
2016 TCOP Model for WPM 20 Year
Cycle No TCOP Case 4-21-17
2016 TCOP Model for WPM 20 Year
Cycle No TCOP Case 4-21-17
2016 TCOP Model for WPM 20 Year Cycle No TCOP Case 4-
21-17 - Labor Predictions.pdf
2016 TCOP Model for WPM 20 Year
Cycle No TCOP Case 4-21-17
2016 TCOP Model for WPM 20 Year Cycle No TCOP Case 4-
21-17 - Project Predictions by Time Interval.pdf
2016 TCOP Model for WPM 20 Year
Cycle No TCOP Case 4-21-17
2016 TCOP Model for WPM 20 Year
Cycle No TCOP Case 4-21-17
2016 TCOP Model for WPM 20 Year Cycle No TCOP Case 4-
21-17 - Spares Predictions.pdf
2016 TCOP Model for WPM 20 Year
Cycle No TCOP Case 4-21-17
2016 TCOP Model for WPM 20 Year Cycle No TCOP Case 4-
21-17.awb
2016 TCOP Model for WPM 25 Year
Cycle 4-24-17
2016 TCOP Model for WPM 25 Year Cycle 4-24-17 - Cause
Cost Predictions.pdf
2016 TCOP Model for WPM 25 Year
Cycle 4-24-17
2016 TCOP Model for WPM 25 Year Cycle 4-24-17 - Cost
Nodes.pdf
2016 TCOP Model for WPM 25 Year
Cycle 4-24-17
2016 TCOP Model for WPM 25 Year Cycle 4-24-17 - Effects
Predictions by Time Interval.pdf
2016 TCOP Model for WPM 25 Year
Cycle 4-24-17
2016 TCOP Model for WPM 25 Year Cycle 4-24-17 - Effects
Predictions.pdf
2016 TCOP Model for WPM 25 Year
Cycle 4-24-17
2016 TCOP Model for WPM 25 Year Cycle 4-24-17 -
Equipment Predictions by Time Interval.pdf
2016 TCOP Model for WPM 25 Year
Cycle 4-24-17
2016 TCOP Model for WPM 25 Year Cycle 4-24-17 -
Equipment Predictions.pdf
2016 TCOP Model for WPM 25 Year
Cycle 4-24-17
2016 TCOP Model for WPM 25 Year Cycle 4-24-17 - Labor
Predictions by Time Interval.pdf
2016 TCOP Model for WPM 25 Year
Cycle 4-24-17
2016 TCOP Model for WPM 25 Year Cycle 4-24-17 - Labor
Predictions.pdf
2016 TCOP Model for WPM 25 Year
Cycle 4-24-17
2016 TCOP Model for WPM 25 Year
Cycle 4-24-17
2016 TCOP Model for WPM 25 Year Cycle 4-24-17 - Spares
Predictions by Time Interval.pdf
2016 TCOP Model for WPM 25 Year
Cycle 4-24-17
2016 TCOP Model for WPM 25 Year Cycle 4-24-17 - Spares
Predictions.pdf
2016 TCOP Model for WPM 25 Year
Cycle 4-24-17
2016 TCOP Model for WPM 5 Year
Cycle 4-24-17
2016 TCOP Model for WPM 5 Year Cycle 4-24-17 - Cause
Cost Predictions.pdf
Staff_PR_122 Supplemental Attachment A Page 76 of 94

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Model the Files Supports File Name
2016 TCOP Model for WPM 5 Year
Cycle 4-24-17
2016 TCOP Model for WPM 5 Year Cycle 4-24-17 - Cost
Node.pdf
2016 TCOP Model for WPM 5 Year
Cycle 4-24-17
2016 TCOP Model for WPM 5 Year Cycle 4-24-17 - Effect
Predictions by Time Interval.pdf
2016 TCOP Model for WPM 5 Year
Cycle 4-24-17
2016 TCOP Model for WPM 5 Year Cycle 4-24-17 - Effect
Predictions.pdf
2016 TCOP Model for WPM 5 Year
Cycle 4-24-17
2016 TCOP Model for WPM 5 Year
Cycle 4-24-17
2016 TCOP Model for WPM 5 Year Cycle 4-24-17 -
Equipment Predictions.pdf
2016 TCOP Model for WPM 5 Year
Cycle 4-24-17
2016 TCOP Model for WPM 5 Year Cycle 4-24-17 - Labor
Predictions by Time Interval.pdf
2016 TCOP Model for WPM 5 Year
Cycle 4-24-17
2016 TCOP Model for WPM 5 Year
Cycle 4-24-17
2016 TCOP Model for WPM 5 Year Cycle 4-24-17 - Project
Predictions by Time Interval.pdf
2016 TCOP Model for WPM 5 Year
Cycle 4-24-17
2016 TCOP Model for WPM 5 Year Cycle 4-24-17 - Spares
Predictions by Time Interval.pdf
2016 TCOP Model for WPM 5 Year
Cycle 4-24-17
2016 TCOP Model for WPM 5 Year Cycle 4-24-17 - Spares
Predictions.pdf
2016 TCOP Model for WPM 5 Year
Cycle 4-24-17
2016 TCOP Model for WPM 5 Year Cycle 4-24-17.awb

Staff_PR_122 Supplemental Attachment A Page 77 of 94
Staff_PR_122 Supplemental Attachment A Page 78 of 94

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Appendix C
Table 21 Complete list of Feeders by Year WPM work completed since 2006 Ranked based on OMT Events for
2012-2016 by Subreason
Year WPM Work
Completed on
Feeder
rotten Pin rotten Total
2016 M23621 3 2 5 LOL1359 2 1 1 4 NLW1222 1 2 3 MLN12F2 1 2 3 SOT522 1 1 2 SPT4S23 1 1 2 CHE12F4 1 1 CLA56 1 1 APW114 1 1 MLN12F1 1 1
2015 GIF34F1 2 4 3 2 11 NW12F3 1 1 4 6 3HT12F7 3 1 1 1 6 NW12F1 2 2 4 L&S12F2 1 2 1 4 APW111 1 2 3 3HT12F3 3 3 C&W12F6 1 1 1 3 SAG742 1 1 2 LOL1266 1 1 2 GAR461 1 1 2 NW12F4 1 1 2 3HT12F5 1 1 2 L&S12F3 1 1 2 L&S12F4 2 2 AIR12F3 1 1 LKV342 1 1 L&S12F5 1 1 L&S12F1 1 1
Staff_PR_122 Supplemental Attachment A Page 79 of 94

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1 1 3HT12F1 1 1
2014 C&W12F1 3 2 1 6 DER651 2 2 1 5 NE12F3 1 1 2 4 NW12F2 2 2 4 WAS781 2 1 3 C&W12F4 2 1 3 C&W12F5 3 3 CDA123 3 3 SAG741 2 2 CDA124 1 1 2 TUR113 1 1 CDA122 1 1 C&W12F3 1 1 3HT12F2 1 1
2013 SPU121 3 3 WIL12F2 1 1 2 MIL12F4 1 1 AVD152 1 1 SE12F2 1 1 AVD151 1 1 3HT12F4 1 1 DEP12F1 1 1 DEP12F2 1 1
2012 TEN1256 2 1 1 4 SE12F5 4 4 MEA12F2 3 3 TEN1257 3 3 COB12F1 1 1 2 COB12F2 1 1 2 DAL133 2 2 BEA12F1 1 1 TVW132 1 1 F&C12F2 1 1 MEA12F1 1 1
2011 VAL12F1 2 3 1 4 10 SUN12F6 1 1 2 M15515 1 1 OLD721 1 1
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1 1 MIL12F3 1 1 ODN731 1 1
2010 CDA125 1 5 6 BKR12F1 1 2 3 LL12F1 1 2 3 CKF711 1 1 2 PRA222 1 1 2 CKF712 2 2 KET12F2 1 1 PRA221 1 1 TEN1254 1
1 ODN732 1 1 LOO12F1 1 1
2009 GRV1273 5 1 2 8 SUN12F2 1 1 2 4 DIA231 3 3 M15514 2 2 SUN12F4 1 1 2 9CE12F4 2 2 HAR4F2 2 2 SLW1368 1 1 HAR4F1 1 1
2008 STM633 5 2 2 9 BUN426 1 1 2 4 HUE142 2 1 3 BUN422 1 1 2 HUE141 2 2 NMO521 1 1 2 SUN12F1 1 1 SLW1358 1 1 CGC331 1 1 BKR12F2 1 1 BUN423 1 1 PDL1201 1 1 SUN12F3 1 1 ROX751 1 1 SE12F1 1 1
2007 GRV1272 1 1
0 RSA431 7 1 3 1 12
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7 2 2 11 BEA12F2 1 4 1 5 11 STM631 4 3 4 11 BLU321 1 8 1 10 CHW12F3 3 2 1 3 9 LAT421 3 1 3 1 8 SWT2403 1 2 1 3 7 SLK12F1 1 4 2 7 CHW12F2 2 3 2 7 CHW12F4 1 2 2 2 7 FOR12F1 4 2 1 7 SOT523 1 1 3 2 7 CLV12F2 6 1 7 LF34F1 1 6 7 CLV34F1 3 2 1 6 ORI12F3 2 1 3 6 COT2401 2 4 6 ORI12F1 5 1 6 SPI12F2 3 2 1 6 CHE12F2 1 4 5 PAL312 1 1 3 5 OGA611 1 1 2 1 5 SPR761 1 1 2 1 5 SPI12F1 3 2 5 WAK12F3 5 5 PRV4S40 4 1 5 DVP12F2 3 1 1 5 RDN12F2 1 4 5 ROS12F5 2 1 2 5 LIB12F2 2 2 1 5 MIS431 3 1 1 5 VAL12F2 2 2 4 GLN12F1 1 3 4 ROS12F6 1 1 2 4 AIR12F1 1 1 2 4 L&R512 4 4 DER652 1 2 1 4 WAK12F2 1 3 4 OSB521 1 2 1 4 FWT12F2 1 3 4
Staff_PR_122 Supplemental Attachment A Page 82 of 94

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2 2 4 SPL361 2 1 1 4 PF213 3 1 4 TUR112 3 1 4 PIN443 1 1 2 4 VAL12F3 2 1 1 4 RDN12F1 3 1 4 FWT12F1 1 1 2 4 ROS12F1 1 3 4 F&C12F4 2 1 3 H&W12F2 1 2 3 BLA311 2 1 3 LEO611 1 2 3 JPE1287 1 1 1 3 ARD12F2 1 1 1 3 RAT233 3 3 WEI1289 1 1 1 3 WAL543 1 2 3 ECL221 1 2 3 SPT4S22 1 1 1 3 FWT12F3 1 2 3 CHE12F1 3 3 SLK12F2 2 1 3 PST12F1 3 3 FWT12F4 2 1 3 BLU322 3 3 BKR12F3 1 2 3 WAK12F4 3 3 NE12F1 3 3 9CE12F2 1 2 3 NEZ1267 2 1 3 NE12F5 1 2 3 F&C12F6 1 1 2 SLK12F3 1 1 2 9CE12F1 1 1 2 ORO1281 1 1 2 LAT422 1 1 2 GRV1271 1 1 2 FOR2.3 1 1 2 ECL222 2 2
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1 1 2 ROS12F4 2 2 F&C12F1 1 1 2 KAM1292 1 1 2 LEO612 1 1 2 KAM1293 1 1 2 TEN1255 2 2 OPT12F1 2 2 WAK12F1 1 1 2 SIP12F4 1 1 2 KOO1298 1 1 2 SE12F3 2 2 IDR252 1 1 CFD1210 1 1 WAL542 1 1 BEA12F3 1 1 9CE12F3 1 1 RIT731 1 1 PVW243 1 1 RIT732 1 1 COT2402 1 1 KAM1291 1 1 POT321 1 1 ROS12F2 1 1 HOL1206 1 1 ROS12F3 1 1 N131222 1 1 ORO1280 1 1 CHW12F1 1 1 CRG1261 1 1 WAL544 1 1 ORO1282 1 1 CLV12F1 1 1 KET12F1 1 1 SPT4S21 1 1 WIK1279 1 1 SPT4S30 1 1 BEA12F4 1 1 LOO12F2 1 1 OTH501 1 1
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1 1 GRA12F1 1 1 TUR116 1 1 GRN12F1 1 1 APW116 1 1 ORI12F2 1 1 IDR253 1 1 SLW1348 1 1 NLW1321 1 1 EWN241 1 1 NMO522 1 1 SPA442 1 1 WAL545 1 1 PIN441 1 1 INT12F2 1 1 PIN442 1 1 SIP12F2 1 1

Staff_PR_122 Supplemental Attachment A Page 85 of 94
Staff_PR_122 Supplemental Attachment A Page 86 of 94

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Appendix D – Life Extension Impact Analysis of
Reinforcing Electric Distribution Wood Poles

Staff_PR_122 Supplemental Attachment A Page 87 of 94
Staff_PR_122 Supplemental Attachment A Page 88 of 94

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Avista chose as part of our strategy to reinforce poles when they have any signs of
ground line decay on an otherwise physical sound structure. Some people question
why this option makes sense compared to just replacing the pole.
Figure 38 and Table 22 show the failure curve and failure curve characteristics for a
pole replacement. The failure curve in Figure 38 shows the failure rate driving poles replaced with the current reinforcement strategy shown in Figure 39 and Table 23.
For comparison, we recreated the pole replacement failure curve assuming that we only
replace poles and the new failure curve and failure characteristics in Figure 40 and
Table 24. Examining the MTTF for Table 22 and Table 24 we see that by reinforcing
poles where we can extends the MTTF for replacing poles by 9 years for the whole population. In order for reinforcing some of the poles to drive the overall population
MTTF by 9 years, the extension of the life of a reinforced pole must be well beyond 9
years since our current practice approximately replaces 2 pole for every one pole
reinforced.
Figure 41 compares the two different failure curves and shows the 9 year difference between the two different strategies.

Figure 38 Cumulative Probability plot for Unreliability for Distribution Wood Pole Replacements from the AWB Models* - Historical
*Note: Time is in Hours
ε: 0.0309
γ2: 0
β2: 4.78
η2: 7.906Ε+05
γ1: 0
β1: 0.7738
η1: 2.428Ε+08
Median rank
Bi-Weibull
Staff_PR_122 Supplemental Attachment A Page 89 of 94

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Table 22 Failure Curve Values for Distribution Wood Pole Replacements - Historical
Bi-Weibull Failure Curve –
Wood Poles Replacement
- h 5190639 Years 90.25 Years
b 0.44 4.78
g 0 0
83.3 Years
Wood Pole
Management Inspection Data Inspection Data

Figure 39 Cumulative Probability plot for Unreliability for Distribution Wood Pole Reinforcements from the AWB Models* - Historical
*Note: Time is in Hours
Table 23 Failure Curve Values for Distribution Wood Pole Reinforcing - Historical
Weibull Failure Curve – Reinforce Poles Weibull Values
Characteristic Life - h 124 Years
2016 Pole Reinforcement Cumulative Probability
9072 3.994E+04 1.759E+05 7.742E+05
Time
0.1
0.2
0.3
0.5
1
2
3
5
10
20
30
50
70
90
99
99.9
Un
r
e
l
i
a
b
i
l
i
t
y

(
%
)
Eta estimator
P0: 0%
B50: 9.567E+05
B20: 6.43E+05
B10: 4.943E+05
ε: 0.01494
ρ: 0.9937
γ: 0
β: 2.852
η: 1.088Ε+06
Median rank
2-parameterWeibull
Staff_PR_122 Supplemental Attachment A Page 90 of 94

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Shape Parameter - b
Offset - g
Mean Time To Failure (MTTF)
Source of Data
Inspection Data

Figure 40 Cumulative Probability plot for Unreliability for Distribution Wood Pole Replacements and Replacing instead of Reinforcing Poles from the AWB Models*
*Note: Time is in Hours
Table 24 Failure Curve Values for Distribution Wood Pole Replacements - Historical
Bi-Weibull Failure Curve –
Wood Poles Replacement
- h 1445 Years 81.79 Years
b 1.166 4.337
g 0 0
74.4 Years
2016 Pole Combined Cumulative Probability
432 5262 6.41E+04 7.808E+05
Time
0.1
0.2
0.3
0.5
1
2
3
5
10
20
30
50
70
90
99
99.9
Un
r
e
l
i
a
b
i
l
i
t
y

(
%
)
Eta estimator
P0: 0%
B50: 6.514E+05
B20: 4.946E+05
B10: 4.082E+05
ε: 0.01668
γ2: 0
β2: 4.337
η2: 7.165Ε+05
γ1: 0
β1: 1.166
η1: 1.266Ε+07
Median rank
Bi-Weibull
Staff_PR_122 Supplemental Attachment A Page 91 of 94

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Source of Data
Management
Inspection Data
Inspection Data

Figure 41 Comparison of the Cumulative Failure with Stubbing and without Stubbing on Wood Pole Replacement Failures
Using the 20 year WPM inspection model above, we isolated a single 36 year old pole
to compare the two different strategies. Estimation of Life extension due to stubbing -
With Stubbing model examined a pole over approximately 2 lifetimes of 150 years using a stubbing strategy one time followed by a pole replacement strategy. The Estimation
of Life extension due to stubbing - Without Stubbing model represent replacing the pole
two times over two lifetimes. The results were then analyzed using the Revenue
Resource Requirement Model (see file Stubbing vs Replace 5-9-17.xlsm). The results
of the model yielded the financial results shown in Table 25.
Based on the results in Table 25, the strategy to reinforce poles were possible provides
more value to customers with a CIRR of 7.73% when compared to only replacing poles.
00.10.20.30.40.50.60.70.80.91
0 20 40 60 80 100 120
Un
r
e
l
i
a
b
i
l
i
t
y

(
%
)
Age (Years)
Comparison of the Cumulative Failure with Stubbing and without Stubbing on the Wood Pole Replacement FailuresCombined Unreliability for Pole Replaced without Pole ReinforcementCombined Unreliability for Pole Replace with Pole Reinforcement
Staff_PR_122 Supplemental Attachment A Page 92 of 94

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Table 25 Financial Analysis on Replace and Stubbing Poles verses Only Replacing Poles
Alternative CIRR
Replace and Stub Poles 7.73%
Only Replace Poles 6.37%

Staff_PR_122 Supplemental Attachment A Page 93 of 94
Staff_PR_122 Supplemental Attachment A Page 94 of 94