20170724AVU to Staff 14.doc

AVISTA CORPORATION
RESPONSE TO REQUEST FOR INFORMATION

JURISDICTION: IDAHO DATE PREPARED: 07/11/2017
CASE NO: AVU-E-17-01/AVU-G-17-01 WITNESS: Heather Rosentrater
REQUESTER: IPUC RESPONDER: Larry La Bolle
TYPE: Production Request DEPARTMENT: State & Federal Regulation
REQUEST NO.: Staff - 014 TELEPHONE: [phone]

REQUEST:

How does the Company measure the improvements a capital project may give to reliability?

RESPONSE:

For maintaining the reliability of our electric transmission and distribution system for our customers, this can be accomplished in several ways as explained in the examples below:

When replacing aging assets based on their end-of-life condition, such as the wood poles in the Company’s electric distribution system, we know from experience that the new pole will be less likely to fail compared with the old pole being replaced. This kind of investment has the effect of helping Avista maintain its overall level of electric reliability, and the reliability benefit can be measured by comparing the average likelihood of failure of the old pole that was replaced with the much-lower likelihood of failure of the new pole. On a larger scale this can measured by comparing the reliability of electric feeder lines that have been rebuilt based on end-of-life replacements for asset condition with that of feeder lines that have not been rebuilt.

In another example, we account for the actual minutes of customer outage time that are avoided by installing remote operating devices on our feeder lines (feeder automation) that allow us to reduce the number of customers that are impacted by an outage event.

The Company, like all electric utilities, is upgrading its electric transmission system to meet new mandatory federal reliability standards. As part of this process, Avista uses mathematical models of its electric system to evaluate a range of operating scenarios that could result in a loss of service to our customers due to a transmission or substation outage event. We then develop investment strategies that would allow us to avoid the outage situations identified in the operations modeling, and to meet the applicable federal reliability standard. The value of the investment for reliability can be measured by comparing the statistical probability of an outage for customers with and without the mandatory investment.

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