20180208PAC to Staff Meridian RAS - Assessment.docx

PacifiCorp Main Grid Planning
PRC-(012 through 014)-WECC-CRT2
Attachment B RAS Assessment
RAS Name
Meridian Area Load Tripping
Reporting Party
PacifiCorp
Group Conducting Assessment
PacifiCorp Main Grid Planning
Assessment Date
12/31/14
Review the scheme purpose and impact to ensure proper classification, is it (still) necessary, does it serve the intended purposes, and does it continue to meet current performance requirements.
The Meridian Area Load Tripping Scheme is designed to prevent voltage criteria violations in southern Oregon during heavy load if both of the 500 kV lines into Meridian are out of service or if both of the 500/230 kV transformers at Meridian are out of service.
The Meridian Area Load Tripping Scheme is currently classified as a Local Area Protection Scheme; however the scheme may be reclassified as a Safety Net. The scheme is designed to protect the Meridian 230 kV transmission system following the loss of both 500 kV sources into Meridian or both of the Meridian 500/230 kV transformers. There is not a credible N-2 contingency involving these system elements, and an operating scheme is in place to sectionalize the Meridian 230 kV system to prevent performance violations for an N-1-1. With these operating procedures, the scheme benefits are limited to Category D contingencies.
Study results indicate that the scheme can be an effective alternative to 230 kV sectionalizing for N-1-1 loss of the 500 kV sources into Meridian. There are no post-contingency performance violations following RAS action or the 230 kV sectionalizing.
Study Years
2011
System Conditions
Heavy summer and heavy winter loads.
Contingencies analyzed
(select what applies)
N-1
N-1-1
N-2
Extreme
N-1-1
Date when the technical studies were completed
2010
Does the RAS comply with NERC standards and WECC Criteria?
Yes
Discuss any coordination problems found between this RAS and other protection and control systems during this (most recent) assessment.
No coordination issues are anticipated with this scheme.
Provide a Corrective Action Plan if this RAS was found to be non-compliant or had coordination problems during this (most recent) assessment (should be NA for owner’s initial assessment).
N/A
Additional Notes