Steve Rueckert Director of Standards TPL Discussion – PCC Steering Committee March 25, 2014

2 TPL-001-WECC-RBP-2.1 Disposition of WR3 –Does NERC TPL require Post Transient Analysis –Regional Variance (standard) or a Guideline Do Western stakeholders want a regional variance to NERC TPL identifying acceptable System Performance Impacts on other Systems

3 TPL-001-WECC-RBP-2.1, WR3 WR3. Reactive power resources, with a balance between static and dynamic characteristics, shall be planned and distributed throughout the interconnected transmission systems to ensure system performance as defined below: 3.1. For transfer paths, voltage stability is required with the pre- contingency path flow modeled at a minimum of 105% of the path rating for system normal conditions (Category A) and for single contingencies (Category B). For multiple contingencies (Category C), post- transient voltage stability is required with the pre- contingency transfer path flow modeled at a minimum of 102.5% of the path rating For load areas, voltage stability is required for the area modeled at a minimum of 105% of the reference load level for system normal conditions (Category A) and for single contingencies (Category B). For multiple contingencies (Category C), post- transient voltage stability is required with the area modeled at a minimum of 102.5% of the reference load level. For this criterion, the reference load level is the maximum established planned load limit for the area under study Specific requirements that exceed the minimums specified in 3.1 and 3.2 may be established, to be adhered to by others, provided that technical justification has been approved by WECC’s Planning Coordination Committee (PCC) R3 applies to internal WECC Member Systems as well as between Member Systems.

4 Is WECC WR3 covered by TPL R5. Each Transmission Planner and Planning Coordinator shall have criteria for acceptable System steady state voltage limits, post-Contingency voltage deviations, and the transient voltage response for its System. For transient voltage response, the criteria shall at a minimum, specify a low voltage level and a maximum length of time that transient voltages may remain below that level. [Violation Risk Factor: Medium] [Time Horizon: Long-term Planning] R6. Each Transmission Planner and Planning Coordinator shall define and document, within their Planning Assessment, the criteria or methodology used in the analysis to identify System instability for conditions such as Cascading, voltage instability, or uncontrolled islanding. [Violation Risk Factor: Medium] [Time Horizon: Long-term Planning]

5 Regional Variance or Guideline Regional Variance –Develop using WECC Standards Process for inclusion in TPL –Ensures consistency across the Region –Becomes mandatory –Harder to include existing approved or new exceptions

6 Regional Variance or Guideline Guideline –Developed by RS using existing requirements from TPL- 001-WECC-RBP-2.1 as a starting point –Could use WECC Standards Process for open and transparent communications –Would be approved by PCC –If most or all registered entities adopted the Guidelines it would still ensures consistency across the Region –Not mandatory unless adopted by applicable entities –Individual entities could include existing approved or new exceptions

7 Impacts on other systems Used to be covered by TPL-001-WECC- RBP-2.1, WR1 –RS recommended, and Ballot Pool approved, deletion of WR1 upon approval of the new TPL –Some WSC members and Planners in the West have questioned whether or not we want to retain this as a regional variance

Questions?