Eleanor Ewry Base Case Coordination Subgroup Chair Base Case Coordination Subgroup Update October 2016 WECC HQ

Agenda Review Annual Study Program & Scope of Work 2017 Annual Survey Interchange Targets for WECC Basecases Purpose Historical vs Modeled Flows

SRWG Charter SRWG Tasks – Compile near- and long-term interconnection-wide models Prepare specifications for system configurations, scenarios, and operating conditions of the models. Propose and coordinate schedules for data compilation, distribution, review, and approval of the models. Monitor data submission for appropriateness and coordinate data issues as required.

SRWG Charter SRWG Tasks – Assess the quality of interconnection-wide models compiled. Develop metrics and monitor results. Work jointly with Modeling & Validation Work Group (MVWG) to compare compiled interconnection-wide models to actual system conditions and events from an interconnection-side perspective.

SRWG Charter Base Case Coordination Subgroup Tasks – Develop a compilation schedule for interconnection-wide models. Maintain procedures for assessing the quality of interconnection-wide models.

Annual Study Program SOW Annual Study Program consists of two activities as outlined in the Scope of Work Development of steady-state and dynamic basecase models Annual assessment of Transmission System performance N-1 contingency analysis for all lines Transient stability analysis for a pre-determined list of disturbances Documented in WECC Annual Study Report

Annual Study Program SOW Typical annual base case compilation schedule includes the following base cases: Five operating cases Heavy and light summer, heavy and light winter, and heavy spring case one year out One five-year summer planning case One five-year winter planning case One 10-year planning case (alternate winter and summer) Three scenario cases

Annual Survey Three scenario cases – one case will “stress” the following in a five-year rotation: i. Idaho/Montana/Wyoming ii. Colorado/Utah/Northern Nevada iii. Pacific NW and Canada including the California-Oregon Intertie iv. California (between Path 15 and West of Colorado River) v. Southern Nevada/Arizona/New Mexico Request for scenario cases will be sent to TSS Representatives in December. Increased focus on case description sheets

Annual Study Program SOW Annual Study Program consists of two activities as outlined in the Scope of Work Development of steady-state and dynamic basecase models Annual assessment of Transmission System performance N-1 contingency analysis for all lines Transient stability analysis for a pre-determined list of disturbances WECC Annual Study Report

Annual Study Program - Disturbances One disturbance run for each region of WECC: ST-0 No Disturbances A ST-DSW-1 Palo Verde Generating Station Outage Double Unit Outage D ST-NWC-1 Chief Joe Brake Insertion ST-CAL-S Colorado River - Red Bluff #1 & 2 C ST-CAL-N Metcalf - Moss Landing & Tesla - Metcalf 500 kV ST-IMW-1 N-1: Brownlee - Hells Canyon 230 kV Line B ST-UCN-1 N-2: Daniel Park - Comanche #1 & #2 345 kV Lines SLG

Annual Study Program SOW Updates are needed to the Scope of Work Remove references to NERC Standards and Functional Entities Correct contingency category for Standard Disturbances Update contents of the annual report

Interchange Targets Targets are not being consistently met in the basecases How are these targets being used? Are they useful? Can they be improved?

Interchange Targets WECC provided actual interchange data for the following time periods for 2014 and 2015: Heavy summer: June – August 1500 - 1700 hours Light summer: June – August 0400 - 0600 hours Heavy spring: March – May 1600 - 2000 hours Heavy winter: December – February 1800 - 2000 hours Light winter: December – February 0300 - 0500 hours

Interchange Targets Example: Reaching the target, but well above historical Path flows.

Interchange Targets Example: Not reaching target, but Path flows are reasonable.

Interchange Targets Example: Reasonable targets and flows

Questions?