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

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

3. 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.

4. 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.

5. 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.

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

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

13. Interchange Targets
WECC provided actual interchange data for the following time periods for 2014 and 2015:
Heavy summer: June – August hours
Light summer: June – August hours
Heavy spring: March – May hours
Heavy winter: December – February hours
Light winter: December – February hours

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

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

16. Interchange Targets
Example: Reasonable targets and flows

17. Questions?