1. WECC Load Modeling and Validation Group Meeting
Transient stability study results with the Phase 2 of composite load model
Irina Green
California ISO
WECC Load Modeling and Validation Group Meeting
October 2017

2. 2017-2018 California ISO Annual Transmission Plan
California ISO performs Transmission Plans annually
Transmission Plan is for the years
Various cases and system conditions are studied including sensitivity cases with high renewable generation
Dynamic stability studies is a part of the Transmission Planning Process
In this year’s Transmission Plan, the new WECC TPL criteria that includes transient voltage recover was used
Studies were performed in assumptions of the single phase air-conditioners stalling disabled (Phase 1), as well as enabled (Phase 2)

3. Composite Load Model
When voltage is below specified values, the model trips fractions of each motor, electronic and static load
The fractions of load that are tripped and voltages at which they are tripped are specified by the user
Distributed generation was assumed having unity power factor
DG also have settings at which voltage and frequency they may be tripped or reconnected

4. WECC Transmission System Planning Performance Criteria TPL-001-WECC-CRT-3

5. Dynamic Stability Plots of Bus Voltages. 2019 Summer Peak
Dynamic Stability Plots of Bus Voltages Summer Peak. Tesla-Los Banos 500 kV Outage
Stalling of single-phase A/C disabled
Stalling of single-phase A/C enabled

6. Dynamic Stability Plots of Bus Loads. 2019 Summer Peak
Dynamic Stability Plots of Bus Loads Summer Peak. Tesla-Los Banos 500 kV Outage
Stalling of single-phase A/C disabled
Stalling of single-phase A/C enabled

7. Load and Distributed Generation Loss, 2019 Summer Peak, Tesla-Los Banos 500 kV outage
Total PG&E composite load 19,018 MW
Loss of composite load: Phase MW, Phase MW
Total PG&E behind the meter DG 840 MW
Loss of behind the meter DG: Phase MW, Phase MW

8. Buses with the Highest Load Loss (Ames 115) and Highest DG Loss (Hicks 230)
Frequency, >60 HZ – load loss is higher than generation loss
Voltage

9. Buses with the Highest Load Loss (Ames 115) and Highest DG Loss (Hicks 230)
Behind the meter PV
Composite load

10. Transient Voltage Recovery Criteria Violations
3Phase fault, outage Vac Dix-Tesla 500 kV, bus Plainfield 60 kV radially connected to Vaca Dixon
No violations without single-phase A/C staling
With single-phase A/C stalling violations on the ends of the feeders and on one 60 kV bus
No criteria violations on the BES

11. Conclusions
Significant difference between the study results with Phase 1 and Phase 2 composite load model
Need more work on the composite load model and parameters
Need clarification on the transient voltage recovery criteria
QUESTIONS? COMMENTS?