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

2017-2018 California ISO Annual Transmission Plan California ISO performs Transmission Plans annually 2017-2018 Transmission Plan is for the years 2019-2027 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)

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

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

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

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

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 1 1200 MW, Phase 2 1221 MW Total PG&E behind the meter DG 840 MW Loss of behind the meter DG: Phase 1 313 MW, Phase 2 314 MW

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

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

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

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?