Load Modeling for Dynamic Studies ROS Meeting – July 2005 ERCOT System Planning

2005ERCOT System Planning2 Dynamics Studies - Time Domain

2005ERCOT System Planning3 Load Types for dynamics studies Lm Sm Dl R.. C Pl + j Ql

2005ERCOT System Planning4 Load Dynamics Response Voltage In Per Unit * With permission from AMSC

2005ERCOT System Planning5 Market - Load Profile Types Residential Low Winter Ratio Residential High Winter Ratio Business Non-Demand Business Low Load Factor Business Medium Load Factor Business High Load Factor Business IDR Non-Metered Lighting (street lights, security lights, etc.) Non-Metered Flat (traffic signals, communication equipment, etc.)

2005ERCOT System Planning6 Load Modeling Objectives Represent typical load customers with enough detail to include significant dynamics Easy to implement at the transmission level (by area, zone or other group) Time-of-the-day block adjustment provided Seasonal adjustment provided Temperature adjustment provided

Deriving Load Models from Measurement EPRI Load Modeling Phase II DFR PMU PQ Monitors Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved.

General Approaches Two approaches to identify load composition and the structure of the load models: –Component based approach (EPRI LOADSYN) –Measurement based approach This project will use the measured response of the system experiencing natural disturbances.

Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Overall Program Scope Phase 1 Phase 1 Provide a systematic methodology and procedures for load modeling and verification based on available natural system disturbance data To develop a prototype program for advanced load modeling and parameter derivation Phase 2 Phase 2 Load model development and validation, method refinement and modifications, software development and enhancements, address key issues, and system integration

2005ERCOT System Planning10 Conclusions Request ROS endorsement and support. Encourage ERCOT transmission owners to participate in this project, either as direct participants or as host sites for load dynamics measurements. Desirables locations for hosting measurement sites: West TX, Dallas, Austin, Corpus, Valley, Houston Better models in engineering studies will enhance the fidelity of the results.