EPG Projects

Cluster Analyses of Reactive Zones

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ERCOT has undergone significant changes in the last few years. ERCOT invested in analyzing the new facilities and update the ERCOT Control Room Awareness of Reactive Zones across the system. The purpose of this project was:

  1. Identify Zones with reactive deficiencies
  2. Monitor Reactive Zones in real-time
  3. Detection of extended low voltage issues (< 345kV) and avoid possible voltage collapse
The project used State Estimator Data and PMU data.


  1. The study identified 13 Reactive Zones within ERCOT grid using SE and PMU data
  2. 106 extended low voltage events within Reactive Zones
  3. Bus Clusters (345kV & 138kV) with high correlation coefficient within each event to show the boundary stations for each reactive zone
  4. Cut planes to suggest 345kV transmission lines to be monitored in real-time for each of the 13 reactive zones
  5. Developed criteria's for ERCOT to establish a reasonable number of reactive zones for additional awareness in the Control Room using EMS and RTDMS monitoring systems
  6. Identified Potential PMU Locations for Future Monitoring for Reactive zones

About EPG

Electric Power Group, LLC (EPG) has been pioneering the development and deployment of synchro-phasor technologies since 2000. Our principals have extensive experience in running and managing utility grids, investigating root causes of major blackouts (WECC 1996, EI 2003), and leveraging this deep domain knowledge to develop industry leading synchrophasor technology applications for wide area real time monitoring, visualization and situational awareness.

The EPG team has extensive hands-on experience with synchrophasor standards, networks, system architecture, deployments and performance analysis through work at EPG for leading ISO's and utilities including PJM, NYISO, ERCOT, CAISO, MISO, BPA, TVA, SCE, AEP, LADWP, SRP, Duke, Dominion, NYPA and other companies.