Robustness Aspects in Real-Time Energy Management Power Network Applications through State Estimator

04/15/2019, 11:00AM-12:00PM, Oak Room, University Union, California State University, Sacramento

SPEAKERS: Veera (Raju) Vinnakota,  CAISO, Sirajul Chowdhury, CAISO


Ever since Power Markets have been functional in United States and elsewhere in the industry throughout the World State Estimator (SE), an Energy Management System (EMS) Application, had turned into an industry-wide subject for its critical role both for running Electric Power Markets and for Grid Reliability operations in real time. For SE to provide a steady-state power network solution in terms of complex voltages at electrical nodes on the grid in real time, two main inputs are 1. The network that is modeled  and 2. Telemetered real time measurements such as Power flows, voltages and transformer tap settings, equipment CB / switch status. A converged solution provides state of the power network in real time which is essential for other real time applications to provide guidance to the Control room operators so as to be prepared ahead of time or to optimize market operation for real time and Day-Ahead operations.

While formulation of State Estimator optimization problem being non-linear in nature, providing a converged solution is the first level of uncertainty, real time or otherwise.  From the point of source where real time telemetered data is originated on the Power grid, such as at sub-stations and generating station, to the computer system on which SE runs in a Control Center, several components working in tandem coupled with uncertainty in availability of measurements to SE in real time pose a great challenge in supporting a reliable SE solution.  Nature of uncertainties in real time include missing a few measurements due to communication errors, loss of a bunch of measurements due to telemetry loss with RTUs, loss of data links impacting real time measurement from several RTUs,  loss of complete data from the whole Balancing Authority participating in Markets and loss of real time data from several BAs due to loss of one or more data links and lastly the loss of computers which serve the data links. Ensuring Market Systems to continue running even during uncertainties in real time measurements, is a challenge and is dealt in this talk.

Additionally,  two more aspects which impact SE availability are the tuning efforts which are put in by the support team and the support structure put in place in the organization to have SE get back to solving when it starts failing to provide a converged solution and are discussed.

Veera (Raju) Vinnakota received his Ph.D. in Electrical Engineering (Power) from Indian Institute of Technology Madras in 1994. He has over 30 years of professional experience out of which over 20 years are in USA, Canada and Belgium in the field of Electric Power Control focusing on Energy Management System ( EMS) Network applications. Raju was an invited professor for about 2 years in establishing a Control Center Laboratory for University of  Liege, Belgium. Raju was with BC Hydro, Canada over 12 years supporting EMS network applications for Control room.  Since 2013 Raju has been working for California ISO engaged in Network Applications’ support for power grid reliability and energy markets. Raju has over 45 research and development publications / presentations in the field of  electric power monitoring and control for real time use, an active contributor in various ways to IEEE Power Engineering Society such as technical presentations, publishing papers, book chapters, panelist, panel chair, chapter chair. His main areas of interest are Power System Security Monitoring and Control for Grid reliability and Energy Markets. Raju is a Senior Member of IEEE, registered Professional Engineer in the province of British Columbia, Canada and is a practicing engineer.


Sirajul Chowdhury received his BSEE from the University of Oklahoma in 1990.  He has been working at California ISO as Senior Advisor in EMS Information Technology division. He has been primary lead for Automatic Generation Control and Operator Training Simulator (OTS) including Market Simulation. Sirajul has been the member of many leading teams on the CAISO initiatives energy imbalance market services, reliability coordinator service, integration of renewable energy services, Electric Vehicles into Grid, Demand response implementation. His recent work at ISO involves designing new control logic for demand response, Electric Vehicle into Grid(V2G) project and storage model for regulation. Sirajul has been a leading contributor to various innovative pilot projects related to renewable integration He is a major contributor to the national award for Solar regulation project by National Association of Regulatory Utility Commissioners (NARUC). Sirajul represents Cal ISO in the Performance Work Group (PWG) involving NERC and WECC Standards.

Before joining Cal ISO in 1999, Sirajul worked at Landis & Gyr Energy Management Systems supplier for about 10 years, delivering AGC software and EMS around the globe.

Sirajul’s interests are in real time systems involving  control system design, energy markets, Automatic Generation Control(AGC), Training simulation including Marketing simulation, Load forecast, Reliability Compliance.