Among the challenges in securely operating a large, interconnected, bulk electricity system is modeling appropriate real-time system limitations for the transmission of electricity. To do this, the IESO employs the model created by NERC, which includes more than 63,000 nodes (Ontario accounts for about 5 per cent of the total). The model is very accurate for planning and operational studies, but the computer time required to run it is far too long to be useful in real-time operations.
Two IESO engineers have developed a solution to greatly reduce the calculation time required to accurately model system limits for Ontario’s power system. At the 25th annual IEEE Canada conference, Dr. Mahmoud Matar presented “Dynamic Model Reduction Using Integrated PSS/E and MATLAB,” the paper he wrote with colleague Dr. Nilkamal Fernandopulle about the work they have done with the IESO’s System Performance and Models team.
Being able to compute system limits rapidly, while staying true to the full NERC model, is an important milestone in the IESO’s Online Limit Derivation Program. One of the key aims of this program is to introduce calculation of system operating limits as close as practical to the time of their consumption, using computer models and tools. Benefits of this multi-year program, some of which are already being realized, include:
• cost savings to the market through reduction of constraints on generation dispatch and outage planning,
• the ability to manage substantial planned system infrastructure changes,
• increased ability to respond to unplanned system events, and
• increased security of operation.