An expert system as a system operator's aid in real-time solutions of the optimal power flow

Abstract Optimal power flow (OPF) is plagued with numerous problems in on-line implementations. Real-time solutions of the OPF imply the minimization of instantaneous costs of active power generation on an operating power system subject to preventing violations of operating constraints. An expert system (ES) is presented which is used in combination with a transmission-constrained economic dispatch (ED) to provide real-time security. The strategy for combining the ES with an ED solution consists of running an ED which identifies the constraint violations in bus voltage magnitudes and in line flows, if any, as well as the set of optimal generations. The expert system then determines the best possible control measure using rules on voltage and line flow control. The goal of the expert system is to expeditiously remediate voltage and branch overload problems. Network sensitivities of voltage magnitudes and line flows with respect to different devices play important roles in the completion of the strategy. Several test cases are shown where the strategy is tested on a modified IEEE 24-bus reliability test system.