The generating unit contingency shutdown accidents in the power systems are increasing around the world, which can bring huge power generation shortage suddenly and result in severe system frequency fluctuations. In this scenario, the secure and stable operation of the power system cannot be guaranteed only by traditional generating units, due to the huge generating unit inertia and insufficient operating reserve capacities. Faced with this challenge, the progressed information and communication technologies make demand response (DR) become feasible to provide contingency reserve for the power system by controlling the power consumption of demand side resources (DSRs). This paper develops the power system model considering DR, where the closed-loop and open-loop transfer functions are obtained to analyze the dynamic performance of the power system under unit contingency shutdown accidents. On this basis, the stability margins of the power system are calculated by Bode plots to illustrate that the power system can become more stable as a result of DR. The proposed models and methods are verified by the numerical studies.
Keywords power system model, dynamic performance analysis, unit contingency shutdown accident, demand response