Derivation of an equivalent circuit for real‐time security assessment

Abstract

More and more system operators are interested in calculating transfer capability in real time using real-time power flow models generated from the energy management system (EMS). However, comparing with off-line study models, EMS models usually cover a limited portion of the interconnected system. It is not practical to extend the EMS model in order to capture the impact of the external systems and as such using an equivalent network becomes necessary for this purpose. Equivalent circuits can be derived from the off-line models for certain pre-determined operating conditions. Such fixed equivalent models may produce invalid results under various real-time operating conditions. Hence, it is necessary to derive an equivalent circuit model that is adaptive to the available real-time information. This study presents a new method of creating an equivalent circuit model based on the measured boundary station parameters such as voltages and power flows. Simulation studies show that such derived equivalent circuit models provide solutions with adequate accuracy in comparison with detailed off-line system model.