Estimation of equivalent models for emergency state control of interconnected power-systems based on multistage recursive least-squares identification

Multistage recursive least-squares (MRLS) identification of the equivalent two-machine model of interconnected electric power systems in emergency state is presented in the paper. Requiring only locally measured variables, the MRLS identification allows the estimation of the reactance of interties and the parameters of the equivalent two-machine model, including inertia constant, damping coefficient, internal voltage, relative rotor angle and relative speed. In other words, on-line estimation of the equilibrium point and the system states of interconnected electric power systems in emergency state is possible. The estimated model can be utilised in various emergency control strategies or other applications Studies demonstrate the effectiveness of the MRLS identification technique