A NEW STATE-SPACE MODEL OF THREE-PHASE POWER SYSTEMS: APPLICATION IN POSITIVE AND NEGATIVE SEQUENCE ESTIMATION

Abstract

Power quality is drawing much concern recently.  In order for monitor power quality of power systems in real time, numerous modelling of power signals (voltages and/or currents) has been proposed to estimate the parameters of the systems. Unfortunately, most of the models fail to completely represent most important characteristics of the signals of a three-phase power system. This paper proposes a new state-space model that can well represent a real three-phase power system by taking into account the unbalance conditions and harmonic distortion of a three-phase power system. The model associated with Extended Kalman Filter is then applied to estimate the positive and negative sequences of the fundamental component. The simulation results show that the proposed approach can accurately estimate the sequences of a three-phase power system in real time.