On-line load characterization by sequential peeling

Load restoration dynamics may cause a voltage stability problem to the power system. The system voltage control schemes are based on the off-line models of the system loads. However, in a real-time control, the control effect should be improved if load parameters can be real-time identified. This paper develops a method that is based on the on-line measured load bus voltage and current phasors during a disturbance. Load is considered as a combination of induction motor, constant impedance, and constant power loads. The change in the load active power due to the disturbance is used to identify the active power of the load different components in a peeling process. Then the induction motor reactive power is estimated using signal processing on the random changes in the load total power. The other components of the load reactive power are then estimated using the disturbance data. The proposed method is confirmed by simulation.