Voltage stability estimation and adaptive load shedding control of the induction motor in power systems

Induction motor has great influence on transient voltage stability. System failure and operation may lead to instability of the induction motor and finally result in voltage collapses. This paper simplifies the induction motor model by ignoring the electromagnetic transient process and employs equivalent Thevenin circuit to simply the external power grid of the induction motor. Moreover, this paper estimates transient voltage stability by quantitive calculation on the critical slip of the induction motor, thus obtaining the load shedding proportion adaptively by calculating the mismatch torque when the induction motor is estimated to be locked. Simulations on the modified IEEE 3-bus system have shown that the critical slip based on quantitive calculation is much close to the practical one, and the load shedding proportion based on calculation is approximate to the minimum load shedding proportion for guaranteeing transient voltage stability.