Linearized local voltage stability index considering induction motor load

Wide-area voltage monitoring and control system needs a fast, accurate index. This paper addresses a linearized motor voltage stability index(LMVSI) considering induction motor load characteristics. The proposed index has two advantages: (1) no need of computing the network equivalents, this will improve the accuracy and computation speed of the index; (2) full linearity, so can be used to predict the load margin. NewEngland 39-bus test system and a 474-bus system are used to test the linearity degree, the computation speed of the index and the real monitoring results of the developed real-time voltage stablity monitoring system, respectively. Test results indicate that the proposed LMVSI is computationally light, fairly linear and highly accurate.