Risk-based voltage stability monitoring and preventive control using wide area monitoring system

nowadays, power system tends to be operated in heavily stressed load, which can cause voltage stability problem. Moreover, occurrence probability of contingency is increasing due to growth of power system size and complexity. This paper proposes a new preventive control scheme based on voltage stability and security monitoring by means of wide area monitoring systems (WAMS). The proposed control scheme ensures voltage stability under major N-1 line contingencies, which are selected from all possible N-1 contingencies considering their occurrence probability and/or causing load curtailment. Some cases based on IEEE 57-bus test system are used to demonstrate the effectiveness of the proposed method. The demonstration results show that the proposed method can provide important contribution in improving voltage stability and security performance.