Power system transient instability detection algorithm based on real time measurement

In this paper, a method is proposed for fast and accurate online detection of transient instability based on real-time measurement. The cluster of critical machines is determined and refreshed at each time. Determination of the irrevocable loss of synchronism is made based on the geometric characteristic of critical machines trajectory. Unlike the previous extended equal-area criterion method, it is unnecessary to calculate the unstable equilibrium point. The speed of algorithm is fast enough to prevent system from transient instability. Simulations are carried out on the IEEE 50 generator test system and a real power system. The results indicate that the proposed method has the features of reliability and effectiveness in identifying the loss of synchronism with inter-area mode.