Comparison between sensitivity method and singular participation factor method for weak buses ranking of static voltage stability

The sensitivity method and the singular participation factor method in evaluating weak buses ranking of static voltage stability were compared with each other. The reason why the weak buses ranking using both sensitivity method and singular participation factor method based on power flow Jacobian matrix and reduced Jacobian matrix are the same was analysed when the operating point of a power system is close to the critical boundary of its static voltage stability region. And the simulation shows that the weak buses rankings based on sensitivity method and singular participation factor method may be different when the operating point of a power system is not close to the critical boundary of its static voltage stability region, but from the viewpoint of improving voltage stability, the result shows that the difference between sensitivity method and singular participation factor method is minor. Additionally, the computational burden of the latter is much less than that of the former. Therefore from the viewpoint of the practice of weak buses ranking, sensitivity method is preferred, and sensitivity of load buses obtained from both the reduced Jacobian matrix which only consists of load buses and power flow Jacobian matrix are the same.