A Novel Criterion for Online Prediction of Voltage Collapse

The trend towards decentralised operation in power systems is getting stronger, pushed by the factors such as market forces and increasing requirement for the use of renewable energy. In this paper, a new criterion for online predicting of transient voltage collapse in power systems is described. This criterion uses the changing ratio of difference between the reactive power generators and reactive power absorbers to predict voltage collapse. The performance of this criterion is studied and tested for a variety of operating conditions in a modified 4-machine power system that connects with infinite bus. The simulation results indicate that the proposed criterion can predict its proximity to voltage collapse by only using the information that can be gained online. This criterion is computationally efficient and suitable for real time prediction of voltage collapse