Performance Evaluation of Voltage Stability Indices for a Static Voltage Collapse Prediction

The frequent happenings of voltage collapse in a power system in the recent time as a result of continuous increase in power demand has been a concern and has posed a great threat to power system utilities. In this paper, to predict a voltage collapse bus, an approach named critical bus voltage stability index (CBVSI) which is based on the voltage deviation of the load bus of the system, the maximum loadability and the total number of step size taken to reach the minimum permissible load of each load bus is suggested. The bus voltage deviation index (BVDI) of each load bus is first computed at each reactive power load variation. The suggested voltage stability index of each load bus is thereafter found. A comparative assessment of the suggested CBVSI with the conventional fast voltage stability index (FVSI) is also done. Results of the simulation obtained show that the method based on CBVSI could be of great significance and serve as an alternative tool for power system engineers in the operation and planning of the system.