Test of Significance and Fiducial Limit of Voltage Stability Index for Indian 205 Bus System

Voltage delivery stability is frequently used to analyze power delivery systems. Under stressed condition, these indices denote the flexibility of voltage stability condition and predict the voltage collapse phenomenon by weak area clustering. The prediction of voltage collapse is very important for the smooth operation of power system, so that situation of voltage collapse could be avoided. For small transmission system, these indices work satisfactorily. In the present work, a large transmission system equivalent to 205 bus Indian transmission system has been examined. The Fast Voltage Stability Index (FVSI) proposed has been applying to test the system under consideration. Various aspects of power delivery system for example voltage profile, maximum load-ability limit, weakest bus and the different weak area clustering have been examined. Although the FVSI values obtained in the test result are capable of identifying the weak buses of the system, yet they vary in a non-linear manner i.e. for increasing values of load, the FVSI values first increase and then decrease.