Voltage Stability Analysis by Simulated Annealing Algorithm

Power system is facing new challenges as the present system is subjected to severely stressed conditions. In order to avoid systemblackouts, power system is to be analyzed in view of voltage stability for a wide range ofsystem conditions.In voltage stability analysis, the main objective is to identify the system maximumloadability limit and causes of voltage instability.In this study, critical bus values in a power system are determined by using Simulated Annealing (SA) algorithm.Firstly, load value of the selected load bus is augmented step-by-step and load flow analysis is done for each case. This process iscontinued till there is no solution and in this way the critical bus values that are limit values of voltage stability are obtained.This study demonstrates the use of minimum singular value method order to determine the maximum loadability in power system.The reactive power at a particular bus is increaseduntil it reaches theinstability point at bifurcation. At this instability point, the connected load loadability. Secondly, by using SA algorithm, maximum loadability limit are directly determined without increasing the load of the selected load bus. The results show that the critical values can be easily determined using SA.This technique is tested on the IEEE-57 bus system.