Maintaining Voltage Stability by Optimal Locating and Sizing by Combined Evolutionary Algorithm

This paper proposes an algorithm for optimal placement of FACTS devices in transmission line to maintain the power system voltage stability and optimal sizing of the FACTS device. The aim of this paper is to improve voltage stability and reduce the total power losses. Here, voltage stability means no variation in the voltages of each bus beyond its boundaries and system stability is the ability of power system to recover the initial steady state after any deviation of the system’s operation. For this work, we presented the combined evolutionary algorithm i.e. Cuckoo Search (CS) and Evolutionary Programming (EP) algorithm to find the optimal location and optimal capacity to be placed at the location for FACTS device. Here, CS is used to find the optimal location of UPFC to be placed in the transmission line and EP algorithm is needed to compute the optimal capacity of corresponding FACTS device at the location. The capacity of the UPFC at that location depends on voltage deviation of the selected bus from slack bus, power loss, voltage instability and the insufficient reactive power in the power system. The presented technique helps in the optimal placement and optimal capacity of the FACTS device to be placed. Thus, the proposed method helps in the improvement of reactive power to meet the voltage stability and the reduction of the total power losses. A simulation on IEEE 30-bus reliability test system (RTS) justifies the reliability of the proposed method for real system applications concerning voltage stability improvement in power system.