Voltage indices improvement using UPFC based on specific coefficients algorithm

Improvement in power system performance can be obtained using flexible AC transmission systems (FACTS). These devices can improve system various highly important parameters; hence the maximum potential of the utilization of the transmission system can be achieved. Unified power flow controller (UPFC) is one of the FACTS devices with capability of the simultaneous control of the bus voltage and real and reactive power flow in transmission systems independently; but because of excessive cost, the number and the location of these devices should be indicated optimally. This paper proposes a method of optimization of UPFC allocation based on specific coefficients algorithm (SCA) to specify the number, location and input values by minimizing the voltage indices of system buses. The proposed SCA noticeably improves the accuracy and performance of traditionally used optimization processes especially in large scale networks. This method is applied to the 118-bus IEEE standard system. The results of ordinary and new optimization algorithm have shown the great improvement in optimization process using SCA.