FIREFLY ALGORITHM BASED OPTIMAL POWER FLOW FOR SIZING OF THYRISTOR CONTROLLED SERIES CAPACITOR TO ENHANCE LINE BASED VOLTAGE STABILITY

Reactive Power compensation in transmission systems improves the stability of the system and also reduces the transmission line losses. Installing Flexible AC Transmission System (FACTS) devices are the effective means to control reactive power compensation. However, due to the high cost of FACTS devices, it is important to optimally place these controllers in the system. Out of the different FACTS devices, TCSC is the most effective device for series compensation. This paper presents a Sensitivity analysis based Complex Power Flow Sensitivity Index (CPSI) proposed for placing the TCSC at an appropriate location. Once the location to install TCSC is identified, the optimal sizing of TCSC is determined through Firefly Algorithm based multi-criterion objective function comprising of four objectives minimize total real power loss, minimize total voltage magnitude deviations, minimize the fuel cost of total real power generation and minimize the branch loading to obtain the optimal power flow. Simulations have been carried out in MATLAB environment for the IEEE 14-bus system and the IEEE 30-bus system. The results have been taken for Firefly Algorithm based Optimal Power Flow without and with TCSC. The results obtained with Firefly Algorithm were compared with Genetic Algorithm (GA). The results we have obtained indicate that FA is an easy to use and better optimization technique compared with GA.