Optimum placement of shunt capacitors in a radial distribution system for substation power factor improvement using fuzzy GA method

• A novel sensitivity index is proposed for finding locations of shunt capacitors.
• Fuzzy multiobjective function is formed and maximized using GA.
• Substation reactive current is minimized for power factor improvement.
• Optimum values of fixed and switched capacitors are obtained.
• Net annual saving is also computed.

In this work a combination of fuzzy multiobjective and genetic algorithm (GA) based approach is proposed for optimal shunt capacitor placement to improve the substation power factor near unity, reduce the real power loss, and reduce the burden on the substation and to improve the voltage profile of the distribution network. In order to obtain best nodes for capacitor placement, a sensitivity index based on real power loss reduction and voltage profile improvement is considered. In the present work, an attempt is made to make reactive current component drawn by distribution network through substation is nearly zero such that power factor at the substation will be near unity. A fuzzy multiobjective function is formed considering substation reactive current component reduction, real power loss reduction, branch current constraint limit, minimum and maximum voltage limit satisfaction. The fuzzy multiobjective function is maximized using GA for obtaining the optimum sizing of fixed and switched shunt capacitors. Simulation results are shown to demonstrate the advantage of the proposed method compared to optimal shunt capacitor placement based on annual energy savings method.