Optimal Capacitor Placement based Improved Reliability Assessment of a Distribution System

Abstract

This paper focuses to reduce the real power losses in a real-time radial distribution system by performing Optimal Capacitor Placement (OCP) using Genetic Algorithm (GA), thereby enhancing the reliability of the entire system. Reliability analysis on Amrita power house II, Amrita University, Ettimadai campus, Coimbatore operating at 22kV/415V system is carried out using ETAP software. System status subjected to different failures as case studies are considered. System performance is analyzed using Adaptive Newton Raphson method. Suggestions for suitable placement of capacitor banks with optimal size and cost is proposed by performing OCP using GA. Comparison of the results of reliability analysis is done with and without capacitor placement. Optimal capacitor placement helps in achieving optimal cost with suitable size and location of the capacitor bank, which is evident from the report obtained from the ETAP software. Out of load bus and breaker failure condition, the predominant remark was the considerable increase in real power loss of the overall system. Thus, the optimal capacitor placement found to be the most suitable solution for reduction of real power losses in a radial distribution system. Results of analysis illustrates that the increased value of sustained interruption system indices like System Average Interruption Frequency Index (SAIFI), System Average Interruption Duration Index (SAIDI) and preferably Customer Average Interruption Duration Index (CAIDI) indicates that the system is highly unreliable without capacitors. The results obtained after capacitor placement indicates reduction in real power losses and thus decrease of reliability indices value. The expected energy that is not getting supplied to the consumer can be estimated and the cost incurred for loss can be reduced with the reliability assessment. Thus long and short term planning could be carried out. Improvements can be done by including more system reliability assessment indices. Total cost incurred due to unreliable condition of the system can be found out. This work would allow further extension by introducing FACTS devices for reliability enhancement.