Voltage Profile Improvement Using Unified Power Flow Controller via Artificial Immune System

Abstract

Voltage profile is one of the concerned issues in power system studies. This is due to the fact that voltage profile decay can be experienced by the system when system is subjected to load increment or disturbances. Unscheduled increment of load variation in a power transmission system has driven the system to be stressful, leading to potential cascading trip on the entire system. Thus, close monitoring of load variation in a power network can help to avoid the system operating close to its maximum capacity. In addressing this phenomenon, special scheme can be implemented such as reactive power compensation; installation of flexible AC transmission system (FACTs) devices and capacitor placement. Identification of the optimal value of compensating capacitors required proper optimization technique; able to search the optimal solution with less computation time. This paper presents the voltage profile improvement using unified power flow controller (UPFC) approach based on artificial immune system (AIS). In this study, AIS optimization engine is developed for voltage profile improvement which utilized UPFCs as the control variables embedded into the system's data. Implementation on the IEEE Reliability Test System (RTS); considering several variations in the AIS properties indicated AIS potential in solving voltage control problems. Verification through comparison of results using evolutionary programming utilizing the similar system data indicated that AIS is feasible to solve voltage depreciation problems.