Multiple Optimal Solutions and Sag Occurrence Index Based Placement of Voltage Sag Monitors

This study presents optimal placement of voltage sag monitors based on new Sag Occurrence Index (SOI) which ensures observability even in case of monitor failure or line outages. Multiple solutions for optimal placement of voltage sag monitors for voltage sag detection have been obtained by genetic algorithm approach such that observability of the whole system is guaranteed. A new Sag Occurrence Index (SOI) is proposed to obtain the severity of voltage sag at all the buses in the system. To obtain the best monitor arrangement in the system, the sum of SOI for each optimal combination is determined. IEEE 24-bus Reliability Test System (RTS) and IEEE 57-bus system were used to demonstrate the effectiveness of the proposed method. The details of implementation and simulation results are also presented.