Utilizing Microprocessor Based Relays as Predictive Tools to Mitigate Voltage Instability Problems That Stem from the Fast Voltage Collapse and Delayed Voltage Recovery Phenomena

Abstract

Fast voltage collapse and delayed voltage recovery are a growing concern in the power industry. Although there are several well-known methods to combat fast voltage collapse and delayed voltage recovery, additional methods can bring further stability to the power system. The powerful microprocessor based distribution relay, Schweitzer Engineering Laboratories-451 (SEL-451), is utilized here to counteract voltage instability that results from excessive induction motor loads on the power system. SEL-451 is used as a predictive tool to predict future voltage levels. These future voltage levels are then used by the relay to decide if undervoltage load shedding is needed.