Development and real-time implementation of an under voltage load shedding scheme using a real-time digital simulator

Abstract

Generation, transmission, and distribution of electric power systems are extremely important to our modern society. It is critical to keep the power grid stable and reliable at all times. Individual power system reliability needs to be enforced to avoid a voltage drop due to contingencies such as a loss of generation or a sudden increase in a load demand. Voltage changes for a given increase in the load demand can lead to voltage instability conditions. The main factor causing instability is the inability of the power systems to meet the demand of the reactive power. This subject has been a concern over the last two decades and a lot of research work has been done in the area of voltage stability and control. Under-voltage load shedding schemes are commonly implemented as an emergency measure in cases where the voltage conditions are drastically dropping due to a sudden increase of the load demand in the system. This paper addresses the problem of designing and developing a robust and efficient Under-Voltage Load Shedding (UVLS) scheme for a real-time implementation in the power system networks. A new multi-stage adaptive UVLS scheme is developed in order to improve the operation and increase reliability and flexibility of the existing UVLS schemes. This scheme is implemented in real-time using RSCAD software environment of the Real-Time Digital Simulator (RTDS)