A study of Under-frequency Load Shedding Scheme : National Grid Model

Abstract

This research deals with the operation of Under-Frequency Load Shedding (UFLS) scheme during contingency period of the National Grid. The National Grid is modeled by using ETAP 7.0 software which is a modern electrical power flow program. The analysis of the operation of UFLS scheme is carried out under different cases of overloading and disturbances to examine the dynamic performance of the power system. In these cases the settings of the Under-Frequency relays are changed to improve the performance of the power system. The typical frequency response of a system with a deficiency in generation is depicted. A part of this research deals with UFLS relays. It explains and discusses principal components and the operation of the frequency relays which are used in the UFLS scheme of the National Grid.