On Power System Frequency Control in Emergency Conditions

Abstract

Frequency regulation in off-normal conditions has been an important problem in electricpower system design/operation and is becoming much more significant today due to the increasing size,changing structure and complexity of interconnected power systems. Increasing economic pressures forpower system efficiency and reliability have led to a requirement for maintaining power systemfrequency closer to nominal value.This paper presents a decentralized frequency control framework using a modified low-orderfrequency response model containing a proportional-integral (PI) controller. The proposed frameworkis suitable for near-normal and emergency operating conditions. An H∞ control technique is applied toachieve optimal PI parameters, and an analytic approach is used to analyse the system frequencyresponse for wide area operating conditions. Time-domain simulations with a multi-area power systemexample show that the simulated results agree with those predicted analytically.