Extended state observer based decentralized load frequency control of three area interconnected system

Decentralized load frequency control is more suitable for a large scale power system. Extended State Observer (ESO) based Decentralized load frequency control is implemented in this paper. Here an interconnected system consisting of combinations of three areas Thermal non-reheat, thermal Reheat and Hydro are considered. The state space model of individual system is designed for Extended State Observer (ESO). The controller poles for individual systems have been obtained by using the symmetrical root locus (SRL) technique. Observer poles for the extended system are kept in such a way that they satisfy required Gain margin and Phase margin criteria for individual power system. The designed system provides zero steady state error for frequency deviation and shows robustness in the face of parameter uncertainty. A numerical example illustrates the ability of the designed system to provide zero frequency deviation in its output and robustness against changing demands and parameter uncertainties.