Decentralized load frequency control in deregulated environments

Decentralized load frequency control (LFC) problem for multi-area power systems in deregulated environments is studied in this paper. A decentralized PID tuning method is proposed by assuming that the tie-line power flows are disconnected. The general transfer function model of LFC for decentralized control design of deregulated power systems is derived first, and then an IMC-PID method is used to design the local load frequency controllers. A method to analyze the stability of the decentralized LFC for conventional environments is also extended to the deregulated case. The proposed method is tested on a four-area power system under various operating conditions. Simulation results show that the proposed design method is simple to follow, can achieve good performance, and results in implementable PID controllers. (C) 2012 Elsevier Ltd. All rights reserved.