Optimized cascaded PI controller for the load frequency regulation of multi-area power systems with communication delays

Abstract

The safe operation of multi-area power systems (MPS) is facing great challenges with the explosive growth of renewable energy, where the load frequency regulation (LFR) may be disturbed due to the unpredictability and uncertainty of renewable energy. This paper considers the communication delays in the area control error signals for the LFR of MPS, where a cascaded proportional–integral–derivative (PID) control scheme optimized by genetic algorithms is proposed to handle the communication delays. By comparing the stability boundaries of PI parameters with/without different time delays, the adverse effects caused by communication delays are discussed. Based on the proposed cascaded control scheme, its parameters are optimized by the genetic algorithms. Simulation results in different scenarios validate the superiorities of the proposed control scheme, where it can reject disturbances of the load variance most quickly and obtain a small overshoot. The proposed cascaded PI control scheme optimized by the genetic algorithms shows great promising potential in load frequency regulation.

Keywords

• Cascaded proportional–integral controller
• Load frequency regulation
• Multi-area power systems
• Communication delays
• Renewable sources
• Genetic algorithms