Load Frequency Control of Two-Area Interconnected Network using Multi-Stage Controller

Abstract

This paper presents the application of structural optimization technique; grasshopper optimization algorithm (GOA) for load frequency control (LFC)  in a two-area power system. The LFC is carried out based on multistage proportional derivative filter type (PDF) with 0.85 plus Proportional Integral  (0.85+PI) controller for obtaining better dynamic system responses. The two control areas consist of thermal power plant units. The nonlinearities of  the system have been carried out by introducing (GDB) Governor Dead-Band and GRC (Generation Rate Constraint) to both control areas. A  performance comparison was carried out with several objective functions, and the integral time absolute error (ITAE) was proven to perform better.  The ITAE performance index has advantage of producing smaller overshoots and oscillations than the integral absolute error (IAE) or integral  squared error (ISE) performance indices. The effectiveness of GOA-PDF+(0.85+PI) controller was compared with other optimization methods like  Salp swarm algorithm with Proportional Integral Derivative (SSA-PID) controller and Genetic Algorithm (GA) with PID. The proposed technique  outperformed SSA-PID in terms of undershoot, overshoot and settling with a percentage improvement of 58.47 %, 59.79 % and 21.97 % respectively  in frequency deviation in area 1. With the proposed controller, the LFC dynamic responses of two-area power systems shall be further enhanced.