An AGC maintains the frequency of the system by balancing the active power generation to the load demand. The frequency of the system is dependent on the active power supply of the system according to the loadchanges. A conventional PID controller is generally employed to achieve AGC. However, proper tuning of controller parameter is required in order to achieve satisfactory controller performance. So, the proper choice of design objectives and the tuning method play very important part in AGC. In this work, a PID controller with derivative term is tuned to control the frequency and tie-line power deviations of a two-area non-reheat thermal system using Ant Lion optimization (ALO) algorithm. ALO is an efficient optimization algorithm which is based on the behavior of ant lions. For optimization purpose, the fitness function is formulated by considering settling times of deviations in frequency and tie-line power deviations and the integral errors. Four different cases of load perturbation conditions in both areas are considered. A comparative assessment of the proposed controller is carried out with PSO based controller and the obtained results are tabulated. Time-domain simulations are carried out to further establish the superior performance of the proposed controller.

Keywords : Automatic generation control; Ant lion optimization; Particle swarm optimization; PID controller; multi-area interconnected system.