Design of Model Predictive Controller (MPC) for Load Frequency Control (LFC) in an Interconnected Power System

In the power system, any sudden load changes leads to the deviation in tie-line power and the frequency. So load frequency control is an issue in power system operation and control for supplying sufficient and reliable electric power with good quality. The main goal of the load frequency control of a power system is to maintain the frequency of each area and tie-line power flow with in prescribed value by adjusting the MW outputs of LFC generators so as to accommodate fluctuating load demands. In this paper, a Model Predictive Control (MPC) algorithm is used so that the effect of the uncertainty due to governor and turbine parameters variation and load disturbance is reduced. In power system load changes are immeasurable in order to measure these changes Fast Sampling Method (FOS), is used as it reduces the estimation error to zero after just one sampling period and Feedforward control method is used for rejecting load disturbance effect in each power system area by MPC. In this paper, parameters ensure stability, accuracy and robustness of load-frequency control system. Obtained parameters are tested on simulations, which are conducted on a 3-Area deregulated power system model. The results are compared with a recently proposed robust LMI based PI control strategy. This comparison confirms that the proposed method has better performance than the LMI based PI controller in the presence of disturbances and uncertainties so that the frequency deviation and power flow changes between areas are effectively damped to zero with small oscillations in a short time. KeywordsDeregulated Power system, Fast output sampling method Load Frequency Control, Load disturbance, Model predictive control, Parameter uncertainty.