Load frequency control of interconnected thermal and hydro thermal system with fuzzy logic controller

Abstract

Load Frequency Control (LFC) is an important issue in power system control. Frequency consistency is needed to operate all electrical apparatus in good condition. The aim of this research work is to design a suitable fuzzy logic based load frequency controller for two area interconnected thermal and hydro-thermal power system including nonlinearities such as, Governor Dead Band (GDB), Generation Rate Constraint (GRC) and Boiler Dynamics (BD), to suppress the frequency oscillation when there is a change in load because connected loads are not seldom constant. This thesis presents a model of two area interconnected thermal and hydro-thermal system with non-linearities and boiler dynamics. Additionally, when the number of interconnection increases and the system is simulated by external disturbance, the control of various time domain specifications within the stipulated time are quite difficult. Area Control Error (ACE) and change in Area Control Error (ACE) are taken as its input. This ACE determines the amount of frequency deviation plus tie-line power deviation in any area. If the ACE parameter response settles down faster with FLC than the conventional controller, then it is said that the proposed controller has more significance and good control performance than existing one. This validation is incorporated in this thesis. There is no established technique available at resent to control the frequency oscillation for multi area LFC with non-linearities and boiler dynamics on both the areas. Those controllers are identified and incorporated in this thesis. Simulation results conclude that the proposed controller has better control performance than conventional PI controller in the presence of GDB, GRC and BD in both the areas, for interconnected thermal and hydro-thermal system separately. The validity of these new techniques is confirmed to its repeatability and is in good agreement with the results published in the literature. newline