Fuzzy logic controlled static VAR compensation in electric power systems

Fuzzy Logic Controlled Static VAR Compensation in Electric Power Systems Since most of the load types in power systems are motor and inductive, they require reactive power as well as active power. Altough the reactive power is needed to generate rotating field in motors and magnetizing current in transformers, the amount of the reactive power in transmission and distribution systems should be kept at minumum level in order to deliver more active power to loads. Therefore, the reactive power requirement supplied from compensating systems that installed at the input terminals of the large loads. In order to have secure, efficient and stable operation of power systems, new control strategies and methods have been developed continuously. In this study, a reactive power compensator that consist of Static Capasitors and Thyristor Controlled Reactors is studied. Thus, dynamic voltage and power factor control are obtained resulting in an increament in the power transmission capacity of transmission systems due to decreased reactive power losses. The compensation with Static Capacitors (SC) and Thyristor Controlled Reactors (TCR) is done by controlling the firing instants of the thyristor groups. However, the operating characteristic of SC+TCR systems are not linear and they can not be modelled efficiently by clssical methods. With the application of fuzzy logic based controllers, it has become easier to control the systems that are to difficult to be modelled mathematically for the classical control systems. In this study, the relationship between system output and input is used by a fuzzy logic based controller to obtain the required system operation without a mathematical model. Key Words: Reactive power compensation, fuzzy logic, static capacitors, thyristor controlled reactors, control systems. VI