Literature Review on Power System using TCSC with Fuzzy PID Controller

Abstract

The basic control objectives of a power system are system voltage control, system frequency control, protection and economic operation. Reactive power control is a subset of overall system control and stability. A power system is said to be well designed if it gives a good quality of reliable supply. By good quality is said meant the voltage levels are maintained within the reasonable limits. If the voltage variation is more than a pre specified value, the performance of the equipment suffers and the life of most of the equipment is sacrificed. When power is supplied to a load through transmission line keeping sending end voltage constant, the load voltage undergoes variations depending upon the magnitude of the load. The higher the load greater is the voltage variation. The transmission line distributed parameters through out the line, on light loads or at no loads become predominant and consequently the line supplies charging VAR (generates reactive power). In order to maintain the terminal voltage at the load bus adequate, reactive reserves are needed. FACTS devices like SVC can supply or absorb the reactive power at receiving end bus or at load end bus in transmission system, which helps in achieving better economy in power transfer. The fuzzy control has emerged as one of the most active and fruitful areas for research in the applications of fuzzy set theory. Fuzzy control is based on fuzzy logic  a logical system which is much closer in sprit to human thinking and nature language than traditional logical system. The fuzzy logic controller (FLC) provides a means of converting a linguistic control strategy based on an expert knowledge into an automatic control strategy. Knowledge acquisition in FLC application plays an important role in determining the level of performance of a fuzzy control system. FLC based on the fuzzy model of a process is needed when higher accuracy and reliability are required. Only small efforts have been expended in applying fuzzy logic as a controller to damp out the small signal oscillations for the FACTS based stabilizers as closed-loop. Index Terms: fuzzy logic controller (FLC), fuzzy logic, FACTS, Reactive power control, SVC , power system stability