A fuzzy logic controlled braking resistor scheme for stabilization of synchronous generator

Following a major disturbance, each synchronous generator connected to a power system experiences a net difference between its mechanical power input and electrical power output which leads to instability of the system. This paper deals with the investigations regarding the transient stability enhancement of a synchronous generator making use of a fuzzy logic controlled braking resistor scheme. Following a fault, variable rotor speed of the generator is measured and the firing-angle for the thyristor switch is determined from the crispy output of the fuzzy controller. By controlling the firing-angle, braking resistor can control the accelerating power in generator and thus improves the transient stability. The effectiveness of the proposed controller has been demonstrated by considering balanced (3LG: three-phase-to-ground) faults near the generator. Simulation results clearly indicate that the proposed fuzzy control strategy provides a simple and effective method of transient stability enhancement of synchronous generator.