Fuzzy based load shedding strategies for avoiding voltage collapse

The phenomenon of voltage collapse eclipses a potential hazard for the transmission systems. It is pertinent that energy management system is embodied with measures to avert the occurrence of voltage instability. The role of fuzzy as a tool augurs suitable on account of the innate nature of instability and the need for a rapid resurgent mechanism. Two fuzzy based load shedding algorithms that use a voltage stability indicator for averting voltage collapse are thus proposed in this paper. The first method identifies the most appropriate locations and uses an analytical procedure to compute the sheddable load, while the second directly predicts the amount of load to be shed at the critical buses. In spite of the fact that both the schemes facilitate to improve the bus voltage profile, in addition to enhancing voltage stability, still the second formulation offers on added weight in terms of its lower execution time and lesser extent of load shedding. The simulation results of the two methods on four test systems highlight its applicability on systems of any size.