Voltage Sensitivity-Based Reactive Power Injection Using Fuzzy Inference System in Power System

Steady-state power system contingencies such as a overloading of transmission lines causes transmission line outages or generator outages, which tends to the situation of voltage instability that may lead to complete blackout. The main reason behind this instability is the inability of system to meet its reactive power requirement. This deficiency causes the bus voltage to deviate from its permissible limit at various buses in power system. Our main aim is to improve the voltage profile of the system by giving reactive power support at sensitive buses only; for this purpose, we are using fuzzy inference system (FIS) to determine the amount of reactive power to be injected at all sensitive buses by evaluating reactive power injection factor (RPIF) using sensitivity at the load buses, performance index of contingencies, and voltage at buses as i/p. Furthermore, we tried to reduce the number of buses by identifying most severe buses (where reactive support can be given without compromising with the voltage quality) according to the number of times of its voltage violations in each contingency. IEEE 24-Bus system is used for the simulation purpose.