Fuzzy logic approach to curtail number of controllers for voltage control in grid connected wind farms

In the past few years, the penetration of wind energy to the grid has been drastically increased. However, the variable nature of wind speed has an impact on power quality. Therefore, the voltage and reactive power control are necessary in a grid connected wind farms due to stochastic nature of wind speed. The wind connected system may consist of large number of voltage controllers i.e. on-load tap changing transformer (OLTC), generator voltage and switchable var compensator (SVC). As per an operator´s point of view, it is difficult to move so many controllers in a short period of time. Hence, it is important to optimize not only the reactive power dispatch for voltage control also the total number of controllers to reduce the complexity of the problem. A technique using fuzzy logic inference system is used to curtail the number of controllers in wind connected power system is presented. In this approach load bus voltage deviations are minimized by changing the controllers according to their sensitivity. 20-bus radial wind system and 163-bus equivalent of Indian southern grid wind system are considered for illustration. The results are compared with linear programming optimization technique and encouraging conclusions are drawn.