Design and coordination of a capacitor and on-load tap changer system for voltage control in a wind power plant of doubly fed induction generator wind turbines

Abstract

In this paper, a novel coordination and control strategy for capacitor banks and on-load tap changer for a wind power plant is introduced. The capacitor banks are controlled in such way that the steady-state usage of the converters for reactive power injection is driven below to a maximum desired value of 0.1 pu. Additionally, the control transients because of the capacitor bank switching are minimized by using a suitable control structure. The tap changer control is coordinated with the plant control to decrease the impact of the capacitors reactive power in the line drop calculation, thus reducing the amount of tap operations and improving the accuracy of the line drop voltage estimation. The coordination of the central controller with the plant components is analysed and tested through electromagnetic transient program simulations.