Hierarchical Multi-objective Reactive Power and Voltage Control Strategy for Wind Farms

Abstract

The reactive power provided by the wind turbine (WT) has the function to adjust the node voltage. However, if the reactive power output by WTs is not reasonably allocated, it is easy to cause problems such as the node voltage exceeding the limit and excessive active power loss. Therefore, a hierarchical multi-objective optimization strategy is proposed, which divides the wind farm cluster into three parts: grid layer, inter-field layer, and inner-field layer. According to the dispatching instructions of the grid layer, the inter-field layer uses the minimum voltage difference of the point of common coupling (PCC) and the minimum active power loss as the optimization goal. Then, the reactive power output by the wind farm and SVG is coordinated. The inner-field layer receives the instructions issued by the inter-field layer and coordinates WTs for reactive power compensation with the goal of reducing voltage difference and active power loss. The calculation examples show that this strategy can efficaciously ameliorate the situation of excessive voltage at key nodes and exorbitant active power loss.