An optimal control strategy for reactive power in wind farms consisting of VSCF DFIG wind turbine generator systems

Abstract

Doubly-fed Induction Generator (DFIG) is a kind of variable-speed constant-frequency (VSCF) wind generator (WG) which can output reactive power when not working in the constant power factor mode and be used as a reactive power supply for wind farm. In this paper, an optimal control strategy for reactive power in wind farms consisting of DFIG is proposed by combining the reactive power compensation ability of both DFIG and reactive power compensation device (RPCD). The control target is minimum power loss and optimal power flow (OPF) of wind farm. First, the reactive power characteristic of DFIG is detailed analyzed. Then the control strategy which includes three modules is presented based on the “Fix-place and Quantitative” thought, and the modules of which are Wind Farm Data Process Module (WFDPM), Wind Farm Data Acquisition Module (WFDAM) and Wind Farm Control Module (WFCM). As the core part of the strategy, WFDPM applies Sensitivity Analysis (SA) and improved genetic algorithm (IGA) to optimize the control strategy. At last, a wind farm consisting of twenty DFIGs of 1.5MW is built in DIgSILENT/PowerFactory, and the results data show that the optimal reactive power control strategy proposed in this paper can effectively achieve the minimum power loss and OPF.