Evaluation and control of voltage support capability in wind-storage grid-connected systems based on entropy weight method

In response to the issues of insufficient voltage support capability and unreasonable reactive power dispatch instructions during grid faults in current wind farms, this paper proposes an evaluation and control method for the voltage support capability of wind-storage grid-connected systems based on the entropy weight method. Firstly, key factors influencing the voltage support capacity are analysed, including energy storage capacity, geographic location of doubly-fed induction generators (DFIGs), operating status, and active/reactive power constraints. A mapping relationship is then established between voltage support capacity and these factors. Secondly, the reactive power demand during grid faults is calculated, and evaluation indices for the voltage support capacity of DFIGs are selected based on influencing factors. The entropy weight method is utilised to comprehensively evaluate the voltage support capacity of each DFIG. By determining the reactive power output priority between the wind farm and the energy storage device, reactive power output commands are distributed proportionally according to the evaluation results to optimize the wind farm's voltage support capacity. Finally, a simulation model of a wind farm comprising 24 DFIGs is developed in Simulink to validate the effectiveness and accuracy of the proposed voltage control strategy.