Reactive Power Compensation And Voltage Control Strategy For Wind Farm

With the deepening of energy crisis and the extent of human attention to environmental protection, wind power gradually become the focus of all renewable energy sources. The penetration level of wind power is increasing, the power quality is seriously affected by randomness and volatility of wind power, and one of the biggest current challenges to wind power grid integration is the control of voltage and reactive power. Aiming at reactive power and voltage issue after the integration of wind power into the electric grid, the wind power forecasting is introduced, and the coordinated model of voltage and reactive power control is established using multiple reactive power compensation equipment through a long-timescale.The model is solved using the PSO algorithm. The main work of the paper is as follows:1) The reactive power loss and the equipment of reactive power compensation within wind farm is analyzed. The voltage is mainly affected by the reactive power in power system.Wind farm reactive power losses include box-type transformer losses, the main transformer losses and the collector line losses. The equipment of reactive power compensation and voltage control include dual-fed wind turbines, OLTC and various reactive power compensation equipment. The reactive power capability of DFIG is studied. The reactive power can't be produced by and can only be redistributed by the OLTC. Reactive power compensation devices include the static reactive power compensation devices(capacitors,reactors, etc.) and the dynamic reactive power compensation devices(SVC, STATCOM).The configuration guidance for the reactive power compensation equipment is studied.2) The topology of DFIGs has a greater impact on the Optimal Reactive Power Dispatch problem within the wind farm. The distribution of the total reactive power between the DFIGs is studied. The impact of the OLTC tap on the ORPD problem within wind farm is considered. The optimal reactive power dispatch model within a wind farm is formulated with an objective of minimizing active power loss and adjusting wind turbine terminal voltage. The PSO algorithm is proposed to get the optimal solution. The test results demonstrate the security and economy of the proposed method in achieving optimal solution.3) The wind power forecasting is introduced, and the coordinated model of voltage and reactive power control is established using multiple reactive power compensation equipment through a long-timescale. The impact of wind power on the grid is mainly due to the uncertainty of the wind power, and the wind power forecasting is introduced to Weakening randomness and volatility of the wind power. The coordinated model of voltage and reactive power control is established using multiple reactive power compensation equipment through a long-timescale. For the equipment which are slow and not suitable for frequent operation,the optimization is done through a long-timescale and the equipment are only operated when wind power fluctuates in large-scale through a long-timescale. The reactive power which fluctuates rapidly in short time-scale are mainly satisfied by the dynamic reactive powercompensation equipment. The reactive power control strategy is proposed and has been demonstrated the security and economy in achieving optimal solution.