Evaluation And Optimization Of Wind Farm Reactive Power Considering Voltage Stability

As the proportion of wind power in power energy structure is higher and higher, due to the large-scale wind farms parallel operation,the operation characteristics of the power grid suffer severely affected. Because the wind is random and uncontrollable, so the wind power output will have a fluctuation, Power flow in the wind farm connected to the grid lines or power transmission channel is changing. Parallel operation of large-scale wind farm will influence the quality of the grid voltage and voltage stability, the wind farm connected grid with long distance is more prominent, so wind farm reactive power compensation on the regulation of the stability of the local grid voltage is particularly important. In recent years, a large area of wind turbine off network incidents continue to occur, main reason is due to wind farm low voltage ride through capability of non-compliance, reactive power compensation device of wind farm can not automatically adjust, resulting in some units can not achieve low voltage ride through(LVRT), system voltage surge after the off grid. Therefore, the relevant departments must make reasonable management of reactive power and voltage to ensure safe and stable operation of wind farm. Doubly fed wind farm with the characteristics of dynamic reactive power capability and converter is connected directly to grid has gradually become the mainstream, but because of the special equipment and location and the randomness and intermittence of wind, wind farm in grid brings certain influence to the voltage stability of the local grid, that limits the its development in a certain extent.In order to reduce the adverse effects of wind farm in grid operation for the system, reduce voltage fluctuation of wind farm network point, improve the voltage qualification rate, meet the control voltage and decrease the network loss. Combined with the demand on the grid and the actual operation of wind farm, presented wind farm under different operation reactive capability evaluation method, evaluated the reactive power output capacity of wind farm, formulated under the different operation the reactive power output limit value table, and put forward a kind of wind farm reactive power optimization control algorithm, this algorithm with in wind farm power loss minimum as the objective function, make the the access point voltage offset rated value minimum, solve the wind farm voltage the question of beyond limit.