Research On Reactive Power Coordination Control Of Wind Farm With STATCOM

In the face of the non-renewable nature of traditional fossil fuels and the environmental pollution problems,the world has taken corresponding measures to deal with these challenges.With the continuous improvement of wind power equipment manufacturing level,wind power has become one of the power generation energy sources with the largest scale and the best commercialized development among all new energy generation types.In the existing operation of the wind turbine,the direct drive permanent magnet synchronous wind generator is widely used in the high-power wind turbine due to its easy maintenance,high reliability,high operating efficiency,small mechanical loss and other characteristics.The reactive power regulation ability of wind farm plays an important role in the stable operation of wind farm.Therefore,wind farms are required to have the ability of reactive power regulation,and can automatically and quickly adjust the total reactive power.After making full use of the fan’s own reactive power regulation ability,the wind farm should be centrally equipped with reactive power compensation devices if it still fails to meet the requirements of connecting to the power grid.Compared with double-fed Induction Generator(DFIG),the direct-driven Permanent Magnet Synchronous Generator(PMSG)is not directly connected to the power grid and can decouple the active and reactive power,so it has stronger reactive power regulation capability.Static Synchronous Compensator(STATCOM),as the representative of the latest technology in the field of reactive power compensation,has greater advantages in performance compared with the traditional Static Var Compensator(SVC),and can respond to the reactive power instructions in a very short time.In this paper,the coordinated reactive power control strategy of STATCOM combined with direct-drive permanent magnet synchronous wind turbine is studied to meet the purpose of voltage regulation of parallel nodes.Firstly,the topological structure and working principle of the direct-driven permanent magnet synchronous wind generator are analyzed,and the mathematical model is established.Then in the Grid voltage value under the condition of asymmetric fault control strategy study of wind power system,the Side USES the maximum torque current ratios to achieve maximum power tracking control of PMSG,the network Side Converter(Grid-Side Converter,GSC)are symmetrical component method is used to power Grid voltage on the positive and negative sequence separation,and USES the current double closed loop control to ensure that the fan operation.Secondly,the reactive power compensation capacity of the wind farm is analyzed and calculated,and the working principle of STATCOM and the control strategy under the fault of value asymmetry of power grid voltage are analyzed and studied.Finally,according to the reactive power regulation characteristics of GSC and STATCOM,the reactive power coordination control strategy of STATCOM combined wind farm is proposed.This strategy includes two steps: reactive power setting and reactive power allocation.A threshold value is set for the range of voltage change at the parallel point.When the change is less than the threshold value,the reactive power support is provided by STATCOM only.When the change is greater than or equal to the threshold value,the reactive power distribution layer will coordinate the allocation of reactive power demands between the two,give priority to the reactive power regulation ability of GSC,and combine with STATCOM for reactive power support.Finally,the STATCOM combined wind farm model is built in Matlab/Simulink,and the simulation verification is carried out for different working conditions.