Study On Low Voltage Traverse Characteristics Of Wind Farms Based On STATCOM

When a large scale wind turbine is connected to the grid,the influence of the wind farm on the power grid becomes more and more important,which brings a great impact on the safety and stable operation of the power grid. When connected to wind farm system failure, resulting in the decline of system voltage,access to the wind farm should not only have not separated from the system of continuous operation for a period of time,but in the failure is eliminated as soon as possible to restore to the normal operation of the state,that is,the wind turbine is a low voltage ride through capability.In order to meet the demand of reactive power in the system of voltage sag, the reactive power compensation device is usually installed in the low-voltage bus at the outlet of the wind farm.In this paper,a reactive power compensation device STATCOM is proposed for the installation of reactive power compensation device at the outlet of the wind farm, and the effect of reactive power compensation on the system is studied.The main research contents of this paper are as follows:Firstly,the importance of reactive power compensation device to fan and even the whole system is analyzed,Running characteristics of doubly fed wind turbine are analyzed,and mathematic model of the double fed wind generator and the system,on this basis,through the modeling and Simulation of doubly fed wind turbine in variable speed system different voltage drop transient characteristics of Shifeng machines and systems, and doubly fed wind turbine in the normal operation of wind turbine and the system’s transient characteristics were compared and analyzed, get doubly fed wind turbine under the condition without any protective measures themselves have some low voltage ride through capability.Studied direct power control strategy of STATCOM current direct and indirect control of the control strategy and the voltage oriented,and the modeling and Simulation of direct power control strategy were analyzed,studied the control strategy on the system control performance,illustrate the correctness and effectiveness of the proposed control strategy.Adopts double closed loop control strategy of STATCOM simulation study,the test results are relevant analysis,the control strategy can compensate system missing reactive,effectively improve the power factor, improve the quality of electric energy conclusion.The reactive power allocation of STATCOM for specific capacity wind farm is studied, and the effect of reactive power compensation on the system with different capacity of STATCOM is studied,and the optimal capacity is determined. In Matlab/ Simulink establish the simulation model of the double fed asynchronous wind turbine wind farm and STATCOM,the STATCOM and the system occurred different degree of voltage sag device input and whether to study the effect of the system and the simulation results are detailed analysis. The results show that the STATCOM capacity allocation is correct,and proved to help fans and the entire system in the event of a voltage drop to maintain voltage stability,the installation of STATCOM after wind farm low voltage ride through capability has certain promotion.