Reactive Power Control Strategy For DFIG With Stator Winding Inter-Turn Short Circuit Fault Connected To A Weak Network

Wind power plants are,however,commonly located in remote areas,where the weak network is sensitive to the change of the output reactive power / active power of the DFIG,and the load fluctuations can significantly influence local bus voltage.In this paper,the main research works are shown as follows:(1)The mathematical model of DFIG in normal and SWITSC faults are established.Then the conventional control strategy of the DFIG in the rotor and the network side converter is analyzed.Based on this,The complete simulation model of DFIG connected to weak network has been established.(2)Through MATLAB simulation and theoretical deduction,the effects of SWITSC fault on the DFIG itself and the weak network are analyzed.The simulation result shows that the reactive and active power output of DFIG will decrease when SWITSC occurs,thereby cause the voltage drop at the point of common coupling(PCC)between DFIG and weak network.In addition,the same results can be obtained from the simulation analysis by theoretical analysis.(3)Based on the influence of DFIG with SWITSC fault on voltage stability of weak grid,an improved the rotor and the network side converter control strategy is proposed to make full use of DFIG's reactive power regulation capability.If the reactive power which is used to maintain the voltage stability exceeds the limit value of DFIG,the STATCOM is properly adopted.A series of simulation results show the correct of the improved strategy.