Research on calculation method for short-circuit current of doubly-fed induction generator during fault ride-through
The fault ride-through fault current control strategies and protection circuits of DFIG wind farms are rather complicated,which results in the existing fault current calculation process being cumbersome and the fault circuit current calculation accuracy being insufficient,which has a great impact on the safe operation of the local power grid.In order to tackle this challenge,a unified fault current calculation method is proposed to achieve accurate mathematical analytical calculation of the output fault current of doubly fed induction generator during fault ride-through.The proposed method mainly includes:1)Unified state space model of the whole fault ride-through process is established by fully considering the different internal protection circuits and control strategies during fault ride-through.The whole fault ride-through process includes the crowbar protection stage,the demagnetization control stage,and the reactive current supporting stage;2)Stator output fault current calculation method,is established by a unified state space model based on stator voltage and stator flux linkage;3)Stator-side and grid-side converter fault current contribution mechanism is revealed in a unified fault current expression by Laplace transform through time-frequency-time domain.A large number of test results verify the correctness and effectiveness of the proposed method.
doubly-fed induction generator(DFIG)state space modelcomplex frequency domain equationsshort-circuit current calculation
万方数据
维普
