基于磁屏蔽型超导限流器的双馈感应风力发电机低电压穿越

Low-voltage Ride Through of Doubly-fed Induction Generator with Magnetically Shielded Superconducting Fault Current Limiter

风能并网导则要求并网风电机组需具备低电压穿越能力。针对双馈感应风力发电机在故障期间保持并网运行问题,提出一种磁屏蔽型超导限流器串于定子侧的解决方案。基于该限流器正常运行时阻抗极小、故障瞬间立即响应为一定阻抗,结合短路故障分析,建立限流器物理仿真模型,并对低电压穿越指标进行数学推理分析论证。该限流器可以减弱定子磁链暂态分量的冲击,改善转子过电流,削减电磁转矩振幅与振荡时间,整体提高双馈感应风力发电机故障穿越能力。最后通过Matlab/Simulink仿真验证该限流器的有效性。

According to the guidelines for the integration of wind power to grid,it is required that the grid-connected wind turbines should have low-voltage ride through(LVRT)capability.Considering the problem with the grid-connect?ed operation of a doubly-fed induction generator(DFIG)under grid fault,a solution for a magnetically shielded super?conducting fault current limiter(MS-SFCL)on the stator-side is proposed.Since the current limiter runs normally at very low impedance,it can be inferred that the impedance will respond immediately when a grid fault occurs.Combined with the short-circuit fault analysis,a physical simulation model of the current limiter is stablished,and mathematical analysis of the LVRT index is conducted.This current limiter can weaken the impact of the stator flux transient compo?nent,improve the rotor overcurrent,and reduce the electromagnetic torque amplitude as well as the oscillation time.In this way,the fault ride through capability of DFIG can be improved as a whole.Finally,the validity of MS-SFCL is veri?fied by MATLAB/Simulink simulations.