感应风电机组LVRT措施对线路电流速断保护影响

Impact of LVRT of Induction Generator on Instantaneous Over-current Protection

风电并网,影响输电线路继电保护动态特性。针对含感应发电机(IG)风力发电系统,分析串联制动电阻(SBR)和静止无功补偿器(SVC)两种低电压穿越(LVRT)措施对短路电流分量及电流速断保护的影响。基于外网故障后IG等值电路,分别采用简化理论分析和详细动态仿真方法,分析LVRT措施的影响。发现保护动作电流为全电流时,SBR使得保护范围变小。保护动作电流为基频分量时,保护范围随着SBR增加先变大后变小,前者可能导致保护失去选择性误动。采用SVC无功补偿时,无论动作电流为全电流或基频分量,保护范围都将增加,保护可能失去选择性而误动;动作电流为基频分量时,保护更容易误动。

Wind power integration may have adverse effect on the operation condition of transmission protection. For thewind power system with induction generators（IGs）,impact of low-voltage ride-through（LVRT）measures,i.e. seriesbraking resistors（SBR）and static var compensator（SVC）,on short current components and overcurrent protection isanalyzed. Based on the equivalent circuit of the IG under network contingency,the simplified theoretical analysis anddetailed dynamic simulation are applied to quantify the impact of LVRT measures. The numerical results show thatwhen the operation current is the full current,the protection region decreases with the SBR;when the operation currentis fundamental-frequency component,the protection region increases then decreases with larger SBR;the former possi-ble leads to maloperation. When using SVC for LVRT,whether the operation current is the full current or the fundamen-tal-frequency component,the protection region increases,possible yielding maloperation,which is more easily with thefundamental frequency component as the operation value.