摘要
在双馈风机(DFIG)中使用Crowbar电路是提高风机低电压穿越能力的一种常用措施,为协调Crowbar与风电场集电线路保护动作之间的关系,提出了集电线路电流保护新的整定方法与控制策略。在Matlab/Simulink中建立了含有Crowbar电路的风电场并网模型,投入Crowbar能够有效提高风机抵御电网电压跌落的性能,但使得风电场集电线路故障电流峰值减小并迅速衰减。对此针对电流速断保护提出采用功率方向元件判断故障区结合快速保护算法,并对整定值进行修正,后备保护采用自保持电路并增加电压判据的控制策略。仿真结果表明,该策略能够满足风电场联络线故障的可靠切除及主网故障时低电压穿越运行的要求。
Crowbar is commonly used in doubly fed induction generator （DFIG） to raise low voltage ride through capability. To coordinate Crowbar and contact line protection in wind farm, a new setting method and control strategy are proposed. Crowbar simulation model is built up in MATLAB/Simulink. Crowbar circuit can improve the LVRT capability of the wind farm, but the current of the protection devices on the contact line decreases rapidly. In order to make protection act correctly, a control strategy is proposed, which combines power flow directional element with fast protection algorithms, corrects setting value for the instantaneous over-current protection, adopts self-maintaining circuit for the back-up protection and adds voltage criteria. The simulation result shows this strategy can make the fault on connection line be cut reliably and raise LVRT capability when faults are on the grid.
出处
《电力系统保护与控制》
EI
CSCD
北大核心
2013年第2期97-102,共6页
Power System Protection and Control
