考虑撬棒保护动作的双馈风机故障暂态特性分析

Fault Transient Characteristic Analysis of Doubly Fed Induction Generator Wind Turbines Considering Operation of Crowbar Protection

从电网的角度来看,风电场表现出来的故障特性不可忽视,尤其是在目前电网低电压穿越的要求下,风电机组表现出更加复杂的故障暂态特性,对电网自身的故障特性造成复杂的影响,给电网继电保护的研究带来挑战。针对目前广泛应用的双馈风力发电机组,对其电网故障下的短路过程进行了数学推导,得出了其短路电流计算表达式,并根据双馈风力发电机组近端严重故障下撬棒保护两种不同的投切控制策略,通过PSCAD/EMTDC仿真平台进行了仿真分析。仿真结果对比分析了撬棒保护两种投切方式对双馈风机故障暂态特性的影响,验证了推导表达式的正确性,对含风电场的电力系统故障分析诊断及继电保护问题的研究提供了一定依据。

In view of grid operation, the characteristics of the wind farm under fauh condition have gained much attention and cannot be ignored. The transient characteristics of wind turbines become more complicated especially in the condition of the low-voltage riding-through imposed by the grid. Moreover, under that condition it may have great influence on the own characteristics of power grid and become a real challenge to the relay protection of power grid. For the doubly fed wind turbine generator which is widely applied currently, this paper makes a mathematical deduction on the grid short circuit process, and gets a short-circuit current calculation expression. Besides, according to the different con- trol strategy of the crowbar protection, PSCAD/EMTDC was used for the simulation analysis. The simulation results veri- fy the effectiveness of crowbar protection on the fault transient characteristic of the doubly fed induction generator wind turbines and provide a foundation for fault diagnosis and research on the issue of relay orotection.