适用于双馈机组风电场的故障电压序分量选相元件

Fault-sequence element of voltage phase selection applied to DFIG-based wind farm

针对双馈机组风电场弱馈特性以及暂态特性中含有转速频率分量的问题,通过分析风电系统背侧正、负序阻抗间的差异以及对故障电压序分量分布的影响,提出了一种基于故障电压序分量的选相方法。结合撬棒保护对故障电压序分量相位的影响,修正相位偏差角,使得该选相方法受风电场弱馈性及其风电系统背侧阻抗不稳定性影响较小。双馈机组风电场侧故障电压主要由电网电压支撑,频率偏差较小,该选相方法易于实现,且具有较大的选相裕度。运用PSCAD软件进行建模仿真,结果验证了该选相元件的有效性。

For the question that it contains speed frequency component in Doubly-Fed Induction Generator （DFIG） based wind farm weak-infeed and transient characteristic, this paper analyzes the differences between positive and negative sequence impedance of dorsal DFIG-based wind farm and the influence on distribution of fault voltage sequence component, and then puts forward a phase selection method based on fault voltage sequence component. Thinking about the effect of Crowbar protection on phase of fault voltage sequence component, it amends the shift angle of phase which makes the phase selection method has little impact by the wind farm of weak feed characteristics and its instability of dorsal impedance of wind power system. The fault voltage of doubly-fed wind power is mainly supported by grid voltage, the deviation of frequency is smaller. The method is easily to be implemented and has larger margin of phase selection. PSCAD is used for modelling and simulation, the simulation results demonstrate the validity of the phase selection element.