含双馈风电机组的电力系统短路电流实用计算方法

A Practical Method to Calculate Short-Circuit Current in Power System Connected With Doubly Fed Induction Generators

分析了电网发生对称短路故障时双馈风电机组的电磁暂态模型和定、转子磁链的故障暂态过程,推导出不同定子电压跌落程度下双馈风电机组定子短路电流的表达式,提出可有效减小短路电流计算误差的定子电压跌落系数修正方法,并通过仿真计算验证了修正后短路电流表达式的准确性。提出了含双馈风电机组的电力系统发生对称短路故障时的短路电流实用计算方法。以故障点为分界,将电力系统简化等值为含发电机支路和系统支路的二支路网络,求取发电机支路和系统支路短路电流周期分量的运算曲线,确定短路点短路电流周期分量的幅值,推导了短路点短路电流非周期分量和转子频率分量的表达式。

Electromagnetic transient model of doubly fed induction generator （DFIG） during symmetrical short-circuit fault occurred in power system connected with DFIG and fault transient process of magnetic linkage in the stator and the rotor of DFIG are analyzed, and then the expression of short-circuit current in stator of DFIG under different stator voltage drop extents is derived and a method to Correct the stator voltage drop coefficient, by which the calculation error of short-circuit current can be effectively reduced, is put forward. A practical method to calculate short-circuit current caused by symmetrical short-circuit fault occurred in power system connected with DFIGs is proposed. Taking the fault point as boundary point, the power system containing DFIG is simplified to an equivalent two-branch network composed of generator branch and system branch, then the operational curves of periodic components of short-circuit currents in generator branch and system branch are solved respectively to determine the amplitude of periodic components of short-circuit currents at the fault point, and expressions of aperiodic component and rotor frequency component of short circuit current at the fault point are derived.