具备不平衡运行控制直驱风机对近区系统负序电流的影响

Influence of Direct-driven Generator with Unbalanced Operation Control on Negative-sequence Current of the System near DDPMSG

针对具备不平衡运行控制的直驱永磁同步风电机组(direct-driven permanent magnet synchronous generators,DDPMSG),提出了一种负序电流注入下,含直驱风机系统的稳态不对称计算方法。在正负序网中,将直驱风机等效为受控电流源,然后根据系统正负序网,列出系统正负序电压电流方程,与直驱风机正负序电流指令值计算方程联立求解,得到系统各参数的序分量。从理论上分析了直驱风机对近区系统负序电流的影响,研究结果表明,相比同步电机,直驱风机使系统其他支路输出的负序电流更大。在双机无穷大以及十三节点配电网的算例中,通过理论计算值与仿真值的对比,验证了所提计算方法和结论的正确性。

A steady - state asymmetric calculation method for power system with direct - driven permanent magnet synchronous generators （DDPMSG） after the injection of negative - sequence current is proposed. In the positive and negative sequence networks, DDPMSG with the control strategy under unbalanced condition could be equivalent to the controlled current source.Then voltage and current equations based on positive and negative sequence networks of power system are listed. The sequence components of parameters of power system could be gained by solving the simultaneous equations combining the voltage and current equations and the current commands equations of the control strategy. The influence of DDPMSG on the negative - se-quence currents of the system near DDPMSG is analyzed theoretically. The results show that DDPMSG may increase negative -sequence currents of other branches comparing with the synchronous generator. Finally, two case studies based on two - ma-chine system and 13 - node distribution network are presented, and the comparative analyses between theoretical calculations and simulation results verify the correctness of the calculation method and conclusions.