不对称故障相位跳变和波形点对DFIG转子电压的影响

Impacts of phase angle jump and point on wave during asymmetrical fault on rotor voltage of DFIG

研究电网故障引起的电压暂降幅值、相位跳变、波形点等多维特征对双馈感应发电机的影响,是完善和提升DFIG低电压穿越能力的重要内容。首先,结合电网不对称故障引起的电压暂降幅值、PAJ、POW等多维特征,推导计及PAJ和POW的DFIG定子磁链、转子电压解析式,并运用磁链和电压空间分析法,分析不对称故障中PAJ和POW对DFIG故障特性的影响机理;其次,结合磁链和电压矢量轨迹特征,以及PAJ和POW影响DFIG转子电压的规律,推导计及PAJ时导致最大转子电压峰值的POW表达式,并以1.5 MW DFIG为例进行仿真,验证上述分析的正确性。最后,根据导致DFIG转子电压峰值增幅最严重的电压暂降多维组合特征,提出完善DFIG低电压穿越能力测试标准的建议。

The grid fault can bring in the amplitude,phase angle jump（PAJ）,point on wave（POW）and other multidimensional features of voltage sags.The study of their impacts on doubly fed induction generator（DFIG）is of significance to help DFIG enhance and improve its low voltage ride through capacity.Firstly,expressions of the DFIG stator flux and rotor voltage are derived under the consideration of PAJ and POW.Furthermore,the flux and voltage space vector analytical method is utilized to analyze the influence mechanism of DFIG fault characteristic caused by PAJ and POW.Then,considering the characteristics of flux linkage and voltage vector trajectory,and also the influences of PAJ and POW on the rotor voltage of DFIG,the POW expression that leads to the peak value of maximum rotor voltage with PAJ is deduced.Furthermore,an example of 1.5 MW DFIG is modeled to verify the results.Finally,According to the multi-dimensional features of voltage sag,which lead to a maximum amplification of DFIG peak rotor voltage,a suggestion is proposed to improve the test standard of DFIG low-voltage ride-through capability.