12相整流发电机接地方式对直流过电压影响的研究

Researches on Influence of Grounding Mode of 12-Phase Generator with Rectifier Load on DC Overvoltage

在 12 相整流发电机发生交流侧单相接地故障时,为了能够有效抑制直流过电压,提出一种发电机中性点接地方式与过电压关系的分析方法。首先运用功率平衡的方法,对直流负载电阻进行零序回路折算,分析并等效出非故障绕组的零序回路,计算出各套绕组的零序电压。再通过向量分析法计算出故障后各相之间线电压,并进行比较分析,得出直流侧最高过电压的计算公式。结果表明,发电机中性点电阻接地时,接地电阻阻值越大,直流侧过电压越小。最后通过仿真及实验结果验证了理论分析的正确性。

In order to effectively suppress DC overvoltage in the occurrence of single-phase grounding fault of the 12 phase generator with rectifier load, an analysis method of the relation between the grounding mode of generator neutral point and DC overvoltage is proposed. First of all, the DC load resistor was converted to resistor in zero sequence circuit by power balance. The zero sequence loop of the non fault winding was analyzed, and the zero sequence voltage of each winding was calculated. Then, through vector analysis method, the line voltage between the phases were calculated and compared in fault state, and the calculation formula of maximum overvoltage on the DC side was obtained. The results show that when resistance is grounded at the neutral point of the generator, the greater the earth resistance is, the smaller the DC side voltage is. Finally, the correctness of theoretical analysis were verified by using simulation and experimental results.