Analysis of influence of grounding fault of the network side of an inverter-side converter transformer on differential protection

被引：0

作者：

Wu J. ^{[1
]}

Guo X. ^{[2
]}

Luo M. ^{[1
]}

Zheng T. ^{[2
]}

Yu X. ^{[1
]}

Huang W. ^{[1
]}

Liu H. ^{[3
]}

Liang Y. ^{[3
]}

Zheng X. ^{[2
]}

机构：

[1] State Grid Ningxia Electric Power Limited Company, Yinchuan

[2] State Key Laboratory for Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing

[3] State Grid Ningxia Electric Power Co., Ltd., Electric Power Research Institute, Yinchuan

来源：

Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | 2020年 / 48卷 / 17期

关键词：

Commutation failure; Converter transformer; Differential protection; Network side failure; Switching function;

D O I：

10.19783/j.cnki.pspc.191319

中图分类号：

学科分类号：

摘要：

After a single-phase ground fault of the inverter side converter side of a UHV DC transmission system, the voltage drop on the grid side may cause commutation failure of the DC system, such that the DC component flows into the converter transformer winding, and causes the transformer core flux to shift, causing the converter transformer to become saturated, causing a faulty inrush current, which in turn affects its safe and stable operation. In this paper, the problem of fault inrush current is generated for the single-phase ground fault of the inverter side commutation network. The characteristics of the grid side fault current under the two conditions of normal commutation and commutation failure of the converter valve are discussed using the theory of switching function. The variation of commutation flux after a single-phase ground fault on the side of the side network is studied. On this basis, the influence of current transformer saturation on commutation differential protection is studied. The results show that the grid-side current transformer is saturated under the fault condition in the side of the converter network, so that the second harmonic content of the commutating differential current exceeds the threshold value, resulting in differential protection mis-locking. Finally, the correctness of the analysis is verified by PSCAD/EMTDC simulation. © 2020, Power System Protection and Control Press. All right reserved.

引用

页码：170 / 178

页数：8

共 26 条

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