Influence of the VSC-HVDC System Structure on the Overvoltage of Single-Pole Grounding Fault
Flexible operation mode is one of the VSC-HVDC system’s advantages, and the power system may continue to operate in the future with different grid structures under maintenance and other working conditions. However, for the VSC-HVDC system with overhead transmission lines, the DC lines are prone to s...
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| Main Authors: | , |
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| Format: | Article |
| Language: | zho |
| Published: |
State Grid Energy Research Institute
2021-10-01
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| Series: | Zhongguo dianli |
| Subjects: | |
| Online Access: | https://www.electricpower.com.cn/CN/10.11930/j.issn.1004-9649.202009036 |
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| Summary: | Flexible operation mode is one of the VSC-HVDC system’s advantages, and the power system may continue to operate in the future with different grid structures under maintenance and other working conditions. However, for the VSC-HVDC system with overhead transmission lines, the DC lines are prone to single-pole grounding fault. Therefore, it is necessary to study the overvoltage of the DC lines with single-pole grounding fault for different grid structures. In this paper, a VSC-HVDC overvoltage model is built based on the ring-type four-terminal DC grid project, and the transient overvoltage characteristics of the VSC-HVDC system with the DC-side grounding fault are studied. The overvoltage levels of key nodes and equipment inside and outside the converter station are analyzed for four different VSC-HVDC grid structures with single-pole grounding fault occurring in the DC line. The results show that the system has a relatively low overvoltage level for the pseudo-U shaped structure, but has a relatively high overvoltage level for the broken-line shaped and real-U shaped structures. The system structures have the similar impact tendencies on the voltage to ground at the valve-side of converter transformer and on the overvoltage of the converter station bus. |
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| ISSN: | 1004-9649 |