| 引用本文: | 郑 涛,薛雨婷,纪良宸.混合级联直流输电系统逆变侧 LCC 换流变故障性涌流影响分析及抑制方案[J].电力系统保护与控制,2026,54(08):142-152. |
| ZHENG Tao,XUE Yuting,JI Liangchen.Analysis and suppression scheme of fault-induced inrush current in the inverter-side LCC converter transformer of a hybrid cascaded HVDC system[J].Power System Protection and Control,2026,54(08):142-152 |
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| 摘要: |
| 混合级联直流输电系统逆变侧采用电网换相换流器与模块化多电平换流器级联的结构。针对逆变侧 LCC 换流变阀侧发生区外故障时难以识别故障相的问题，提出一种换流变扩展差动保护方案。首先，分析逆变侧 LCC 换流变阀侧单相接地故障引发故障性涌流，明确指出投入故障相旁通对可以抑制故障性涌流，而若投入非故障相旁通对则会加剧其发展。然后，考虑到逆变侧 LCC 换流器与 MMC 换流器之间的复杂电气耦合联系，分析了故障性涌流对逆变侧 LCC 换流变及 MMC 换流变的不利影响。针对现有保护配置下 LCC 换流变阀侧区外故障难以准确识别故障相的问题，提出换流变扩展差动保护方案，实现故障相识别并抑制故障性涌流。最后，基于 PSCAD/EMTDC 平台验证所提换流变扩展差动保护方案在识别故障相和抑制故障性涌流方面的有效性。 |
| 关键词: 混合级联 换流变压器 故障性涌流 差动保护 旁通对 |
| DOI：10.19783/j.cnki.pspc.251090 |
| 分类号: |
| 基金项目:国家自然科学基金项目资助(52377099) |
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| Analysis and suppression scheme of fault-induced inrush current in the inverter-side LCC converter transformer of a hybrid cascaded HVDC system |
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ZHENG Tao, XUE Yuting, JI Liangchen
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State Key Laboratory for Alternate Electrical Power System with Renewable Energy Sources (North China Electric Power University), Beijing 102206, China
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| Abstract: |
| The inverter side of a hybrid cascaded HVDC system adopts a cascade structure of a line-commutated converter (LCC) and a modular multilevel converter (MMC). To address the difficulty in identifying the faulted phase when an external fault occurs on the valve side of the LCC converter transformer, an extended differential protection scheme for the converter transformer is proposed. First, the fault-induced inrush current (FIIC) caused by a valve-side single-phase-to-ground (SPG) fault on the LCC converter transformer is analyzed. It is clearly demonstrated that activating the bypass pair of the faulted phase can suppress FIIC, whereas triggering the bypass pair of non-faulted phases will aggravate its development. Second, considering the complex coupling between the LCC and MMC inverters, the adverse effects of FIIC on both LCC and MMC converter transformers are analyzed. To overcome the difficulty in accurately identifying the faulted phase during a valve-side external SPG fault of the LCC converter transformer under existing protection configurations, an extended differential protection scheme is proposed, enabling faulted phase identification and FIIC suppression. Finally, simulations conducted on the PSCAD/EMTDC platform verify the effectiveness of the proposed protection scheme in both faulted phase identification and FIIC suppression. |
| Key words: hybrid cascaded converter transformer fault-induced inrush current differential protection bypass pair |
