| 引用本文: | 曾德辉,王钢,李海锋,刘胤良,郭敬梅.小电阻接地配电网多回线故障分析与自适应零序电流保护[J].电力自动化设备,2019,39(5): |
| ZENG Dehui,WANG Gang,LI Haifeng,LIU Yinliang,GUO Jingmei.Fault analysis of multi-feeder grounding fault and self-adaptive zero-sequence current protection scheme for low-resistance grounding distribution network[J].Electric Power Automation Equipment,2019,39(5): |
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| 摘要: |
| 当小电阻接地配电网发生同母多回线接地故障时，每条馈线的零序电流相比于单回线故障时有较大差别，馈线零序电流保护可能不正确动作。为此，首先推导了发生多回线同名相单相接地与单回线单相接地故障时馈线零序电流间的关系，揭示了保护不正确动作机理。提出了考虑负荷且能适用于不同类型多回线接地故障的零序电流计算方法。基于实际变电站参数搭建RTDS仿真模型，分析了不同类型多回线接地故障对零序电流保护的影响。在此基础上，提出了自适应馈线零序电流保护方案，利用故障前电压等参数将发生多回线接地故障时的零序电流修正为发生单回线接地故障时的零序电流，在不改变原有保护定值的情况下使零序电流保护能够自主适应于不同类型的多回线接地故障。基于RTDS和自主研发的保护测控装置的测试结果表明，所提保护方案不受负荷电流的影响，能够在不同类型的多回线接地故障发生时正确动作，且能够提高馈线零序电流保护对过渡电阻的耐受能力。 |
| 关键词: 配电网 小电阻接地 多回线故障 零序电流保护 故障分析 继电保护 |
| DOI：10.16081/j.issn.1006-6047.2019.05.007 |
| 分类号:TM761 |
| 基金项目:国家自然科学基金资助项目(51477057) |
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| Fault analysis of multi-feeder grounding fault and self-adaptive zero-sequence current protection scheme for low-resistance grounding distribution network |
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ZENG Dehui1, WANG Gang1, LI Haifeng1, LIU Yinliang1, GUO Jingmei2
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1.School of Electric Power, South China University of Technology, Guangzhou 510640, China;2.Electric Power Research Institute of Guangdong Power Grid Co.,Ltd.,Guangzhou 510080, China
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| Abstract: |
| When grounding fault occurs on multiple feeders of the same bus, the zero-sequence current of each feeder will be greatly different from that when single-feeder grounding fault occurs. Therefore, the zero-sequence current relay protection of feeder may operate improperly. The relationship of zero-sequence current between single-phase grounding fault of same phase on multi-feeder and single-phase grounding fault on single-feeder is deduced to reveal the mechanism of improper operation of protection. A zero-sequence current calculation method considering load and suitable to various types of multi-feeder grounding fault is proposed. Then, the influence of multi-feeder grounding fault on zero-sequence current protection is analyzed by RTDS simulation model based on parameters of actual substation. On this basis, a self-adaptive zero-sequence current protection scheme of feeder is proposed, which modifies the zero-sequence current under multi-feeder grounding fault to the zero-sequence current under single-feeder grounding fault by using the pre-fault voltage and other parameters. This self-adaptive zero-sequence current protection scheme can autonomously adapt to different types of multi-feeders grounding faults without changing the original protection settings. Test results based on RTDS and the self-designed protection device show that the proposed protection scheme is immune to load current, and can operate correctly when different types of multi-feeder grounding faults occur. In addition, the fault resistance endurance of zero-sequence current protection can be improved by the proposed protection scheme. |
| Key words: distribution network low-resistance grounding multi-feeders fault zero-sequence current protection fault analysis relay protection |
