| 引用本文: | 李海锋,陈嘉权,曾德辉,梁远升,王钢.小电阻接地系统高灵敏性零序电流保护[J].电力自动化设备,2018,(9): |
| LI Haifeng,CHEN Jiaquan,ZENG Dehui,LIANG Yuansheng,WANG Gang.High sensitive zero-sequence current protection for low-resistance grounding system[J].Electric Power Automation Equipment,2018,(9): |
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| 摘要: |
| 对小电阻接地系统的零序电压、电流关系进行分析，发现发生高阻接地故障时母线零序电压与故障线路零序电流存在比例关系，则零序电压可间接反映过渡电阻的大小，由此提出一种基于零序电压幅值修正的高灵敏性零序电流保护方案。该方案结合现有的零序电流保护原理，通过引入零序电压信息对零序电流测量值进行修正，各线路修正后的零序电流测量值与故障线路首端发生金属性接地故障时的情况相似，保护动作整定值与现有的阶段式零序电流保护相同，从而大幅提高保护在高阻接地故障时的灵敏性。结合工程实际因素，讨论了各参数的整定原则。基于PSCAD/EMTDC的仿真和基于RTDS的装置测试验证了所提保护方案的有效性，其可将保护耐受过渡电阻能力提高到1000 Ω左右。 |
| 关键词: 小电阻接地系统 高阻接地故障 零序电流保护 继电保护 |
| DOI：10.16081/j.issn.1006-6047.2018.09.029 |
| 分类号:TM77 |
| 基金项目:国家自然科学基金资助项目(51477057) |
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| High sensitive zero-sequence current protection for low-resistance grounding system |
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LI Haifeng, CHEN Jiaquan, ZENG Dehui, LIANG Yuansheng, WANG Gang
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School of Electric Power, South China University of Technology, Guangzhou 510641, China
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| Abstract: |
| The relationship between zero-sequence voltage and current of low-resistance grounding system is analyzed, which reveals that the zero-sequence voltage of bus is proportional to the zero-sequence current of fault line when high impedance grounding fault occurs. Thus, the value of fault resistance can be indirectly reflected by zero-sequence voltage. On this basis, a high sensitive zero-sequence current protection scheme based on magnitude revise of zero-sequence voltage is proposed. Combining with the principle of the existing zero-sequence current protection, the measuring value of zero-sequence current is revised by the zero-sequence voltage. The revised value of zero-sequence current of each feeder is similar to that under single-phase metallic grounding fault at the head of the line, and the setting values of the proposed scheme are similar to those of the existing zero-sequence current protection, so the sensitivity of protection is significantly improved under high impedance grounding fault. The specific setting principles of parameters for the proposed scheme are discussed considering the factors of practical engineering. The simulation in PSCAD/EMTDC and the RTDS-based digital dynamic device test of actual protections prove that the proposed scheme is effective and the capability of the fault resistance endurance can be increased to about 1000 Ω. |
| Key words: low-resistance grounding system high impedance grounding fault zero-sequence current protection relay protection |
