| 引用本文: | 盛亚如,丛伟,卜祥海,李晓明.基于中性点电流与零序电流投影量差动的小电阻接地系统高阻接地故障判断方法[J].电力自动化设备,2019,39(3): |
| SHENG Yaru,CONG Wei,BU Xianghai,LI Xiaoming.Detection method of high impedance grounding fault based on differential current of zero-sequence current projection and neutral point current in low-resistance grounding system[J].Electric Power Automation Equipment,2019,39(3): |
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| 摘要: |
| 在分析小电阻接地系统发生接地故障时故障线路、非故障线路零序电流与中性点电流相量关系的基础上，提出了一种基于中性点电流与线路零序电流投影量差动的高阻接地故障判断方法。接地故障发生后，故障线路经过接地点和系统中性点构成基本的零序回路，由于中性点电流呈阻性，故障线路零序电流在中性点电流上的投影与中性点电流的差值较小，而非故障线路零序电流基本呈容性，非故障线路零序电流在中性点上的投影与中性点电流的差值较大，据此引入比值计算的方法可较为灵敏、可靠地检测出高阻接地故障。分析了线路参数不对称、负荷不对称、系统电压不对称等情况对所提方法的影响，PSCAD仿真结果表明，所提方法能够可靠地检测出高阻接地故障，受各种不对称情况的影响较小，具有较高的灵敏度和可靠性。 |
| 关键词: 小电阻接地配电网 高阻接地故障 电流投影量 电流差动 |
| DOI：10.16081/j.issn.1006-6047.2019.03.003 |
| 分类号:TM77 |
| 基金项目:国家自然科学基金资助项目(51877126) |
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| Detection method of high impedance grounding fault based on differential current of zero-sequence current projection and neutral point current in low-resistance grounding system |
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SHENG Yaru1, CONG Wei1, BU Xianghai2, LI Xiaoming1
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1.Key Laboratory of Power System Intelligent Dispatch and Control, Ministry of Education, Shandong University, Jinan 250061, China;2.Zibo Power Supply Company, State Grid Shandong Electric Power Company, Zibo 255000, China
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| Abstract: |
| Based on the analysis of the vector relation between the neutral point current and zero-sequence current of faulty and normal lines, a detection method of high impedance grounding fault based on the differential current of zero-sequence current projection and neutral point current is proposed. As grounding fault occurs, the fault line passes through grounding point and neutral point of the system to form a basic zero-sequence circuit. Because the neutral point current is resistive, the difference between the projection of zero-sequence current of fault line on neutral point current and the neutral point current is small. However, the zero-sequence current of non-fault line is capacitive, so the difference between the projection of zero-sequence current of non-fault line on neutral point current and the neutral point current is large. Therefore, the ratio method is introduced to detect high impedance grounding fault effectively. Then a further investigation is made about the effects of asymmetric line parameters, asymmetric load and asymmetric voltage of the system on the presented method. Simulative results by PSACD proves that the presented method can reliably detect high resistance grounding fault, which is less affected by various asymmetric conditions, and has high sensitivity and reliability. |
| Key words: low-resistance grounding distribution network high impedance grounding fault current projection current difference |
