| 引用本文: | 梁 栋,王 玮,孙中玉,徐丙垠,翟国亮.TN-C-S系统双突变量电流分离漏电保护方法[J].电力系统保护与控制,2022,50(15):168-177.[点击复制] |
| LIANG Dong,WANG Wei,SUN Zhongyu,XU Bingyin,ZHAI Guoliang.A current separation leakage protection method using double mutations for TN-C-S systems[J].Power System Protection and Control,2022,50(15):168-177[点击复制] |
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| 摘要: |
| 针对低压配网TN-C-S系统固有剩余电流大、多级剩余电流漏电保护难以投入的问题，提出一种基于剩余电流和不平衡电流突变向量的电流分离漏电保护方法。首先，分析TN-C-S系统剩余电流成分，提出负荷投切不影响剩余电流向量与不平衡电流向量之比M，而单相接地故障发生时刻会导致M值突变。其次，利用低压配网负荷投切频繁的特点连续更新M值，实时计算系统漏电流突变幅值，以漏电流突变幅值越限作为故障判据。仿真和实测数据表明，所提方法对50 mA以上漏电故障的正确识别率达99%以上，变压器出口处可靠动作阈值可低至70 mA，能够满足TN-C-S系统多级漏电保护的灵敏度要求。 |
| 关键词: 漏电保护 电流分离 剩余电流 不平衡电流 双突变量 |
| DOI：DOI: 10.19783/j.cnki.pspc.211293 |
| 投稿时间：2021-09-21修订日期：2022-02-22 |
| 基金项目:国家自然科学基金项目资助(52077221) |
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| A current separation leakage protection method using double mutations for TN-C-S systems |
| LIANG Dong,WANG Wei,SUN Zhongyu,XU Bingyin,ZHAI Guoliang |
| (1. School of Electrical and Electronic Engineering, Shandong University of Technology, Zibo 255000, China;
2. School of Electrical Engineering, Shandong University, Jinan 250000, China) |
| Abstract: |
| To solve the problem that multi-level residual current (RC) leakage protection cannot be used in LV TN-C-S distribution systems because of the large inherent RC, a current separation leakage protection method based on RC and unbalanced current mutation vectors is constructed. First, the RC in TN-C-S systems is analyzed. It is proposed that load switching without faults does not affect M, the ratio of the RC vector to the unbalanced current vector, and single-phase grounding faults will lead to sudden changes of M. Then, M is continuously updated using the characteristics of frequent load switching in the LV systems, and the leakage current mutation amplitude of the system is calculated in real time. The ‘amplitude exceeding limit’ is used as the fault criterion. Simulations and field tests show that the proposed method has a correct recognition ratio of over 99% for leakage faults above 50 mA, and the reliable action threshold at the outlet of the transformers can be as low as 70mA. This meets the sensitivity requirements for the multi-level leakage protection of TN-C-S systems.
This work is supported by the National Natural Science Foundation of China (No. 52077221). |
| Key words: leakage protection current separation residual current unbalanced current double mutations |
