Comprehensive evaluation of corroded grounding electrodes considering the impulse characteristics
Comprehensive evaluation of corroded grounding electrodes considering the impulse characteristics
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DOI：
10.3389/fmats.2023.1146926
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发表时间：
2023-03
期刊：
影响因子：
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通讯作者：
Xuemeng Wang;Lan Xiong;Zhan-zhan Zhang;Yihua Dan;Jun Deng
中科院分区：
文献类型：
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作者：
Xuemeng Wang;Lan Xiong;Zhan-zhan Zhang;Yihua Dan;Jun Deng
接地极埋在恶劣的土壤环境中，会造成腐蚀。接地极的腐蚀直接影响电力系统的安全稳定运行。因此，准确地检测接地电极的腐蚀程度就显得尤为重要。现有方法存在以下问题：1）以工频接地电阻作为单一判据，缺乏考虑冲击特性，难以准确判断腐蚀程度，存在安全隐患。2)缺乏考虑埋地土壤的环境PH值、含水量、含盐量等因素，容易导致对腐蚀程度的误判。针对这一问题，本文研究了考虑冲击特性的接地体腐蚀综合评价方法。从热稳定性、冲击特性、工频特性等方面研究了接地体的最小安全直径和土壤环境腐蚀的影响因素。根据各评价因子与腐蚀性之间的关系，计算隶属度，并与偏差平方和确定的综合权重相结合。采用模糊评价方法得到腐蚀性评价矩阵Y，提出腐蚀性指数C来量化腐蚀强度。结合最小安全直径，预测了接地极的剩余寿命范围，划分了接地极的腐蚀程度。最后提出了考虑脉冲特性的腐蚀综合评价算法。结果表明，该方法不仅考虑了土壤环境因素，而且考虑了接地极的接地特性，特别是冲击特性。该方法比其他仅考虑土壤环境的评价方法更全面，可实现接地极的非开挖腐蚀检测。因此，本文的工作对杆塔接地极的运行维护具有重要意义。
The grounding electrodes are buried in a harsh soil environment, which will cause corrosion. Corroded grounding electrodes directly affect the safe and stable operation of the power system. Therefore, it is particularly important to detect the corrosion degree of the grounding electrodes accurately. The existing methods have the following problems: 1) Power-frequency grounding resistance is used as a single criterion, and lack of considering the impulse characteristics, which is difficult to accurately judge the corrosion degree and could cause a potential safety hazard. 2) Lacking considering the environmental PH value, water content, salt content, and other factors of the buried soil, which is easy to lead to misjudgment of corrosion degree. To solve the problems, this paper studies a comprehensive evaluation of corroded grounding electrodes considering impulse characteristics. Based on thermal stability, impulse characteristics, and power frequency characteristics, the minimum safety diameter of grounding electrodes and the factors that affect the corrosion of the soil environment are studied. According to the relationship between each evaluation factors and corrosivity, the membership is calculated and combined with the comprehensive weight determined by the sum of the squares of deviation. The fuzzy evaluation method is adopted to obtain the corrosive evaluation matrix Y , and the corrosive index C is proposed to quantify the corrosive strength. Combined with the minimum safety diameter, the residual life range of the grounding electrodes is predicted and the corrosion degree is divided. Finally, a comprehensive corrosion evaluation algorithm considering impulse characteristics is proposed. The results show that this method not only considers the soil environmental factors but also considers the grounding characteristics of the grounding electrodes, especially the impulse characteristics. This method is more comprehensive than other evaluation methods which only consider the soil environment and can realize trenchless corrosion detection of grounding electrodes. Therefore, the contribution of this work is of great significance to the operation and maintenance of tower grounding electrodes.