某110kV老旧变电站接地网系统改造前的评估

摘要

为提高变电站接地网改造效率,采用电阻抗成像(EIT)技术对某110 kV老旧变电站开展接地网改造前状态评估,并对地网建模成像.检测发现,除目视可见断点外,接地网引下线存在5处隐蔽断点,急需处理;而水平地网所处土壤腐蚀性弱,各支路阻抗值增幅均在允许范围,未出现明显锈蚀.据此,为该变电站制定了仅更换引下线、不改造水平地网的个性化维修方案,显著降低改造成本、避免接地材料浪费.电阻抗成像技术可实现对接地网腐蚀的快速准确诊断,将接地网从“黑箱状态”转变为“可视状态”,改善接地网腐蚀检查的盲目性,提升设备管理水平.%In order to improve the reconstruction efficiency,the grounding grid of an 110 kV substation was evaluated by the electrical impedance tomography (EIT) technology.Results indicated that five breakpoints of the down lines were found underground,but the impedance increase of grid was in a reasonable scope,proving that the level ground grid had not suffered serious corrosion.According to the evaluation results,a reconstruction program of just replacing the grounding metal of down lines was proposed,which could reduce the reconstruction cost of grounding grid and the waste of grounding metal.EIT technology could be used to evaluate the corrosion of grounding grid rapidly and effectively,which could reduce the blindness of grounding grid corrosion detection and improve the fine management level of grounding apparatus.