接地极附近杆塔接地体电腐蚀研究

Study on Electric Corrosion of Electric Tower Metal Grounding Body Near the HVDC Earth Electrode

相对于周围土壤而言,接地极附近的金属接地体能够提供导电性更强的导电通道,因此金属接地体中也会有接地极中的电流流过,处于土壤中的杆塔接地体因电流和运行环境的作用将会有电腐蚀,从而影响附近线路杆塔的接地性能。结合直流接地极工作条件和附近输电线路电气结构,在3种不同土壤模型的基础上建立了接地极对杆塔影响的理论分析模型;并考虑接地极在不同阴阳极模型条件时,对附近单回单基杆塔接地体的电腐蚀特性展开研究;在不同土壤模型条件下对线路总腐蚀量进行分析,最后针对接地极附近杆塔接地体提出了4种典型的防腐措施。

Because the conductivity of metal grounding body is better than the soil,the earth current of HVDC earth electrode is easier to flow through the metal grounding body,which would producethe electric corrosionto themetal grounding equipment near the HVDC earth electrode.Electric corrosion of HVDC earth electrode on the nearby transmission line towers are studied in the paper,.Combining the earth electrode operation conditions with nearby the transmission line structure,the theoretical calculation model is established under three soil resistivity models,and then the current distribution of metal grounding body for the nearby transmission line towers is analyzed.With the condition of different operation time for the positive and negative earth electrode,the corrosion quantity of each tower grounding body is calculated,and the total of corrosion quantity for thetransmission line is obtained.At last,four kinds of protective measures for the towers and metal grounding body are proposed.