土壤异质性对模拟直流场环境下X70钢的腐蚀行为影响

Influence of Soil Heterogeneity on Corrosion Behavior of X70 Steel in Simulated Direct Current Electric Field

摘要:

通过模拟直流接地极不平衡电流场，研究了X70钢在四川宜宾±800kV复龙特高压直流换流站接地极附近土壤中的腐蚀行为。结果表明：土壤性质对埋地金属的腐蚀性影响较大。其中，土壤pH值对X70钢在直流接地极附近土壤中的腐蚀速率影响显著，腐蚀速率与土壤酸碱性的关系为：酸性＞中性＞碱性。同时，土壤总含盐量越大，金属腐蚀速率越大。该研究为评估直流接地极附近埋地金属设施的腐蚀影响和新建特高压直流工程接地极的设计规划选址提供一定的依据。

Abstract:

The corrosion behavior of X70 steel is studied through the simulation of DC electric field, which is buried around the ultra high voltage direct current (UHVDC) grounding electrode of Fulong ±800 kV converter station in Sichuan province of China. The results indicates that the soil property has a significant impact on the corrosion behavior of X70 steel. The corrosion rate of X70 steel is accelerated in the acid soil, and in different soil environments, the corrosion rate of X70 steel is ranked in the order: acid soil＞neutral soil＞alkaline soil. Besides, higher content of the salt in the soil will increase the corrosion rate of X70 steel. This study will provide important references for assessing the corrosion influence of the underground metallic facilities near UHVDC grounding electrodes, and especially be helpful for the site selection of the grounding electrode for new UHVDC transmission projects.