Study on Corrosion Behavior of Copper-Clad Steel for Grounding Grids

Abstract

Grounding grid is an important device guaranteeing the operation of the people, electrical equipments and power grid. However, the corrosion of grounding grid affects the security of the power grid system, what's worse, it makes huge economic losses and serious social impact. We found from the research that the copper-clad steel for grounding grids has any advantages to better economic gain and good corrosion resistance at the same time. In this paper, using electrochemical impedance spectroscopy (EIS), polarization curve measurement, scanning electron microscopy (SEM) and so on, the corrosion behavior of copper-clad steel for grounding grids in the coastal soil have been researched. The results indicated that an increase of the soil salinity decrease the corrosion resistance of copper-clad steel, and the latter stage is less than the mid-term stage. The resistance increase and then tend to be stable with the increase of immersion time. The corrosion resistance of copper-clad steel in the non-salinized and light salinized soil is better.

Research Advances of Soil Corrosion of Grounding Grids

“…In acidic soils containing sulfides, copper has poor corrosion resistance, and its corrosion process gradually accelerates [ 23 ]. Moreover, copper is easily connected with other underground steel components, which can form a galvanic corrosion cell, causing accelerated damage to the steel components [ 24 , 25 ]. In addition, the heavy metal ions produced after copper corrosion can harm the environment and pollute soil and groundwater.…”

“…In addition to the three commonly used ground conductor materials, many new conductor materials are now put in use. Copper-plated steel, copper-clad steel, and hot-dip tin-plated copper steel are used as alternative materials to copper, which have the advantages of low cost, good electrical conductivity, nicer corrosion resistance, and mechanical strength [ 19 , 25 ]. However, due to the limited thickness of the copper protective layer, once the protective layer is damaged, the exposed copper and the steel substrate form a galvanic corrosion cell, which then accelerates the corrosion of the steel substrate [ 19 , 41 ].…”