Research Advances of Soil Corrosion of Grounding Grids

Review on Soil Corrosion and Protection of Grounding Grids

The corrosion of grounding grid materials in soil is a prominent factor in power and electrical equipment failure. This paper aims to delve into the corrosion characteristics of grounding grid materials and the corresponding methods of safeguarding against this phenomenon. Firstly, the influencing factors of the soil environment on the corrosion of the grounding grid are introduced, including soil physicochemical properties, microorganisms, and stray currents. Then, the corrosion behavior and durability of common grounding grid materials such as copper, carbon steel, and galvanized steel are discussed in detail and compared comprehensively. In addition, commonly used protective measures in China and outside China, including anti-corrosion coatings, electrochemical protection, and other technologies are introduced. Finally, it summarizes the current research progress and potential future directions of this field of study.

Chemical imaging reveals environmental risk of minor tungsten and lead shotgun pellet constituents during weathering in soil

Tungsten (W)-based shots are considered more environmentally safe than lead (Pb)-based shots, but knowledge about the W-shot fate in the soil environment is still limited, especially in terms of minor constituents such as iron, copper, and nickel (Ni). Contaminant behaviour in soil strongly depends on pH; in turn, the corrosion of metal composites may affect the pH locally. The aim of this study was to compare Pb- and W-shot weathering dynamics in soil (silt loam, pH 6.3) and reveal the interplay of shot weathering-induced pH-changes on the mobility of elements using in situ chemical imaging (Diffusive gradients in thin films for labile elements, planar optodes for soil pH) and batch incubation experiments over time (16 months). Despite our expectation to find acidification due to W oxidation, we observed a pH increase by 0.2 units in extracted soil solutions and by 0.6 units in the soil around W-shots as Ni dissolved from the binder phase of the shot. After 10 weeks, release of labile Ni was 3-times higher compared to W despite the low Ni content in the shot (7 %, m/m). Pb-shot oxidation increased soil solution pH by 0.5 units which likely supported mobility of Pb-shot-derived antimony (Sb). Steep gradients of labile W and Pb and soil solution concentrations <0.8 μmol L^-1 indicated that transfer from shot to soil was low. Contrastingly, labile Ni and Sb were found up to ~4 mm from the shot surface and in higher soil solution concentrations as suggested by the shot constitution, indicating higher mobility of minor as compared to major shot constituents. After 16 months, 36 % of total Ni were dissolved in the soil solution highlighting the environmental relevance of minor shot constituents in Pb-shot alternatives after short term weathering in soil.

Editorial for the Special Issue on Corrosion and Etching at Micro/Nanoscale

Micro- and nanoscale corrosion and etching at are important in several fields, from the fabrication of sensors and membranes to investigations of the properties of micro- and nanocomposites [...].

Influence of Current on Soil Corrosion of Galvanized Steel of Grounding Grids

Grounding grid materials are vulnerable to soil corrosion, which is detrimental to the safe operation of the grounding grids and even lead to serious accidents of power transmission. In this paper, galvanized steel was used as the typical grounding grid material which was buried in the soil and then electrified with AC and DC current for two weeks. The corroded samples under different current conditions were characterized and compared. The experimental results show that the corrosion degree of galvanized steel gradually aggravated with the increasing of the current, especially under DC current. Further, the mechanism of the influence of current on soil corrosion is explored. It is found that under the same magnitude of current, the corrosion degree of galvanized steel under DC current is greater than that under AC current.