Design, Measurement And Protection Study Of Large Grounding Grid

With economic development and accelerating the pace of construction of power projects, large power plants and substations are increasing continuously. Grounding grid is an important guarantee for safe operation of Power plant and substation, and the grounding performance is always paid attention by design and operation department.However, with the emergence of large power plants and substations, in order to control the cost of investment, and ensure the long-period safe operation of grounding grid, how to select the appropriate material for grounding grid is studied by many designing department.. With the emergence of large-scale grounding grid, grounding resistance getting smaller and smaller, while environment of power plants and external are changing, factors affect the ground resistance measurement of large grounding grid are also increasing. Now the traditional grounding resistance measurement requirements can not effectively eliminate all affected factors, which lead to blindness grounding grid innovation, and affected the safety operation of power plants and substation. In addition, how to protect the grounding grid and extend the use life are also focused by operation department.In this paper, problems that measurements discrepancy is relatively high, as well as deviation from design value, after several grounding grid resistance measurement carried out in Beilun Power Plant PhaseⅠ,Ⅱproject are studied. After several measurement data analysis, the characteristics of large grounding grid, small resistance, strong interference, etc., are found. Based on the preliminary study on various factors affecting the initial measurement, a series of measurement method are proposed to eliminate the affected factors, which are very useful to low soil grounding resistance measurement and theoretical calculations.At the same time, the grounding grid of Beilun Power Plant PhaseⅢproject is facing corrosion problem due to strong corrosive soil.According to analysis of the soil characteristics of the environment of grounding grid,and factors affecting corrosion of grounding grid, different anti-corrosion measures is adopted at different stages of project construction, in order to avoid corrosion damage of grounding grid, which will affect personal and equipment safety, These anti-corrosion measures will be useful for future anti-corrosion of grounding grid.