Service Life Estimation for the Small- and Medium-Sized Earth Grounding Grids

Service lifetime estimation for earth grounding grids as a problem or a task faced by the industry is presented. A mathematical model based on Freschi´s semianalytical model to determine the performance of the earth grounding grid at a certain year after being buried is proposed. The mathematical model can also explain the performance degradation of the earth grounding grid in principle and mathematically. According to the model, a scheme to estimate the service life of the earth grounding grid is proposed. A case study is given to illustrate how the scheme works. If the estimated service life of an earth grounding grid is not satisfactory, some measures, such as cathodic protection, should be considered to extend the service lifetime of the earth grounding grid.