Seasonal influence on the substation grounding grid performance and its optimal design to neutralize the influence

Abstract

The paper investigates the seasonal variation and its impact on the vital parameters and thereafter suggesting a suitable grounding technique to neutralize this seasonal influence. The influence of rainy season on Indian soil condition has been studied numerically with the help of software module. The dip in soil resistivity during raining season significantly reduces the step and touch voltage, which has considerably less impact on the safety consideration. It does not require a separate deign method of the earthing grid, however in the winter season, the soil layer froze and forms a high resistivity upper soil layer. The limits of touch and step voltage, GPR values considerably increases and poses a potential threat to the people working in the area where the grid has been established. Frozen soil changes the model of soil analysis. The design should be based on the complete examination of depth of penetration of frozen soil layer. The impact of the frozen soils layer on the substation grounding grid performance and its influence on design prospect of grounding systems in homogeneous soil were studied in Indian soil condition and the design prospect of the grounding grid were discussed for homogeneous soil model.