Research on Distribution Characteristics of Earth Potential of Grounding Electrode for Transmission Line Tower

摘要

In order to study the transient characteristics and distribution of earth potential of the grounding device of the transmission tower when lightning strikes the transmission line, the field measurement of the high-voltage transmission towers selected in Shaanxi Province is carried out, the influences of the lightning current wavefront time and half-wave time on the earth potential peak value, distribution law of the earth potential of three grounding grids of different structures and the potential distribution of the same rounding electrode in the soil environment with different resistivity are analyzed. The testing results show that the shorter the lightning current wavefront time is, and the higher the soil resistivity is, the larger the peak value of earth potential will be, the earth potential around the grounding grids of different structure types is decreased gradually from the central injection point of the grounding network to the edge of the grounding grid, the potential gradient of the accessory in the center of the grounding grid is greater than that at the edge of the grounding grid, but the local dispersion law around the three grounding grids presents different features. The research results can be referenced in optimization design of the grounding grids of the transmission lines, reduction of the impulse grounding resistance, etc.