Optimization Research on Grounding Resistance of Power Transmission Line Tower Foundation

Improving the current divergence characteristics of the tower foundation can effectively reduce the tower grounding resistance and reduce the cost of secondary artificial grounding. At present, it is necessary to further study the grounding of the tower foundation. In this paper, the finite element simulation software COMSOL is used to build single-pile concrete foundation simulation models and multi-pile concrete foundation simulation models. Five kinds of tower foundation external resistance reduction methods based on flexible planar composite grounding materials are proposed, such as full-laying, lower-half-laying, upper-laying, middle-laying and lower-laying. The effects of external radius, tower depth and groundwater layer position on grounding resistance are investigated. The effects of the aquifer on the current density distribution are compared. The effects of aquifers on current density distribution and the effects of three multi-pile resistance reduction schemes on ground potential and current density are compared. The simulation results show that increasing the external radius and tower depth is beneficial to improve the efficiency of reducing the resistance. From the big to the small, the efficiency of resistance reduction by external application of pile-by-pile is full application, lower half application, lower, middle and upper. The aquifer reduces the grounding resistance of the foundation, and when the aquifer is closer to the surface, the effect of reducing the resistance is more obvious. When the multi-pile foundation with higher voltage level adopts external application to reduce resistance, the efficiency of external application of ring wrap is higher than that of pile-by-pile application. The conclusions of this paper can provide reference for the actual transmission line design and lightning protection grounding construction.