Analysis of the Implementation of Effective Grounding in 400 kV Overhead Lines

Grounding is one of the key elements ensuring the reliable operation of overhead lines. The purpose of this paper is to provide a comprehensive assessment of grounding using a 400 kV overhead line as an example. The paper presents the results of diagnostic grounding measurements of various types of 400 kV overhead line poles, performed according to technical documentation and taking into account local terrain characteristics. The paper examines a large number of overhead line poles in both uniform and varied terrains, taking into account soil conditions based on geotechnical documentation. Furthermore, the paper presents a simulation analysis of lightning current dissipation through the grounding of a selected pole, taking into account geotechnical soil investigations with respect to soil stratification. The final section of the paper includes guidelines on grounding and assessment of the technical condition of grounding systems, which may be useful to transmission and distribution network operators.