Evaluation of Several Grounding Approaches in the Distribution Network

Distribution line grounding systems are mostly installed to lower touch and step potentials and lightning-induced outages. Reliability may suffer when the grounding system malfunctions, and operations and maintenance funds may be diverted to investigate and rectify the issues at a higher cost to the utility. Grounding systems present several difficulties. The variety of building materials and soil types makes corrosion a highly complex problem. The two most common ground electrode configurations are vertically driven ground rods and horizontally positioned counterpoise. Frequently, topography, soil conditions, or rights-of-way access determine which is used. Furthermore, theft and rising construction costs, driven by utility requirements, have created a new challenge: the need for alternative grounding materials. This technical update identifies factors that could impact the service life of a grounding system and help utilities estimate the service life. Site visit will be used to measure the ground resistance and propose alternative grounding materials.