Modeling of Currents on Long Span, Dielectric Cables on HV Overhead Lines

It is well established that all-dielectric self-supporting cables on high-voltage overhead power lines can suffer from damage through the mechanism of dry-band arcing. A number of heuristics have evolved over the past 20 years and these are used to determine whether such cables are capable of reliable performance. A key element to planning is modeling the installation conditions. In addition to the geometry of the high-voltage line, such a model needs to consider the climatic environment and potential pollutants on the cable. In this paper, a model is built based on the commercial software current distribution, electromagnetic fields, grounding and soil structure analysis which is widely used in the power industry. The model developed is shown to be consistent with a number of previously published models. It is demonstrated that the relative sags of all-dielectric self-supporting cable and conductors are key to the severity of the installed situation. It is also shown that the towers do not need to be modeled for the most severe cases of high pollution, but are required for accuracy in medium and low pollution cases