Cables Scab, A Scientific Characterization of The Degradation of XLPE and HV/ HR-PVC Insulation Under the Influence of Ultraviolet Radiation and Excessive Mechanical Stress in An Environment Extremely Hostile to Polymers
Abstract
Excellent standard polymer-insulated resistive electrical cables suffer from outer layer deterioration due to excessive mechanical stress, which leads to damage to the jacket (the outer layer of the insulation). Prolonged exposure to ultraviolet (UV) radiation causes physical and chemical changes that affect the adjacent cables, compromising the reliability of the electrical system.
This paper presents a scientific and field description of a condition called "cable scab," a term that refers to a pattern of gradual surface deterioration affecting adjacent cables. This term does not cause immediate failure but rather represents an early indicator of critical deterioration. The concept is extended to include poor implementation during laying. The description is supported by a physical explanation using Einstein's photochemical breakdown equation, an analysis of the effect of UVA,B,C on XLPE and HR-PVC, and technical recommendations for inspection and treatment are provided.