Non-destructive Evaluation Of Non-shielded Power Plant Cables By Tme-domain Dielectric Spectroscopy

In a search to identify non-destructive test methods for evaluating the condition of non-shielded power plant cable insulation, time-domain spectroscopy (TDS) was investigated in conjunction with several types of cable materials and constructions. At the outset, i t was decided to consider only those methods which did not necessitate subjecting the cables to unduly high voltage stresses and which could be readily implemented in power plant environments. Techniques t o detect discrete defects, such as cuts, pinholes and bruises, were explored separately [l] and, therefore, are not covered in this report which concentrates on the determination of overall deterioration. Although the investigation included shielded a s well as non-shielded cables, only two varieties of this latter category are discussed in this paper.