Failures clarification of MV nonmetallic screened aerial bundled cables

Medium voltage nonmetallic screened aerial bundled cable (ABC) has been used in Brazil for 20 years as a solution for substation exits, narrow streets and crossings. The benefits of such cables are well known. This simple cable construction has been appointed by some customers as the reason for an unexpected number of in-service failures. During the survey of plausible causes of failures several hypotheses have emerged, including an unsuitable electric field control, since the polymeric semiconducting outer layer (SMC) does not have the same characteristics of a metallic screen. This work reports the cable behaviour when subjected to a multi-stress test that simulates operation conditions, aiming to clarify failure mechanisms of such cables