Study on Precipitate Aggregation Mechanism in Prefabricated Termination for XLPE Cable

A stress relief cone (SRC) plays an essential role in the prefabricated termination of an XLPE cable system to sustain the electrical insulation capability at the cable's end section. Precipitate is generated on a certain part of the SRC surface due to long-term operation, which could lead to a dielectric breakdown; however, its generation process has not yet been clearly elucidated. This study focuses on dielectrophoresis to clarify the formation process of precipitate. First, a model electrode simulating the SRC shape is created, and the state of precipitate aggregation using a precipitate-simulating ferroelectric substance is reproduced. Next, a numerical calculation model of dielectrophoresis is used to derive the density distribution of the precipitate over time. As a result, the precipitate aggregation state could be reproduced, which is similar to a dismantled SRC after a long-term operation. For these reasons, the authors conclude that the precipitate could be the aggregate of fine particles precipitated from the rubber material of the SRC by dielectrophoresis.