Voltage stress reduction for distribution line covered conductor

Abstract

Interruptions due to vegetation frequently occur at the distribution line in Indonesia. Follows to that, the distribution utility decided to replace the bare conductor with the one-layer XLPE cable. However, new problems occurred mainly at the link between the XLPE cable and the post insulator on each of distribution pole. The high permittivity material of XLPE and the ceramic insulator enhance the local electric field that produces pinholes on cables. In the later phase, the pinholes become more extensive and if there is a lightning strike that causes a voltage that exceeds the Basic Insulation Level of the insulator, then the electric arc will flow from the conductor to the ground isolator through the pinhole. This paper proposed a novel design to cover the cable, including its accessories. Based on a simulation using a finite element analysis, the electric field stress is reduced by the following steps: 1. Add a semiconductor layer on the XLPE layer, 2. Replace the ceramic insulator with the polymer one, 3. Modify the binding between the cable and the post insulator by using a unique clamping method.