Next-Generation Insulation Material in DC Cable Joints to Enable Renewable Energy Integration.

Abstract

Polymeric insulation materials in cable joints plays a crucial part in the HVDC transmission system. Developing the breakdown strength in the cable joints is desirable to enable further integration in renewable energy. As a result, many researches are investigating the space charge behaviour on insulations of the cable joints. It was found that the space charge of the interface between two insulation materials in the cable joints significantly impact the breakdown strength. Therefore, this project has investigated the electric field and the space charge behaviour at the interface in four different scenarios. The project is based on the experiment result obtained from the HVDC lab. For this MSc project, the pulse-electro-acoustic (PEA) is selected as a method to test the interfacial space charge behaviour between two 100 µm low-density polyethylene (LDPE) samples. The position of the polished surface at the interface is varied and the electric field for each of the scenario is calculated using LabView software. The results were interpreted based on literature review. Our finding conclude that the interface surface that are closer to the electrode impact the electric field more than the interface closer to the anode because of the negative charge injection from the electrode. Finally, polished and clean interface demonstrate the most reliable scenarios for breakdown strength and space charge profile as results shown.