Self-healing of electrical tree damage of polyethylene/microcapsules insulation composite material

Abstract

During the use of polyethylene (PE) cable in power systems, electrical tree damages can inevitably occur inside the insulation materials, causing partial discharges and threatening the safety of the power supply. It is difficult to detect the micro damages inside the materials by existing technology, and replacing cables creates a lot of solid waste. The microcapsule self-healing technology derived from bionics can automatically detect and heal micro damages inside the material in time, avoiding accidents and saving resources. In this paper, the self-healing abilities and mechanism of the PE/microcapsule composite materials to the electrical tree damage are studied by means of experiments and simulation. PE/microcapsule composite materials are prepared, and the composite material with 1 wt% microcapsule is demonstrated to have better insulation strength. Microcapsules can attract the development of electric trees and limit their size, while the electrical tree can trigger the self-healing behavior of microcapsules in time. The self-healing behavior can effectively heal the electrical tree branch channel, restore breakdown strength and polarization current, and reverse the deterioration process of the material. Molecular dynamics (MD) simulation confirms that there is good chemical compatibility between the healing product and PE matrix, ensuring a good self-healing effect.