Analysis of Insulation Materials of Cable Systems by Method of Partial Discharges

The problem of formation and development of the partial discharges (PD) in isolation of the high-voltage equipment in the conditions of its operation represents a great interest as for the personnel operating the equipment, and for developers of the equipment and researchers of electric isolation. PD constitute a big danger to insulation because of its fast destruction in local zones and the subsequent breakdown of insulating intervals. Previously, intensive researches has been conducted, in Germany, the USA, Japan and in some other countries, for the purpose of development and deployment of effective nondestructive methods of diagnostics of insulating materials of technical systems under operating conditions [1, 2]. The weakest links in cable systems are insulating materials (OIP- paper oil insulation, polyethylene (PE), viped polyethylene (VPE). Thus this study aims to develop a physical principle of determining defects in insulating materials by the PD method. We can allocate the following types of aging and destruction of electrical insulation of power cable lines (PCL): thermal aging, electric treeings, and water treeings. The sequence and interrelation of the processes causing electric aging and breakdown of isolation, is shown in Fig. 1.