Some investigations on packet charge formation in LDPE

The HVDC (high voltage direct current) transmission through cable is being seen as an alternative to augment the regional connectivity. The major hindrance to HVDC transmission, beyond a certain voltage through cable, is insulation breakdown in cables. It is believed that space charge is one of the reasons for aging of insulation or cable breakdown. Although some progress had been made in understanding the packet charge phenomenon, but still many queries about it remained to be answered. Generally the charge packets in LDPE (low density polyethylene) are observed at an electric field of 100kV/mm or higher. In the present work authors have investigated the effect of sudden step voltage application on packet charge phenomenon. The electric field from 100-150 kV/mm was applied to the samples. The analysis of space charge data obtained experimentally in the authors´ laboratory indicates the dependence of packet charge formation on step voltage application.