Effect of magnetic compound electrode on space charge injection and accumulation in LDPE

Abstract

Space charge accumulation is the main factor in accelerating the degradation of polymeric insulation in high-voltage direct current (HVDC) cables. It is essential for the development of HVDC cables to suppress the space charge in the insulating layer. In this paper, an approach is presented to decrease carrier injection from the inner semiconductive layer to the insulating layer, using a magnetic semiconductive compound. The semiconductive shielding compound was prepared by adding strontium ferrite to a carbon black/ethylene-vinyl acetate/low-density polyethylene (LDPE) matrix. The addition of strontium ferrite led to an increase in the residual magnetic induction of the semiconductor shielding layer. Unmagnetized and magnetized semiconductive compounds were used as electrodes to test the injection of carriers into the LDPE insulation layer. When SrFe12O19 had been added, the charge injected into the LDPE by the magnetized semiconductive layer was less than with an unmagnetized semiconductive layer. When the content of SrFe12O19 was 5 wt. %, 10 wt. %, 30 wt. %, and 50 wt. % in the semiconductive compound, the charge in the LDPE was reduced by 4.2%, 8.1%, 12.5%, and 27.1%, respectively.

Space Charge Suppression Method of Insulation Layer of HVDC Cable Based on Semi‐Conductive Shielding Layer Modified by Nitrogen‐Doped Graphene

“…The preliminary study shows that the modification of the semi‐conduction layer can effectively reduce the space charge accumulation in the insulation layer. [ 8 ]…”

“…[1,2] As the voltage level increases, space charge accumulation in the insulation layer becomes one of the key issues that restrict its manufacture and development. Space charge accumulation in the cable insulation layer will cause local electric field distortion, [3][4][5][6][7][8] which will lead to the aging or deterioration of the material and reduce the overall insulation performance of the cable.…”

Effect of CNFs-Ni/LDPE electrode on space charge injection in LDPE insulating layer

“…After long-term operation, it is proved that the semiconductor shielding layer has a great relationship with the service life of the cable [6], [7] . The semiconductive shielding layer of high-voltage DC cable with excellent performance can effectively inhibit the injection of carriers from the metal core to the insulating layer.…”

Effect of graphene modified semi‐conductive shielding layer on space charge accumulation in insulation layer for high‐voltage direct current cable

“…There have been studies showing that the characteristics of the semi‐conductive layer will affect charge accumulation of the insulation layer [17–21]. Our latest study found that the modification of the semi‐conductive layer can effectively reduce charge accumulation in the insulation layer [22]. Hence, it is expected to be an effective method to reduce space charge accumulation of HVDC cables by modifying the semi‐conductive layer.…”