Effect of SrFe12O19 Orientation in the Inner Semiconductive Layer on Charge Accumulation Characteristics of HVDC Cable

A method of space charge suppression for high-voltage direct current (HVDC) cable is proposed by the modification of the semiconductive layer. In this work, the magnetic particle of SrFe
₁₂
O
₁₉
is used to modify the semiconductive shielding layer, and the effect of SrFe
₁₂
O
₁₉
orientation on the charge accumulation of the insulation layer has been studied. First, the semiconductive composite with different SrFe
₁₂
O
₁₉
contents is prepared and their physicochemical properties are characterized. Second, the effect of the SrFe
₁₂
O
₁₉
orientation in the semiconductive layer and the doping contents on the charge accumulation in the insulation layer is analyzed by measuring the resistivity and space charge. The experimental results show that a certain amount of SrFe
₁₂
O
₁₉
(≤10 wt%) can effectively reduce the positive temperature coefficient (PTC) effect, and the orientation can more effectively reduce the space charge injection from the metal wire core to the insulation layer, thus inhibiting the charge accumulation in the insulation layer. While when the content of magnetic particles is high, it will promote the second injection of the charges, leading to an increase of the charge accumulation. The work provides a new idea for space charge suppression of HVDC cable insulation layer.