Study on Interfacial Charges of Double-layer Crosslinked Polyethylene

In the factory joints of cables with the insulation of cross-linked polyethylene (XLPE), an interface exists between the two layers of XLPE. The study on the charge accumulation characteristics at the interface is of great significance for the design and application of high voltage direct current (HVDC) cable system. In this work, we prepared the XLPE slices with different cross-linking times, and then hot-pressed them for different times to make the double-layer samples. The interface charge distributions of double-layer samples were measured by pulse electro-acoustic (PEA) method. The polarity of the interface charges will changes with the cross-linking time. Different interface charges induce various insulating electric field distortions. This may provide an approach to estimate the field distortion in factory joints for HVDC cables.