Propagation characters of PD UHF signal in a prefabricated joint of XLPE cable

Abstract

Abstract Investigating the propagation characters of UHF partial discharge (PD) signals in cable joint is helpful to the application of UHF method in XLPE PD monitoring. In this paper, a propagation model about UHF signal in a prefabricated joint is constructed. Based on it, it effects of some factors, i.e. longitudinal distance of detection location, lateral location of detection, detecting angle, pulse width, pulse amplitude, the size of metal shield and the thickness of semiconductive layer, on the PD signal propagation are studied. It is found that the signal amplitude decays faster in the joint than that in the body, and the signal intensity is much stronger inside the metal shield than that outside. The maximum amplitude of electromagnetic wave radiated by the PD source appears in the radial direction along the radius of the cross-section. The short duration of discharge pulse contributes to the appearance of high-order modes, while the response signal is proportional to the PD source. The metal shield and semiconductive layer increase the signal attenuation. These results provide insight into some design parameters of UHF antenna and its installation location.