To clarify the evolution characteristics of discharges at the cross-linked polyethylene (XLPE)-silicone rubber (SiR) insulation interface of cable joints in actual operation

an equivalent circuit model of streamer breakdown-arc discharge at the XLPE-SiR insulation interface is constructed on the basis of the joint structure and discharge path in this paper. It is determined that the dielectric strength of the insulation interface (KI) is the core control parameter of streamer breakdown characteristics

while the arc equivalent resistance (rD) and the resistance of the semiconducting layer (RS) jointly regulate the arc discharge characteristics. Then

the effects of three key factors of insulation interface pressure

interfacial insulation pyrolysis evolution

and the positive temperature coefficient (PTC) effect of the semi-conductive layer on the characteristics of insulation interface streamer breakdown-arc discharge are determined by the synergistic analysis method of AC-DC breakdown experiments. Finally

the evolution characteristics of streamer breakdown-arc discharge at the XLPE-SiR insulation interface are analyzed in combination with discharge optical detection and discharge theories. The results show that the insulation interface pressure has a strong inhibitory effect on the initiation and breakdown of insulation interface streamers

and is independent of the arc discharge characteristics of the insulation interface. The pyrolysis evolution of the interface insulation promotes the development of insulation interface streamer initiation-breakdown-arc discharge. The PTC effect of the semiconducting layer accelerates the dissipation of the arc at the insulation interface by limiting the current

and is independent of the streamer breakdown at the insulation interface. This research provides theoretical and experimental supports for the prevention of discharge faults in cable joints.