DC Flashover Characteristics of Fluorosilicone Rubber-PEEK Interface in Underwater Electrical Connector

The underwater electrical connector is a key device for power supply in deep seas, where the Fluorosilicone Rubber (FSR) -PEEK is often used as the insulation and sealing component. In this paper, a solid-solid interface discharge experimental platform was established, and the flashover characteristics of the FSR-PEEK interface as well as the influence of the interface pressure were investigated. The results showed that, in the range of 0.005–0.6 MPa interface pressure, the flashover electric field strength (Efsh) of the FSR-PEEK interface increased rapidly at first and then gradually got a saturation. Efsh was only 2.67 kV/mm at 0.005 MPa and reached 4.10 kV/mm at 0.05 MPa. And Efsh increased little and was 4.10–5.41 kV/mm at 0.05–0.6 MPa. The cavity in the interface, acting as the weak-point of the interface insulation, was responsible for the flashover. With the increase of the interface pressure, the cavity is compressed and the average size of the cavity decreases, resulting in a significant increase in interfacial insulation strength. The results provided some useful data for the design of the Underwater Electrical Connector.