Surface flashover characteristics of fluorinated polyimide films in liquid nitrogen

Abstract

With the emergence of superconductor technology, high temperature superconducting (HTS) power devices are quickly being developed. Among them, the HTS cable is receiving considerable attention and application in power systems due to high capacity and low loss. To develop a HTS power cable system, the terminal technology is essential component. The HTS cable terminations must withstand a temperature as low as 77K. So, it is necessary to study the termination insulation materials and electrical properties at cryogenic temperature. Polyimide film (PI) and liquid nitrogen (LN 2 ) have been used as insulation material and coolant in HTS cable systems. Surface flashover may lead to degradation and breakdown of HTS cable termination insulation. To optimize the insulation design of HTS cable termination, the method of direction fluorination was used for modulating the electrical properties and restraining the surface discharge of the PI film. In this paper, the surface flashover characteristics of original and fluorinated PI were investigated under 50 Hz AC voltages in LN 2 . The results show that the direction fluorination of PI film can improve the surface flashover strength.

Study on surface discharge of nonlinear conductive epoxy resin/SrTiO3 composites in 80–300 K temperature zone

“…In addition, the performance of the insulation material is affected by temperature, and the charge accumulation phenomenon of current lead insulation is more obvious when working in the wide temperature range from liquid nitrogen temperature to room temperature [8,9]. It aggravates the degree of electric field distortion and makes flashover one of the main causes of terminal insulation failure of superconducting equipment [10,11]. In order to improve the long-term operation reliability of superconducting power equipment, the surface flashover mechanism and insulation performance improvement method of EP should be further studied in high voltage and wide temperature zone environment.…”