Improvement of electric strength for high voltage connectors in J-PARC RCS kicker system

Suganuma, Kazuaki ; Kamiya, Junichiro   ; Watanabe, Masao  ; Takayanagi, Tomohiro   ; Togashi, Tomohito; Ueno, Tomoaki

The insulating oil became brownish-red and sticky solid materials emerged at the connectors of the coaxial cable for transmitting high-voltage pulse. Then, maintenance of the system increased extremely. In order to identify the cause, the author analyzed the gas contained in the discolored insulating oil. The cause was considered to be the deterioration of oil at less than 300 C and the deterioration of oil due to electric discharge. In addition, the connector configuration simulation was conducted. It was found that electric fields tend to concentrate in the air layer at the upper part of connector and at the polyethylene tip of the receiving connector. A structure in which electric fields are alleviated was determined with the simulation, and electricity was applied, and the inner condition was observed. As a result, when the inner diameter of the outer cylinder was increased, oil deterioration was alleviated and dielectric strength voltage was improved.