Short-Term Electrical Insulating Characteristics of Some Polymeric Materials Immersed in Liquid Nitrogen

This paper reports the short-term partial-discharge and electrical breakdown characteristics of some film-type and fibrous materials and laminates of fibrous and film-type materials immersed in liquid nitrogen (LN2) Partial discharge inception and extinction voltages, and also the distribution of their magnitude and repetition rate are studied in the various specimens with and without artificial cavities at pressures up to 0.4 MPa. The results emphasize the relative roles played by the gas bubbles inside the cavity and the structure of the material.