Title :
Partial discharge inception characteristics of LN2/epoxy composite insulation system under thermal bubble condition
Author :
Hayakawa, N. ; Maeda, H. ; Chigusa, S. ; Okubo, H.
Author_Institution :
Dept. of Electr. Eng., Nagoya Univ., Japan
Abstract :
In this paper, we investigated electric field strength (PDIE) at partial discharge (PD) inception in liquid nitrogen (LN2)/epoxy composite insulation system with thermal bubbles at atmospheric and pressurized conditions. We measured PDIE and PD charge, and simultaneously observed the bubble diameter, number and their behavior using a high-speed video system of 200 frames/s. PDIE characteristics were analyzed using Weibull statistics. The pressure dependence of bubble diameter, PD charge and scale parameter of PDIE was systematized for different thermal bubble conditions. Experimental results revealed that (1) PD was initiated in thermal bubbles in LN2, (2) the scale parameter of PDIE decreased with the increase of Vrate defined as the volume ratio of thermal bubbles to the gap space, (3) PDIE was found to mutually depend on not only Vrate but also gas density in the thermal bubbles
Keywords :
Weibull distribution; bubbles; composite insulating materials; dielectric liquids; electric strength; epoxy insulation; high-pressure effects; nitrogen; partial discharges; LN2/epoxy composite insulation; N2; PD charge; Weibull statistics; atmospheric conditions; bubble diameter; electric field strength; gas density; high-speed video system; liquid nitrogen; partial discharge inception characteristics; pressurized conditions; thermal bubble condition; thermal bubbles; Charge measurement; Cryogenics; Current measurement; Dielectric liquids; Dielectrics and electrical insulation; Electric breakdown; Electrodes; Nitrogen; Partial discharges; Space heating;
Conference_Titel :
Dielectric Liquids, 1999. (ICDL '99) Proceedings of the 1999 IEEE 13th International Conference on
Conference_Location :
Nara
Print_ISBN :
0-7803-4759-5
DOI :
10.1109/ICDL.1999.798955
