TY - JOUR
T1 - DC breakdown voltage characteristics of saturated liquid helium in the presence of metallic particles
AU - Hara, Masanori
AU - Maeda, Yuji
AU - Nakagawa, Nobutaka
AU - Suehiro, Junya
AU - Yamada, Shuichi
N1 - Funding Information:
This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture (MESC), Japan, the cooperative research funds from the NIFS, Japan and the 21st Century Center of Excellence (COE) Program of MESC, Japan.
PY - 2006/6
Y1 - 2006/6
N2 - This paper deals with the breakdown voltage characteristics of saturated liquid helium in the presence of a needle-shaped or spherical metallic particle to obtain insulation design data for pool-cooled, low-temperature superconducting coils and to find the predominant factor affecting the breakdown voltage of liquid helium at a given state. The results show the following. (1) The generation of bubbles at the instant of collision of a particle with an electrode is caused mainly by the kinetic energy released from the moving particle to the liquid helium, while the electrostatic energy accompanying the microdischarge between the particle and the electrode has a lesser effect on it. (2) The lowest breakdown voltage at different particle conditions appears in the case of a free needle particle. The low breakdown voltage is caused by the bubble triggered by the particle collision, the high electric field at the tip of the needle particle, and the rich initial electrons supplied by the microdischarge.
AB - This paper deals with the breakdown voltage characteristics of saturated liquid helium in the presence of a needle-shaped or spherical metallic particle to obtain insulation design data for pool-cooled, low-temperature superconducting coils and to find the predominant factor affecting the breakdown voltage of liquid helium at a given state. The results show the following. (1) The generation of bubbles at the instant of collision of a particle with an electrode is caused mainly by the kinetic energy released from the moving particle to the liquid helium, while the electrostatic energy accompanying the microdischarge between the particle and the electrode has a lesser effect on it. (2) The lowest breakdown voltage at different particle conditions appears in the case of a free needle particle. The low breakdown voltage is caused by the bubble triggered by the particle collision, the high electric field at the tip of the needle particle, and the rich initial electrons supplied by the microdischarge.
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U2 - 10.1109/TDEI.2006.1657957
DO - 10.1109/TDEI.2006.1657957
M3 - Article
AN - SCOPUS:33746607754
VL - 13
SP - 470
EP - 476
JO - IEEE Transactions on Dielectrics and Electrical Insulation
JF - IEEE Transactions on Dielectrics and Electrical Insulation
SN - 1070-9878
IS - 3
M1 - 1657957
ER -