PROJECT TITLE :

Size effect on breakdown strength in sub-cooled liquid nitrogen for superconducting power apparatus

ABSTRACT:

Toward the sensible and rational insulation style of high temperature superconducting power equipment, the ac breakdown (BD) characteristics and mechanisms of liquid nitrogen (LN2) were systematically investigated and mentioned for various pressures at P = zero.one-0.3 MPa and temperatures at T = sixty five-seventy seven K underneath quasiuniform electric field with the sphere utilization factor ζ= 0.986-zero.674. We have a tendency to obtained the BD strength (EB) in sub-cooled LN2 (SLN2) and analyzed them in terms of size effect, taking account of the stressed liquid volume (SLV) with the electric field distribution in SLN2. Along side the other researchers??? data on BD characteristics of LN2, we tend to extended the evaluation by applying the concept of α% SLV (SLV with the electric field strength more than the decisive electric field issue, α of the most electrical field strength). As the result, we tend to derived that EB with the 50 p.c likelihood decreased linearly with the increase in αpercent SLV on a universal line, EB = seventy eight.4 x (αpercent SLV)-one/eight.fifteen, that was no matter the pressure and temperature of LN2.