TY - GEN
T1 - Very low frequency breakdown strengths of electrical insulation materials at cryogenic temperatures
AU - Sauers, I.
AU - Tuncer, E.
AU - Polizos, G.
AU - James, D. R.
AU - Ellis, A. R.
AU - Pace, M. O.
PY - 2009
Y1 - 2009
N2 - For long cables or equipment with large capacitance it is not always possible to conduct high voltage withstand tests at 60 Hz due to limitations in charging currents of the power supply. Very low frequency (typically at a frequency of 0.1 Hz) has been used for conventional cables as a way of getting around the charging current limitation. For superconducting grid applications the same issues apply. However there is very little data at cryogenic temperatures on how materials perform at low frequency compared to 60 Hz and whether higher voltages should be applied when performing a high voltage acceptability test. Various materials including G10 (fiberglass reinforced plastic or FRP), kapton (commonly used polyimide), polycarbonate, and polyetherimide, and in liquid nitrogen alone have been tested using a step method for frequencies of 60 Hz, 0.1 Hz, and dc. The dwell time at each step was chosen so that the voltage stress time would be the same in both the 60 Hz and 0.1 Hz tests. The data indicated that, while there is a small frequency dependence for liquid nitrogen, there are significant differences for the solid materials studied.
AB - For long cables or equipment with large capacitance it is not always possible to conduct high voltage withstand tests at 60 Hz due to limitations in charging currents of the power supply. Very low frequency (typically at a frequency of 0.1 Hz) has been used for conventional cables as a way of getting around the charging current limitation. For superconducting grid applications the same issues apply. However there is very little data at cryogenic temperatures on how materials perform at low frequency compared to 60 Hz and whether higher voltages should be applied when performing a high voltage acceptability test. Various materials including G10 (fiberglass reinforced plastic or FRP), kapton (commonly used polyimide), polycarbonate, and polyetherimide, and in liquid nitrogen alone have been tested using a step method for frequencies of 60 Hz, 0.1 Hz, and dc. The dwell time at each step was chosen so that the voltage stress time would be the same in both the 60 Hz and 0.1 Hz tests. The data indicated that, while there is a small frequency dependence for liquid nitrogen, there are significant differences for the solid materials studied.
UR - http://www.scopus.com/inward/record.url?scp=77949289788&partnerID=8YFLogxK
U2 - 10.1109/CEIDP.2009.5377781
DO - 10.1109/CEIDP.2009.5377781
M3 - Conference contribution
AN - SCOPUS:77949289788
SN - 9781424445592
T3 - Annual Report - Conference on Electrical Insulation and Dielectric Phenomena, CEIDP
SP - 315
EP - 318
BT - CEIDP - 2009 Annual Report Conference on Electrical Insulation and Dielectric Phenomena
T2 - 2009 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, CEIDP
Y2 - 18 October 2009 through 21 October 2009
ER -