Title :
Streamer injection and growth under impulse voltage: a comparison of cyclohexane, Midel 7131 and Nytro 10X
Author :
Hestac, O.L. ; Berg, G. ; Ingebrigtsen, S. ; Lundgaard, L.E.
Author_Institution :
SINTEF Energy Res., Trondheim, Norway
Abstract :
Streamer growth and charge injection vs. applied impulse voltage has been studied in cyclohexane, Midel 7131 (ester based transformer liquid) and Nytro 10X (mineral transformer oil). Experiments were conducted in point-plane geometry under 50 ns/740 μs impulse voltage. The tip electrodes were electrochemically etched to 2.0 μm and 2.3 μm with electrode gaps of respectively 19.5 mm and 17 mm. Shadowgraphic imaging and a sensitive differential charge measurement technique were used to detect the streamer shape and charge. The experimental setup used can detect charge injections as low as 0.1 pC, and has an image resolution of 4.5 μm. When comparing Midel 7131 to Nytro 10X similar streamer shape and length under positive and negative polarities at the same voltage were found, but Midel 7131 had a higher initiation voltage and less charge was injected into this liquid compared to Nytro 10X at the same voltage.
Keywords :
charge injection; charge measurement; dielectric liquids; discharges (electric); transformer insulation; transient response; 17 mm; 19.5 mm; 2.0 micron; 2.3 micron; Midel 7131; Nytro 10X; charge injection; cyclohexane; dielectric liquid electric breakdown; differential charge measurement technique; electrochemically etched tip electrodes; electrode gap; ester based transformer liquid; impulse voltage polarity; mineral transformer oil; point-plane geometry; shadowgraphic imaging; streamer growth; streamer initiation voltage; streamer length; streamer shape; Charge measurement; Electrodes; Etching; Geometry; Image resolution; Minerals; Oil insulation; Shape measurement; Streaming media; Voltage;
Conference_Titel :
Electrical Insulation and Dielectric Phenomena, 2004. CEIDP '04. 2004 Annual Report Conference on
Print_ISBN :
0-7803-8584-5
DOI :
10.1109/CEIDP.2004.1364307