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The electrical breakdown characteristics of oil-paper insulation under steep front impulse voltages
- Source :
- IEEE Transactions on Power Delivery. 9:1926-1935
- Publication Year :
- 1994
- Publisher :
- Institute of Electrical and Electronics Engineers (IEEE), 1994.
-
Abstract
- Disconnecting switch operations in gas insulated equipment cause transient voltages with risetimes as steep as 5 to 20 nanoseconds and magnitudes as high as 2.5 pu. There is very little information on the effect of these transients on oil-paper insulated equipment. There have been reports, however of transformer and bushing failures caused by these transients. The electrical breakdown characteristics of oil-paper insulation under steep front impulse were studied in this project, which was co-sponsored by the Canadian Electrical Association and BC Hydro. V/sub 50/ (50% breakdown probability voltage) breakdown data was obtained with steep front (10 ns/2500 /spl mu/s), lightning and switching impulse waveforms. Insulation breakdown voltage vs breakdown time (V-t) data and multiple impulse breakdown data were obtained with the steep front impulse waveform. The V/sub 50/ results showed that the breakdown strengths were lower for steep front impulses than for lightning impulses. The multiple impulse breakdown results showed that oil-paper insulation breakdown strength can be lower than 100 kV/mm. These results are alarming, since they suggest that oil-paper insulated equipment subjected to steep front transients will fail at voltages below the lightning impulse design level (BIL). The volt-time data had a discontinuity. The breakdown process at risetimes below about 50 ns was different from the breakdown process at risetimes above 50 ns. >
- Subjects :
- Engineering
Dielectric strength
business.industry
Transformer oil
Acoustics
Electrical insulation paper
Electrical breakdown
Electrical engineering
Energy Engineering and Power Technology
Dielectric withstand test
Electrical equipment
Rise time
Breakdown voltage
Electrical and Electronic Engineering
business
Subjects
Details
- ISSN :
- 08858977
- Volume :
- 9
- Database :
- OpenAIRE
- Journal :
- IEEE Transactions on Power Delivery
- Accession number :
- edsair.doi...........d5f22483fbd316d8ab5879301f81947a