VFT performance of a 180/110 mm co-axial gap in SF6 up to 4 bar absolute

• Published in: 11th International Symposium on High-Voltage Engineering (ISH 99) pp. 1.201.P4 - 1.204.P4
• Main Authors: Nielsen, S.D, Reynders, J.P, Jandrell, I.R
• Format: Conference Proceeding
• Language: English
• Published: London IEE 1999
• Subjects: Applied sciences; Electrical engineering. Electrical power engineering; Exact sciences and technology; Inorganic insulation; Switchgear; Testing. Reliability. Quality control; Voltage measurement; SF6; positive polarity; SF6 insulation; oscillation frequency; negative polarity; gap geometries; 1 to 4 bar; insulation co-ordination purposes; 110 mm; disconnector switch operation; measured breakdown voltage; voltage dividers; gas insulated switchgear; voltage divider location; VFT performance; co-axial gap; V-t data; GIS; 13.6 MHz; transient analysis; switching impulse generation; capacitor discharge; voltage measurement; transformer primary; 180 mm; Test method; Electrical insulation; High voltage; Gas insulated equipment; Impulse; Transients
• ISBN: 0852967195; 9780852967195
• ISSN: 0537-9989
• DOI: 10.1049/cp:19990542

Disconnector switch operation in GIS generates VFT voltages in the system. It is important, for insulation co-ordination purposes, to obtain accurate VFT V-t data for typical gap geometries found in GLS. This paper presents experimentally obtained VFT V-t data for a 180/110 mm co-axial gap. The VFT has a time to first peak of 35 ns and a oscillation frequency of 13.6 MHz. Due to the location of the voltage divider in a compartment adjacent to the gap, a correction factor of 1.1 is used to relate the measured breakdown voltage to that in the gap. Positive polarity VFT V-t data is presented for 1, 2, 3 and 4 bar absolute and negative polarity VFT data for 3 and 4 bar absolute. Two methods of generating the VFT's are used. The first is to power up the test transformer at power frequency. The second is to generate a switching impulse by discharging a capacitor into the primary of the test transformer. (4 pages)