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Toepler's spark law in a GIS with compressed $SF_6-N_2$ mixture

Singha, Santanu and Thomas, Joy M (2003) Toepler's spark law in a GIS with compressed $SF_6-N_2$ mixture. In: IEEE Transactions on Dielectrics and Electrical Insulation, 10 (3). pp. 498-505.


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This paper deals with the experimental measurements and analysis of the formative time lags to breakdown and an estimation of the Toepler's constant for gas gaps, under the application of 50 Hz AC voltage. The experiments were carried out in a 145 kV gas insulated system (GIS) bus duct with pure $N_2$, pure $SF_6$ and $SF_6-N_2$ mixture as insulating media. The formative time lags to breakdown in the gas gaps were measured using a fast response capacitive sensor. Toepler's spark law has been used to explain the breakdown phenomenon in the GIS and the values of Toepler's constant $(k_t)$, which gives an estimation of the formative time lags, were determined. Results show that the formative time lags vary inversely with gas pressure and the gas mixture concentrations for two gaps studied (0.46 mm and 0.61 mm). In the case of another gap (0.20 mm), the variation in the formative time lags with pressure as well as $SF_6$, concentration in the mixture has been found to be negligibly small between gas mixtures, although significant variation can be seen between pure $SF_6$ and pure $N_2$. Toepler's constant, $K_t$, increases with gas pressure as well as $SF_6$ concentration in the mixture for the gaps studied. Hence, $k_t$ is a function of the gas pressure and the concentrations of $SF_6$ in the gas mixture for the above-mentioned gaps.

Item Type: Journal Article
Publication: IEEE Transactions on Dielectrics and Electrical Insulation
Publisher: IEEE
Additional Information: �©1990 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Keywords: Gas insulated systems;Very fast transient over voltage; Toepler's spark law;Formative time lags;SF6-N2 Mixtures
Department/Centre: Division of Electrical Sciences > High Voltage Engineering (merged with EE)
Date Deposited: 21 Dec 2005
Last Modified: 19 Sep 2010 04:22
URI: http://eprints.iisc.ac.in/id/eprint/4704

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