Results 261 to 270 of about 10,890 (317)
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2008 23rd International Symposium on Discharges and Electrical Insulation in Vacuum, 2008
The results of switching tests of a DC vacuum circuit-breaker designed for rated voltage 3.3 kV and rated current 3000A are presented. The circuit-breaker is intended for current interruption in the networks with fault currents up to 30 kA. To interrupt the direct current, the authors used a method of artificial current transition through zero in the ...
D. Alferov +5 more
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The results of switching tests of a DC vacuum circuit-breaker designed for rated voltage 3.3 kV and rated current 3000A are presented. The circuit-breaker is intended for current interruption in the networks with fault currents up to 30 kA. To interrupt the direct current, the authors used a method of artificial current transition through zero in the ...
D. Alferov +5 more
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IEEE Transactions on Power Apparatus and Systems, 1972
The effectiveness of the commutation principle, using vacuum interrupters as a means for interrupting high direct current at high voltage, has been demonstrated convincingly by a large number of tests. Currents in excess of 15 kA at 20 kV have been interrupted by a single device in an inductive circuit.
A. Greenwood, P. Barkan, W. Kracht
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The effectiveness of the commutation principle, using vacuum interrupters as a means for interrupting high direct current at high voltage, has been demonstrated convincingly by a large number of tests. Currents in excess of 15 kA at 20 kV have been interrupted by a single device in an inductive circuit.
A. Greenwood, P. Barkan, W. Kracht
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Vacuum-state estimation of vacuum circuit breakers
SPIE Proceedings, 1994The vacuum state of vacuum switching elements after production is checked normally by Penning- or Magnetron methods (combined electrical and magnetic field). Vacuum in the range of 10-1 - 10-4 Pa can be measured in this way. After assembly into circuit breakers however, these methods are not applicable.
Damstra, G.C. +2 more
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High voltage vacuum circuit breakers
IEEE Transactions on Power Apparatus and Systems, 1975A new line of high voltage vacuum power circuit breakers is being developed for 121 kV and above and will use the new vacuum interrupter module presented in a companion paper3. The first ratings in production will be 242 kV with interrupting capabilities of 40,000 amperes, followed by breakers rated 50,000 amperes; both of these will have continuous ...
R.B. Shores, V.E. Phillips
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Low Surge Vacuum Circuit Breakers
IEEE Power Engineering Review, 1985Low surge vacuum circuit breakers were developed which used a new electrode material cobalt-silver-selenium alloy. Their chopping current level was below 1.0 A and their high frequency current interruption ability was about 24 Aus. These levels were much lower than those of conventional electrode materials and did not change after load current ...
Y. Kurosawa +5 more
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Estimation of vacuum condition in vacuum circuit breakers
Proceedings ISDEIV. 18th International Symposium on Discharges and Electrical Insulation in Vacuum (Cat. No.98CH36073), 2002In this paper a method is described for the estimation of the pressure inside vacuum circuit breakers which have been in operation for several years. The method is applicable for measurements in the field and uses only electrical measurement techniques.
Merck, W.F.H. +2 more
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Surge limiters for vacuum circuit breakers
IEEE Transactions on Industry Applications, 1988Computer modeling was used to confirm the applications which require surge protection and to verify that surge limiters installed within the switchgear will provide this protection. The basic phenomena which cause vacuum-switchgear-related surges are reviewed, and the need for surge limiters is discussed.
S.H. Telander, M.R. Wilhelm, K.B. Stump
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Medium voltage DC vacuum circuit breaker
2015 3rd International Conference on Electric Power Equipment – Switching Technology (ICEPE-ST), 2015The increased use of directed current (DC) as an enabler for the integration of renewable sources gains rising interest also for power transmission and distribution networks. Some preliminary installations showed some benefit of this technique compared with alternating current (AC) and pushed the development of switchgear for high (HV) and medium ...
Lars Liljestrand +4 more
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Continuous vacuum monitoring in vacuum circuit breakers
2014 International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV), 2014Vacuum presence monitoring is a routine maintenance procedure carried out on vacuum circuit breakers, in which the CB is isolated from the electrical network. The presence of the vacuum is verified by applying a voltage across the open contacts of the vacuum interrupters VI's higher than the breakdown voltage of such contacts in air. This procedure has
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Maintenance-free vacuum circuit-breaker
Second International Conference on the Reliability of Transmission and Distribution Equipment, 1995The introduction of vacuum switchgear represented the first step in the direction of a maintenance-free medium-voltage circuit-breaker. Switching in a vacuum was the first quenching principle to assure constant electrical and dielectric properties throughout the device's entire service life of more than 20 years, involving for example more than 100 ...
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