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Recently, the self-blast principle of extinguishing the arc by the blast pressure which is generated by the arc itself has been widely applied to the high voltage circuit breaker. In the self-blast principle, the pressure relief valve fitted on the piston is opened to release excessive pressure in the compression volume during high current interruption. The design of the pressure relief valve operation...
Superior characteristics of SF6 gas have enabled its successful use as the interruption media in high voltage circuit breakers. Unique combination of physical properties considers high dielectric strength, high thermal interruption capability and high heat transfer performance. However, having in mind its high global warming potential (GWP), long term use of SF6 gas in the future should be called...
Special attention needs to be given to the processes that occur in alternating current arcs at the instant when the current naturally passes through a zero. The short interval of time around current zero, named the "interaction period" [1], is of crucial importance for arc-quenching, when it is decided whether the interruption will be definite or whether arc reignition will occur. As a matter...
The interruption of capacitive currents is a very common switching case, unlike the breaking of short-circuit currents. The current involved is quite small and therefore easy to interrupt. However, a recovery voltage higher than 2 per unit appears across the contacts half a cycle after current zero. This circumstance inevitably increases the risk of restrikes, which may have rather undesirable effects,...
The density and SF6 gas pressure distribution along the nozzle of a HV circuit breaker plays an important role in the process of current interruption. Therefore, the analysis of the pressure distribution is essential for researchers and designers of HV SF6 circuit breakers. In this paper, simulation software for HV SF6 circuit breakers, which is based on an integral-physical enthalpy flow arc model,...
A considerable part of the energy released by electric arc during breaking of a short-circuit current is being absorbed in the moving and stationary arcing contacts. The rest of the energy is being released as thermal stresses of the nozzle and of other parts of the arcing chamber, as well as heating, dissociation and ionization of the arc extinction medium, and in losses to the nearby environment...
The biggest drawback in modelling the reliability of high voltage circuit breakers is the lack of access to data on failures in service, due to the very long lifetime of circuit breakers. This paper presents the application of reliability calculation based on Bayesian statistics to a 245 kV SF6 circuit breaker and its operating mechanism. By using the Bayesian theorem, the prior probability density...
Energy released by electric arc during short circuit switching is mostly absorbed by the surrounding cold SF6 gas. However, a considerable part of this energy is also transferred and absorbed by other elements of the circuit breaker interrupter which are located near the electric arc. The most important parts are the transfer of energy to the arcing contacts and to the nozzles, absorption of the energy...
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