Objective
A model quenching chamber has been developed which will allow better knowledge of gas dynamics. The software model allows optimisation of chamber geometry, dielectric recovery in the interelectrode zone to be studied and extrapolation of known results. This in turn will lead to a reduction in tests required and design costs.
The research carried out investigated the reduction or elimination of the time required for prototype testing by developing a computer aided design procedure for circuit breaker chambers within the voltage range 72 to 300 kV and currents between 12 and 60 kA, and with a maximum power of 30 GW. Thus the phenomena related to the switching of short circuit currents in the breakers are modelled. Measurements were taken throughout the research. These covered velocity, temperature and pressure in the odd gas flow, radiation and arc observations.
Spectrographic measurements of the arc temperature and electron density were made up to the region of zero current after a power arc. This was the first time this had been achieved very low current, post-arc, electro-technical measurements were also taken. A new model for arc-network interaction may result from this work.
The calculations were compared to actual experience in the real industrial situation. Overall quantities, corresponding to the energy state of the equipment, namely the arc voltage and gas pressure were compared. The data are good enough for the other data specified in the model to appear credible.
Circuit breaker design is still achieved using semiempirical rules and so it requires long and expensive tests. The objective of this project is to develop a software tool in order to reduce this testing time and the costs involved. To fit into existing computers, the physical hypotheses, mathematical methods, and numerical simulation must have a reasonable processing time.
Amid viscosity and turbulence were ignored and the Euler equations therefore have to be solved. Given the experimental conditions, this is a reasonable hypothesis. Geometry was assumed to be axisymmetric, which could be justified in view of the arc rotation.
The numerical method was based on the Godounov scheme. A Collela solver, chosen for its efficient calculations, is well adapted to the real properties of sulphur hexafluoride variations between 250 k and 30,000 k.
The arc allowances called for it to be treated as a gas whose properties were taken as those of sulphur haxafluoride as regards thermodynamic and electrical behaviour levels. Consequently, the conductive and convective fluxes had also to be taken into account. Radiative exchanges were treated following the work of Lowe.
THE AIM OF THE PROJECT IS TO REDUCE OR ELIMINATE THE TIME REQUIRED FOR PROTOTYPE TESTING BY DEVELOPING A COMPUTER AIDED DESIGN PROCEDURE FOR CIRCUIT BREAKER CHAMBERS WITHIN THE VOLTAGE RANGE 72 TO 300 KV AND CURRENTS BETWEEN 12 AND 60 KA, AND WITH A MAXIMUM POWER OF 30 GW: THE PHENOMENA RELATED TO THE SWITCHING OF SHORT CIRCUIT CURRENTS IN THE BREAKERS ARE MODELLED.
COMPARISONS ARE MADE BETWEEN THE MODEL AND EXPERIMENTAL TESTS.
Fields of science (EuroSciVoc)
Programme(s)
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Multi-annual funding programmes that define the EU’s priorities for research and innovation.
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Funding scheme (or “Type of Action”) inside a programme with common features. It specifies: the scope of what is funded; the reimbursement rate; specific evaluation criteria to qualify for funding; and the use of simplified forms of costs like lump sums.
Coordinator
4000 LIEGE
Belgium
The total costs incurred by this organisation to participate in the project, including direct and indirect costs. This amount is a subset of the overall project budget.