Modeling of Thermal Processes Associated to an Electric Arc

The primary objective of this paper is to study the thermal effects of the electric arc on the breaker apparatus contacts for forecasting and improving the contact durability. We will propose a model which takes account of the main influence factors on the erosion contacts. This phenomenon is very complicated because the amount of ejected metal is not necessarily constituted by the whole melted metal bath but this depends on the balance of forces on the contact surface. Consequently, to calculate the metal ejection coefficient, we propose a method which consists in comparing the experimental results with the calculated ones. The proposed model estimates the mass lost by vaporization, by droplets ejection and by the extraction mechanism of liquid or solid metal. In the one-dimensional geometry, to calculate of the contact heating, we used Green’s function which expresses the point source and allows the transition to the surface source. However, for the two- dimensional model we used explicit and implicit numerical methods. The results are similar to those found by Wilson’s experiments.





References:
[1] M. W. Baldwin, "Electric arc furnace impact on generator torque”. Power Systems conf and expo, IEEE PES. 2004, vol 2, pp. 776-780.
[2] I L Babich, A L Cheredarchuk, A Veklich N, and V V.A. Zhovtyansky, "Spectroscopic investigations of the cathode region of the three burning copper arc. Discharges and electrical insulation in vacuum”, Proceedings ISDEIV, XVIIth Int Symp, 1998, vol 1, pp. 215-218.H. Poor, An Introduction to Signal Detection and Estimation. New York: Springer-Verlag, 1985, ch. 4.
[3] G. Rego, l. m. n.b f. Santos, B. Shroder, V S Maques and J.L. Santos, "In situ temperature measurement of an optical fiber submitted to electric arc discharges. Photonics technology letters, ieee, 2004, vol 9, pp. 2111-2113.
[4] R L Doughty, T E Neal, G M Laverty, and H. Hoagland, "Electric arc hazard assessment and personnel protection” . Industry applications conf record IEEE, 2000, vol 4, pp. 2782-2789.
[5] C. Turner, H. Turner h, F. Frey, "The relation between wear of copper contacts and arc current". ERA Report, - Ref. 5119, 1996.
[6] A. misserand., "Conductivité thermique ”, Editions Eyrolles, Paris, 1965, p 554.
[7] J.P. charberie, J. deveautour and P H Teste,,"A numerical method for thermal process in an electrode submitted to an arc in air and its experimental verification”. Holm conf on elect contacts, Philadelphia, 1992, pp. 65-70.
[8] H.S. Carslaw,, J.C Jaeger, "Conduction of heat in solids”. Second Edition, Clarendon press, oxford,, 1990, p 375.
[9] D. Euvrand., "Résolution numériques des e.d.p” , Edition Masson. 1998.
[10] L. Féchant, "Le contact électrique". Edition Hermes, Paris, 1996.
[11] H. Allagui, A. Ouni and M. Javoronkov, "Forecast of the durability of the contacts of a contactor with the turning arc”. Medium east symp on simulation and modelling, Sharjah, UAE, 2002, pp. 132-136.
[12] W. R. Wilson, "High current arc erosion of electric contact material”. Trans. AIE, Pow & and Syst, 1965, pp. 657-664.
[13] H. Allagui, M. Mekki. and M. Javoronkov, "Electrodes erosion in a liquid medium”. IEEE Int Symp On Indus Electronics, Aquila, Italia, 2002, pp. 1289-1294.
[14] J. Deveautour, "Contribution à l'étude des interactions arc-électrodes. Influence de la structure métallurgique sur les mécanismes d'érosion des appareils de coupure”. PHD of Paris 6 University.1992.
[15] V. Maxime, "Etude des mécanismes de défaillance du contact électrique dans un micro-interrupteur en technologie MEMS. PHD of Grenoble Polytechnique Institute, 2010.