engleski

Analysis of Low-voltage current limitation

The principles of low voltage current limitation in modern current-limiting breakers are described in this paper. Electro-mechanical energy conversion between electro-dynamical part and mechanical operating mechanism governs action of the moving contacts. Arc generated in arcing chamber is crucial part of the process. Modelling of the function of arc voltage enables simulation of the current breaking, as well as the calculation of main characteristics of transient phenomena like ket-through current, arcing time, arcs energy, let-through energy etc. A programme package which enables quick and efficient analysis of current limiting during the breaking process is described. Results of computation and experimental research for one type of limiting circuit breaker are presented. Comparison between computed and measured results shows a great degree of correspondence. Analysis of the results gives a foundation for systematic optimisation of main parts of the circuit breaker: contact system, the arcing chamber and the operating mechanism. Finally, the described programme package enables a study of interaction of the circuit breaker with other devices in power system.

Circuit breakers; current limitation; electro-mechanical energy conversion; numerical computation

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