Modeling of Arc Discharges in Power Circuit Breakers. Final Report

摘要

Power system growth places increasing performance requirements on power circuit breakers. As part of the effort to develop these breakers, a more detailed understanding of arc interruption is needed. One approach to providing this understanding is arc modeling, such as reported here. Previous mathematical studies of arcs have been largely of two types; either they have been extremely simple to allow mathematical manipulations to proceed, or they have been highly complex to attempt as accurate as possible representation of the arc. In the former case, the models are often unrealistic and just as often are not mathematically rigorous, while in the latter case they are so complicated that physical insight is lost. The study in this project falls close to the first category, although an attempt is made to be as realistic as possible and insure that the mathematical reasoning is rigorous. The question that this model attempts to answer is: ''What effect does electrode geometry have on an electric arc.'' This problem is attacked in a quantitative way in terms of the curvature of the electrodes. The next question is whether, after a given interruption attempt, the fault will be cleared. A new type of mathematical attack on this problem was initiated with the model, and it shows that an interruption criterion can be obtained in a rigorous and physically meaningful way. The analysis is based on the stability of the mathematical model. The results show how much any interruption depends on arc characteristics and circuit parameters. Real power circuit breakers are influenced by convection and radiation, which are mechanisms for energy dissipation. In order to make the model more realistic, it has been extended to incorporate these effects. Previous experience with the simpler models has given an insight as to how to deal with these complications. (ERA citation 03:021529)