频率对低压断路器空气电弧燃弧特性影响的实验研究

It is required that air circuit breakers should interrupt the short-circuit current under a wider frequency range to meet the application of protecting the direct-driven permanent magnet generators for wind turbines;however, the dynamic charac-teristics of arc may directly affect the breaking performance of the circuit breaker. Consequently, the breaking experiments of miniature circuit breaker and modeled case circuit breaker at different frequencies were carried out to obtain the arc current and arc voltage, meanwhile, the arc energy, normalized time and let-through energy during the whole arc burning period were calculated. The influence of frequency on the key physical quantities representing the dynamic characteristic of the arc was researched. Then, the normalized time was defined to represent the hindering effect of the eddy currents in a splitter plate on the arc motion. Finally, the influence of arc chamber structure on arc dynamic characteristic was analyzed. The results reveal that the normalized time and the current limiting factor will increase and the arc energy will decrease when the frequency increases. Therefore, the circuit breaker designed under the power frequency should be used with less current when working under non-power frequency conditions. The effect of frequency on the dynamic characteristics of air arc is preliminarily revealed in this paper, providing technical guidance for the development and optimization of the broadband circuit breaker.