With the development of renewable energy and the expansion of the DC-based power grid, interest in DC transmission and distribution has been rapidly growing. To build a reliable transmission and distribution power grid, the role of DC circuit breakers is more important than anything else. Currently, DC circuit breakers in the commercialization stage include semiconductor, LC resonance, and hybrid type mechanical circuit breakers. The conventional DC circuit breakers interrupt the current by forcibly bearing an arc, and there are circuit breakers that use arc chutes and semiconductors. They have very fast interruption speed, but excessive heat occurs in the interruption operation, resulting in frequent failures and, in serious cases, large fires. Therefore, economical and stable DC circuit breakers are required to construct a reliable DC power grid, and the arc interruption technology of the arc extinguishing chamber, which is the most important part of a circuit breaker, is very important.
In this study, a new arc induction type DC circuit breaker was proposed. The arc induction type DC circuit breaker was a mechanical circuit breaker using an induction needle. It induced and absorbed the arc generated at the contact through the opening operation of the interrupting pole. The induced arc was extinguished through the ground wire. This method was different from the conventional method in which the arc chute of a mechanical circuit breaker directly bore and extinguished an arc by absorbing it. The proposed method was faster and more stable through the arc induction and absorption of the induction needle.
In this paper, the magnetic flux according to the design conditions for the induction needle of the arc induction type DC circuit breaker was analyzed using HFSS, which is the electromagnetic field analysis software. Design conditions included the shape, quantity, position, and direction of the induction needle as well as the induction interval change. Simulation prototype model was designed by setting the simulation results as the design conditions of the established induction needle, and the magnetic field flowing according to the presence of the induction needle was compared. As a result, it was possible to reduce the magnetic field generated between the contacts by approximately 20% through the opening of the interrupting pole when the induction needle was used.