DIRECT CURRENT INTERRUPTION BY A CURRENT ZERO IMPULSE OF CONSTANT STEEPNESS

Due to the current and future development of electrical transmission and distribution technologies, the importance of direct current circuit breakers is increasing. Requirements on direct current breakers differ significantly from those on alternating current breakers. The lack of a natural current zero, the absorption of the energy stored in the system during every switching event, and a fast interrupting performance are unique key requirements for direct current breakers. Different approaches to interrupt direct currents by using mechanical gas or vacuum breakers, semiconductors or combinations of both are possible and have different benefits and drawbacks. Purely mechanical direct current breakers are often built up with parallel resonant circuits to create an artificial current zero in…