Hybrid circuit-breaker for interrupting currents having high dc components

A hybrid circuit-breaker for interrupting currents having high DC components, said hybrid circuit-breaker comprising firstly a compressed-air circuit-breaker including at least one interrupting chamber having terminals thereof connected in parallel with an impedance selected from a resistance of several thousand ohms and a capacitance of several hundreds of thousands of picofarads, and secondly a sulfur hexafluoride circuit-breaker including at least one interrupting chamber, said first and second circuit-breakers being connected in series and said hybrid circuit-breaker further comprising the means for controlling said first and second circuit-breakers for opening said first and second circuit-breakers substantially simultaneously or with the compressed-air circuit-breaker opening a few thousandths of a second earlier than the SF.sub.6 circuit-breaker, and wherein said compressed-air circuit-breaker further includes means for automatically giving a close command to said compressed-air circuit-breaker in the range of 2 hundredths of a second to 3 hundredths of a second after an open command is received by said compressed-air circuit-breaker.