Parallel connection of several vacuum interrupters in a circuit-breaker pole

The work presents some results on the experiments showing the capability of increasing the rated normal current and short-circuit breaking current of the vacuum circuit-breaker by a parallel connection of VI in a pole. It is shown which factors can provide a required division of the current between VIs at closed contacts during the whole service life of the circuit-breaker. The current division between VIs under opening is studied. It is shown that it is better with the use of VI with AMF and a very long delay in the contact opening disturbs the current division between VIs.