Optical Observation of Self-Gas-Flow in GCB

The generation of self gas flow in a model SF6 gas circuit breaker without puffer action is observed by high speed photography, shadow photography using a Q-switch ruby laser and time-and space-resolved spectrography. The model breaker is specially designed for observation of gas flow in all the spaces from the cylinder to the exhaust space. The results of the observations are Icompared with a free burning arc and show that the self gas flow to the arc in the breaker reduces the diameter of the arc, and raises the temperature of the arc core. This model breaker interrupts the current of 3 kArms with a transient recovery voltage of 2 kV/¿sec, though the pressure rise of the cylinder is less than 0.3 x l05 Pa.