Interruption in SF
6
A-12 72A-1898 Rev. A 11/01
Monday, November 26, 2001 1:09 pm
Double-Pressure
SF
6
Circuit Breakers
Figure A.11 shows the structure of a Double-Pressure SF
6
Circuit Breaker
(Reprinted from Reference 2. Permission granted by Marcel Dekker, Inc.).
Figure A.11 Double-Pressure SF
6
Circuit Breaker Operation
This is the early design of SF
6
Circuit breakers. Its operation is similar in
principle to that of Air-Blast Circuit Breakers: It is comprised of mainly a
high-pressure metal reservoir, where most of the SF
6
is kept, and an
interrupter compartment containing the circuit breaker contacts,
surrounded by SF
6
at lower pressure. For the current breaking operation,
the circuit breaker contacts part while the high-pressure gas is released
from its reservoir to the interrupter compartment, where it blows out the
arc. After the current interruption, the gas is pumped back to its reservoir
.
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