Vacuum circuit breakers are used as
switchgear in high voltage applications. In these types of circuit breakers,
the quenching takes place in a vacuum. The equipment uses the vacuum
interrupters to break the current supply and protect any equipment, appliances,
etc., from power surges or overloads. The
service
life of vacuum circuit breakers
is longer than conventional circuit
breakers, and they need almost no maintenance. Vacuum circuit breakers are
considered ideal for industrial and electrical utilities and applications.
These circuit breakers are also known for
their high insulation strength. In comparison to the different insulation
materials used in other types of circuit breakers, vacuum is a superior
dielectric medium. It is better than all the other insulation mediums except
air and SF6 at high pressure. When the contacts are separated in vacuum, the dielectric
strength across the contacts becomes much higher, and this helps break the
circuit easily.
The benefits of vacuum circuit breakers are
described here.
Vacuum circuit breakers are cost
effective, less bulky and more efficient than the other circuit breakers. Only
the SF6 circuit breakers can match their efficiency levels, though the
gas-based option is more expensive than a vacuum circuit breaker
Vacuum circuit breakers do not need any
type of refilling with gas or oil. They do not need any auxiliary oil system or
oil handling. Vacuum breakers are free from periodic maintenance needs.
They do not involve the use of oil and gas
and are, thus, pollution free.
Current interruption occurs at first
current zero after contact separation with no re-striking. It makes vacuum
circuit breakers exceptionally good for capacitors, cable switching, and long
line dropping.
Vacuum breakers are non-inflammable and
operate silently unlike the other variants used for industrial purposes.
The breakers are compact, eat up less
space and can be installed in any type of orientation.
There is no material decomposition in the
vacuum as the hermetically sealed vacuum interrupter keeps the circuit breaker
intact from all the environmental effects.
The vacuum maintains the small resistance
of the contacts throughout its life as these contacts are not oxidized in the
airless environment.
Vacuum circuit breakers can be used up to
230KV. They are especially recommended for higher voltages if long life and
maintenance free operations are desired.
