Single Bus Scheme In Substation
The single-bus scheme is not normally
used for major substations. Dependence on one main bus can cause a
serious outage in the event of breaker or bus failure without the use
of mobile equipment.
This arrangement involves one main bus
with all circuits connected directly to the bus. The reliability of
this type of an arrangement is very low. When properly protected by
relaying, a single failure to the main bus or any circuit section
between its circuit breaker and the main bus will cause an outage of
the
entire system.
In addition, maintenance of devices on
this system requires the de-energizing of the line connected to the
device. Maintenance of the bus would require the outage of the total
system, use of standby generation, or switching to adjacent station,
if available.
The station must be deenergized in
order to carry out bus maintenance or add bus extensions. Although
the protective relaying is relatively simple for this scheme, the
single-bus scheme is considered inflexible and subject to complete
outages of extended duration.
Since the single bus arrangement is low
in reliability, it is not recommended for heavily loaded substations
or substations having a high availability requirement. Reliability of
this arrangement can be improved by the addition of a bus tiebreaker
to minimize the effect of a main bus failure.
No comments:
Post a Comment