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rms
5
Applications
1S20
New Switchgear Applications
For new switchgear installations a modern numeric feeder
protection relay is likely to be employed which will have numerous
programming and configuration options.
The basic concept is the same as for the existing switchgear
application described above except that the additional features
and flexibility of modern feeder protection relay allows improved
system integration.
This may be achieved by using the second arc trip output contact
to interface to a programmable status input on the feeder
protection relay. Depending on the model of protection relay
being used this input may be programmed to provide an alarm
message on the HMI, time stamped event record available via its
communications link.
Where this level of system integration is employed the 1S20 does
not need to be mounted on the front panel as the alarm
indications are available on the feeder relay. Remote reset of the
1S20 LED is achieved by momentary interruption of the power
supply using a SCADA controlled series contact. The DIN rail
mounting option is a convenient alternative in this situation.
Combined Bus Bar & Switchgear Arc Protection
Figure 7 shows an application where a single 1S20 is applied for
the protection of the Cable box & CT chamber plus the CB chamber
& BUS chamber using three sensors.
In this configuration one arc trip output is used to trip the feeder
circuit breaker in the event of an arc fault in the cable box / CT
chamber. The second trip output is set for independent operation
to trip the BUS breaker (BUS overcurrent check stage not shown),
in the event of an arc fault in the CB chamber or BUS chamber.
Figure: 7:
One arc sensor - Cable box / CT chamber Independent trip to CB
Two arc sensors - CB chamber & BUS chamber Independent trip to BUS breaker
(BUS overcurrent check stage not shown)
Figure: 6:
Two point sensors in zone 1 - Cable box and CT chamber
One point sensor in zone 2 for CB chamber
1S20
1S30
1S30
1S30
50/51
Trip BUS CB(s)
1S20
1S30
1S30
1S30
50/51
Trip BUS CB(s)
1S20
1S30
1S30
1S30
50/51
Trip BUS CB(s)
1S20
1S30
1S30
1S30
50/51
Trip BUS CB(s)
