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Due to RMS continuous product improvement policy this information is subject to change without notice. 1S20/Issue R/28/02/2010 - 3/11
COMBINED BUS BAR & SWITCHGEAR ARC PROTECTION
Figure 4 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 4:
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)
BUS Bar Applications
BUS BAR ARC PROTECTION
Figure 5 depicts how the 1S20 may also be applied for the
protection of bus bars. The number of sensors in the bus
chamber is dictated by the switchgear design and the length of
switchboard.
In most indoor metal clad switchgear the bus bar chamber is a
continuous chamber between panels only broken into segregated
sections at a bus section breaker & as such the strategic
placement of one or two arc sensors in each bus bar chamber run
is normally adequate.
Some indoor metal clad switchgear may segregate the bus
chamber of each panel from the next via insulated bus chamber
side barriers per panel, if this is the case then each bus chamber
per panel would need to be monitored by at least one arc sensor.
1S20
1S30
1S30
1S30
50/51
Trip BUS CB(s)
1S20
1S30
1S30
1S30
50/51
Trip BUS CB(s)
In large enclosures the arc sensors should be placed at
approximately 5m intervals.
1S20
1S30
1S30
50/51
50/51
50/51
Figure 5:
One, two or three arc sensors located in the BUS chamber
