Bus Bar Protection with Arc sensors

[NickParker]

Is bus bar protection (partial/full differential) not required if there is a protection by arc sensors in the cable, breaker and bus bar chambers?
Note: It is a M-T-M double ended switchgear; Bus tie normally closed along with IS-Limiter.

 

[dpc]

Not all faults are arcing faults.

 

[che12345]

Dear Mr NickParker (Electrical)(OP)20 Feb 23 17:00
"...Is bus bar protection (partial/full differential) not required if there is a protection by arc sensors in the cable, breaker and bus bar chambers? ..."

1. Bus bar protection (partial/full differential) IS required EVEN if there is a protection by arc sensors in the cable, breaker and bus bar chambers.
2. Bus bar differential protection works on current difference. The arc sensor works on the arc (light). They work on different principles and different purposes.
Che Kuan Yau (Singapore)

 

[RRaghunath]

IS limiter will ensure the Tie is open rapidly in case of a fault exceeding the busbar rating. This way, the fault current is brought down to below busbar / breaker ratings.
Arc sensors act quickly to isolate the faulty bus in case of any arcing fault in the busbar zone.
Coupled with the above, suitable interlocks to prevent bolted faults such as closing of incomer with busbar earthed for maintenance etc. should suffice I believe.