Protection System DC Bank Grounding

[proznick]

I am putting together the DC system for a power plant protection system. For the floating DC system, looking for any pro's or con's for fusing both the DC positive and negative inputs of the protection relays or only needing to fuse one side.

Is there any standards with respect to fusing for the protection's DC system.

thanks for any replies in advance.

RP

 

[slavag]

ONLY BOTH.
Regards.
Slava

 

[dpc]

+1 for fusing BOTH sides.

 

[davidbeach]

Another for BOTH.

 

[stevenal]

Agree with both. The single line to ground fault causes no trip and no overload. The second ground fault of the opposite polarity causes the trip. But what if the two faults are on the opposite polarities of separate and unequally sized circuits? The smaller unprotected wire of one circuit will burn waiting for the longer time of the second circuit's fuse to clear.

Not a standard, but a good IEEE PRC reference is at

http://www.pes-psrc.org/k/rlytrckt.zip

 

[proznick]

Thanks to all

RP