51 & 67G Line Protection

[Mbrooke]

Can I assume this line is radial? And not part of an interconnected network? But then why would it have a bay VT?

https://imgur.com/a/bFUVLZC

 

[Bill West]

SYN on the line VT indicates an interconnection. The lack of direction on the line 51 relay works okay for 115KV bus faults because the transformer 87T covers them and is presumably faster. If the line 51 has an instantaneous element a false flag may occur but the line breaker is going to be opening for 87T anyway.

Bill

 

[Mbrooke]

Yes- however- I can't see a none directional 51 being able to work for a networked system.

 

[Bill West]

Pardon me, I miss-followed a CT line for 87T. There is a "Bus Diff" arrow below the line CB, that's what will clear bus faults before 51 line operates.

Bill

 

[Mbrooke]

Yup

 

[Mbrooke]

@Bill West and other readers- if needed- here is the bay wiring and mimic board:

Just realized their isn't an auto reclose relay lol. Rest looks good however.