Correct notation for current Differential Scheme for Auto Transformer

[dfdt]

We use 87 to denote bias Differential function.My question is what no is appropriate to denote current differential scheme applied on auto transformer where CTs from HV side , LV side and Neutral point with identical ratio are summed on per phase basis.In my view the no 64R is not appropriate as the scheme will detect both phase and ground faults.

 

[davidbeach]

It is still a differential and thus still an 87.

 

[dfdt]

Thanks David and i agree with you but my issue is how do I differentiate between the two as we intent to use both schemes in the same relay

 

[arrehman1]

Perhaps a 64P for phase fault detection and 64G for ground fault detection?

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The Wye Wye Transformer Connection video:

http://gpac.link/1GdGRSQ

 

[dfdt]

doesn't no 64 inherently signifies ground fault?

 

[arrehman1]

The ANSI Device Number 64 is for ground detector relay

I don't think there is a "phase" detector relay ANSI device number. Otherwise that would make things a little easier. So you'll have to be creative with how you use these device numbers. 64P is a suggestion given the circumstance.

http://GeneralPAC.com

- Awesome video tutorials for power systems PAC!
The Wye Wye Transformer Connection video:

http://gpac.link/1GdGRSQ