REF protection % of winding covered

[sivajith]

Hello,

I'm looking for a litrature/ manual/explanation (which is availble on web) on how to calculate % of winding covered from a Resricted Earthfault setting.Can anyone shed some light on to this?

Thankyou

 

[7anoter4]

In "Fundamentals of Short-Circuit Protection for Transformers"
the restricted earth fault (REF) and negative-sequence
transformer differential (87TQ) functions are explained as a
means to detect ground faults near the neutral and turn-to-turn
faults, respectively.
See:

http://www.selinc.com/WorkArea/DownloadAsset.aspx?id=7263

 

[sivajith]

thanks