help me to calculate stabilizing resistor for earth fault relay

[sethuramanj]

hello engineers, please help me to calculate stabilizing resistor for earth fault relay. as i know,

Rstab = V/I

i know how to find v, but i am confused about I value. whether i use CT secondary current (i.e) 5A or relay setting current. looking for your help..

 

[collies99]

For what relay ? What's the applucation ? What's your relay setting both 50 and 51 ?

I guess you are using residual CT connection and not a core balanced CT? (had to ask).

 

[ScottyUK]

Sounds like a high impedance restricted E/F scheme. Have a look at Alsthom's MCAG relay for some examples - obviously the manual applies to this specific relay, but the principles apply to all.

http://www.alstom.com/Global/Grid/Resources/Documents/Automation/HIREFBP/R6136D.pdf

 

[cranky108]

Or is this a broken delta on a set of PT's?