Distance protection relay - Reference temperature cable impedances

[hhhansen]

Hello all

I need to parameterize a distance protection relay based on measurements of cable synchronous and zero sequence impedances on a 50 kV line.

However I am in doubt about the reference temperature to be used for the resistance values. We have measured them at 3°C, but I can´t find anything about requirements to which temperature the results are to be corrected. Are anything stated in the standards or manuals for distance protection relays and in case where ?

Best Regards

Hans-Henrik.

 

[davidbeach]

Resistance should be calculated at 50 or 75C, much closer to what it will be immediately prior to a fault. But, it also doesn't matter a whole lot, at typical line angles, the magnitude of Z is not much more than the magnitude of X.

Try Anderson's Analysis of Faulted Power Systems.

 

[hhhansen]

Hello David
Thank you very much for the answer. Are you able to make reference to an IEC, EN, etc. standard about the temperatures.

Best Regards
Hans-Henrik