primary test, liine diff protection with transformer and cabel....

[struja]

Hi....
Does enybody has any experiens or any idea of making some kind of primary test for testing the line differential Protection.
My question is, is it possible to performe this kind of test (and is it necessary from tehnical point of view) for uderground cabel, 2,5 km long, 35kV, between two substations. Also, there is a transformer which is also in this circuit (as the CT's for diff protenction on one side are in the bushing of the transformer).
How to do this kind of test?
Could it be done on way that we connect 400V AC supply on one side, in one substation, (for example Diesel generator) and make 3ph short circuit in other substation behind the CT? Would resistance of the transormer and cabele have big influence on the test? Does enybody have any example? Or is should be done on some other way?
Or it could be done by injection current in one phase and ground in one substation and connect this phase to ground in other substation? I think this is not possible becouse we have to push current also through transformer with yd connection...I dont know how will it work....?
Sorry for long question, but I wonted to give you some of my thinkings...
Thanks for replay.

 

[slavag]

Yep. You have a good and right solution.
Diesel generator on the one side, short circuit on another side.
We make it for 500-600 meters cable and transformer, but 2km is not problem too.
Good Luck.