hi all
i have seen a low tension CT of a ration 400/5 and read that its Ith=20KA
and i wondered how can they specify that short time current level,
as i know it is specified for primary current which it is not built in ct
i mention that i know if the current in primary side risen up it is not...
i think according to IEC standards
we apply 70KV (for 33KV winding) in power frequency withstand test for one minute and check transformer
and we apply abt. 25 KV after that for partial dischage test in order to chech the 33kv winding insulation .
thanks