ProtectionEngineer
Here is the Z p.u. calculation(based on the transformer KVA rating):
Z p.u. = Z actual / Z base
Z actual = 85 Ohms
Z base = ((19919)^2)/(800 x 10^3)
Z p.u. = 85 / 500
Z p.u. = .170 = (Zero Sequence Impedance p.u.)
Hidalgoe,
Looks like this one has been beaten to death, however, I 'll add a few comments. I would think that you would want to perform a load flow study first. By load flow study, I mean getting actual load data from the field. If you have long Radial lines emanating from the trunk of that...
busbar,
My intentions are to use a single set to protect all described transformers. I am going to use - ((667*2)*3) for my bank MVA total. rbulsara has confirmed this as well. As for the tap changers, this DS feeds a residential area in the middle of nowhere and is slated to be re-built in the...
I agree that it is a hodgepodge setup, however, it is an existing system that has worked for 15-20 years, don't ask me why it was done like this. I suspect that connecting the transfomers in parallel had to do with an emergency situation and what they had at the time to work with. As I stated...
I am currently working on sizing primary fuses for a three wire 34.5 kV distribution system. The connection is delta(HS) - grounded wye(LS). There are four single phase transformers, two connected in parallel - each with a 667 KVA rating, the other two are not in parallel and have a KVA rating...
