zero sequence
zero sequence
(OP)
hi,
How can we calculate the zero sequence impedance of a
transformer? Can we do by using nameplate values?
How can we calculate the zero sequence impedance of a
transformer? Can we do by using nameplate values?






RE: zero sequence
RE: zero sequence
RE: zero sequence
RE: zero sequence
In other words, jumper the three high-side phases together. Also, jumper the low-side phases together. Hook up a variable voltage source to the primary and connect it between one of the primary terminals to the one of the low voltage terminals. Want to have a CT around one of the phase leads before it gets to the jumper.
Gradually increase the voltage from 0 until you get rated secondary current. Suppose if you have a 33 kV primary with a 5% impedance suspected. It should take about 953 V to give you rated secondary current. The actual %Z will be the voltage needed to give rated current divided by the line-to-neutral current time 100.
To get a %R and %X, you need to have a wattmeter in the circuit or a means of measuring power factor.
RE: zero sequence
RE: zero sequence
You are quite right. You can't energize a jumpered delta winding and expect to get any current to flow on the other side. Nonetheless, if it's a delta wye transformer connection, you can energize the wye side in this manner and short out the delta side.
For a zero sequence model, knowing that you have an infinite impedance on the delta side is important, but you also need to know what you get on the wye side. My suggestion will satisfy that part.
RE: zero sequence