Good day!
Never heard of a 72.5-kV vacuum bottle.
As far as I know, vacuum bottles are only up to 34.5 kV. Above 34.5 kV, SF6 gas is used as interrupting medium. Can you please share any literature on your equipment. I may have been out of pace with technology developments. :-)
Thanks.
Good day!
My humble opinion:
A. If the ground wires are not routed back through the core-balance current transformer, the set-up could not detect phase-to-ground faults.
Total I = Ia + Ib + Ic + Ig = 0
B. If the ground wires are routed back through the core-balance current transformer, the...
"Similarly a Yd8 can be achieved from a Yy0 by rolling the conductors from R -> Y -> B."
Further, a Yd8 can not be formed from a Yy0 transformer. You can not alter the winding configuration no matter how you swap the transformer leads. A Yy transformer will always be Yy. A Dy will always be Dy.
Good day!
My humble tip...
Swapping two corresponding leads in the primary and secondary of a transformer will effectively change the functional vector group of the transformer. The nameplate vector group still remains the same.
To determine what is the vector group change, use the...
Hi!
It could be possible that the trip contact of your protection relay is set to latched operation which you might have misconstrued as welded. A simple reset of the protection relay may release the latched trip contact.
Regards.
In your case, the relay internally calculates the sum of the three phase currents to determine the ground fault current. In some relays, there is a fourth current input (In), aside from Ia, Ib, and Ic, which is physically wired to take the sum of the three phase currents and thus it is measuring...
Just wondering...
Case 2 would work well with Y autotranformers? The OP mentioned that the 480-V side needs a wye connection connection so I presume the loads would be a combination of L-N and L-L types. Is there no possibility of neutral shift when the L-N loads are not properly balanced...
I suppose the point of synchronization is on the 480-V side.
If the synchronization point was on the 12-kV side, there would probably be no problem synchronizing to the utility. There would be no neutral shift on the transformer windings since these neutrals are tied to the generator neutral.
In many digital relays, ABB for example, how the CT polarities are wired in differential relaying 'does not matter', not in the real sense of the word but you just inform the relay that the CTs are wired Type I or Type II. The relay will then internally compensate the current flow directions...
"And if there is no grounded source why point available and neither the transformer why point is grounded, what will be the path for fault currents in case of a line to ground short circuit in primary side."
For a single LG fault in the primary side (LV side), no fault current will flow if the...
If I were that other plant customer, I would request for billing metering to be installed near my facility so I would not absorb the losses in the long line and most probably eradicate the erratic registrations. Basing from your statement that the long line was once a spare feeder, I would...
"No transformer or reactor - Isc = 31.105kA.
With a 225 kVA transformer, 5.2% FLA 270A: Isc = 4.445 kA
with a 289A, 3-phase line reactor: Isc = 5.968 kA
We need to reduce the Isc to under 18kA, which is what the panel is rated for."
Pardon me if I did not get the picture but fault level with...
Imagine this example:
A substation transformer supplies four feeders. Each feeder has its own maximum demand. If you add arithmetically the maximum demands of the four feeders, chances are the sum is higher than the maximum demand measured at the transformer secondary.
This is mainly because...
