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Unbalanced Transformer Loads
- Thread starter tryhard
- Start date
If neutral is not earthed at all, then system is floating because it is not referenced to eart. If neutral is earthed (even poorly) neutral voltage is null, since no current can flow to earth.
If your question refers to the neutral voltage displacement due to umbalanced loads, then you can calculate it using the following formula:
DV = (V1*Y1 + V2*Y2 + V3*Y3)/(Y1 + Y2 + Y3 + Yn)
Where:
DV = Displacement voltage (Phasor)
V1, V2, V3 = No load output voltages (phasors) of phases 1, 2 an 3 (R, W, B)
Y1, Y2, Y3 = Complex admitances of Wye connected loads between correspondig phases and neutral (internal tranformer impedance shall be included)
Yn = Complex admitance between neutral and star center, if any
Note that when star center and neutral line are tightly internconected, then Yn tends to infinity and DV to zero.
Hope to help you Julian
If your question refers to the neutral voltage displacement due to umbalanced loads, then you can calculate it using the following formula:
DV = (V1*Y1 + V2*Y2 + V3*Y3)/(Y1 + Y2 + Y3 + Yn)
Where:
DV = Displacement voltage (Phasor)
V1, V2, V3 = No load output voltages (phasors) of phases 1, 2 an 3 (R, W, B)
Y1, Y2, Y3 = Complex admitances of Wye connected loads between correspondig phases and neutral (internal tranformer impedance shall be included)
Yn = Complex admitance between neutral and star center, if any
Note that when star center and neutral line are tightly internconected, then Yn tends to infinity and DV to zero.
Hope to help you Julian
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