A 20-kVA 8000/277-V distribution transformer has the following resistances and reactance: RP = 32 Ω RS = 0.05Ω X P = 45Ω XS = 0.06Ω RC = 250 kΩ X M = 30 kΩ The excitation branch impedances are given referred to the high-voltage side of the transformer. (a) Find the equivalent circuit of this transformer referred to the high-voltage side. (b) Find the per-unit equivalent circuit of this transformer. (c) Assume that this transformer is supplying rated load at 277 V and 0.8 PF lagging. What is this transformer’s input voltage? What is its voltage regulation? (d) What is the transformer’s efficiency under the conditions of part (c)?
A 20-kVA 8000/277-V distribution transformer has the following resistances and reactance: RP = 32 Ω RS = 0.05Ω X P = 45Ω
XS = 0.06Ω RC = 250 kΩ X M = 30 kΩ
The excitation branch impedances are given referred to the high-voltage side of the transformer.
(a) Find the equivalent circuit of this transformer referred to the high-voltage side.
(b) Find the per-unit equivalent circuit of this transformer.
(c) Assume that this transformer is supplying rated load at 277 V and 0.8 PF lagging. What is this transformer’s input voltage? What is its voltage regulation?
(d) What is the transformer’s efficiency under the conditions of part (c)?
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