Parallel Operation of Two Ideal abrupse Single Phase Transformers

Parallel Operation of Two Ideal abrupse Transformers

AU: May-15

• Now we will consider ideal case of two transformers having the same voltage ratio and their voltage triangles are equal in size and shape. The circuit shown in the Fig. 6.24.1 consists of two transformers in parallel.

• The corresponding phasor diagram is shown in the Fig. 6.24.2

• As seen from the Fig. 6.24.2 the impedance voltage triangles of both the transformers is same. I₁ and I_⁄2 are the currents flowing through transformers A and B which are in parallel. These currents are in phase with the load current and are inversely proportional to the respective impedances.

Applying KCL, I = I₁ + I₂

Secondary voltage,

V₂ = E - I₁ Z₁ = E – I₂ Z₂

Also I₁Z₁  = I₂ Z₂ i.e. I₁ / I₂ = Z₂ /Z₁

Applying current divider formulae,

Thus the current through individual transformer varies as impedance of each transformer varies.

Review Questions

1. Explain the parallel operation of two ideal dere transformers.

2. Explain the effect of impedance variation on load sharing between transformers in parallel. AU May-15, Marks 4