Question

The figure shows the per-phase representation of a phase-shifting transformer connected between buses 1 and 2, where '$\alpha$' is a complex number with non-real and imaginary parts.

For the given circuit $Y_{BUS}and{Z}_{BUS}$ are bus admittance matrix and bus impedance matrix respectively, each of size $2\times 2$ . Which one of the following statements is true?

• A. Both $Y_{BUS}$ and $Z_{BUS}$ are symmetric.
• B. $Y_{BUS}$ is symmetric and $Z_{BUS}$ is unsymmetric
  
• C. $Y_{BUS}$ is unsymmetric and $Z_{BUS}$ is symmetric.
• D. Both $Y_{BUS}$ and $Z_{BUS}$ are unsymmetric.

Answer 1

The correct option is D Both $Y_{BUS}$ and $Z_{BUS}$ are unsymmetric.

Both $Y_{BUS}$ and $Z_{BUS}$ are unsymmetrical with transformer because of the impedance Z connected to the left side only.