Consider the oneline diagram shown in Figure 3.40. The three-phase transformer bank is made up of three identical single-phase transformers, each specified by \(X_{1}=0.24 \Omega\) (on the low-voltage side), negligible resistance and magnetizing current, and turns ratio \(\eta=N_{2} / N_{1}=10\). The transformer bank is delivering \(100 \mathrm{MW}\) at 0.8 p.f. lagging to a substation bus whose voltage is \(230 \mathrm{kV}\).

(a) Determine the primary current magnitude, primary voltage (line-toline) magnitude, and the three-phase complex power supplied by the generator. Choose the line-to-neutral voltage at the bus, \(V_{a^{\prime} n^{\prime}}\) as the reference. Account for the phase shift, and assume positive-sequence operation.

(b) Find the phase shift between the primary and secondary voltages.

Transcribed Image Text:

Generator ww AY Step-up transformer bank To rest of the system 230-kV substation bus