### Determine the percentage regulation of the transformer

Please show as much working as possible and comment where possible. An 11 kV to 415 V transformer has a rating of 100 kVA. The winding resistance and leakage reactance when referred to the secondary are 0.0142 Ohm and 0.0569 Ohm respectively. Determine the % regulation of the transformer at: (a) unity power factor (b) 0.