A 3-phase 50 kVA, 6.6/0.4 kV 50 Hz transformer is ?/Y connected. It yielded the following test results:
![1883_9ab43ce3-96aa-4ea6-ac76-e362b9af71c9.png](https://secure.tutorsglobe.com/CMSImages/1883_9ab43ce3-96aa-4ea6-ac76-e362b9af71c9.png)
Calculate the pu circuit parameters of the transformer. Determine its efficiency and voltage regulation at full load 0.8 pf lagging. Calculate also the maximum efficiency and the load (0.8 pf ) at which it will occur.