(Solved): Problem 4 (20 Points): A Single-phase Step-down Transformer Is Rated 13 MVA, 66kV/11.5kV. The Follow...

Problem 4 (20 points): A single-phase step-down transformer is rated 13 MVA, 66kV/11.5kV. The following measurements are made. 1-2 ECE 405/505: Power System Design & Analysis Spring 2020 Short-Circuit Test: with the 11.5 kV winding short-circuited, rated current flows when the voltage applied to the primary is 5.5 kV. The power input is read as 100 kW. Open-Circuit Test: the test with 11.5 kV applied results in a power input of 65 kW and a current of 30 A. Determine: a) Reqı and Xeqı in ohms referred to the high-voltage winding; b) Gc and Bm in siemens referred to the high-voltage winding; c) (for ECE595 student only) Compute the efficiency of the transformer for a load of 10 MW at 0.8 p.f. lagging at rated voltage.