Consider the one-line diagram of a system and the data shown below:
G1: 25 MVA, 13.8 kV, X" = 0.15 p.u.
T1: 30 MVA, 13.2/69 kV, X = 0.11 p.u.
T2: 30 MVA, 69/13.2 kV, X= 0.11 p.u.
G2: 15 MVA, 13.8 kV, X'' 0.15 p.u.
L1: 100 km, z = 0 + j 0.65 Ω/km
All per-unit quantities are based on the rating of that item of plant.
Draw an equivalent one-line diagram for this system showing the various impedances in per unit using a base of 100 MVA.
Ignore pre-fault currents and assume that the generator terminal voltage is equal to its nominal value.
Calculate the fault current in amperes that flows when a balanced three-phase fault occurs at bus 1 (located between 'T1 and L1 Repeat these calculations for a fault 10 km down the line L1, For both fault locations, what is the proportion of the fault current that is supplied by generator G1 and what is the fault level?
