A short circuit study is to be performed for the 132/33/11 kV substation shown below.

a) List the data required for the study (assuming that the impedance of interconnections within the substation is negligible

b) List the short circuit points and substation conditions for which the study will be made to arrive at the maximum and minimum possible values of short circuit level at various voltages.

c) Calculate the short circuit MVA in 33 kV section 1 bus using the following data/conditions.

132 kV source 1 fault level: 1250 MVA

132 kV source 2 fault level 1000 MVA

132 kV line 1 impedance is 6.96 Ohms

132 kV line 2 impedance = 3.48 ohms

Per unit impedance of Tr-1 and Tr-2 at 50 MVA base are equal and the value is 0.15 pu

132 kV bus coupler is closed

33 kV bus coupler is closed

D)- Develop a brief functional specification of the transformers marked Tr-1 and Tr-2 in the figure shown in the previous problem keeping in view the normal requirements for such application/ratings. (Pl refer to reading materials)

Hint: Calculate line pu impedances to an approximation of 2 decimals