Which one is not a reason for performing fault analysis?

If Van has a phase angle of 50 degrees, what is the phase angle of Vbc? 

For a medium line, VS=458kVLL, and line parameters are as follows: A=D=0.952

The rms value of v(t)=Vmax cos(wt) is given by

In the following power system, if  prefault voltage at Bus 2 is 1 pu, and subtransient reactance of generators are 0.15 pu, what is the approximate magnitude of a 3-phase bolted fault current at Bus 2? Neglect resistors and loads. PS(2).png

In the following power system, what is the imaginary part of Y22? PS(2).png

What is the main advantage of using per unit system?

In the following power system, power flow solution will determine how many main unknowns? PS(2).png

A transmission line has the following parameters: z=0.02+j0.33 S/km y=j4.7×10-6 S/km Length=300 If sending and receiving end voltages are 500kV, what is its maximum theoretical real power transmission capability? 

In the following power system, if V2∠δ2= 0.9717∠-2.7o , what is the real power loss on Line 12? (Sb=100MVA) PS(2).png