Unsymmetrical fault calculations

Question 1

Question 2

Current in the neutral wire 

Question 3

Question 4

In the polar form , we have 

ER0 =100 volt = 

ER1 = ( 200 -j100) volt  in polar form 

ER2 = - 100  volt in polar form 

Phase voltage, ER = ER0 + ER1+ER2 = 100 + (200-j100)+(-100) volt , 

Phase Voltage Y = 

 angle 260 and angle -99.89 is same

Phase voltage EB = ER0+aER1+a²ER2 ,

Question 5