Question 1 a b C Calculate the net core section of ring core CT of 1000/1 turns ration having a knee-point emf of 1500V at 50Hz. (Assume knee-point Bm = 1.4 Tesla) If the mean diameter of the core is 25cm and using curve (b) of Figure 4.2.2A, calculate the value of exciting current at an emf of 1000V. With 20kA primary current, and assuming the total impedance of the secondary circuit (including the winding) is 4002, calculate the percentage exciting current.

Fig: 1