For a power system, the following information is given:
Prior to occurrence of a fault at bus 2, the voltage at bus 2 is given as: 1.04∠0 pu.
The sequence network Thevenin impedances as viewed from bus 2 are:
Z1 = j0.16 pu
Z2 = j0.2 pu
Z0 = j0.12 pu
A double line to ground fault (phase b to c connected together and connected to ground through Zf) occurs at bus 2. The fault impedance is:
Zf = 0.05 pu
(a) Draw the sequence networks connections for this fault. (2 marks)
(b) Calculate the sequence fault currents in per unit (positive sequence current I1, negative sequence current I2, and zero sequence current I0, which represent the fault current). (6 marks)
(c) Determine the neutral fault current in pu. (2 marks)
