Repeat Problem 9.21 for a bolted double line-to-ground fault.

Problem 9.21

Determine the subtransient fault current in per-unit and in kA, as well as contributions to the fault current from each line and transformer connected to the fault bus for a bolted single line-to-ground fault at the fault bus selected in Problem 9.6.

Problem 9.6

Faults at bus \(n\) in Problem 9.5 are of interest (the instructor selects \(n=1\), 2,3 , or 4). Determine the Thévenin equivalent of each sequence network as viewed from the fault bus. Prefault voltage is 1.0 per unit. Prefault load currents and \(\Delta-Y\) phase shifts are neglected.