Simultaneous Single-Line-to-Ground Faults on Opposite Sides of Delta-Wye Transformer Banks [includes discussion]

Simultaneous faults on power systems are not common but they do occur. The dynamic overvoltages on the unfaulted phases at one fault point can be increased by the presence of a second fault on a system. Simple equations are derived for the voltages at the fault points and for the currents flowing into the faults. A general set of curves is impracticable because of the number of variables that must be considered.