In power system analysis, symmetrical (three-phase) fault current and post-fault bus voltages for large networks are computed using Thevenin's theorem applied at the network level via bus impedance (Z-bus) or bus admittance (Y-bus) matrix formulations, rather than reducing the network to a single Thevenin equivalent, which becomes computationally intractable for systems with many buses. The Z-bus method is the preferred systematic algorithm because it avoids the repeated matrix-inversion burden of the Y-bus approach, allowing fault current and voltage changes at every bus to be derived from a single bus impedance matrix and the pre-fault voltage at the faulted bus.
In power system analysis, symmetrical (three-phase) fault current and post-fault bus voltages for large networks are computed using Thevenin's theorem applied at the network level via bus impedance (…