Electric Power Distribution Handbook, T. A. Short

Fault Simulator

This app models faults at different points on a power system with different transformer connections. The line-to-ground voltages in per unit are shown in blue, and the currents in kA are in green.

image/svg+xmlA B C a b c ~ ~ ~ Transformer 120 MVA, Z = 11% 1 2 3 4 Transformer 21 MVA, Z = 7% 138 / 7.97 kV 12.47 / 7.2 kV 480 / 277 V 1.00∠90° 1.00∠-120° 1.00∠-30° 1.00∠90° 1.00∠-120° 1.00∠-30° 1.00∠90° 1.00∠-120° 1.00∠-30° 1.00∠90° 1.00∠-120° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30° 1.00∠-30°

Examples

Here are some examples to try:

Assumptions

This model is a steady-state model. The transformers are “ideal” and do not include any magnetizing or saturation effects. The impedances also do not reflect winding configurations. The voltages and some of the transformer and line characteristics can be adjusted. Click the “Toggle more…” links to see extra inputs.

It is possible to input transformer connections that you really shouldn’t use (see the discussion in section 5.4.5) with a floating neutral. The bad effects won’t be apparent because of the idealized transformer models used.

More detail

OpenDSS is another tool that’s useful for this type of analysis if you want to do custom analyses.