Symmetrical components are a technique to resolve unbalanced system quantities like fault currents into balanced sequence components. They simplify the analysis of unsymmetrical faults with multiple reliabilities into isolated single component networks.

A short circuit fault is characterized by a low impedance connection between two nodes, allowing excessive current. An open-circuit fault refers to an accidental break or discontinuity in a conductor resulting in no or little current flow.

Symmetrical faults have the same magnitude and displacement for all phase fault currents, requiring only positive-sequence analysis. Asymmetrical faults produce zero and negative sequences too, needing 3-sequence networks and multiple solutions, making them more complex.

Relay settings decide their operating characteristics like pick-up values, time delays, etc. Without coordination studies based on system conditions and fault calculations, relays may not isolate faults quickly or may operate unnecessarily on load currents.

In an electric power system, a fault or fault current is any abnormal electric current. For example, a short circuit is a fault in which a live wire touches a neutral or ground wire.