In general, equipment in power systems are represented by equivalent circuits, which are designed for the individual tasks of power system analysis, e.g., for the calculation of no-load current and the no-load reactive power of a transformer, the no-load equivalent circuit is sufficient. Regarding the calculation of short-circuits, voltage drops and load characteristic a different equivalent circuit is required. The individual components of the equivalent circuits are resistance, inductive and capacitive reactance (reactor and capacitor), voltage source and ideal transformer. Voltage and currents of the individual components and of the equivalent circuit are interlaced by Ohm's law, which is valid for the three-phase system (RYB-system) as well as for the system of symmetrical components (012-system). A detailed deduction of the mathematical methods and equations is not given within the context of this section of the book, but only the final equations are quoted.

Inspec keywords: equivalent circuits; short-circuit currents; power systems; electric impedance; power apparatus

Other keywords: capacitive reactance; symmetrical components; no-load reactive power; load characteristic; ideal transformer; power system analysis; reactor; voltage drops; RYB-system; no-load current; electrical equipment; Ohm's law; short-circuit calculation; impedance calculation; power system equipment; voltage source; three-phase system; inductive reactance; no-load equivalent circuit; capacitor

Subjects: Power apparatus and electric machines