This example three-phase power distribution system uses a variety of load types to create realistic static and transient grid-loading conditions and system asymmetries. These include constant power and variable resistance loads, lamps and motors with complex start-up load current profiles, as well as imbalance in the generator, lines and transformers.
The models provide not only the characteristic behavior of each component, but also internally track the power input, output and dissipation, per phase and in total, so that power flow can be easily monitored. This system can also be used to assess, for example, the potentially destabilizing effect of a constant power load. Its “negative resistance”, or inverse relationship between the input voltage and current, can be observed in the simulation results by zooming in on a few individual AC cycles.