Modelling of voltage sags and voltage interruptions requires accurate representation of the dynamic characteristics of the main system components, particularly the synchronous generators and induction motors, power electronic equipment and their protection and control. The EMT programs meet all these requirements adequately and can thus be used with confidence in the simulation of sag characteristics, their effects and the role of sag compensation devices. Subject to the unpredictability of the arc furnace characteristics, EMT simulation with either deterministic or stochastic models of the arc behaviour can be used to investigate possible mitigation techniques. Flicker penetration can also be predicted with these programs, although the derivation of the IEC short and long-term flicker indices is currently computationally prohibitive. However, real-time digital simulators should make this task easier.

Inspec keywords: arc furnaces; IEC standards; flicker noise; power supply quality; synchronous generators; power electronics; real-time systems; induction motors

Other keywords: long-term flicker; induction motors; IEC short flicker; stochastic models; synchronous generators; dynamic characteristics; EMT programs; voltage sags; steady state applications; real-time digital simulators; mitigation techniques; arc furnace; flicker penetration; power electronic equipment; deterministic models; voltage interruptions

Subjects: Power supply quality and harmonics