Voltage sag is a power quality event where the voltage magnitude is reduced to values between the 90 and 10% of the nominal voltage and which duration is extended from 0.5 cycles up to 60 seconds. The main causes for voltage sags are faults and short circuits, lightning strokes and inrush currents. In General, it is possible to consider voltage sags as the origin of between 70% and 90% of the industrial power quality problems. Dynamic voltage restorers (DVRs), FACTS device such as static compensator (STATCOM), static series synchronous Compensator (SSSC), and Unified Power Flow Controller (UPFC), energy storage devices and fault current limiters (FCLs) are used to protect sensitive loads from the effects of voltage sags in the power systems. This paper illustrates how the performance of FCLs in power system helps to enhance voltage quality. Three types of FCLs (superconducting based included resistor type and inductive type, and thyristor based) are investigated in a case study of power system
through computer simulation.
Alireza Jalilian, Hossein Heydari, Faramarz Faghihi, and Mojtaba Safdari
High Voltage & Magnetic Materials Research Center
Iran University of Science and Technology