Series and shunt active power conditioners for compensating distribution system faults

The growing concerns regarding electric power quality and availability have lead to the investigation of solutions to eliminate or mitigate the problems created on critical loads by faults in distribution systems. Series and shunt active power conditioners have been proposed and used for this purpose. This paper discusses and compares the potential of D-STATCOMs and DVRs to provide these functions. It introduces a compensator rating factor which defines the ability of the compensator to support the load voltage in the presence of single and three phase faults. The algorithms required to carry out voltage support are derived and alternatives discussed, including the use of sequence components and direct voltage regulation. New approaches are proposed. Similarities and differences between shunt and series compensators are determined. It is shown that the series compensator is more effective in handling symmetrical and asymmetrical faults. Simulation and experimental results are provided to illustrate the transient performance of the compensator and their ability to support load voltages.