Static Var Compensators for Balancing the Single Phase Traction Loads in Central Queensland

Large single phase loads may be connected to an a.c. system with low short circuit levels if static var compensators are installed for load balancing, power factor correction and voltage support. Static var compensators are variable reactance devices usually using thyristors to switch and control the current in capacitive and inductive elements. This paper considers the methods used to determine the locations and ranges for the static var compensators required in conjunction with electrification of the Central Queensland coal railways. A three-phase load flow program has been developed and used for the required studies. Interactions with disturbances caused by dragline loads in the area are considered. Disturbances due to traction loads, such as harmonics, resonant over voltages and voltage fluctuations are discussed.