reserves to support the network frequency after a severe disturbance in either power system. The refurbishment of the New Zealand HVdc link was a unique exercise with its challenging objectives. These include the high-seismic design requirements, working within constrained switchyards, and maintaining a supply of the existing HVdc link during construction of the new pole 3. Extensive planning was required to overcome these challenges and perform additional product development not normally associated with conventional HVdc projects. Mackay Oonooie Moranbah Mt. McLaren Clermont Capella Powerlink SVC Refurbishments in Queensland, Australia The FACTS refurbishment was performed for one large SVC called Nebo and nine other smaller SVCs connected to the railway system in Queensland. The railway system is used for transporting coal from inland central Queensland to the coastline. The SVCs provide voltage stabilization as well as negative phase sequence control. These issues are a by-product of the electrical rail system being a two-phase load connected to a three-phase network. The imbalance in the load creates a negative sequence current, which can lead Nebo Coppabella Dysart Gregory Rockhampton Emerald Blackwater Dingo Grantleigh figure 4. SVC locations (red) and nearby cities (white) in Queensland (map image: Google Earth). to poor performance of the electrical network. The SVCs are dispersed across the railway network to better maintain acceptable electrical performance. table 1. Nebo and railway SVC ratings. Site Name Phase Swing Range CAP IND Cooling (kW) TFMR (Mva) TCR (Mvar) TSC (Mvar) FC (Mvar) SVC (kV) Mt. McLaren - 33 -18 100 36 51 0 33 5.7 Dingo A-B 10 -13 - 40.5 69 0 10 7.7 B-C 10 -13 146 - - - 10 - C-A 17 -6 - - - - 17 - A-B 13 -4 - 36 51 0 13 5.7 B-C 7 -10 100 - - - 7 - C-A 7 -10 - - - - 7 - A-B 17 -14 - 60 93 0 17 10.4 B-C 19 -12 167 - - - 19 - C-A 16 -15 - - - - 16 - A-B 20 -11 - 60 93 0 20 10.4 B-C 20 -11 167 - - - 20 - C-A 18 -13 - - - - 18 - Gregory - 30 -21 100 36 51 0 30 5.7 Moranbah - 42 -51 17 60 93 0 42 10.4 Dysart - 29 -40 146 40.5 69 0 29 7.7 Blackwater - 18 -33 100 36 51 0 18 5.7 Nebo - 260 -80 583 260 170 170 90 17.7 Grantleigh Oonooie Coppabella Abbreviations: CAP: capacitive MVar, IND: inductive MVar, TFMR: transformer, TCR: thyristor controlled reactor, TSC: thyristor switched capacitor, and FC: filter capacitors. march/april 2016 ieee power & energy magazine 77