SVC for maintaining power quality in a 220 kV grid feeding a steel plant
Since 2002, Ferriere Nord S.p.a., a steel plant situated in northern Italy, has been operating an Hitachi Energy static var compensator (SVC) in its electric arc furnace (EAF) based melt shop. The SVC was installed in order to mitigate flicker generated by the EAF; however, other benefits such as increased furnace productivity and decreased energy losses were also considered. The installation was part of a general meltshop expansion which also comprised the uprating of an existing EAF transformer from 55 MVA to 75/85 MVA. There is also a ladle furnace for refining in the plant, rated at 32 MVA.
The SVC has replaced an old saturable reactor which was operated in series with the EAF. By means of the SVC, the flicker severity factor at the 220 kV point of common coupling has been limited to Pst (95) = 1.3 with the EAF and ladle furnace in operation.
|Controlled voltage||21 kV|
|SVC rating||0-90 Mvar capacitive|
|Harmonic filters|| 2nd harmonic / 30 Mvar
3rd harmonic / 30 Mvar
4th harmonic / 30 Mvar
|Control system||Phasewise, open loop susceptance regulator, plus a three-phase closed-loop susceptance regulator.|
|Thyristor valve||BCT equipped, water cooled, with indirect light triggering.|