An SVC Light rated at 10,5 kV, 0–44 Mvar supplied by Hitachi Energy has been in operation since 1999 at the Uddeholm Tooling AB steel plant at Hagfors, Sweden. The SVC Light, which was installed on a Turnkey basis, has the purpose of mitigating flicker which emanates from the steel making process.
Uddeholm Tooling is a steel producer with its metallurgy based on scrap melting in an Electric Arc Furnace (EAF) and subsequent refining by means of a Ladle Furnace (LF). The EAF is rated at 31,5 MVA with a 20% temporary overload capability, whereas the LF is rated at 6 MVA plus a 30% overload capability. Both furnaces are fed from a 132 kV grid via an intermediate voltage of 10,5 kV.
The feeding grid is relatively weak, with a fault level at the Point of Common Coupling (PCC) which normally does not exceed 1000 MVA. This is a fault level quite unsufficient to enable operation of the two furnaces while maintaining reasonable power quality in the grid. Before the advent of the SVC Light, the Hagfors steel mill was a source of power quality problems, disturbing both surrounding power users as well as the mill itself.
With the SVC Light in operation, the residual flicker level at the PCC was projected not to exceed Pst (95%) = 1. This target has been met.
|Furnace bus voltage||10,5 kV
|Rated power, EAF||31,5/37,8 MVA|
|Rated power, LF||6/7,7 MVA|
|Dynamic range, SVC Light||0 – 44 Mvar (capacitive)|
|Flicker reduction factor||~3,5|
|Attained flicker level at PCC with SVC Light in operation||Pst (95%) = 1|
|Power factor at PCC||P.F. > 0,95|
|Productivity increase||4 tonnes/hour|
|Specific electrode consumption decrease||0,2 kg/tonne|
|Specific energy consumption decrease||25 kWh/tonne|