Measurements close to a 31.5 MVA AC arc furnace with and without SVC Light~?

摘要

Flicker registrations and furnace performance measurementsrnhave been carried out at Uddeholm Tooling AB inrnHagfors, Sweden. The flicker measurements were performedrnsimultaneously on the 130 kV and 10 kV systems,rnwith and without SVC Light~? in operation. Otherrnconsumers connected to the network have over the yearsrncomplained due to bad quality of the supplied voltage.rnSolving the flicker problems have also improved thernoperation of the arc furnace, such as increased productionrnand decreased energy losses, and extended the flexibilityrnof the feeding power system. This clearly indicatesrnthat a reduction of the rapid voltage fluctuations causingrnflicker will be mutually beneficial for the plant owner,rnnetwork operator as well as for other customers connectedrnto the network.rnTwo methods for determination of the flicker reductionrnachieved by the SVC Light~? are studied. In the firstrnmethod, the flicker reduction is specified as the relationrnbetween the measured flicker with and without the SVCrnLight~? in operation. In many steel plants the possibility tornoperate the furnace without dynamic compensation isrnlimited, and this method cannot always be applied. Thernsecond method is based on instantaneous current andrnvoltage values measured simultaneously. Influencesrnfrom varying operational patterns of the furnace with andrnwithout SVC Light~?, as well as between different melts,rnare eliminated. Both methods show valuable and usefulrnresults.rnThe SVC Light~? concept offers improved possibilitiesrnfor power quality and voltage control of e.g. flickerrnfrom electric arc furnaces with ratings up to and exceedingrn100 MVA.