STATCOM, a prerequisite for a melt shop expansion-performance experiences

A new electric arc furnace, EAF, for stainless steel was to be installed in northern Finland. Due to the large power of the new EAF, above existing furnaces, and the relatively weak grid, concerns were raised. The concerns were mainly focusing on flicker, annoying illumination fluctuations caused by voltage fluctuations. However, also power quality properties as for instance unbalance were considered. Requirements were set up by the transmission utility, Fingrid, on flicker improvement in the installation as a condition to proceed. To cope with this, a compensator had to be installed. A STATCOM was found to be the optimal technology to meet the requirements. The STATCOM finally built was based on the ABB SVC light^® concept. The paper gives an introduction to the EAF installation and its compensation. Results from initial flicker simulations and from verifying performance measurements in the form of flicker improvement ratio and reduction in negative phase sequence currents are also given.