Localized Upgrading of USP for Medium-voltage Drive System of Piercing Mill and Application Effectiveness

Described here in the paper are the working conditions for and purpose of use of the piercer main drive system.Also analyzed are the problems as staying with the SVGN system.Unstable gate power supply acts as the main cause for frequent gate fault of the IGCT.Accordingly the solution for localized,non-standard upgrading of the UPS is proposed,i.e.,modifying the UPS output voltage into an earth-floating system,and adding by-pass isolation transformer as well as backup battery redundancy and intelligent buttery monitoring unit.Before the UPS upgrading,there had been a fault of the IGCT every two or three months.And after the UPS upgrading,no fault has ever occurred again.