Modeling and Analysis of Under-Load Tap-Changing Transformer Control Systems

Specific prearcing Joule-integral of fusible elements were measured as 106 percent for Cu, 46 percent for Al, 10 percent for SUS and 8 percent for NiCr with reference to that of Ag: 8.93 x 104A2s/mm4. 5) Breaking time is longer with a smaller current. 6) Peak arc voltages after the element fusion are 2-3 times larger with distilled water, Si-oil or Si-compound as a filler material, than those with arc extinguishing sand, and they increase with a smaller cross section of the fusible element and a higher current.