| 摘要 |
FIELD: electrometallurgy. SUBSTANCE: electrode currents Ie are measured and compared with setting values Ies including dead zone Z; in case of their deviation, respective electrode is displaced or tap changer of furnace transformer is switched over towards compensation for this deviation. Novelty is that, in addition, electrode-to-bottom resistances Re are measured and resistance settings Res are specified, line voltages Ul are measured at low-voltage side of furnace transformers, permissible difference dU of these voltages is set, and, if high-current electrode cannot be lifted, lagging-phase electrode (compared to high-current one) is lifted; if lagging-phase electrode cannot be lifted, tap changer of transformer whose winding starting lead is connected to high-current electrode is switched over in the direction of voltage decrease; if it cannot be switched over, that of transformer whose winding finishing lead is connected to high-current electrode is switched over; if this is impossible, tap changer of transformer electrically isolated from high-current electrode is switched over. Similar approach is used in case of current decrease in which case selection of control action involves, in addition, checking of currents through other electrodes. Inability of electrode displacement is associated with leaving dead zone by electrode-bottom resistance or with extreme positions of electrode holders, or with current increase in moving electrodes down. Inability of switching over tap changers is associated with too high difference in dU or with extreme voltages or currents in switching tap changer towards voltage increase. EFFECT: improved reliability of control. |
