Method and device for regulating a strand casting system

A method for regulating a strand casting plant,

• wherein the strand casting plant comprises a mold and a strand guide downstream of the mold,
• wherein liquid metal is poured into the mold, in particular via an inflow unit, which liquid metal solidifies on walls of the mold, so that a metal strand having a solidified strand shell and a still liquid core forms,
• wherein the metal strand is drawn out of the mold by means of rollers of the strand guide arranged spaced apart,
• wherein a measured variable is determined, which correlates with the variation of the casting level forming in the mold, this measured variable is processed with incorporation of at least one computing rule and is used to reduce the variations of the casting level,
• wherein the mutual spacing of opposing rollers of the strand guide is cyclically changed before the complete solidification point (D) to reduce the variations of the casting level, namely by cyclic change of the roller spacing, opposing the variations of the casting level, of opposing rollers of the strand guide,
• wherein frequencies of the variations of the casting level are detected and at least one observer is provided which, on the basis of these frequencies, determines a compensation value (k′) for a target value (SET) of the roller spacing of the rollers, characterized in that the actual value (ACT) of the roller spacing is used as one of the input variables for this observer, in order to compensate for a phase shift and/or amplitude of the actual value (ACT) of the roller spacing.