Continuous casting is used to solidify most of the steel produced in the world. Therefore great efforts in the design and control of continuous casting plants have been made to increase throughput and quality of the product. In this work we focus on modeling for controller design and simulation of the mold level regulation. In particular important uncertainty and disturbance effects are captured and new approaches in this modeling are shown. The derived model can be used for controller design and controller validation. Furthermore exceptional cases and the implemented software can be tested in advance. It also provides an analysis tool of new continuous casting plants and allows minimization of plant disturbance behavior when the plant is designed.