State feedback controller with subordinate mass flow control as optimized temperature control for superheaters

摘要

During a boiler construction change at the power station Pleinting Unit 2 the heating surfaces of the superheater were enlarged. Due to these changes in the temperature control loop, the temperature deviations could no longer be regulatedsatisfactorily by the hitherto installed conventional controllers. Using state feedback controllers thereafter these deviations were reduced considerablyThe configuring and parameter setting of the used state feedback controllers was extremely easy because only one tuning factor was needed. So further optimizations with customer benefits could be worked out. The state feedback control was supplemented byan enthalpy calculation with subordinate mass flow control. Thus, it has become possible to inject water into saturated steam during start-ups in case of high temperature deviations. The achieved results are verified by time trends measured at the plant.