Nonlinear Modelling of Kerman Combined Cycle Power Plant Drum-Boiler and Drum Level control especially in trip conditions

There are various methods of power generation such as combined cycle power plants. There are many variables in a power plant boiler unit, but the most important variables are Pressure and specially drum level that control system should be put it in the safe range. The purpose of this article is, modifying the oscillatory behavior of the drum level of Kerman combined cycle power plant and especially control of drum level in trip conditions. At first in this article, high pressure drum boiler of Kerman combined cycle power plant is modeled and analyzed. Then drum level control logic of power plant is analyzed and modifications are being made to improve this logic and the results are compared in practice. In the new logic, a control loop (PI) is used for the error signal of the output steam and the input water to the drum and a control loop (PID) for the level error signal and for more accurate estimation, limiting the drum input water and protective conditions, drum pressure signal is used. In fact the new logic is cascade control by measuring four elements for estimating the input water to the drum. The results show that the new logic reduces the Kerman power plant drum boiler level oscillations and keeps the drum level in trip conditions very well.