Modeling of a Turbine System for Digital Instrumentation and Control System Design

To study the dynamic behavior of steam turbine system, model of steam turbine is required. In this paper, 1st mathematical modeling of the steam turbine unit is developed based on continuity equation than model of extraction steam turbine is developed based on continuity equation having 3 sections, i.e., High pressure (HP), Intermediate pressure (IP) and low pressure (LP) turbine. Transfer function model is, then, implemented in MATLAB/Simulink to obtain the torque characteristics of steam turbine system. Over speeding of steam turbine can prove to be catastrophic in an Nuclear Power Plant Station (NPPS). Steam turbine, therefore, should run at a prespecified reference speed. In this research work, Two control algorithms are designed for speed control of steam turbine namely Proportional (P) Control, Proportional-Integral (PI) Control. These control systems are developed for generic steam turbine model taking re-heater valve into consideration. Speed characteristics are, then, obtained for each control algorithm. Comparison of different control schemes is also studied. the better performance of steam turbine is achieved using developed Controllers.