Mathematical modeling of the high-pressure hydraulic drive of a regulating valve control system of the steam turbine of a steam-electric plant

BACKGROUND: High-pressure hydraulic drives are used to control the shut-off valves of steam and gas turbines. Currently, there is a trend of transition from the low-pressure control systems to the high-pressure control systems, which leads to decrease of size of a control unit and to ensuring easy reparability. The Bosch Rexroth high-pressure hydraulic actuators are widely used. These hydraulic drives are capable of moving the shut-off valve element during up to 0.3 s. AIM: Development of the mathematical model to obtain main dynamic characteristics of a hydraulic drive of the regulating valve control system of the steam turbine of a steam-electric plant. METHODS: The studies of dynamic characteristics were carried out with a numerical method using the MATLAB/Simulink software. RESULTS: The mathematical model of the high-pressure hydraulic drive of the regulating valve control system of the steam turbine of a steam-electric plant, capable of moving the shut-off valve element during up to 0.3 s, was developed. The dynamical characteristics, such as displacement and velocity of the shut-off valve element of the regulating valve, pressure change in the hydraulic cylinder cavities, displacement of a plunger of a spool valve, are presented. The possibility of reducing the list of the used hydraulic equipment was also considered: a comparison of the system with accelerator valves and without accelerator valves was carried out. CONCLUSION: The practical value of the study lies in the possibility of using the developed mathematical model in the study of various types of hydraulic drives.