Research And Application On The Core Control System Of Steam Turbine

For its content, there are four units consist of the turbine control system:automatic control, automatic protection, automatic detection and program control. Digital electro hydraulic control system (DEH) is used mostly in domestic large and medium-sized turbine at present, control core adopt computer to realize PID control, it can be fully involved in the unit start and stop, load adjusting, rotate speed adjusting, the turbine protection and surveillance through the digital electro-hydraulic regulator (CPC), so as to achieve the safe and stable operation of the unit.This thesis mainly study automatic control system because of the turbine control task and steam turbine as a large high speed rotating machinery for speeding bring destructive harm and disastrous consequences. Turbine speed control system uses a single-loop PID control system featuring stable control, small overshoot and quick response. This thesis establishes a speed setting system dynamic mathematical model, with emulating, and designs of the PID speed control system, through running in the Qian’an Iron Steel company power station in the turbine-generator unit, it has normal working practice to achieve a fast and accurate adjustment speed of the purpose.However, as with major power plant, the turbine speed control system has a prominent issue in the actual production process, which is after the construction and maintenance, the characteristics of speed control system valve, oil system dynamic characteristics such as motivation to travel change, resulting in PID controller parameters for a given properly, leading to boot debugging process often adjusting valve opening and the phenomenon of the load violent swing, and even lead to unit overspeed shutdown.To solve this problem, this thesis designs a fuzzy self-tuning PID controller, used in steam turbine digital electro-hydraulic control system, intelligent system controlled by the fuzzy PID control algorithm, when the system internal disturbance occurrs or the system characteristics change, the controller parameters can be auto-tuning, the PID controller with full control of high precision, good stability advantage, so that the unit is running stable. To avoid the power to adjust dynamic parameters after repeated blind PID. Through the establishment of mathematical models, simulation of the system, the control unit achieves the production targets in operational requirements.With this digital electro-hydraulic control system, to avoid the unit load during the boot process the volatility of the steam turbine body damage, and, by reasonable parameter set, a lot less to explore the process of PID parameters, the unit smooth acceleration, compressing the time of starting-up, can generate more electricity.