| Industrial steam turbine is the steam turbine except that used in the center electricity stations and ships. Industrial steam turbine is extensively used in the industrial field such as petrifaction, electric power, metallurgy, architectural material, environment protection, energy sources, etc. and is the key power set in the large industry equipment. Its control system which undertake the task of modulating the rotate speed and burthen and the task of controlling the work condition directly influence the security, reliability, economy and the automation degree of the machine. The traditional mechanical-hydraulic control system has some disadvantages which are determined by its structure, such as low governing precision and automation degree, fixed work characteristic, small governing function, etc. However, the import electro-hydraulic control system has some disadvantages of high cost, inconvenient maintenance, etc. So it is imperative to develop the digital electro-hydraulic control system with excellent performance, high reliability, good currency and high performance-price ratio for modern industrial steam turbine.In this thesis, the digital electro-hydraulic control system of industrial steam turbine is studied and expatiated detailedly. The speed modulation system, surveillance system and protection system are designed separately. In this system, PLC is selected as the core of the control system and the double closed loop structure is adopted which raise the fast responsiveness of the control system. In this thesis, the detecting system is selected, calculated and disposed. According to control demand the hardware and software of the PLC system are designed, the friendly human machine interface is developed. The electro-hydraulic servo system is designed, its mathematical model is established and the simulation of the system is performed.The results show that the control system has good characters. The speed modulation system can adjust the rotate speed of the industrial steam turbine according to the demand of the users and have well static and dynamic characteristics. The surveillance system can show the users various accurate datas through the touch screen, so that the users can observe the running state of the industrial steam turbine. The protection system can protect the system well. When the running parameter exceed the given data, the industrial steam turbine will give an alarm signal or stop so that to protect the steam turbine. This system has high automation degree. It is facility to mount and maintain, reliable to operate, and precise to adjust and detect and it has well characteristic.
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