Analysis on the development trend of thermal autom

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Analysis of the development trend of thermal automation

Guide: thermal automation in power plants is slowly developed in the path of thermal power generation, and the development of automation also provides an effective foundation for China's power industry. At present, China has strengthened the technical reform in thermal power generation, and the thermal automation of power plants has been greatly developed at this stage. With the rapid development of high technology in the world and the rapid improvement of unit capacity in China, the thermal automation technology of power plants continues to absorb the latest achievements from related disciplines and develop and improve rapidly

in recent years, it is changing with each passing day: on the one hand, DCS, as the main control system of the unit, has undergone great changes in control structure and control scope; On the other hand, with the application of plant level monitoring and management information system (SIS), fieldbus technology and control technology based on modern control theory, new vitality has been injected into the thermal automation system. Through the application of advanced control technology, thermal power generation is expected to develop into an environment-friendly industry, which not only contributes to the energy demand of social development, but also promotes its own development

current situation of thermal automation

thermal automation technology is a kind of technology that uses control theory, thermal engineering technology, intelligent instruments, computer technology and other information technology to detect and control thermodynamic related parameters, so as to realize detection, control, optimization, scheduling, management and decision-making of the production process, so as to ensure safety, increase output, improve quality, reduce consumption Comprehensive high-tech for the purpose of reducing staff and increasing efficiency. It mainly refers to the automatic control of the operation of boilers, steam turbines and their auxiliary equipment, so that the unit can automatically adapt to the changes of working conditions and maintain safe and economic operation

generally speaking, the thermal control system is composed of measuring devices, actuators and control systems, but the sensors adopted by Shanghai xinrenda Instrument Co., Ltd. are American, with high accuracy. Generally, they can be used for more than 150000 times. Among them, there are no new changes in the principle and structure of the measuring device and actuator, but the introduction of intelligence, network communication interface Dr. Julian marschewski of microprocessor kostron explained: "When it comes to battery base and battery integrated module, it can realize computer remote setting and control, and gradually develop towards fieldbus, and its core has been gradually replaced by computer control system.

due to the particularity of thermal power plant, there are many power equipment involved, the thermal system is huge, the production process is complex, and most of the equipment has been in bad conditions such as high temperature, high pressure, high speed, flammability for a long time. Modern thermal control system The system often also includes automatic protection, automatic detection, automatic alarm, sequence control and so on

during the Eleventh Five Year Plan period, with the maturity of SIS application technology, the further development of DCS and the rapid application of fieldbus, thermal power plants have set off a wave of information construction and have transformed to digital power plants. Although it continues to improve, there is still a gap, which is mainly reflected in the low degree of overall control of machine, boiler and electricity; Thermal measurement and instrument technology need to be improved; Safety monitoring and protection devices have narrow coverage and incomplete functions; The automatic input rate of automatic regulation of the unit is low; Program control is less used and more open-loop applications

at present, the unit unit has achieved centralized control and electrical control has been incorporated into DCS. In fact, thermal automation and electrical automation have not yet achieved real integration. In the future, one unit will only have one main attendant, and the electrical control must form a whole with the control of steam turbine and boiler. Only by doing this can the automation level of China's thermal power plants rank among the international advanced levels

new progress in thermal automation

with the development of automation technology, thermal automation technology has also developed very fast. Various sensors and transmitters produced by new principles, new materials and new processes are constantly developed, and the control system and control devices are also changing with each passing day. New control theories and strategies are emerging and applied in production practice

advanced concepts and algorithms create aps

cross reference and conditional bootstrap concepts that the analog automatic regulation loop refers to the starting and stopping process state of the equipment controlled by the switching value sequence as the condition for switching the working mode, and the switching value sequence control system uses the working mode of the analog automatic regulation loop as the starting condition, cross referencing each other. Once the other party's conditions are met, the sequence control or automatic adjustment circuit will automatically push up the control level, complete the condition bootstrap, and then independently perform the subsequent tasks. This concept makes it possible to realize full working condition, full process and full automatic operation in the complex variable control system

the new concept of cross reference and conditional bootstrap for complex transformer system has completely changed the traditional control method, optimized the system division, start and stop sequence and operation mode, and the basic logic is based on intelligent control and intrinsic safety. Compared with the normal operation of the unit, the start and stop time of the unit is short, but the automatic control ability and reliability of the unit to adapt to various working conditions are greatly improved by APS, which benefits the safe and economic operation in the long run

therefore, the automatic program startup and shutdown system (APS) of the unit has the characteristics of one key sequence control startup and shutdown, two sets of regulation through the whole process, two switches in three states, clear division of four-level control, five functions under one unified, six breakpoints continuous automation, etc. since it was applied in Zhuhai Power Plant in 1999, there is almost no possibility of misoperation. Practice has proved that the design is scientific, practical, mature, convenient to use, reliable Economic safety plays an important role in the long-term stable operation of the unit

power plant 3D and collaborative design work

with the continuous development of computer technology, 3D technology has been gradually applied in power plant design since the 21st century. Three dimensional design not only brings revolution to power plant design, but also provides powerful technical means for digital power plant, which runs through the whole life cycle of power plant. At the same time, due to the introduction of collaborative manufacturing concept, Guangdong Electric Power Design and Research Institute began the application research of combining 3D technology with collaborative design

because all professional design elements are parameterized in the same database and three-dimensional models, and stored in the same database in the form of data, they can be displayed in the form of three-dimensional models. In the three-dimensional model, you can browse and roam all parameters containing attributes in the model, and three-dimensional and two-dimensional can be related to each other, Thus, the three-dimensional and collaborative technology provides a good basic platform for accelerating the realization of major original breakthroughs in digital power plant management. With the required same and powerful basic database platform, the secondary development work can be carried out, and the digital power plant management can be realized by using the existing functional software package

through the three-dimensional model of the power plant, both visual viewing and digital management can be carried out, such as roaming equipment in the plant and plant, parameters and positioning coordinates of pipelines, especially combined with MIS to realize an accurate and visual digital management system of the power plant. At present, collaborative design has been carried out among disciplines in Yangjiang nuclear power phase I project, and the collaborative design of P ID of various process systems in the maintenance discipline has been completed, achieving the expected results

fdcs: Electrical and thermal control integration

fieldbus, as a complete fieldbus control system, is currently difficult to be quickly applied to the whole power plant. Although DCS is the mainstream control system of the current operating units of the power plant, its detection and execution and other field instrument signals still use analog signals, which cannot meet the requirements of diagnosis, maintenance and management of field instruments on the engineer station, It limits the vision of the control process

in the future, fieldbus will be interdependent with DCS and PLC. Fieldbus will develop its own application space with the help of DCS and PLC platform, and DCS and PLC will improve their functions with the help of fieldbus

for example, FDCs, which realizes the integration of FCS and DCS Based on controller, is compatible with traditional DCS and FCS to realize the integration of thermal and electrical control. Compared with independent DCS and FCS, FDCs has incomparable advantages. It adopts Fieldbus to realize the localization of intelligent devices, and connects intelligent sensors and actuators, which saves cables, is rich in information, and is convenient for installation and debugging; What if the measurement data is inaccurate when using the simulation controlled tensile testing machine? The system integration technology provides an application platform for the operation guidance and performance analysis of the whole plant. At the same time, the electrical protection measurement and control unit enters the FDCs system through FCS to realize the integration of electrical and thermal engineering

Application of energy-saving and environment-friendly high-voltage frequency conversion technology

saving energy, reducing consumption, and building a resource-saving and environment-friendly society has become an eternal topic of social development today. In order to survive, power plants must comply with the trend of energy conservation and environmental protection. Using frequency converter technology to transform has become an important work of current thermal power plants

through research and analysis, hydraulic coupling and internal feedback speed regulation are gradually replaced by frequency converters. Therefore, the main means of implementing variable speed drive at this stage is frequency converters. In view of the fact that the output of the power module series multilevel converter is close to the sine wave, the input adopts rectification of 30 pulses or more, the input and output harmonics are very small, there is no impact on electricity and motor, the technology is mature, there are a large number of domestic manufacturers, and the cost is low, so the power module series multilevel converter is preferred for equipment below 5000kW. The frequency converter with three-level technology should be selected for the frequency conversion transformation of motors above 5000kW. In recent years, large capacity series multi-level frequency converter is also widely used

after more than ten years of development, the high-voltage inverter has made a qualitative leap in design technology, manufacturing technology and the quality of power electronic components, and its reliability has been greatly improved, basically achieving a two-year fault free record. Through investigation, the quality of high-voltage frequency conversion equipment fully meets the requirements of power plant drive and is widely used in other power companies

in a word, with the increasingly stringent requirements of national laws on environmental protection and the progress of computer network technology, the future thermal system will focus on the theme of energy conservation, efficiency enhancement and sustainable development, and develop towards wireless, intelligent, networked, transparent, integrated protection, control, measurement and data communication. New measurement and control principles and methods will be continuously applied, which will enable the operation and fault treatment of the unit, It is as convenient as operating an ordinary computer. (hard rock)

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