1 Hardware composition and software structure of modern large-scale thermal power unit simulation system
1.1 Hardware components of the simulation system
There are three ways to control the control room of a large-scale thermal power unit in China: a. The main control panel and console are the main control and operation means, supplemented by the screen display operation; b. The operator station with screen operation and display ( OIS) is mainly equipped with a small-scale control panel, equipped with a certain amount of analog operator and logic operator as standby operation equipment; c. It is simply operated and displayed by computer screen, and there is no instrument panel and console. Then the corresponding simulation system also has three hardware components. The hardware components provided in this article are based on b.
The Operator Station (OIS) uses five PCs of the same specification, each with a dedicated keyboard and a 20-inch display screen of the same specification. The electro-hydraulic control system DEH uses a dedicated PC and a 20-inch display screen. The instructor workstation is an HP-715 small workstation. Two local operating stations use X-terminals. For the simulation of monitoring boiler combustion flame, chimney exhaust, boiler water level, etc., multimedia technology was used, and three PCs were used. All of the above PCs and X-terminals act as lower-level machines, and exchange data through Open Ethernet and HP-9000/800-K100 servers as hosts, with a communication rate of 10 MB/s. The simulator also performed a 1:1 simulation of the auxiliary operation panel. It should be noted that the various computer models in the hardware system are not strictly regulated. Generally, with the development of the computer, the latest models on the international market and the original machines with higher performance and price ratios are selected.
1.2 Software structure of computer simulation system
Generally based on multi-user, multi-tasking operating systems, such as UNIX, VMS, etc. The simulation support environment is established by means of database management, process communication, memory sharing and real-time task scheduling. And with its support to achieve multi-level modeling tools, including source code management, engineering management, automatic modeling tools and auxiliary software necessary for simulation training, such as instructor station software, local operation station software.
The simulation environment software is a large-scale software essential for the development and operation of modern simulators. In a sense, it is the operating system of the simulator. The world's major simulation companies have their own supporting environment software, such as S3 of the US S3T company engaged in power plant simulation development, CETRAN of ABB Company, and ROSE of CAE of Canada. These softwares play an important role in supporting the development of the simulator at the current or current level of computer software development.
From the perspective of several major manufacturers of power plant simulation machines in China, the main reason is to borrow, rent or modify the similar simulation software of foreign simulation companies in the 1980s. Only Tsinghua University independently developed the support software “Integrated Simulation Support Environment†with independent copyright, referred to as ISSE.
ISSE has a complete support environment function. Based on the database management kernel of B-TREE algorithm (balance tree algorithm), it provides management of various simulation machine elements such as variables, source code, working condition files, and I/O interfaces. Support for all phases of simulator development, including graphical modeling. Based on technologies that share memory, semaphores, and real-time kernels, ISSE provides reliable and accurate task scheduling and a variety of in-circuit debugging capabilities. Thanks to the idea of ​​large-scale programming and data-driven, ISSE provides a variety of means for the development of the sub-group form of the project, and can achieve a multi-mode function. ISSEs are all written in C++ and form the ISSE development class library. The system has been fully implemented on HP-UX, DECOpenVMS, SGIIRIX and other operating systems, reflecting the idea of ​​supporting the environment as a simulated operating system. In addition, ISSE provides a development interface based on network communication to facilitate communication between third-party software and ISSE.
The ISSE software structure has three levels, namely library, tool software and application software.
1.3 Object Model
The various thermal systems of power plant units are formed by connecting some thermal equipment, such as heat exchangers, fans, pumps, valves, vessels, etc., to form a fluid network. The dynamic process of a thermal system depends not only on the characteristics of the individual thermal devices themselves, ie the device modules; it also depends on the way in which these devices are connected, ie the topology. Therefore, fluid network modeling technology has become an important technology in power plant simulation. FLOWNET, a fluid network computing software developed by Tsinghua University, can establish a single-phase incompressible, single-phase compressible fluid network model, which is solved by semi-implicit Euler integral algorithm and large sparse matrix technology, which solves the problem of stability in network computing. Issues such as sex and real-time.
In order to model more quickly and intuitively, with the support of ISSE, the graphical editor GNET was added, and it became a graphical and modular modeling software, forming a new fluid network automatic modeling tool.
After determining the topology of the thermal system, according to the graphical editor function of GNET, the icons corresponding to different devices are called, and then connected according to the module inlet/outlet to form the simulated thermal system. At the same time, the corresponding FORTRAN source program is generated. After instantiation, that is, inputting parameters and data of the simulated device and system, the simulation system can be debugged.
2 Development history and current situation of China's thermal power plant simulation system
2.1 Characteristics of China's power industry development
Since the early 1980s, China's power industry has developed rapidly with the status of advanced industry. By 1996, it had a generating capacity of about 2 billion megawatts. Among them, thermal power installed capacity accounts for about 75%, hydropower accounts for about 24%, and nuclear power accounts for less than 1%. Thermal power generation accounts for nearly 80% of the country's total power generation.
In the 1980s, China's power industry installed a batch of 200MW large thermal power units. By 1990, 142 units were in operation. With the increase of power grid capacity, by the 1990s, the main unit installed in China's large thermal power plants was mainly 300MW-600MW large-scale units, and even 800MW has already begun installation. In the eighth five-year plan, the annual installed capacity of generator sets was 18 million kilowatts. By 1996, the number of 300MW-600MW units had reached 90, and most of them were imported advanced foreign equipment. Their automatic control systems also use computer distributed control systems (DCS), and it is difficult for operators to master the operation technology of these units.
Since China's primary energy reserves are the most abundant in coal, there are about 1.2 billion tons of raw coal produced each year. About 500 million tons are used for power generation, and only a small number of thermal power plants use oil or natural gas as fuel. Therefore, the structure of China's thermal power plants is based on coal-fired units. Pulverized coal preparation, flue gas dedusting, desulfurization and coal combustion processes in coal-fired power plants reduce the formation of nitrogen oxides, which bring complexity, technical difficulties and high investment to the structure and thermal system of power generation equipment.
2.2 Necessity of power plant simulation training
As early as the mid-1970s, China's power industry introduced four large thermal power plants from western developed countries for the first time. They were the French 300MW coal-fired unit of Yuanbaoshan Power Plant, the Italian 350MW oil-fired unit of Dagang Power Plant, and the introduction of Japan by the Douhe Power Plant. 200MW coal-fired unit and Qinghe power plant are Soviet 200MW coal-fired units. They are all ultra-high pressure (steam pressure 13MPa) or sub-critical (steam parameters 17MPa) unit with steam reheating system. Their automatic control system mainly uses machine, furnace coordinated control and computer monitoring. These characteristics reflect the advanced level of the world's thermal power plants at the time. In the process of building the factory, the technical problems of these new units have been mastered in front of the power sector leaders. While conducting theoretical training in China and sending people to study abroad, we are also considering how to develop China's own power plant simulation training technology.
In the 1975 US Federal Department of Energy's safety report, it was pointed out: "The reliability of a power plant can be improved by improved design and enhanced maintenance, but it only accounts for 20-30% of reliability. Another 70-80% relies on For the operating staff."
In 1988, Tsinghua University conducted a survey of domestic power plant operators. The result was that a group of operators who had not undergone simulation training in a power plant had seven accidents on the 200 MW unit for 18 consecutive months, six of which failed to operate correctly. The operation was forced to stop, causing personal injury in one accident and 15 days in another accident. Another power plant had four load dumps in 10 months, but it was operated by operators who had participated in simulation training. Their furnaces, machines, and electric operators work together to handle accidents correctly. There is also a power plant that has five accidents in 11 months, including protection actions, load shedding, boiler fire fighting, etc. It is also operated by personnel trained in simulation. As a result, there are four times to quickly eliminate the accident and recover within ten minutes. normal production. These data indicate that simulation training plays a crucial role in the safety of electricity production.
2.3 China's thermal power plant training simulator from scientific research to product development process
2.3.1 Independent development of China's power plant system simulation technology and training simulator from the beginning of scientific research
With the development of digital computers, the world's industrially developed countries, after more than 10 years of research, in 1971 almost simultaneously in the United Kingdom, the United States, Japan appeared a practical thermal simulation training system. For example, in 1971, a 750MW full-unit simulator was installed in the Pittsburgh Thermal Power Plant in California, USA, and a digital computer was used. In the same year, a training simulator for a 350MW unit was installed at the Sendai Thermal Power Plant in Japan, which also used an all-digital computer. The British Central Power Generation Bureau built a 660MW full-range simulator at the White House Road Training Station in Leeds, using an analog-digital hybrid computer.
In the mid-1970s, China introduced four large-capacity, high-parameter, and advanced generator sets abroad. At the same time, Tsinghua University in Beijing proposed to China's Ministry of Water Resources and Power Industry to develop China's thermal power unit simulation system in 1975, and obtained the Ministry of Water Resources and Electric Power. With the approval and financial support, the development of China's first “large-scale thermal power unit simulation system†was started. The simulation object is determined to be the first domestic 200MW coal-fired generating unit produced by the three major power plants in Harbin, which is operating in Chaoyang Power Plant, Liaoning Province.
At that time, China was still in an era of non-opening, and there was no in-depth technical exchange with foreign countries. It could only rely on China's own technical strength as a scientific research project. Overcoming the difficulties of no advanced computer equipment and software, in a domestic DJS-130 small computer, in 1982 completed China's first large-scale thermal power simulation system, began China's own ability to develop power plant simulation machine History has made China one of the few countries in the world that have the ability to develop such simulators. Therefore, the first prize of the Ministry of Power Industry's outstanding scientific and technological achievements and the first prize of the National Science and Technology Progress Award were called the milestone of China Power Training by the power sector. Using this simulator, China's first thermal power operation simulation training center was built in Tsinghua University. In the past five years, about 2,000 operational technicians were trained for the power industry. In 1984, Tsinghua University began to develop China's first full-range high-precision simulator that completely replicated the control room of the 200MW unit of Harbin No. 3 Power Plant. It was completed in 1988 and installed at the Shenyang Electric Power College of the Northeast Electric Power Management Bureau. This is the earliest two suitable thermal power simulators developed and developed by China itself.
2.3.2 Mature conditions for product promotion
In 1988, the Ministry of Energy of China held a technical conference on power plant simulators attended by the leaders of the provincial and municipal power bureaus at the installation site of the first full-scale simulator of the complete replication control room, and proposed that China has the ability to develop its own power plant. High-precision simulators determine the promotion, development and application of simulation techniques in power systems. In October 1988, the Ministry of Energy issued the “Notice on the Development of Thermal Power Unit Simulation Training Devices†to the provincial and municipal power bureaus and large power plants. The document stipulates that the simulation machine is listed as an important technological progress project of the power industry. The planning and fixed point are urgently planned, and the simulation machine of various capacity units of 200MW or more is established. The operation personnel must carry out simulation training for not less than one month in the simulation machine before they are employed. And gradually make regular rotation training for personnel.
At this stage, China has introduced several foreign-developed power plant simulators. For example, in 1986, the National Nuclear Safety Administration introduced a 900MW pressurized water reactor nuclear power simulator from the United States, installed at Tsinghua University; a 550MW principle thermal power simulator was installed in North China Electric Power College; in 1987, the main equipment of Huaneng Dalian Power Plant from Japan Brought into a 350MW thermal power simulator, installed in Dalian Electric Power Technology School; introduced a 300MW thermal power full range simulator from the United States in 1988, installed in Beijing Electric Power School, but this simulator is very expensive, up to 6.7 million US dollars, this It is unbearable for China's national strength.
2.3.3 The peak of China's development of thermal power simulator
In the 1990s, energy development in western developed countries was almost stagnant, and the construction of new power plants was reduced. Therefore, their power plant simulator industry did not have enough markets and closed down.
The outstanding feature of the development of power plant simulators in this stage is in China: After the Chinese Ministry of Energy issued the “Notice on the Development of Thermal Power Plant Simulation Training Devices†in 1988, the blind development of domestic power plant simulator development companies is also in the history of the world. Yes, by the end of 1993, there were more than 20 power plant simulator development companies or centers. However, the number of domestically executed simulators operated during this period was only 15 units, of which 8 were produced by Tsinghua University, 3 by North China Electric Power College, 2 by Asian Simulation Company, 1 by Southeast University, and 1 by Xi'an Thermal Power Research Institute. Tsinghua University and North China Electric Power College were jointly awarded as one of the top ten scientific and technological achievements in 1992 by the State Science and Technology Commission and other units.
At the same time, grid dispatching simulators, hydroelectric simulators, and substation simulators are also being developed, but in small numbers. In 1992, China’s first power system dispatching simulation system completed by Tsinghua University was installed in the dispatching center of Northeast Electric Power Management Bureau, and won the first prize of scientific and technological progress of the Ministry of Power and the second prize of national scientific and technological progress; the first hydropower simulation in China completed in 1993 The machine is simulated by the Fengman Hydropower Station in Jilin Province.
By 1997, the number of thermal power unit training simulators in China's power sector had reached 68. In addition to Guangxi, Hainan and Tibet, thermal power simulation training centers were established in all provinces and cities. Some new large thermal power plants also have their own training simulators.
3 Distribution of thermal power simulators put into use and under construction in China
According to incomplete statistics, in just ten years, the number of thermal power plant simulators that China has put into operation and signed contracts in 1997 has rapidly reached 68; nuclear power simulation machines 3; hydropower plant simulation machines 2; power grid dispatching simulation There are 5 sets of machines, and these training simulators belonging to the power industry total 78, making it the second largest power industry simulator in the world after the United States. Among them, the thermal power simulation machine alone has the world's number one, and nearly 90% of it is developed and developed by the country itself, which fully shows that China has strong simulation technology and simulation machine development strength. The training centers of various provinces and cities have owned or planned to build 200MW-600MW various types of thermal power training simulators; there are also many power plants such as Huaneng Fuzhou Power Plant and North China Panshan Power Plant, which have their own simulation machines.
The distribution of these simulators is: Northeast Power Grid occupies 10 thermal power simulation machines, one power grid simulation machine, one hydroelectric simulation machine; North China Power Grid occupies 16 thermal power simulation machines, one nuclear power simulation machine, one power grid simulation machine; East China The grid has 18 thermal power simulators and one nuclear power simulator. Huazhong Power Grid has 12 thermal power simulation machines, one nuclear power simulation machine and two power grid simulation machines; the Southwest Power Grid has seven thermal power simulation machines. 5 thermal power simulators in the Northwest Power Grid, one hydroelectric simulator, and one grid simulator.
From the perspective of development units, Tsinghua University has 23 units, including 19 thermal power plants, two hydropower plants, and two power grid simulators; North China Electric Power Institute has developed 18 thermal power simulators; and 15 Asian simulation companies have developed 14 of them. Thermal power, a nuclear power simulator. The total number of simulators developed by the above three units is 56, accounting for 72% of the total number of simulation machines in China's power industry. 9 units have been imported from the United States, Japan, France and other countries. The remaining 13 units were completed by 8 other domestic simulation development units.
Not only that, China has the ability to export power plant simulators. In August 1995, Tsinghua University completed the task of exporting China's first simulator to Pakistan. The simulation target was the 210 MW fuel oil plant of Muzafargo Power Plant. At the same time, due to the independent development of thermal power simulation system and technology, the development of object-oriented, engineering-oriented modular, graphical, high-precision modeling methods; independently developed to support simulation machine development, debugging, operation management and other simulation support Environmental software. These modeling and support software tools were exported to South Korea in 1996, becoming the world's leading country with the ability to export power simulation technology.
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