The Application of Three DCS Systems in Mawan Power Plant
Diesel Engine,Generator Engine,Automobile Engine Fenghua Jade Motor Co., Ltd. , http://www.engines-world.com
The steam turbine is the N300-16.7/537/537 subcritical, primary intermediate reheat, and high-pressure cylinder single-cylinder double-cylinder double-reverse steam reaction type steam turbine that was produced by Harbin Steam Turbine Technology with the introduction of American Westinghouse Technology. Turbine start adopts high pressure main valve control mode. At 2900R/MIN, the high-pressure main valve and the high-pressure control door are switched and the high-pressure control door is controlled to increase the speed and load. Each unit is equipped with two high pressure main valves, six high pressure control doors, two medium pressure main valves, and two medium pressure control doors.
The generator is manufactured by Harbin Electric Machinery Factory and the cooling method is water-hydrogen-hydrogen.
The No. 1 and No. 2 units used the United States Bailey's INFI-90 decentralized control system. The two units were put into operation in 1993 and 1994 respectively. The No. 3 and No. 4 units used the PROCONTROL-P distributed control system of ABB of Switzerland. Taiwan units were put into operation in 1996 and 1997 respectively; Units 5 and 6 used the XPDS-400 distributed control system of Shanghai Xinhua, and Unit 5 was put into operation in November 2002. The following three sets of systems generate electricity in Mawan. A simple comparison of the design application of the plant.
First, the hardware comparison 1, the network structure comparison INFI-90 uses a redundant factory loop (PlantLooP) to connect the central processing unit and OIS, the communication medium for the coaxial cable, the cable quality and contact resistance requirements of each contact High, data communication is blocked when a breakpoint and poor contact occur in the loop. In addition, the communication speed of this ring network structure is also restricted by the speed of the module bus, making the communication speed slower. The #2 unit of our plant has repeatedly caused the communication interruption due to the failure of the coaxial cable and endangered the safe operation of the unit. The coaxial cable as the communication medium does have its inherent defects.
Although PROCONTROL-P uses a local area network structure, its local area network is still implemented by coaxial cable, and inherent defects of coaxial cable still exist. Because the man-machine interface part and the real-time control system are connected through a server, the requirement for the server during the operation is high, and once the server has a problem, the device loses the monitoring and control. Our factory had lost more than 20 minutes of monitoring and control of field equipment due to server crashes.
XDPS-400 adopts optical fiber as the communication medium and is designed in the form of double rings, which fundamentally overcomes the inherent disadvantages of coaxial cables. This ring network is a kind of virtual ring network that is physically a logical logic network of the ring network and has a network self-healing function. When any device or network line in the ring network is damaged or breaks, it will not cause system communication interruption, and due to people Both the machine interface system and the decentralized processing unit use the same communication medium and communication protocol (TCP/IP), which makes the communication hardware and software both very simple and clear, and also makes the system expansion very easy.
2. Comparison of Modules The modules in the PROCONTROL-P14 system have no distinction between main modules and submodules, and there is no input module or output module. Relatively speaking, the types of modules in the system are less. Modules are both functional and versatile. However, since the PROCONTROL-P system is a combination of P13 and P14, there are more communication modules between the two systems. Therefore, the total number of module types is greater than INFI-90 and XDPS-400. The module type of the XDPS-400 system should be very small if it is to remove the dedicated module of the DEH/MEH system. In particular, the entire system has only one kind of communication interface module, which is enough to explain the high degree of integration due to the type of the module. The reduction in the number of corresponding Spare Parts has also been reduced. In addition, because the XDPS-400 system implements a system that directly drives field devices, some intermediate relay cabinets and expansion relay cabinets are eliminated, simplifying the system structure and saving the unit investment.
3. Comparison of power supply The INFI-90 control system uses a 220V dual-channel decentralized power supply. The protection system uses a form of electrical tripping. The PROCONTROL-P control system uses a 48VDC dual-circuit centralized power supply and the protection system uses a power-off tripping method. Therefore, the PROCONTROL-P control system not only requires a highly reliable DC power supply loop, but also requires good AC power supply quality. Although the XDPS-400 also uses a 220V dual-way distributed power supply, its FSSS protection system uses the AC-DC power-off trip mode, and the ETS system uses the power-off trip mode. Therefore, the overall requirements of the three systems for the power system are relatively high, but the XDPS-400 system is designed MFT DC hard logic trip circuit. In the case of DCS system two-way AC power loss, the system can also send MFT signal, With high reliability.
Second, the software comparison 1, the complexity of the software system comparison INFI-90 control system hardware, software, and system structure is relatively simple, easy to master and maintain, man-machine interface part is relatively simple, through the structure of an extremely simple engineer workstation ( EWS) can realize configuration modification, configuration download and fault diagnosis, but the human-machine interface system is a non-open system, and the configuration tool is implemented in the form of a command line, which is not intuitive. The PROCONTROL-P system has a large and complex man-machine interface system. There are multiple servers and user terminals in the system. The server and user terminal computers also use different operating systems, such as Unix and OpenVMS operating systems, configured. Modifying, compiling, and downloading are very tedious and slow but intuitive. In addition, the PROCONTROL-P control system is actually composed of two completely different systems: P13 and P14. There are two completely different hardware, software and configuration tools. Although the system has greatly improved in terms of man-machine interface, because the system is too complex, it is difficult to learn and master, and the maintenance and learning workload of the thermal maintenance personnel is increased. Xinhua’s XPDS-400 system has the advantages of the above two systems and eliminates some of their shortcomings. It uses the current popular Ethernet network architecture, using PCs as an engineering station and Windows NT as a working platform, making the system It looks simple and clear. The openness of the system is relatively high and the configuration is graphical. Configuration files do not have to be manually compiled and can be directly applied after the graphical mode is modified. The signal descriptions are all in Chinese, and the human-machine interface is very friendly.
2. Comparison of System Compatibility Flexibility The INFI-90 system and PROCONTROL-P system are difficult to connect with other systems, and the peripheral system of the power plant has high access cost. Especially PROCONTROL-P system, it is very difficult to realize the interface with it, the cost is very high, the system flexibility is extremely poor, our factory MIS system can't carry on the interface with it until now. The XDPS-400 system has more outstanding advantages in terms of compatibility. From the bottom design, they have considered and left a variety of popular standard interfaces, making the system highly share files and data. It is not too difficult to directly add or modify control devices within the INFI-90 and XPDS-400 systems, but adding devices within the PROCONTROL-P system is not a simple task, so from the standpoint of system flexibility, PROCONTROL-P The system is far worse. These three systems can provide some data reports. The INFI-90 data report is not beautiful, but it is also practical; PROCONTROL-P system can only provide some fixed data reports, the flexibility is too bad; XDPS-400 uses Office file format, It can flexibly provide more diverse Chinese data reports.
3. Comparison of Function Blocks Three systems use function modules to implement the logic control of the device. However, the function of the function blocks is quite different. There are more than 200 function blocks in INFI-90, and the types are relatively complete, but they are not intuitive to use and have relatively simple functions. Most of the function blocks must be carefully set against each function parameter in the function block manual. The configuration drawing can only be performed through the command line, and the function blocks cannot be compressed.
The PROCONTROL-P system has been improved in these areas. Its function blocks are generally more powerful. There are many functional blocks that are specifically designed for the control of power plant equipment, such as dedicated function blocks for compensated correction of the drum water level. The user is like a black box, little is known, but at the same time it lacks some good functional blocks, such as it does not have functional blocks similar to the SMIH predictor properties in INFI-90, making the system superheated and reheated. Steam temperature control is difficult to get a big improvement.
Although the function blocks in the XDPS-400 are not too diverse, they are all practical. Because it uses a computer graphic design method, the design of the configuration diagram becomes very simple and clear, and the parameter selection of the function blocks is online. Makes debugging of the configuration very convenient. The description of the signal description and function blocks on the configuration diagram has been implemented for the first time, which greatly reduces the language barrier and the XDPS configuration diagram is more suitable for China's national conditions. And the biggest advantage is that its configuration software can be installed on any PC to perform off-line configuration. Once the configuration is completed, simulation can be performed. In the off-line situation, you can see if the configuration is correct. There are no procedures for online configuration, such as compilation and cross-reference, and it can take effect directly after the change.
Third, the system dispersive degree compares XDPS-400 system, INFI-90 system and PCONTROL system in PROCONTROL-P is a typical master-slave module control system, their concentration is higher, all control strategies are concentrated in the main module Inside, all submodules must work under the control of the master module. Once the master module fails, all devices controlled by the master module will lose control. The P14 system in PROCONTROL-P is a typical decentralized control system. The internal modules of this system are equal regardless of master-slave and they are all equal. Due to high dispersion, the damage of a functional module has little impact on the system. The drive-level interface part is connected to the controlled device in a standard manner, which is convenient and quick when dealing with problems or solving problems.
Fourth, the system reliability comparison XDPS-400 system uses dual DPU, dual network redundancy structure, the network node through the switch to connect, switches and switches through the fiber connection, the operation of a node communication interruption will not affect The normal operation of other nodes has virtually increased the reliability of the system. Although the INFI-90 and PROCONTROL-P control systems also use a dual-ring redundant network structure, they are all in the form of coaxial cables. The communication interruption of the point will cause the normal communication of the entire loop.
V.Comparison of the degree of integration of the system The INFI-90 system implements integrated control of systems such as DAS, SCS, BMS, CCS, and DEH/MEH. Although PROCONTROL-P also implements the same content control, it actually It is implemented by two systems (P13 and P14). The degree of integration of the XDPS-400 is relatively high. In addition to including the control of these systems, it also includes the control of the electrical system ECS, seawater circulating cooling water system, seawater desulfurization system, and high and low bypass systems. The SOE function is also Integrated into the DCS system, no need to separately purchase SOE systems. Through the communication interface unit, it can also realize the monitoring or control of most of the plant's most peripheral PLC systems such as soot blowing system, electrical excitation system, furnace four-tube leakage system, and air compressor system. As the degree of integration has increased, the thermal workers have only used the same human-machine interface, which has greatly reduced their workload.
VI. Comparison of operational conditions Unit #5 has been operating for nearly half a year since it was commissioned. During this period, it should be said that the system is fairly stable. So far, there have been no trips due to system reasons. The modules in the system are also relatively stable. Since the handover to production in November 2002, we have only replaced a digital input module. Since the operation monitoring screens are all described in Chinese, the operating personnel generally can grasp the characteristics of the system relatively quickly. From the general reflection of the operation and thermal workers, we still agree with this system.
7. Conclusion In general, Xinhua's XDPS-400 system has certain advantages in many aspects, especially human-machine interfaces. It has the advantages of being simple, practical, flexible, reliable, intuitive, easy to learn, and highly integrated. However, in terms of system data, it should also learn from foreign companies and it should be constantly improved and improved. PROCONTROL-P control system will be eliminated by the market due to its complex system structure, poor integration characteristics, and difficulty in mastering. It should be an outdated generation product. The INFI-90 system should be strengthened with the development of electronic technology. The degree of openness of the system will also increase, but its spare Parts prices are too expensive.