Harbin ash slag system centralized control in the third power plant

First, the status quo before the transformation China's first domestic 600MW unit, Harbin Third Power Plant No. 3 machine was put into operation in 1996. At the time, the bottom ash slag system was contracted by the UCC Company of the United States. The PLC used two MODICON 984B dual-system hot backup systems with 800 series I/O modules. The analog tray method was used to control the process flow; the hydraulic ash removal monitoring system consisted of Beijing Shengxin Era Technology Development Co., Ltd. completed the use of PLCE984-785 hot standby system + CRT monitoring method; electrostatic precipitator monitoring system completed by the Dalian Institute of Electronics, using the MODICONPLCE984-685 + CRT monitoring.

In the ash control system for the new No. 4 600,000 kW unit, the process equipment (valves, etc.) of the bottom ash slag system is still supplied by UCC. Due to the original PLC's capacity and communication problems, the CPU was upgraded to an E984-785. The software programming and debugging were completed by the cooperation of the Harbin III Thermal Power Plant and Beijing Shengxin Era Technology Development Co., Ltd. The PLC+CRT monitoring method was adopted. The hydraulic control system for ash removal was completed by Beijing Shengxin Era Technology Development Co., Ltd. PLC's CPU was still using the E984-785 hot standby system of the No. 3 machine. Only one new remote I/O station network was added and a new one was added. The machine completed the monitoring function; the electrostatic precipitator control system was still completed by Dalian Electronics, which consisted of a number of MOPCON's COMPACT series A984-141. Through RS-485 (MODBUS protocol) network and host computer communication, complete the corresponding monitoring function. Unit 4 was put into operation at the end of 1999.

It can be seen from the above that the operation of several subsystems uses the upper computer, and some use the analog disk, which is inconvenient to operate. At the same time, because each system is independent of each other, it also brings great difficulties to the maintenance of the entire ash system. In addition, in order to reduce the number of employees in the factory, the ash system operator of the entire No. 3 and No. 4 aircraft has only 2 members. Therefore, the human-machine interface part of the ash system of No. 3 and No. 4 machines must be completely transformed. As a result, the Harbin III Thermal Power Plant commissioned Beijing Shengxin Era Technology Development Co., Ltd. to complete this work, and put forward the following technical requirements:

1. According to the technical requirements of decentralized control and centralized monitoring, all hydraulic ash removal systems, bottom slag systems, and electrostatic precipitator systems for No. 3 and No. 4 machines must implement a unified user interface. That is, all the above subsystems can be monitored on any one host computer.

2. The monitoring system of the upper computer must be safe and reliable. There must be alternative means. If any one of the upper computers fails, other upper computers can replace their functions to complete the corresponding monitoring operations.

3. The picture of the entire system should be beautiful, visual and three-dimensional. At the same time, I/O refresh and screen update speed must meet the process requirements.

4. It is necessary to reserve the interface with the factory MIS system in order to achieve a higher level of management functions.

5. To reserve the interface with the factory-level INTRANET, the security mechanism through the firewall can access real-time field data through the universal IE browser.

Second, the reform program to develop According to the number of actual I / O points of these subsystems, the total number of actual I / O points controlled by all PLC exceeds 6000 points, plus the middle of the host computer control point, the entire I / O Points will exceed 10,000 points! After many technical solutions, the design of the entire network system is shown in Figure 1.

1. Host computer system hardware configuration a. The choice of IPC is very important. It is the basic hardware platform of human-machine interface. Its performance and quality are directly related to the reliability of the entire control system. The three host computers used in the centralized control system of all the ash supporting workshops we use are INTEL IPCs. The main hardware indicators of each industrial computer are: CPU frequency PII400, memory 128M, hard disk 8G, 8MAGP graphics card, 10/100M adaptive Ethernet card.

b. CRT

The CRT uses a 21-inch right-angle screen, the screen resolution is 1024X768; 16-bit true color; 85HZ refresh rate.

c. The server uses a high-quality IBM server (PII450, dual CPU, 256M memory, 10/100M adaptive Ethernet card)

d. The switch uses a 12-port BAY-350-12T10/100M adaptive switch. The purpose of using the switch is to increase the point-to-point transmission speed in the network.

2. The network of the system The network of the whole system is divided into two levels: The first-level network is an industrial standard control network, and its main role is to guarantee the real-time exchange of data between the PLC and the host computer. The secondary network uses the very popular Ethernet network today, and the speed is 100M. Its main role is to complete the communication between the host computer.

a. The primary network level 1 network is a 1 Mbps MODBUS PLUS network (hereinafter abbreviated as MB+), and the network has successfully installed more than 100,000 nodes in the world. After years of practice, it proves that both reliability and real-time performance can stand the test. MB+ is a very reliable, efficient industrial control network for MODICON PLC. MB+ combines high-speed, peer-to-peer communications, and ease of installation to simplify applications and reduce installation costs. This local area network allows host computers, controllers, and other data sources to communicate peer-to-peer throughout the plant via inexpensive twisted-pair or fiber optic cables. The MB+ acts as a deterministic token-passing network to transmit communications at 1 megabit for quick access to process data. Typical applications include controller networking and interlocking, data acquisition, program loading/unloading, remote online programming, connection to operator interfaces, and host data collection. This network combines the features of multifunction services for the integration of I/O, controllers, computers, or any other MB+ compatible device. A network performs all the required tasks. Its specific composition is as follows:

The No. 3 electromechanical dust removal control PLCE984-685 is connected to the MB+ network via a built-in MB+ communication port.

The E984-785 hot standby PLC for the hydraulic ash control of No. 3 and No. 4 machines was connected to the MB+ network via 1 MB+ communication port.

The PLCE984-785 for the bottom slag control of No.3 and No.4 machines also uses a built-in MB+ communication port to access the MB+ network.

In order to save PLC cost, the No. 4 machine's electric dust control system uses eight small A984-141 PLCs. Eight PLCs are connected via an RS-485 network (subject to the MOD-BUS communication protocol) to the MB+ bridge BM85. BM85 Above there is an MB+ communication port and 4 MODBUS communication ports, which actually play the role of the communication protocol conversion between MOD-BUS and MB+.

Three MBCs and IBM servers were respectively equipped with a MB10 adapter card SA85 to connect to the primary network.

The above equipment (PLC, bridge, IPC, and server) constitute a 9-node MB+ industrial control network.

b. Secondary network secondary network It mainly undertakes the task of data exchange between the upper computer; between the host computer and the server; between the server and the MIS system. In order to increase the communication speed, 100M Ethernet, which is already very mature, is used, and the communication protocol uses TCP/IP. In this system, its role is as important as the primary network.

The composition of the secondary network consists of a 10/100M adaptive switch connecting three IPCs with 3Com's 3C905BTX network card and an IBM server to form a 100M Ethernet.

3. Software section a. The operating system operating system uses Chinese WINDOWSNT4.0 (SP4). The reason for using NT is because it has very good stability and reliability, and the operating style of the interface is consistent with the popular WINDOWS95/98. Its powerful network function and support for INTERNETSERVER also provide convenience for future expansion of functions.

b. The configuration software configuration software is INTELLUTION's FIX32V6.15. FIX32 uses a distributed client/server architecture with 100% data integrity. FIX32 is the most complete SCADA solution on the WINDOWSNT platform. There are three main reasons for using the FIX32 monitoring software package:

1) FIX32 distributed database structure. Its global database is distributed over each FIX node on the network. The sum of the databases of each FIX node on the network is the global database of the entire system. The performance of the centralized control system of the entire ash-assisted workshop is completely dependent on the design of the database.

2) High performance I/O driver. The driver supports complex redundant connections, communication fault detection and other functions.

3) FIX32V6.15 has provided comprehensive Chinese support, which brings great convenience for use and maintenance.

c. The allocation of the database to the local database is like this:

The No. 1 industrial control computer is equipped with the FIX32 I/O database of the No. 3 unit hydraulic ash control system and the No. 3 unit UCC bottom slag control system.

The No. 2 industrial control computer is equipped with the CFC32 I/O database of the UCC bottom slag control system of Unit 4 and the electric dust removal control system of Unit 3;

The No. 3 industrial control machine is equipped with the FIX32 I/O database of No. 4 unit hydraulic ash control system and No. 4 unit electric dust control system;

The data collected and controlled by each industrial control machine is derived from the global database on the database server of the local machine, constantly refreshing all the I/O data, and maintaining the entire image of the other three sub-databases. When an industrial computer fails, another industrial computer should be able to completely replace the failed industrial computer to achieve monitoring tasks. To implement this technical requirement for users, we must analyze the path of all database accesses, as shown in Figure 2:

The database of the three IPCs on the Ethernet network is denoted by A, B, and C respectively. The database on the Ethernet server above is denoted by G.

The setting of the monitoring screen on the three IPCs is the same. Data access works as follows:

1. A can access B, C at any time on the network. The paths are AB, AC. Definition AB, The redundant backup connection for the AC data connection is AG.

2. B can access A,C at any time on the network. The paths are BA, BC, respectively, and BA, the redundant backup connection of the BC data connection is BG.

3. C can access A, B at any time on the network. The paths are CA, CB, and define CA. The redundant backup connection for CB data connection is CG.

We take full advantage of the redundant connectivity provided by the FIX32 database. For example, in working mode 1, if the industrial control unit of node B or node C fails, or both industrial computers at node B and node C fail, then node A will automatically connect to the AG path. Due to the global database image maintained in the G node, the above screen operations on the A node are still valid, and the normal link of all I/Os is completely realized.

In fact, we are making full use of the software technology to achieve the hardware backup. Satisfy the user's technical requirements.

Why do we load the three IPCs with a local database instead of a global database? If each IPC is loaded with a global database, is it not easy to implement alternate functions? There are two main reasons:

1) As we have already mentioned, the 600,000 units of the electrostatic precipitator, the hydraulic ash, the actual I/O points of the bottom slag control system exceed 6,000 points, plus the number of points used internally, our global database I The number of /O points exceeded 10,000 points. If each IPC is loaded with a global database, the workload of IPCs will be very large and the efficiency will be low. The data refresh time on the monitoring screen will be very slow.

2) The MODBUSPLUS network runs above 9 nodes. If each industrial computer is loaded with a global database, each IPC must access all PLCs through the MB+ network. This will increase the burden on the MB+ network by many times, and the work efficiency is very high. low.

Third, the effect of commissioning The entire system after more than a month of debugging has passed the acceptance of the power plant at the end of 1999. From the effect of the actual operation: system design and software design is very successful, the monitoring picture I / O refresh time does not exceed 1 second, the picture refresh time in l-2 seconds to complete! The picture update speed and I/O refresh time meet the production requirements. After nearly half a year of operation, the stability and reliability of this technical solution have also been tested in practice, and users have also given full affirmation.

IV. Conclusions The computer monitoring network of the auxiliary processing plant in the grey processing is reasonable and reliable. Software design and application are just as reasonable and reliable, and remote monitoring of the auxiliary workshop is realized. In the two 600,000 units, only one monitoring point was set in the auxiliary workshop of the same type associated with the ash. Improve the overall level of control and labor productivity of the entire plant, reducing the operating cost of production. The level of monitoring of auxiliary systems for large-scale units has been raised to a new level; at the same time, it has also made an exploratory contribution to the reform of the management mechanism of power plants.

We firmly believe that the centralized monitoring of auxiliary workshops of the same type will be widely used in the technological transformation of new power plants and old power plants.

The company is very grateful to the leadership and technical staff of the thermal plant of the Harbin III Thermal Power Plant for their strong support and assistance in this project. Their spirit of cooperation and professionalism are the fundamental conditions for the rapid and smooth investment of this project. At the same time, we are grateful to Li Haichen, Senior Engineer of Thermal Engineering Department of Northeast Electric Power Design Institute, for the technical guidance of this project.

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