Abstract: To adapt to the needs of power market development and reform, thermal power plant performance evaluation, and daily power energy statistics and balance rate calculation, establishing a stable and reliable automatic power energy acquisition system in thermal power plants has become inevitable. This paper takes the construction of the automatic power energy acquisition system of Jiangsu Xinhai Power Generation Co., Ltd. as an example to discuss several issues in the construction of an automatic power energy acquisition system for thermal power plants. Keywords: power plant, automatic power energy acquisition system, balance rate. In the process of power market operation, the physical quantity traded between buyers and sellers is electrical energy. The collection, monitoring, statistics, analysis, and calculation of power generation and supply, electricity exchanged on tie lines, network loss (line loss) electricity, and time-of-use and classified electricity are the main contents of power market operation; the construction of an automatic power energy acquisition system is the foundation for realizing power market operation. For thermal power plants, the main tasks are to statistically analyze power generation and supply, and to statistically calculate unit balance rate and shift handover electricity to strengthen management and take corresponding measures to reduce losses and improve efficiency. Taking Jiangsu Xinhai Power Generation Co., Ltd. as an example, we operate on a four-shift system. Traditionally, meter readings were performed at each shift change, followed by manual data entry and statistical calculations. This manual meter reading and statistical analysis could not meet the requirements of real-time, time-of-use, and dynamic analysis and management, making a change in the electricity data collection method imperative. Jiangsu Xinhai Power Generation Co., Ltd.'s automatic electricity data collection system was basically completed by the end of September 2001. This system has collected all electricity data from all units, completing functions such as automatic data collection, storage, total calculation, statistics, and report printing. The system replaced manual meter reading, improving data synchronization, timeliness, accuracy, and completeness. It automatically compiles statistics on the company's power generation and various balance rates, improving the speed and automation level of statistical calculations. The system is used for shift-based performance evaluation, improving the company's management level and efficiency. Departments can view all data and reports via the Web and perform various secondary developments, improving the utilization rate of electricity data. The system (as shown in Figure 1) consists of two parts: a main station and acquisition terminals (ERTUs). Data transmission between the main station and ERTUs is conducted via network communication. The main station uses the COM-2000 system from Nanjing Huaruijie Automation Equipment Co., Ltd., and the plant station uses the company's MPE-III remote data terminal for electrical energy. [b]1. Configuration of Jiangsu Xinhai Power Generation Co., Ltd.'s Automatic Energy Acquisition System[/b] 1.1 Main Station System Configuration This system uses a high-performance PC as the hardware platform. The system's database server uses dual-machine backup, with each machine serving as a hot standby, and maintains data consistency. The front-end machine is responsible for data acquisition and connects to GPS for network-wide time synchronization. The back-end machine is responsible for processing and saving data. The report workstation is responsible for editing and printing all reports. The Web server provides Web browsing, and each MIS workstation can view all data and reports via the Web. The main network uses a 10/100M network, with switches connecting the server and all computers. The system operating system uses the widely used and highly secure Windows 2000 Server. Network communication uses the TCP/TP protocol. The database uses the commercial data management system SQL Server 2000 with Client/Server mode. Programming is done entirely using VC, VB, Delphi, etc., and EXCEL is integrated as a reporting tool to generate richly illustrated graphical reports. 1.2 Main Functional Modules of the Main Station System (1) Database Management System The COM-2000 database management system adopts a standard commercial data management system. Data processing is the core of the entire system, which involves data structure, data access, data maintenance, data sharing and other aspects of management. The database is roughly divided into four parts, namely system information database (archive information database), original database, secondary statistical database and formula statistical database. The system database stores information such as system configuration and parameters. The original database mainly contains the electricity meter data from each acquisition terminal. The secondary statistical database mainly contains the data from the original database after calculation and statistics. The formula statistical database comes from the secondary statistical database and stores the calculation results of the formula. (2) WEB Service Management System The WEB service management system responds to WEB service requests from the Internet/Intranet and provides the database data and WEB page format requested by the client. (3) Front-end Communication and Data Processing Management System This system completes the collection and processing of data from the acquisition terminal of the automatic energy acquisition system. The data acquisition adopts a high-capacity high-speed data transmission component to ensure accuracy. All operations are completed online, and can be used immediately after input, with good responsiveness. The specific functions are: to complete the protocol conversion, coefficient processing and rationality check of the received messages, and to hand over the processing results to the database. The communication status and specific communication messages can be viewed in real time. (4) Data statistics and formula management system This system completes the setting of statistical calculation formulas and the timed statistical tasks, such as the timed statistical tasks of shift electricity, daily electricity, monthly electricity, annual electricity and total electricity, balance, line loss, transformer loss and other data. (5) Report and graphic setting display and printing system Users can set the format of reports and graphic displays according to actual needs, complete the timed printing of report data such as shift electricity, daily electricity, monthly electricity, annual electricity, and can display and print historical data of any meter, any acquisition terminal or the whole plant according to user requirements. (6) Terminal and meter parameter setting, download and summoning system This system completes the online setting and download of the base value, turn ratio, time period scheme, PT, CT and other parameters of each meter in the acquisition terminal from the main station, and can view the terminal and meter status and parameters online. (7) Internal Network Communication Management System This system is the link between various subsystems in the whole system. Its functions are: to realize high-level network communication for applications based on the network support provided by the operating system; to determine the data flow direction according to the data flow pattern defined by the application and improve the communication efficiency of the application. The system adopts a complete Client/Server mode and is based on the TCP/TP protocol, which ensures the portability of the entire platform between different network communication protocols. (8) Alarm Management System This system prompts and alarms specific changes that occur in the system according to user requirements, data processing results, and changes in equipment status. For example, if the power value exceeds the limit or the equipment is abnormal, alarms can be issued in various ways such as pop-up prompts and voice. Alarm information can be printed and saved, and can be queried and retrieved by time period. (9) Remote Diagnosis Management System This system is used to complete the diagnosis and maintenance of the user's system. The system can connect to the user's system through a dial-up MODEM to analyze and diagnose its operation; it can remotely update the system program to eliminate system faults; and it can remotely publish system update messages to improve the system's usability. (10) Security Mechanism Management System This system completes security verification to prevent illegal operations. Users are managed in a tiered manner, with different operating permissions assigned based on user category; during critical operations, the legitimacy of the user's operating permissions is checked; critical operation processes are recorded to improve system management. 1.3 The power energy acquisition device adopts the MPE-III remote power energy data terminal. The device uses AC and DC dual power supplies and simultaneously acquires data from pulse and digital meters throughout the plant. Power energy data for each time period is time-stamped and retained for one month; remote communication is achieved using polling; it has functions such as accepting local or remote parameter downloads, self-diagnosis, remote diagnosis, and self-recovery; it features a Chinese LCD display; settings, viewing, and verification are password protected; and it has input and output voltage and current protection, lightning protection, and DC reverse polarity input protection. 1.4 Communication Method The communication between the main station system and the remote power energy acquisition terminal is via network. Due to the short distance, each acquisition terminal is directly connected to the main station system's network switch. Data transmission between the power energy acquisition terminal and the power meter is directly via RS-485 port; a pulse acquisition board is added for pulse meters. 2. Several issues in the construction of the automatic energy acquisition system for thermal power plants 2.1 Construction of the main station system (1) The automatic energy acquisition system is different from the SCADA/EMS system. When the power industry shifts to market-oriented operation, the production and operation of the power grid will become more detailed, and the automatic energy acquisition system will inevitably become an independent system. (2) The construction of the automatic energy acquisition system must comply with the relevant national metrological management standards and technical specifications. (3) Database design. When selecting a database, on the one hand, performance and function should be considered; on the other hand, the inheritance with the existing dispatch automation system database, as well as open platform and data interface issues should also be considered. The design of the database content of the automatic energy acquisition system should involve future compatibility issues. China's automatic energy acquisition system has gone from nothing to something, and market rules will inevitably be continuously modified and improved. Changes in database structure and content should be minimized and avoided as much as possible. A perfect database system is an important task in the research and design of the automatic energy acquisition system. (4) System security. The functions realized by the automatic energy acquisition system involve the vital interests of enterprises. The system should have strong anti-interference capabilities, and the system operation must be stable and reliable. (5) Data integrity. Since energy consumption is continuous, energy measurement is a series of cumulative energy values ​​that increase over time. It is required that data should not be lost in the event of any failure during the entire process of measurement, collection, transmission, storage and processing. Especially when conducting shift-based energy statistics and settlement, data integrity becomes the foundation of the automatic energy collection system. The system data processing should adopt a hierarchical processing method to store data to ensure the security and integrity of energy data. (6) Data modification. The system must ensure that the collected original energy data is complete and accurate. The stored original energy data can only be viewed and cannot be modified; each backup energy data can only be modified by authorized personnel, and modification records should be saved. (7) Data recoverability. The system should have the ability to recover data in the event of system failure caused by unexpected circumstances to ensure the security and integrity of energy data. (8) Data timeliness. Energy data should be collected, transmitted and stored with time stamps in 5-minute (or 1-minute) units to facilitate energy statistics and shift-based assessment. (9) System timeliness: The entire power system is always in a dynamic balance state of power generation, transformation, transmission, distribution and consumption. Power trading involves production, sales and purchase simultaneously. The automatic power acquisition system should use a standard clock (GPS) as the reference to ensure that each metering point completes the metering of power and the storage of power data with time stamps based on the same time reference. The main station system is connected to the GPS clock. The system synchronizes the time with the acquisition terminal, and the acquisition terminal synchronizes the time with the electricity meter (the electricity meter is required to support this). (10) System fault tolerance: The software and hardware of the automatic power acquisition system should have good fault tolerance. When the software and hardware functions experience general failures, or when operators or maintenance engineers make general errors during operation, the main functions of the system will not be lost or the normal operation of the system will be affected. (11) System flexibility: my country's power market has its own characteristics. The application functions of the automatic power acquisition system should have great flexibility, be able to adapt to policy and market changes, and meet the requirements of different users. (12) System scalability. The system design must adopt a standardized and modular structure. The installation of the functional expansion parts should be simple and convenient, and should not cause any harmful effects on the system. (13) System openness. Under the premise of ensuring safety, the automatic energy acquisition system requires strong system openness to ensure the principles of fairness, impartiality and openness in the operation of the power market and improve the reputation of power companies. (14) System maintainability. The software and hardware of the automatic energy acquisition system should be easy to operate and maintain. The system should have online maintenance processing function. The maintenance processing of the automatic energy acquisition system must be carried out without interruption and interference with the normal operation of the system to ensure system safety. (15) System interface. The automatic energy acquisition master station system should provide standard interfaces for SCADA, EMS and MIS systems to realize data sharing. (16) System access control. The security, reliability and data accuracy of the system are directly related to the economic interests of the enterprise. The automatic energy acquisition system must have strict access control function. 2.2 Energy acquisition terminal (1) The acquisition terminal is required to have high stability and reliability. The main components should have backups. (2) RS-485 data communication should be used between the data acquisition terminal and the electricity meter. 2.3 Electricity Meter (1) Electricity meters are the foundation of the automatic energy acquisition system and are very numerous. Electricity meters are required to be stable and reliable in operation, have high accuracy, long service life, reliable communication, and be easy to install and maintain. (2) Electricity meters and the automatic energy acquisition system can automatically synchronize time to achieve a unified clock. 3. Conclusion This paper discusses several issues in the construction of the automatic energy acquisition system of thermal power plants based on the actual construction of the automatic energy acquisition system of Jiangsu Xinhai Power Generation Co., Ltd. The automatic energy acquisition system is a relatively complex system, involving all aspects of system design and construction, and is closely related to the management model of enterprises and the operation mode of the power market. To build a stable, reliable, and practical automatic energy acquisition system, enterprises, research departments and manufacturers need to cooperate closely to gradually solve the problems that arise in the system construction, improve the performance and indicators of the automatic energy acquisition system, and meet the requirements of China's power market operation standards.