Introduction With the implementation of "unmanned" or "minimal" operation in hydropower plants and the deepening of power system reform based on "separation of power plants and grids, and competitive bidding for grid connection," new requirements have been placed on the production, operation, and management of hydropower plants, as well as higher demands on hydropower plant automation technology. The development and application of computer monitoring systems are essential for hydropower plants to achieve "unmanned" or "minimal" operation. The rapid development of computer technology, information technology, and network technology has provided a broad stage for the development of hydropower plant automation systems, both structurally and functionally. Hydropower plant automation work must also adapt to the new situation and undergo new development. Today's hydropower plant automation system should be a comprehensive system integrating computers, control, communication, networks, and power electronics. It should not only be able to monitor individual power plants but also further realize the economic operation and safety monitoring of cascade river basins and even inter-basin hydropower plant groups. This article explores some technical issues related to the development of hydropower plant automation systems. 1. Organizational Process of Automation System Development 1.1 User Participation in the Development Process Computer monitoring systems differ from general electromechanical products. User participation in the development process is essential for the system to fulfill its monitoring functions. This is because: Due to the scalability of computer hardware and the flexibility of software, the structure, scale, function, and performance of monitoring systems cannot be standardized; there are no fixed systems available for purchase on the market. Source: http://tede.cn User requirements vary greatly. The scale, importance, and equipment condition of power plants differ, leading to different requirements for monitoring systems. The participation of power plant management models and production technicians in development is the best way to integrate user intentions, habits, and understanding of automation into the product. Participation in development enables users to quickly master system development technology, facilitating system upgrades, improvements, refinements, and maintenance, and enabling better use of the system's various functions. The monitoring system generally goes through the following processes from design to commissioning: design bidding, contract negotiation, establishment of a joint design and development team, collection of user data files, equipment procurement by the developer, system integration and software development, factory acceptance, on-site installation and commissioning, factory testing, and commissioning. Users should participate throughout the entire process, but actual participation in development begins after contract negotiations are completed and all technical conditions are finalized. This includes user data file preparation, system integration, and development. 1.2. User Data File Preparation: The greatest workload in monitoring system development lies in system customization, and the quality of customization depends on the sufficiency and accuracy of user data. Therefore, before developing with the manufacturer, users should organize professional technical personnel to collect and prepare on-site data. Production technical personnel should include operators, computer and network technicians, and automation technicians. Data prepared by operators includes: workstation monitoring screens, operation reports, historical record point definitions, event log reports, operation keyboard definitions, voice alarm statements, telephone and ON-CALL paging definitions, statistical calculation formats, etc. Data prepared by computer and network technicians includes: computer network structure, MIS system operating system platform, MIS system and automation interface software, bridges, firewalls, etc. Data prepared by automation technicians includes: database definition tables, various operation procedures and anti-misoperation interlocking conditions, I/O definition tables for each LCU, LCU sequential control and automatic switching procedures, AGC and AVC control parameters and boundary conditions, and external communication data lists, etc. Data file preparation typically takes about 3 months. For new power plants not yet in operation, due to equipment not yet being in place, unclear operating status, and incomplete drawings and documents, data file preparation may take several years. 1.3 Joint Design and Development Team Liaison Meeting: The joint design and development team should generally include technical and commercial personnel from both parties. The main contents of the initial liaison meeting are generally as follows: The user reports on the on-site data preparation status and submits relevant materials; The developer reports on equipment procurement and solicits user opinions on equipment changes and system integration schemes; Both parties' understanding of the contract and technical clarification; Determining the development organization method and development timeline; During subsequent development, depending on contract requirements and actual technical difficulties, 1-3 more joint design and development team liaison meetings may be held. 1.4 System Integration and Software Development: Hardware system integration serves two purposes: firstly, to verify the feasibility of the system structure and hardware equipment specified in the contract documents; and secondly, to build a platform for software development. This work should be carried out by the developer based on a simplified network structure. The user should establish a plant development working group, generally consisting of 5-15 people, and designate a group leader. The user work group should include: automation professionals, computer professionals, and experienced operators with basic computer knowledge. The developer should provide the application development platform and necessary training. During development, the user work group can independently complete the following tasks: editing monitoring screens; editing operational reports; editing real-time database source files; editing historical database source files; editing control flows for each LCU; editing source files for external communication data modules, etc. The user work group can assist the developer in completing the following development tasks: AGC and AVC control flows; defining events and alarm records; defining voice, telephone alarms, and ON-CALL messages; master station operation procedures and anti-misoperation interlocking procedures; statistical analysis and calculation of historical data, etc. The on-site user work group should regularly report on development progress, supervise the entire project execution until development is completed, and participate in factory acceptance testing. 2. Introduction to the Development Process of the Taipingshao Power Plant Monitoring System The development of the Taipingshao Power Plant computer monitoring system began in 1997. The project scope included the computer master station, network equipment, and common equipment LCUs. The project selected the Automation Institute of the Northeast Electric Power Research Institute as its partner. The project progress at each stage is as follows: Signing of cooperation intention: Early 1997: Automation upgrade plan and construction schedule plan: 1997: Technical conditions and contract drafting: 1998: Technical plan and equipment selection: 1998: Preparation of field data files: February-April 1998: User working group development: May-October 1998; September-December 1999 (Unit 1 in 1998; Units 2-4 in 1999). First LCU connected to the new master station network: October 1998: System commissioning: November-December 1999: As testing progressed, various functions were gradually put into use. By the end of 1999, remote measurement, remote control, and remote adjustment of the four units were achieved. In this project, user participation in development was mainly divided into two phases. The first phase was the data file preparation phase, involving more than 20 people and lasting 3 months. The second phase was the development phase, involving 15 people and lasting 6 months. 3. Discussion of Technical Issues in the Computer Monitoring System The monitoring system is a highly customized automatic control system. The system's practicality, advancement, reliability, and flexibility depend on the requirements of the customer (including management, design and development, and usage). Here, we discuss some technical issues. 3.1 Power Supply for the Monitoring System: The power plant control layer should have both DC and AC control power supplies. The LCU and peripheral automation devices of the monitoring system should preferably adopt a dual AC/DC power supply method with mutual backup and seamless switching. The voltage selection of the power supply device should ensure AC power supply and DC backup under normal conditions to reduce the burden on the DC system. Operational experience shows that UPS has a very short service life in the field environment and is difficult to maintain, so it is not advisable to use it (Taipingshao Power Plant is considering improving the DC power supply). The operating environment of the monitoring system's main station equipment (workstations, servers, and network equipment, etc.) should meet national requirements, and an AC + UPS power supply method is preferable. 3.2 Interface between the Monitoring System and the Excitation, Protection, and Speed ​​Controller Systems The LCU generally uses two methods with the aforementioned automation devices: digital input/output (DIO) interface and communication. For the DIO method, since the exchanged signals correspond one-to-one, the wiring is intuitive and easy to debug and troubleshoot. However, it involves more wiring, and some control functions, such as active and reactive power regulation, require complex PID control programs to be written within the LCU. Inappropriate PID parameters may also lead to poor regulation performance. Field applications show that this method can meet the requirements for reactive power/voltage closed-loop regulation, but for active power closed-loop regulation, overshoot, incomplete regulation, or prolonged regulation time often occur. The aforementioned three types of automation devices should preferably use communication. The LCU directly transmits the setpoint to the electronic speed controller and excitation device, realizing the initial setting of active and reactive power. The LCU obtains the detailed internal status of each automation device and the fault recall sampling value data packet of the microprocessor protection system (if the microprocessor protection system has this function) through the communication link. Although the monitoring system has interface connections with the excitation, protection, and speed controller devices, each system should maintain relative independence and have "mutual inspection" and fault-tolerant functions in communication. A failure in one system should not affect the normal operation of other systems. Signals directly used as control and regulation conditions in the aforementioned devices (such as main switch status, unit speed, and unit status) should not be transferred or reused between them, but should be directly acquired from the equipment through highly reliable channels. 3.3 Functional Coordination between the Monitoring System and Local Automatic Control Loops and Devices Units or common auxiliary equipment, such as cooling water systems, oil pumps, deep well pumps, and air compressors, generally have local automatic control devices. When handling the relationship between local automation and the monitoring system, the principle of local automation as the primary focus should be followed. The monitoring system undertakes the tasks of monitoring and backup control through the acquisition of switch and analog signals (without communication). Once an anomaly occurs, a signal is issued, and emergency control is performed through independent signal acquisition. DC power supply devices should also be considered local automatic devices. The monitoring system only monitors the operating status of the DC system and power supply devices and does not participate in control. There is no need to establish network or serial communication connections. 3.4 Considerations for Event Logging and Fault Recording Both event logging and fault recording devices are tools for operation and accident analysis. Event logging is generally integrated into computer monitoring systems, but due to limitations in sampling speed and memory, it often cannot provide sufficient waveforms for accident analysis. Fault recording is generally used in switchyards as a tool for collecting and analyzing line fault data. Units do not need to be equipped with fault recorders, as this would lead to repeated signal acquisition, complicate secondary circuits and cable layout, and make it impossible to collect a complete set of signals (critical quantities and intermediate calculation data points for some equipment cannot be interfaced). It is more reasonable to distribute the functions of accident logging and fault recording among the monitoring system and microprocessor-based protection devices, microprocessor-based excitation regulators, and microprocessor-based speed controllers with fast AC sampling capabilities, respectively. This requires that the microprocessor-based protection devices, microprocessor-based excitation regulators, and microprocessor-based speed controllers have functions such as fault identification, storage, and time synchronization. 3.5 Considerations for Signal Feedback Panels Signal feedback panels are crucial human-machine interfaces for centralized monitoring and control in power plants. Their intuitive, clear, and reliable display, along with fixed positions for instruments and components, greatly facilitates operation and maintenance, especially in emergency situations. Operators have a clear overview of the entire plant's status, a function that cannot be replaced by computer screens (using large-screen TVs or projectors is also undesirable). Signal feedback panels should ideally incorporate pointer instruments to reflect the system's dynamic processes (e.g., system oscillations). 3.6 Access Sources for Industrial Television, Fire Alarms, Security Systems, Fault Recorders, and MIS: http://tede.cn Given the prominent role of monitoring systems in power plant operation and control, the fewer systems connected, the better. When information exchange is low, I/O access should be used whenever possible to ensure the safe operation of each system, avoiding communication connections. For industrial television, due to the large amount of image signal data and its high network resource consumption, it should not be transmitted through the monitoring network but rather form its own network, with a dedicated CRT for industrial television installed in the control room. However, if the industrial television system is to achieve automatic image control and switching, it should still be connected to the monitoring system via communication. The communication link should only transmit information for automatic image control and switching unidirectionally from the monitoring system. The industrial television system should be networked with the power plant's Management Information System (MIS) to allow authorized users to access the images. Fire alarms are crucial for operational monitoring, but their data volume is relatively small, making connection to the monitoring system a reasonable option. Fire alarm signals and security monitoring signals can be transferred to the industrial television system for automatic image control and switching. Fault recorders are high-capacity data acquisition, recording, and analysis devices, but their real-time data analysis is limited, with a significant offline component. Therefore, they should each operate as independent systems with their own central analysis stations. From an operational management perspective, after the power plant achieves "unmanned operation" or "minimal staffing," there are very few operators in the control room. Data analysis for these two systems is time-consuming and highly specialized, unsuitable for on-duty personnel. If these two systems are networked with the MIS system, the monitoring system can monitor their faults and actions only through I/O. Professional technicians can access both systems through the MIS to perform data analysis and remote management functions. Source: www.tede.cn To achieve the integration of power generation and power plant management, the Management Information System (MIS) should be networked with the monitoring system. Due to the large number of MIS users and the diverse data on the MIS, for security reasons, in addition to isolation measures such as firewalls, a unidirectional data flow (from the monitoring system to the MIS) should be adopted between the two networks, and a dedicated MIS terminal should be installed in the control room. 4. Development of Automation Systems The automation system of a hydropower plant consists of I/O devices (sensors and actuators), control hardware, control software, human-machine interfaces, and connections to information systems. Hydropower plant automation began in the early 1980s with the development of single-function devices. This document outlines the development process of computer monitoring systems and the application of typical systems. 4.1 Functionally Distributed Star-Topological Hierarchical Monitoring System: This system integrates single-function microcomputer devices. Each microcomputer device has a specific function, but each has different functions. For example, some microcomputer devices specialize in collecting switch signals, some specialize in collecting analog signals, and some specialize in control operations. This system has made some beneficial attempts in terms of distribution, but from a model perspective, it is not a very mature system. 4.2. Star-shaped hierarchical monitoring systems distributed by equipment units: For ease of maintenance, generator sets are used as units, integrating data acquisition and control into a microcomputer or PLC device, forming a local control unit (LCU). The LCU cannot directly connect to Ethernet, and computers are very expensive, making it impossible to equip each LCU with a CPU (Central Processing Unit) connected to Ethernet; therefore, the microcomputer is used as a front-end machine. This system uses a dedicated computer, representing a significant step forward in application networking, but the corresponding international standards are still incomplete, and an ideal open system environment cannot yet be formed. 4.3. Distributed monitoring systems based on open systems: With the development of computer and network technologies, computer application software is becoming increasingly complex and large, and the investment in software development is also increasing. How to enable these huge resources to run not only on computers manufactured by one company but also on computers manufactured by another company has led to a series of open system standards: TCP/IP, POSIX, SQL, ODBC, JDBC, OPC, etc. Distributed computer monitoring systems based on open systems have universality and portability; the monitoring system software can be installed on any computer with open system characteristics. Open systems have provided a powerful historical platform for the development of computer monitoring systems in hydropower plants. 4.4. Object-Based Distributed Monitoring Systems: The rapid development of computer hardware technology has provided a broad platform for software development. Software technology, in addition to adhering to open system standards, should now also follow object-oriented technology standards, such as Sun's Java RMI and Microsoft's COM/DCOM. Due to the complexity and diversity of object-oriented principles, hydropower plant computer monitoring systems abstract hydropower plant operating equipment such as generator units, main transformers, and switches into objects based on object-oriented technology. From system design and programming language selection to the user interface, all processes are based on object-oriented concepts, principles, and technologies, resulting in significant convenience for users in terms of use and maintenance. 5. Technical Measures for Hydropower Plant Automation Systems Hydropower plant automation systems must possess a complete hardware structure, an open software platform, and a powerful application system. 5.1 System Architecture Currently, the architecture of monitoring systems is primarily network-oriented. System-level devices mostly use general-purpose network devices such as Ethernet or FDDI to connect to high-performance microcomputers, workstations, and servers. At the controlled equipment site, PLCs or intelligent local control units are frequently used, which are then connected to basic-level intelligent I/O devices, intelligent instruments, and remote I/O via fieldbuses to form local control subsystems. These subsystems, combined with the plant-level system, form the entire control system. With the expansion of functions such as safety production, economic management, and the power market, higher demands are placed on the capabilities of computer systems. The selection of 64-bit workstations and servers in system-level devices has become the inevitable choice for the vast majority of systems. Intel's 64-bit Titanium CPU and Microsoft's 64-bit Windows operating system are also about to be launched, which will bring PC-based and Windows-platform-based monitoring system users a huge addressing space and powerful computing capabilities far exceeding those of 32-bit PCs. The development of high-speed switched Ethernet (100M bit/s or 1G bit/s) technology has overcome the shortcomings of previous low-speed Ethernet in real-time applications. Its more open standards and support from numerous manufacturers give it significant, even irreplaceable, advantages over other network products such as FDDI in many aspects, including equipment selection, product replacement, price, and hardware/software portability. For local control units, intelligent controllers combined with fieldbus technology represent a promising trend. According to IEC standards and the Fieldbus Foundation, a fieldbus is a digital, bidirectional, multi-branch communication network connecting intelligent devices and automation systems. It possesses the following technical characteristics: system openness; interoperability and availability; intelligence and functional autonomy of field devices; highly decentralized system structure; and adaptability to the field environment. Increased unit capacity, increased control information volume, increased control tasks, heavier control load, and network communication failures can all lead to a decrease in the control capabilities of local control units. Given the dispersed nature of controlled objects in hydropower plants, a fieldbus is used to connect distributed intelligent instruments, intelligent I/O, intelligent actuators, intelligent transmitters, and intelligent controllers into a unified system. This perfectly embodies the characteristics of distributed control, improves system autonomy and reliability, and saves a significant amount of signal and control cables. Therefore, using a fieldbus network is well-suited to the trend of distributed and open development. Of course, the fieldbus control system primarily relies on the support of distributed intelligent sensors, intelligent instruments, and intelligent actuators at the controlled object's location, and currently, many of these in hydropower plants are still outdated equipment. A gradual transition is necessary to eventually replace the old digital/analog hybrid equipment and technologies, forming a completely new all-digital system. 5.2 Software System Platform 5.2.1 Supporting the Development of Software Platforms and Application Packages To adapt to the development of open, standardized, networked, high-speed, and easy-to-use technologies, the software support platform and application packages in computer monitoring systems should become more generalized, open, and standardized. Based on the high reliability requirements of the power industry, UNIX operating systems are widely used in the monitoring systems of large and medium-sized hydropower plants. Small and medium-sized hydropower plants, which mostly use PC-based computers, tend to use Windows operating systems. Regarding databases, commercial databases are still insufficient to fully meet the real-time requirements of power production control. The common approach is to combine proprietary real-time databases with commercial historical databases. However, the proprietary nature of some databases leads to inconvenience in data transformation, highlighting their inadequacy in the current context of the power industry's push for informatization and digitalization. A better solution is to adhere to unified standard interface specifications, enabling convenient data exchange on a unified "digital bus." 5.2.2 Application of New Technologies such as Web and Java: Web and object-oriented Java technologies will be increasingly introduced into computer monitoring systems. The author learned that NARI Automation's newly developed NC-2000 monitoring system fully adopts object-oriented development technology, and the human-machine interface is implemented using cross-platform Java. It not only provides users with a more convenient and feature-rich interface for programmable secondary development, but also significantly reduces the application support software for the front-end operator station due to the adoption of Web and Java technologies, achieving a true "thin client" experience. For example, in large and medium-sized power plants, high-performance UNIX workstations or servers can be used as the main control and data servers for the entire system, while PCs can be used as operator stations. Thanks to Java's compile-once, run-once feature, the same human-machine interface can be easily obtained at the operator station and other nodes within the monitoring system, including the main processor. With the support of Internet/Intranet and Web technologies, the same interface can be accessed directly from any networked location, such as the plant management office, the chief engineer's office, and production departments. It can even be accessed from any location via telephone connection on a microcomputer (necessary security measures must be added to ensure safety). 5.2.3 Powerful Configuration Tools: Users do not need in-depth knowledge of operating system commands or complex programming skills. Whether on UNIX or Windows systems, the configuration interface allows for convenient completion of: database measurement point definition; object definition; various module definitions for local control units; processing algorithm definition; communication port definition; communication protocol definition; application definition and maintenance of various functions such as sequential control flow generation, detection, and loading. Many functions can be selected simply by clicking the mouse, which is quick and convenient, avoiding input errors caused by using editing programs, truly reflecting the object-oriented, reliable, open, user-friendly, scalable, and transparent nature of the main system services. 5.3 Powerful Application Systems: With the development of computer technology, its performance is increasingly high, and its applications are becoming increasingly widespread. As unmanned monitoring operations develop in greater depth, higher demands are placed on computer monitoring systems, both in terms of system structure and functionality. Several aspects are explained below: 5.3.1 Historical Database System The historical database system is actually a component of the monitoring system. It simply categorizes and stores historical data, events, and related information that originally needed to be saved in the monitoring system in a commercial database, allowing for querying, printing, or backup when needed. The historical database system is implemented on a separate computer, featuring a user-friendly interface, convenient operation, and rich display formats. This configuration reduces the burden on the monitoring system, simplifies its software complexity, increases its real-time performance, and allows interconnection with other systems, such as MIS systems, through standard database interfaces such as SQL, ODBC, and JDBC. 5.3.2 Electricity Monitoring System In hydropower plants, electricity meters are installed on every generator, every line, and even every main transformer. Traditional electricity measurement is generally achieved by sending electricity pulses from the meters to a computer monitoring system. Because the monitoring system has many components, initial electricity values ​​must be set within the system. If any equipment malfunctions or stops working, the electricity measurement will have errors or previous measurements will be lost, requiring the initial values ​​to be reset. This method cannot guarantee the accuracy of the electricity monitoring results, and the maintenance workload is also significant. Currently, there are smart electricity meters on the market with intelligent communication interfaces. These meters can completely save electricity data and retrieve it at any time through the communication interface. Therefore, based on these meters, and by connecting them through their communication interfaces, a computer equipped with historical data management functions can form an electricity monitoring system. This system can operate relatively independently or communicate with the monitoring system to achieve information sharing and provide a reliable basis for the operation and management of hydropower plants. 5.3.3 Efficiency Detection System Real-time monitoring of turbine efficiency plays a crucial role in the economic operation of power plants. Online monitoring of hydropower turbines can be used for on-site acceptance tests after installation or major overhaul of hydropower plant units to check whether the design, manufacturing, installation, and maintenance quality meet the requirements. It can also provide real-time data on turbine performance under different water flow and operating conditions through long-term continuous monitoring of unit operation, providing a reference for determining the number of units in operation, optimizing load allocation, and performing condition-based maintenance in the economical operation of the power plant. Therefore, online monitoring of turbine efficiency has always been a major scientific and technological challenge for achieving economic and technical indicators and economic operation of power plants. However, for many years, on the one hand, online flow monitoring technology has not been widely adopted; on the other hand, various limitations have made it difficult for efficiency testing to play its due role in power plants. Therefore, although the rapid development and widespread application of new technologies such as computers, communications, information, and measurement and control in power plants have provided a mature technical foundation for the development of online efficiency monitoring projects, the current power system reform plan based on the separation of power plants and grids has been introduced, and competitive bidding for electricity in the market will become an inevitable trend. Therefore, while ensuring safe operation and meeting the requirements of the power system, continuously improving water resource utilization and equipment availability, and reducing operating and maintenance costs have become urgent tasks for every power plant. 5.3.4 Operating Personnel Training Simulation System: Computer monitoring systems, facing actual operating equipment, cannot be operated arbitrarily; otherwise, misoperation may occur, leading to accidents—a situation no hydropower plant wants to see. So, how can inexperienced or newly arrived operating personnel quickly familiarize themselves with the environment, improve their operational skills, and adapt to their roles? Besides training, internships, and examinations to familiarize themselves with the business, there should be a training simulation system where operating personnel can actually operate the equipment. The training simulation system can supplement the monitoring system; any important control operation or complex operation should be verified on the training simulation system to ensure the integrity and correctness of the operation, ensuring the safe operation of the hydropower plant. 5.3.5 Condition-Based Maintenance System: This is a hot topic in hydropower plants. Equipment condition-based maintenance and equipment life assessment are not only an inevitable trend in equipment maintenance work but also a highly technical systems engineering project. Condition monitoring primarily utilizes modern, advanced testing equipment and analytical techniques to collect and monitor parameters of key components of hydropower plant main equipment in real time, such as generator vibration and sway, generator insulation, stator partial discharge, and transformer insulation. This data is then comprehensively analyzed by an intelligent (expert) system that integrates accumulated on-site operation, maintenance, and testing data with expert experience to provide a realistic assessment of potential mechanical, hydraulic, and electrical problems. Making a highly accurate assessment remains challenging, and extensive experimental work has been conducted both domestically and internationally, yielding some valuable experience. In implementation, it is also a relatively independent system. However, most hydropower plants in China now have relatively complete computer monitoring systems with a large number of monitoring devices. From the perspective of saving investment and practical application, there is a large amount of data that needs to be shared between the condition-based maintenance system and the monitoring system. When considering the condition-based maintenance system, it should be considered in conjunction with the existing monitoring system to organically combine the two. This can save investment in some duplicate components and allow operation and management personnel to monitor the health status of production equipment at any time when performing real-time production control. This allows equipment in good health to fully utilize its potential, equipment in a sub-healthy state to reduce its load to an appropriate level, and equipment with health problems or those on the verge of problems to be repaired in a timely manner. 5.3.6 Production Management System Currently, although many power plants have relatively complete computer monitoring systems, due to various reasons, the monitoring signals of some field equipment cannot be input into the monitoring system to complete automatic monitoring. Therefore, equipment inspection is essential. To strengthen the management and improve the quality of inspection work, the production management information subsystem can be used to create inspection routes before the shift's inspectors depart, check equipment operation status, record equipment operating parameters, and after the inspection is completed, input relevant equipment operating parameters and other information into the production management information system for analysis and comparison, and record it in the historical database for future reference. According to technical regulations, power plants must obtain corresponding primary and secondary work permits when performing equipment operation or maintenance. These tasks can also be completed using the production management information subsystem. After the computers of relevant departments are connected to the system's network, there is no need to carry work permits back and forth to sign and cancel them. It becomes a completely digital transmission, saving time and effort, and allowing for real-time and historical queries of the signing and cancellation details. The production management information system also performs tasks such as: shift supervisor logs, intelligent operation tickets (which can be analyzed by the production management information subsystem based on real-time data from the monitoring system and checked against safety interlock conditions), equipment defect management, and operation ledgers. 5.3.7 The intelligent telephone alarm service system provides real-time intelligent alarm notifications based on alarm signals generated by the monitoring system, according to the priority level of the alarm signals and the processing priority of the notified party. It intelligently processes events occurring at the production site and transmits alarm information to relevant personnel as quickly as possible through various communication methods such as internal communication systems, telephones, paging, and mobile communication, enabling them to respond promptly. It is not only an intelligent system that can trigger alarms via various communication tools, but also a powerful interactive voice information service center. Users can access the operating data of the production equipment they are concerned about anytime, anywhere by dialing into the system. The system also provides a rich and flexible configuration interface, allowing maintenance personnel or operators to easily define various user requirements and implement various complex functions. The systems mentioned above are all closely related to existing computer monitoring systems. Depending on the specific situation, they can be configured as relatively independent systems, exchanging data with the computer monitoring system through a high-speed network. They can also be configured as subsystems of the computer monitoring system. It provides a complete set of service functions for hydropower plants, from basic data acquisition and equipment control to economic operation decisions for the electricity market, supporting modern management of power plant production to a new level. 6. Technical Conditions for "Unmanned" or "Minimally Manned" Operations in Hydropower Plants Unmanned operation, compared to manned operation, involves automated systems performing the daily tasks of on-duty personnel. This includes regularly inspecting operating equipment, recording relevant parameters and events, operating equipment according to operating procedures, and handling accidents or malfunctions to prevent their escalation. This achieves a faster, more reliable, and safer operating mode than manned operation. While automated systems possess some accident handling capabilities and can prevent accidents from escalating in localized areas, the causes of accidents or malfunctions are highly complex. A few can be recovered through certain measures, but most cannot be quickly restored and require timely on-site analysis and handling by maintenance personnel. Therefore, "unmanned" or "minimally manned" operation in hydropower plants must meet the following conditions: 6.1 A Computer Monitoring System: A computer monitoring system is a crucial component for achieving "unmanned" or "minimally manned" operation.它具有采用水电厂的机组、辅机、油水风系统、主变、开关站、公用设备、厂用电系统以及各种闸门等的电气量、开入量、温度量、压力、液位、流量等输入信号，完成各种生产流程，如开停机、分合开关等顺序控制，机组有功功率和无功功率的调节，AGC、AVC，以及其他设备的操作控制。同时监控系统还具有丰富的人机界面，防误操作的措施和一定的反事故处理能力。 6.2、具有远程控制、调节功能监控系统不仅具有现地的各种监视、操作和控制功能，而且要具有能与远方控制系统通信能力，上送有关信息，接收远方控制系统的命令来实现远程控制和调节。 6.3、具有ON-CALL功能现场运行的设备一旦出现事故或故障时，就需要维护人员立即前往现场，了解事故或故障现象，分析事故或故障原因，及时排除事故或故障。如何使维护人员甚至领导能及时、准确、详细的掌握事故或故障信息，这就是无人值班水电厂计算机监控系统必须具备的功能：ON-CALL功能，可以通过电话、呼机或手机发布呼叫信息或手机短信息。 总之，水电厂通过开发自动化系统，能够提高设备的整体健康水平，保证设备的安全稳定运行，为"无人值班"或"少人值守"奠定基础。