Keywords: System, Hydropower Plant, Equipment, Development, Control, Network, Structure, Intelligence, Technology 1. Introduction With the deepening of "unmanned operation" (minimal staffing) and condition-based maintenance in hydropower plants, higher demands are placed on the production, operation, and management of hydropower plants. The power system reform based on "separation of power plants and grids, and competitive bidding for grid connection" also presents new requirements for hydropower plant automation technology. 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 must also adapt to the new situation and develop into a comprehensive system integrating computers, control, communication, networks, and power electronics, possessing a complete hardware structure, an open software platform, and powerful application systems. It should not only be able to monitor individual power plants but also further realize the economic operation and safety monitoring of cascade, river basin, and even inter-basin hydropower plant groups. This article discusses several aspects of hydropower plant automation systems. 2. 2.1 Hardware Structure Currently, the structure of hydropower plant monitoring systems is basically network-oriented. System-level equipment mostly uses Ethernet or fiber optic ring networks (FDDI) and other general-purpose network devices 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 fieldbus to form a local control subsystem. This subsystem, combined with the plant-level system, forms 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 has become the inevitable choice for the vast majority of systems at the system level. The development of high-speed switched Ethernet technology has overcome the shortcomings of previous low-speed Ethernet in real-time applications. Its more open standard 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, product price, and hardware and software portability. For local control units, intelligent controllers combined with fieldbus technology represent a promising development 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 distributed system architecture; • Adaptability to the field environment. Increased unit capacity, increased control information volume, increased control tasks, heavier control load, and network communication failures can all reduce the control capabilities of local control units. Given the dispersed nature of controlled objects in hydropower plants, fieldbus technology connects 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 fieldbus networks is well-suited to the distributed and open development trend. Of course, fieldbus control systems primarily rely on the support of intelligent sensors, intelligent instruments, and intelligent actuators distributed across the controlled environment. Currently, many of these components in hydropower plants are still outdated equipment. A gradual transition is necessary to eventually replace these older digital/analog hybrid equipment and technologies, forming a completely new all-digital system. 2.2 Software System Platform 2.2.1 Supporting Software Platforms and Application Packages: To adapt to the development of open, standardized, networked, high-speed, and easy-to-use technologies, the software support platforms and application packages in computer monitoring systems are trending towards generalization, openness, and standardization. Based on the high reliability requirements of the power industry, the UNIX operating system is 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 the Windows operating system. Regarding databases, because commercial databases cannot fully meet the real-time requirements of power production control, the currently widely used combination of dedicated real-time databases and commercial historical databases will continue to exist. The specialized 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 approach is to adhere to unified standard interface specifications, enabling convenient data exchange on a unified "digital bus." 2.2.2 Application of New Technologies such as Web and Java New technologies such as Web and object-oriented Java will be increasingly introduced into computer monitoring systems. 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. Leveraging Java's compile-once, run-once feature, coupled with the support of Internet/Intranet and Web technologies, not only can the same human-machine interface be easily accessed at operator stations, main processors, and other nodes within the monitoring system, but the same interface can also be accessed directly from PC network locations within the plant, such as the plant manager's office, chief engineer's office, and production technology department. Furthermore, the same interface can even be accessed from any location via telephone (necessary security measures must be added to ensure safety). 2.2.3 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 • Communication protocol definition Sequence control flow generation, detection, loading, and other application definitions and maintenance. Many functions can be selected simply by clicking the mouse, which is quick and convenient, avoiding the input errors inevitably caused by using editing programs. This truly reflects the object-oriented, reliable, open, user-friendly, scalable, and transparent nature of the main system services. 3. Powerful Application Systems Computer technology has advanced to the point where its performance is increasingly higher while its price is decreasing, leading to its increasingly widespread application. With the deepening development of unmanned operation, further requirements have been placed on computer monitoring systems, both in terms of system structure and functionality. Several aspects are explained below: 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. 3.2 Efficiency Monitoring 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 economical power plant operation. 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. With the rapid development and application of a series of new technologies such as computers, communications, information, and measurement and control in power plants, a mature technological foundation has been provided for the development of online efficiency monitoring projects. Currently, the 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, equipment availability, and reducing operating and maintenance costs has become an urgent task for every power plant to achieve its important goal of enhancing its competitiveness in the market. 3.3 Condition-Based Maintenance System This is a hot topic in hydropower plants. Condition-based maintenance and equipment life assessment are not only an inevitable trend in the development of equipment maintenance work, but also a highly technical system engineering project. Condition-based maintenance mainly utilizes modern advanced testing equipment and analysis technology to collect and monitor parameters of certain key parts of the main equipment of hydropower plants in real time, such as: unit vibration and sway, generator insulation, generator air gap, tailrace vacuum and pressure pulsation, stator partial discharge, transformer insulation, etc. Through an intelligent (expert) system that integrates on-site accumulated operation, maintenance, and test data and expert experience, the system comprehensively analyzes the operating patterns, predicts potential hidden dangers, detects equipment defects and faults early, and provides targeted maintenance for operating equipment. In implementation, it can function as a relatively independent system. However, most hydropower plants in China already 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 significant 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 holistically with the existing monitoring system to organically combine the two. This can save investment in some redundant components and allow operation and management personnel to monitor the health status of production equipment at any time during real-time production control, thus rationally determining the workload of the equipment. Economic production scheduling software can also automatically consider equipment health and workload issues based on this data, making production scheduling more rational. 4. Conclusion Based on the development trends of hydropower plant operation and maintenance methods, this paper discusses the development of related aspects of hydropower plant automation hardware and software systems. Currently, hydropower plant computer monitoring system technology is relatively mature and has been successfully applied in large and medium-sized hydropower plants and newly built power plants. The systems mentioned in this paper are all closely related to the computer monitoring system. They can be configured as relatively independent systems and exchange data with the computer monitoring system through high-speed networks. It can also be configured as a subsystem of a computer monitoring system. Such a computer monitoring system should be called a comprehensive management system for hydropower plant production. It provides a complete set of services for hydropower plants, from the most basic data acquisition and equipment control to economic operation decision-making for the electricity market, so that the modern management of power production can be taken to a new level. References [1] Wang Qiang, Han Yanxiang A review of power system plant and dispatch automation, Automation of Power System, No. 24, 2000 [2] Gu Jingfang, Fang Huiqin, Zhou Zhiqing, et al. A review of the brilliant achievements of China's hydropower plant automation and a prospect for the new century, Hydropower Automation and Dam Observation, No. 1, 2002