What kind of system is SCADA?

From Baidu Baike http://baike.baidu.com/view/51065.htm 1. Overview of SCADA Systems A SCADA (Supervisory Control And Data Acquisition) system is a system for data acquisition and supervision control. SCADA systems have a wide range of applications; they can be used for data collection, monitoring, control, as well as process control in various fields such as power systems, water supply systems, petroleum, and the chemical industry. In power systems and electrified railways, it is also known as a remote control system. 　　A SCADA system is a computer-based automation system for production process control and scheduling. It can monitor and control the operating equipment on-site, enabling functions such as data collection, device control, measurement, parameter adjustment, and various signal alarms. 　　Due to the different requirements for SCADA in various application fields, the development of SCADA systems in these fields also varies. 　　In power systems, SCADA systems are the most widely used, and their technology is the most mature. As one of the most important subsystems of an Energy Management System (EMS), it offers advantages such as complete information, improved efficiency, accurate understanding of the system’s operating status, faster decision-making, and the ability to quickly diagnose system failures; it has thus become an indispensable tool for power dispatching. It plays an irreplaceable role in improving the reliability, safety, and economic efficiency of power grid operation, reducing the workload on dispatchers, achieving automation and modernization of power dispatching, and enhancing the efficiency and quality of dispatching. 　　SCADA has been used in railway electrification remote control systems for some time now, and it has played a significant role in ensuring a safe and reliable power supply for electrified railways as well as in improving the level of management in railway transportation operations. In the development of SCADA systems for railway electrification, advances in computing technology have led to the emergence of different products in various periods. Meanwhile, China has also imported a large number of SCADA products and equipment from abroad, all of which have contributed to the advancement of railway electrification remote control systems toward higher standards. 　　SCADA plays an important role in oil pipeline projects; it manages the sequential control of pipeline transportation, monitors equipment, handles the synchronized transmission and recording of data, and oversees the operational status of systems along the pipelines as well as at various station control points. As the field control units of the pipeline automatic control system, the station control systems at each station not only carry out monitoring tasks for their respective stations, but also are responsible for transmitting relevant information to the Hefei dispatching and control center, receiving and executing commands issued by it, as well as storing all data records. In addition to these basic functions, modern SCADA pipeline systems also feature new capabilities such as leak detection, system simulation, and early protection against water hammer. II. The Development History of SCADA Systems SCADA (Supervisory Control and Data Acquisition) systems are, in full, systems for data acquisition and supervision control. Since its inception, the SCADA system has been closely linked to the development of computer technology. The SCADA system has gone through three generations since its development to date. 　　The first generation of SCADA systems were those based on dedicated computers and specialized operating systems, such as the SD176 system developed by the Electric Power Automation Research Institute for the North China power grid, and the H-80M system designed by Hitachi in Japan for China’s railway electrification remote control systems. This phase spans from the introduction of computers into SCADA systems until the 1970s. 　　The second generation were SCADA systems based on general-purpose computers in the 1980s. In this generation, other computers such as VAX and various general-purpose workstations were widely used, and the operating system was generally the general-purpose UNIX operating system. At this stage, in the automation of power grid dispatching, the SCADA system is combined with economic operation analysis, automatic generation control (AGC), and network analysis to form the EMS system (Energy Management System). The common feature of first-generation and second-generation SCADA systems is that they are based on centralized computer systems, and the lack of openness in these systems makes system maintenance, upgrading, and integration with other networks very difficult. 　　The EMS/SCADA systems of the 1990s, which followed the principle of openness and were capable of large-scale networking based on distributed computer networks and relational database technology, are known as the third generation. This phase was the period of fastest development for SCADA/EMS systems in our country, with various state-of-the-art computer technologies being integrated into these systems. This period was also when China made the largest investments in power system automation and grid construction; the plan to invest 270 billion yuan over the next three years to upgrade urban and rural grids illustrates the level of emphasis placed on power system automation and grid development. 　　The prerequisites for the fourth-generation SCADA/EMS systems are already in place or will be soon, and they are expected to emerge at the beginning of the 21st century. The main features of this system are the use of Internet technology, object-oriented technology, neural network technology, and JAVA technology, etc., to further enhance the integration of SCADA/EMS systems with other systems, in order to meet the requirements of safe and economical operation as well as commercial operations. 　　Breakthrough progress has been made in the application technology of SCADA systems in the remote control systems of electrified railways, and their use has also seen rapid development. Due to the different characteristics of electrified railways and power systems, the development path of SCADA systems is not entirely the same as that of power systems. Among the mature products for the telecontrol systems of electrified railways are the HY200 microcomputer-based telecontrol system developed by our institute, as well as the DWY microcomputer-based telecontrol system developed by Southwest Jiaotong University. These systems are reliable in performance and highly functional; they play an important role in ensuring the safety of power supply for electrified railways and improving the quality of that power supply. They have made a significant contribution to the use of SCADA systems in railway electrification. 　　III. Outlook for the Development of SCADA Systems SCADA systems are constantly being improved and developed, with technological progress never ceasing. Today, with the increasing demand for SCADA systems in power systems and railway electrification systems, as well as the development of computer technology, new requirements have arisen for such systems. Generally speaking, these requirements include the following: 1. Extensive integration of SCADA/EMS systems with other systems. SCADA systems serve as real-time data sources for the automation of power systems, providing a large amount of real-time data to EMS systems. At the same time, real-time grid data is required in systems such as simulation training systems and MIS systems; without this real-time grid data, all other systems become useless. Therefore, over the past decade, how SCADA systems can be connected to other non-real-time systems has become an important topic in SCADA research ； Currently, the SCADA system has successfully achieved connectivity with the DTS (Dispatcher Simulation Training System) and the enterprise MIS system. The integration of SCADA systems with electrical energy metering systems, geographic information systems, water dispatch automation systems, production dispatch automation systems, and office automation systems represents a development trend for SCADA systems. 　　2. Comprehensive Automation of Substations By using RTUs and microcomputer-based protection devices as the core, it integrates the control, signaling, measurement, and metering circuits of substations into a computer system, replacing traditional control and protection panels. This approach helps reduce the floor space required by substations and the investment in equipment, while improving the reliability of the secondary systems. The comprehensive automation of substations has become a topic of research in relevant fields; companies in China such as Dongfang Electronics have already introduced corresponding products, but it is still in the research phase regarding railway electrification. 　　3. Research and application of new technologies such as expert systems, fuzzy decision-making, and neural networks. These technologies are used to simulate various operating conditions of power grids, and scheduling assistance software as well as management decision-making software are developed. Expert systems then use different actual situations to determine the optimal operating methods or ways to handle failures, thereby enabling rational and economical power grid scheduling and improving transmission efficiency. 　　4. Applications of Object-Oriented Technology, Internet Technology, and JAVA Technology Object-Oriented Technology (OOT) is an appropriate tool for the design of network databases, market models, and software for power system analysis. The use of OOT in SCADA/EMS systems represents a trend in development. 　　With the development of Internet technology, the browser interface has become the basic platform for computer desktops. Applying browser technology to SCADA/EMS systems and using the browser interface as the human-machine interface for power grid dispatch automation systems is highly beneficial for expanding the scope of application of real-time systems and reducing maintenance efforts ； In the next generation of SCADA/EMS systems, the traditional MMI interface will be retained for use by dispatchers, while new web servers will be provided for non-real-time users to browse; eventually, all these interfaces will be unified into a single type of human-machine interface. 　　The JAVA language combines object-oriented technology with Internet technology, integrating compilation and interpretation in a seamless manner. It fully implements the four core object-oriented principles: encapsulation, polymorphism, inheritance, and dynamic binding. It also offers advantages over C++ in terms of multi-threading support and security, along with many other features. JAVA technology is set to bring about a revolution in EMS/SCADA systems. 　　IV. SCADA Leak Monitoring System The SCADA leak monitoring system (taking one pipeline as an example) consists of a transmitter, server, remote client, communication network, and other components, as shown in Figure A. The transmitters currently installed on long-distance pipelines mainly include pressure transmitters, temperature transmitters, and flow rate transmitters. It should be noted that most pipelines in the country do not have flow transmitters installed at either end. 　　A communication network is the physical pathway for information transmission within a system. Communication and data transfer between the F9G and the upper-level servers, as well as access by remote clients to the server’s database and to the server itself, are all carried out through a communication network. This system can rely on various types of communication methods such as local area networks, optical fibers and telephone lines, as well as microwaves, and thus possesses good adaptability. In addition, the system provides an 0’) access function, allowing any computer that is connected to the server via a network and has ST or another web browser installed to become an 0’) client of the system. 　　This system has achieved remarkable results when applied to the oil transport pipelines in a certain oil field. Its use **has enhanced the level of automation in oil field production and management, bringing significant economic and social benefits to the oil field. This post was last edited by flyfish on 2009-3-5 10:39.]