Development and application of the most intelligen

2022-07-25
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The development and application of intelligent power distribution system Abstract: the development of modern industrial technology has put forward higher requirements for the reliability of power distribution system operation and its intelligent management. The wide application of microprocessor technology and the substantial improvement of computer system reliability have led to the rapid development of intelligent electrical components and the emergence of intelligent electrical management system. Compared with the development of integrated protection and system monitoring (SCADA system) of 6kV and above medium and high voltage systems and its application in power system, as a switchgear directly facing end users, its intelligent research and application started late...

key words: development and application of intelligent distribution system 1 Overview

the development of modern industrial technology has put forward higher requirements for the reliability and intelligent management of distribution system operation. The wide application of microprocessor technology and the substantial improvement of computer system reliability have led to the rapid development of intelligent electrical components and the emergence of intelligent electrical management system. Compared with the development of integrated protection and system monitoring (SCADA) system for 6kV and above medium and high voltage systems and its application in power system, as a switchgear directly facing end users, its intelligent research and application started late. Many existing intelligent monitoring systems applied to low voltage are basically modified on the basis of SCADA system, which can meet the basic monitoring functions, but can not fully reflect the characteristics and requirements of low voltage electrical system. Therefore, American energy control Corporation (AEC) has developed and launched microcomputer integrated protection devices, intelligent distribution instruments and their management systems that meet industrial control requirements and have high reliability, so as to more conveniently and effectively realize the distribution management of 0.4kV and above voltage levels. The intelligent power distribution system is equipped with switches with various types of twists and turns of wire core, which is an important reason for insulation eccentricity. 1. Intelligent components with communication function (such as the intelligent power distribution instrument of AEC company) are connected with the computer system through digital communication to realize the automation and intelligence of substation switchgear operation management. The system can realize the functions of real-time data collection, digital communication, remote operation and program control, protection setting management, event recording and alarm, fault analysis, various reports and equipment maintenance information management. The intelligent monitoring system shall be able to realize the object-oriented operation mode with strong anti-interference ability. The main control functions shall be completed by the intelligent components at the equipment level to form a network integrated fully distributed control system, To meet the requirements of real-time, fast and reliable system operation. The intelligent components in the system can be divided into: power quality monitoring, switch protection and control, motor protection and control, etc. Due to the application of fieldbus technology, the intelligent components in the system can run independently without relying on the computer network, which greatly improves the real-time and reliability of the system operation, and meets the needs of electrical equipment operation management and factory production process control

2. Application of fieldbus technology

fieldbus is a system used in the production field to realize bidirectional serial multi node digital communication between microprocessor measurement and control equipment. It is also known as the bottom network of open and digital multi-point communication. In the mid-1980s, with the development of microprocessor technology and network technology, the 4 ~ 20mA analog transmission mode of DCS system was gradually replaced by the digital network transmission mode. Fieldbus control system (FCS) developed rapidly and was widely used in the automation field

fcs is both an open communication network and a fully distributed control system. As the link of intelligent equipment, it connects the intelligent equipment hung on the bus as the network node to the network system, and further constitutes the automation system to realize the basic control, calculation, parameter setting, alarm, display, monitoring, system management and other comprehensive automation functions. In FCS, various departments then conduct a comprehensive analysis of the curve, and the components are connected by a communication network. The data transmission adopts the bus mode, and the system signal transmission is completely digitized. There is no master control component in the system in a strict sense, and resources are shared. All intelligent components can run independently without relying on computers

fcs completely eliminated the 4 ~ 20mA analog transmission mode and reduced a large number of field wiring; The control and adjustment process of FCS is on-site components, which effectively improves the real-time and reliability of system control, and avoids the system from being paralyzed due to host failure

the OSI reference model of ISO international organization for Standardization in ISO iec7498 standard defines the 7-layer framework of network interconnection, and specifies the functions of each layer in detail, so as to realize the interconnection, interoperability and application portability in the open system environment

considering that a large number of intelligent devices in the industrial production site are scattered in a large range, and the humanized description of control oriented Xinjie in a single node makes the experimental operation more concise, with little information, but high requirements for real-time and rapidity, in order to reduce the intermediate links, meet the real-time requirements and reduce the cost of the industrial network, Most of the communication models adopted by fieldbus are simplified in varying degrees on the basis of OSI reference model. It adopts three typical layers in the OSI model: physical layer, data link layer and application layer, omitting 3 ~ 6 layers. It has the advantages of simple structure, simple execution and cooperation, low cost, and meets the performance requirements of industrial field applications (as shown in Figure 1). Through the consistency and interoperability test, the products of different manufacturers that meet the technical requirements of Fieldbus can be interconnected on the same bus, which brings great benefits to the system integration of users

Figure 1 OSI and typical fieldbus models several influential fieldbus technologies, including modbus, LonWorks, etc. Their communication models are different, and their applications have their own characteristics. They have formed a unified standard and show their own advantages in specific application fields. The advantages of fieldbus technology mainly include:

(1) saving hardware investment. The intelligent devices of the fieldbus system are scattered in the field, and can directly perform control and calculation functions, which can reduce a large number of

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