Application of Internet of things in monitoring system of variable distribution station

1 Introduction

With the continuous development of computer technology, the integration of computer science and other disciplines is becoming more and more close. The integration of computer science and the various disciplines of power system has promoted the development of China's smart grid business. However, as most of the substation is located in the field area, very susceptible to the surrounding environment, weather and other effects, substation equipment failure rate is also increasing, and the corresponding failure to make timely response and processing time is also more and more long. Therefore, in order to deal with the fault of substation equipment in time and effectively, to ensure the stability of power supply, the monitoring technology of variable distribution station based on the IoT ZigBee Digital transmission technology is introduced into the grid control system.

The realization of substation automation is based on the information of substation monitoring system, the substation monitoring system needs the effective means of communication, the control command of controlling center is transferred to the equipment of remote substation, and the real-time data of the substation is obtained quickly and accurately. The rationality of communication system design will directly affect the success or failure of substation monitoring system. Therefore, the fast and unobstructed substation communication system is an important link in the Substation monitoring system. The introduction of IoT ZigBee Digital transmission technology into the substation communication system can further improve the accuracy of the communication system and improve the efficiency of the substation monitoring system.

2 Internet of Things Technology Overview

The Internet of Things is also known as the Sensor network, the English name of things, for the first time in the United States, the International Conference on mobile computers and networks iot,1999 the concept of the Internet of things. It based on radio frequency identification (RFID) technology, combined with existing network technology, middleware technology, database technology, and so on, to build a thing and things, things and people, people and people in the physical Internet. In this network, the system can identify, locate, track, monitor and "transparently" manage objects in real time and automatically. The Internet of Things (IoT) technology is a comprehensive application of many modern disciplines, involving the disciplines of automatic control, computer science and communication information, and its key technologies include sensor technology, computer program software system, micro-processing technology and communication network technology. The architecture of the Internet of Things is recognized as having 3 levels, from bottom to top the perceptual layer, the network layer and the application layer. As shown in 1.

Figure 1 The 3 levels of the Internet of Things

(1) Perceptual layer

The perceptual layer is responsible for the perception and collection of information. The sensing layer consists of two parts of the sensor and the short distance network transmission system. Among them, the sensor uses the radio frequency Identification Technology (RFID) reader, intelligent sensor and other information-aware devices to detect and collect information; a short-distance network transmission system transmits the information collected by the sensor to the gateway, or transmits the control commands issued by the application layer to the controller.

(2) Network layer

The main function of network layer is to realize the reliable and effective transmission of perceptual layer data information, which includes Internet, mobile communication network and other special network. The network layer is divided into two parts of access unit and access network. Access unit refers to the aggregation of data information collected by perceptual layer, and transmits the processed data to the network, which is the network bridge connected with the perceptual layer, and the access network refers to the transmission of the data information to the Internet through the existing Internet, mobile communication network and other special networks.

(3) Application layer

The main function of the application layer is to further integrate, classify and summarize the data information which is initially integrated through the network layer, and combine the final data information with the terminal of the application platform to complete the comprehensive utilization of the data information. The application layer mainly supports information collaboration, interoperability and sharing, which includes application support platform and application Server system. The key technology of application support platform is the middleware technology of Internet of Things, which is a kind of independent system software or service program which realizes data transmission, filtering and data format conversion between all kinds of sensor and RFID hardware device and application operating system, it shields the complexity of the underlying data system and reduces the complexity of program design. A bridge between related hardware devices and applications. Internet of things applications refers to the user's direct operation of a variety of application terminals, due to the different needs of users, the variety of Internet of things applications are also very rich, can meet the diverse needs of different users.

3 application of Internet of things technology in transformer substation monitoring System

The intelligent power distribution in the power grid is the important foundation and support of the smart grid. The intelligent transformation of power distribution, the focus is to improve the monitoring and control of the substation, more quickly reflect the fault, more reliable supply of electricity. Realize intelligent equipment monitoring and early warning, visual Field Operation support and intelligent line patrol.

At present, the distribution station equipment covers a wide range of points, there are three main problems. First, some substation is built in the urban population concentration, traffic-intensive areas, so the route of the grid is complex; second, for some long-term variable distribution terminal Station, there are old line, pipeline congestion, cable coverage difficult situation; Third, for some important areas of the substation terminal station, Not suitable for large-area cable laying and other construction. The best way to solve the above three problems is to apply IoT technology to the substation. All the power equipment of the substation will be connected to the Internet of things, not only can the communication task of the substation be completed easily, but also can monitor the operation data between the substation power stations in real time, and better grasp the operation condition of the substation.

In the Internet of things technology, ZigBee digital transmission technology is a short-distance, low-speed wireless network technology, which has the advantages of low power consumption, high reliability and self-networking function, and has great development advantage in short-distance communication.

Figure 2 is based on ZigBee Wireless digital transmission distribution monitoring System block diagram, the entire system is composed of three levels. The perceptual layer mainly uses ZigBee  technology, ZigBee Network consists of a convergence node (ZigBee Wireless data transmission network terminal) and a number of sub-nodes (ZigBee datalogger). ZigBee Digital Network terminal through the Internet, CDMA and other remote communication network, mainly responsible for initiating and coordinating the entire ZigBee wireless module network, while realizing the perceptual layer and substation Management Center data interaction. ZigBee Data Collector mainly completes the of the transformer distribution equipment and the surrounding environment data. At the same time, fixed IoT debice Agent is set up in perceptual layer, which is mainly responsible for the preliminary collation and summarization of the information collected by perceptual layer.

Fig. 2 Block diagram of a ZigBee variable distribution monitoring system

The network layer uses the Wired + wireless hybrid communication mode to transfer data from the IoT Debice agent to the application layer via ZigBee wireless module. The data information collected by the ZigBee data collector is initially processed and consolidated by the fixed IoT Debice agent, and the IoT server server is set up at the Zigbeezigbee Wireless module network terminal. The IOT server server will initially process the sensing information through the middleware platform for further analysis, and then form the application layer required business data to meet the application layer of the actual requirements of the substation monitoring system.

The application layer adopts the C + + language or the Java language, unifies the ASP technology or the Web technology, establishes the Internet of things application platform, mainly for the intelligent processing of the data stream formed on the IoT server server side, provides the user with the rich diverse function and the service

4 Concluding remarks

With the further development of IoT technology, the application of Internet of things technology to substation monitoring system can help staff to master the operation information of each substation and monitor the important substation on-line. ZigBee is the core of IoT technology, and through the application of ZigBee digital transmission technology, the data processing ability of substation monitoring system is enhanced, and the monitoring system of substation based on IoT technology is further perfected.

Application of Internet of things in monitoring system of variable distribution station