Research on remote monitoring system of substation

　　1 Introduction

　　With the continuous improvement of my country's power grid dispatching and management level, the construction of power communication networks in many regions has made great progress and basically realized digital communication. The channel bandwidth and channel quality have been significantly improved by using communication methods such as optical fiber, digital microwave or wireless spread spectrum. In order to fully and intuitively understand the real situation of the substation, remote visual monitoring is an essential monitoring and management means. It can timely and accurately grasp the situation of the substation in the dispatching center tens of kilometers or more away, and operate and control various situations, so as to achieve true unattended operation.

　　2 Current operation status of unmanned substations

　　In recent years, with the rapid expansion of the scale of power grids, the technological level of power systems has been continuously improved, and the number of unmanned substations has increased day by day. In particular, with the continuous improvement of the automation level of substations, the proportion of accidents caused by non-electrical factors has become increasingly higher. How to reduce or avoid the occurrence of such accidents has become the primary problem to be solved in order to achieve unmanned substations. The image monitoring system, namely remote viewing, is a further supplement and improvement to the "four remotes" (remote control, remote communication, remote measurement and remote adjustment). It can monitor the operation of equipment in the substation and the surrounding environment, monitor the heating level of power equipment, realize fire prevention and anti-theft alarms, and solve security issues.

　　At present, many substations have realized the "four remote" functions. Nowadays, remote image monitoring technology has become increasingly mature. It is called the fifth remote remote viewing, which enables relevant personnel to understand the situation of the substation site in a timely manner, provide substation site images for control center operators, and handle faults and safety.

　　Video surveillance systems also have some disadvantages: 24-hour video recording takes up a lot of videotapes and is unnecessary. Surveillance personnel must watch the video at any time to prevent missing faults and unsafe images. When checking, they have to watch from the beginning, wasting a lot of manpower, material resources and time.

　　3 Substation remote monitoring system

　　The substation remote monitoring system is an improvement and supplement to the video monitoring system. It can realize the comprehensive automation of the substation and share information, thereby reducing hardware and improving the utilization rate of equipment, simplifying secondary wiring, reducing the area and cost of the substation main control room, and greatly saving manpower, material resources and other investments.

　　3.1 Composition of substation remote monitoring system

　　The composition of the substation remote monitoring system is shown in Figure 1.

Figure 1 Substation remote monitoring system[page]

　　The images are collected by on-site visual sensors, and the on-site conditions are transmitted to the management center via wireless Ethernet using wireless bridges or wireless text messages or multimedia messages. The on-site images are processed by the management center staff. Only a few of the on-site conditions are listed here as shown in the figure.

　　Specific composition structure:

　　3.1.1 Image monitoring part (innovation points and key issues to be solved)

　　The system image monitoring range is the entire substation. It uses a full range of pan-tilt cameras and lenses with high definition, high magnification, and low illumination requirements to ensure that all areas of the substation are monitored without blind spots. On this basis, through advanced graphics processing technology and algorithm research, the automatic graphics alarm and autonomous control and management operation of the substation are realized. At the same time, the substation alarm image is published to the MIS network of the superior department of the power company through a wireless bridge or wireless SMS or MMS. After installing the monitoring system client software, online customers can remotely monitor the controlled substation.

　　Obviously, traditional video surveillance based on manual operation cannot meet the needs of practical applications. A new generation of monitoring technology is developed. After the camera obtains the video sequence, it first improves the image quality through image restoration or super-resolution restoration technology, and then detects, classifies and tracks the targets in the scene, thereby realizing the analysis and understanding of the video content, including anomaly detection in the scene, human identity recognition, and understanding and description of the video content. Most of the existing algorithms are proposed for this type of problem, mainly including background subtraction method, adjacent frame difference method and optical flow method, etc., to intelligently analyze and understand its content and make corresponding judgments. It is at the advanced stage of intelligent monitoring technology and is the key to realizing intelligent monitoring.

　　Super-resolution restoration technology: During the image acquisition process, the imaging system cannot obtain all the information of the original scene due to the limitations of imaging conditions and imaging methods. The imaging process is often affected by many factors such as optical blur, motion blur deformation and noise, resulting in a decrease in the quality of the acquired image. Super-resolution restoration technology uses signal processing methods to improve image quality while trying to restore information outside the cutoff frequency of the imaging system. It is an effective method to improve spatial resolution and image quality (this can be achieved by reading the image into Matlab simulation software). The biggest advantage of this technology is its low cost, and the existing low-resolution imaging system can still be used. In fact, super-resolution restoration technology and image restoration technology are closely related in theory and can be considered as the first generation of image restoration technology. This part is the research on visual sensors. The research on the new generation of intelligent visual monitoring technology is a very challenging frontier topic. It gives the monitoring system the ability to observe and analyze the content of the scene, realizes the automation and intelligence of monitoring, and therefore has application potential. The intelligent analysis process of the visual monitoring system consists of several basic links such as moving target detection, classification, tracking and video content analysis. Video content analysis includes anomaly detection, human identity recognition and video content understanding and description.

　　The image monitoring part mainly solves the research of video monitoring system and visual sensor based on ARM S3C2440. S3C2440A is a 32-bit embedded RISC (reduced instructions set computer) microprocessor designed by Samsung based on ARM920T core. Its maximum operating frequency can reach 533MHz. It integrates a rich set of peripheral interfaces, including camera interface. It has the advantages of high performance and low power consumption, and is suitable for image acquisition, transmission and other applications. That is, instead of using a general video monitoring system, a visual monitoring system is used - - - - - It does not record at any time, but only starts recording when there is a burglary alarm or fire alarm, and then uses graphic processing technology and algorithms, that is, image-based target recognition, and it must be accurate and timely so that remote personnel can understand the situation in time and take corresponding measures.

　　3.1.2 Wireless transmission and control

　　We plan to cooperate with Shenzhen Qianjin Company on 150km WLAN signal coverage and reception. The wireless system requires the ability to build a wireless LAN within a 150km range and to be able to roam with vehicles within the coverage area.

　　There is a base station every 15 kilometers, with no communication lines between stations. Services include 10-channel voice and 500kbps data.

　　Supplementary requirements: The advancement of the system's technical architecture, the scalability of future functions and performance, the reliability of communications, the stability of the system and the relatively low amount of engineering work should be ensured.

　　3.2 Realizing comprehensive automation of substations

　　It can achieve information sharing, thereby reducing hardware and improving equipment utilization, simplifying secondary wiring, reducing the area and cost of the substation main control room, and greatly saving manpower, material resources and other investments.

　　4 Conclusion

　　In short, remote viewing technology has achieved remarkable results in improving quality, safety, management and other aspects. With the rapid development of automation technology, the application prospects of remote viewing technology are broader. The substation remote viewing system solves the visualization and environmental monitoring problems of the substation site. It is a necessary supplement to the four remote functions. It provides a reliable guarantee for the realization of unmanned and unattended substations. It has extremely high use value and utilization value. The development and construction of substation remote viewing systems should be strengthened. At the same time, the promotion and application of remote viewing systems has practical and historical significance for improving the safety and reliability of substation operation, improving the scientific nature of operation management, and promoting the modernization of management work.