Using i.MX536 to build a new generation of intelligent monitoring equipment for national power grid transmission lines

With the rapid development of the national economy, the distribution of high-voltage transmission lines is becoming more and more widespread. The rapid growth of transmission lines brings more and more patrol and maintenance work to line operators, but it is essential to observe and patrol dangerous points of lines in places such as cross-overs, densely populated areas, and natural disaster areas. At present, most cases still use regular manual patrol methods, and the patrol period is generally one month. During the patrol period, the environmental conditions of the lines and the surrounding areas are unknown, which buries huge safety hazards for the operation of transmission lines. In recent years, accidents have increased year by year, indicating that the traditional manual patrol method can no longer meet the existing safety needs. Therefore, it is urgent to adopt new technical means to carry out line patrol and maintenance work. In the case of a large number of transmission lines, state line maintenance methods are implemented to maintain and ensure the safe operation of the power grid.

In today's era of rapid technological development, we must actively develop and apply scientific and technological technologies to improve the management level of transmission lines and the application of online monitoring technology for transmission lines to maximize the safe operation of the power grid.

Transmission line online monitoring refers to equipment installed directly on the transmission line, which can record the operating status of transmission lines, towers, insulators and other power facilities in real time. It is an important means to achieve status monitoring and status maintenance. Transmission line online monitoring refers to the equipment status information provided by advanced status monitoring technology and diagnostic technology to judge the abnormal situation of the transmission line, and has the ability to predict equipment failure; line operation and maintenance personnel can arrange maintenance plans and implement maintenance according to the status of the transmission line. Transmission line online monitoring technology is an important basis for fault judgment and status maintenance.

The online monitoring system of transmission lines mainly uses various detectors and sensors to monitor the operation of field transmission lines, and converts the temperature, micro-meteorology, leakage current, icing conditions, body and corridor environmental changes of transmission lines into digital information such as images and data, which are transmitted to the online monitoring control center through GPRS, Zigbee and other communication channels, so as to help operators understand and analyze the line operation status, accumulate line operation data, and diagnose and predict the line operation status.

Since the transmission lines are located in the wild, the environmental conditions are complex and extremely severe weather is prone to occur, the reliability of online monitoring equipment is required to reach a very high level; at the same time, since the transmission lines themselves may fail, in order to ensure continuous monitoring under fault conditions, the power supply system of the monitoring equipment itself cannot simply rely on the power supply of the transmission line grid, and must use a feeding method combined with solar cells as a backup power supply, so the system itself must be able to achieve low power consumption; and in order to prevent non-environmental accidents such as theft and vandalism and analyze various dynamic behaviors of faults, the new generation of monitoring equipment needs to be able to analyze and process videos, and transmit videos wirelessly. Finally, due to the large-scale nature of transmission line detection, the new generation of equipment must have a lower cost than the previous generation of equipment that is assembled by patchwork, and can simultaneously mount multiple sensors and perform calculations, mount various relays and other peripherals for control, and ensure the stability and reliability of the system when various peripherals are running, so as to facilitate large-scale promotion and application.

These problems require that the embedded processors used in the new generation of online power grid monitoring equipment must have high-level industrial environment temperature requirements, low power consumption characteristics, sufficient image and video processing capabilities, and rich peripheral interfaces. Freescale 's i.MX53 chip is the most mature and advanced ARM processor currently available for the industrial automotive field. The power line detection equipment designed with this processor has a very high cost-effectiveness. The figure below shows the system structure of the new generation of online power grid monitoring equipment implemented with this processor.

Figure 1: Power monitoring equipment system block diagram

As can be seen from the figure, an independent ARM processor is used to collect and input sensor signals of state parameters such as conductor temperature, ice coating, wind deviation, sag, micro-meteorology and video images. After analyzing and compressing various data, they are transmitted to the monitoring center or other nearby detection points through various flexible wireless networking methods such as 3G, GPRS, WIFI, Bluetooth, Zigbee, 433, 915M and other wireless networks. In order to prevent catastrophic damage to the monitoring point, the device itself can also complete data backup through various types of storage media: SD card, NANDFLASH; the device has various wired communication methods such as RS232, RS485, optical fiber, etc. to complete the line on-site and remote control work, which effectively increases the reliability of the equipment. The entire equipment uses components that meet the automotive temperature level and can work stably and continuously at -40℃ to 85℃. The overall design of the equipment meets various protection level requirements such as waterproofing and salt spray, and can be used in most harsh high and low temperature and humidity environments. The following figure is a schematic diagram of the overall network and a site map. [page]

Figure 2: Network diagram

Figure 3: On-site photos

The new generation of transmission line monitoring device based on i.MX536 jointly developed by Chenhan Electronics and a domestic power company has promoted the development of transmission line information transmission technology, realized a transmission line monitoring center that integrates transmission line status monitoring, operation management, and command decision-making, and improved the supervision ability of the transmission line operation status. The system architecture is reasonable, the operation is stable, the application effect is good, and the overall technology has reached the international leading level.

The online monitoring system for transmission lines realizes real-time monitoring and control of the operating status of transmission equipment, meeting different application requirements such as daily operation duty, fault repair, and emergency command. It has strong promotion value and provides important technical support for the State Grid Corporation to implement the "three sets and five major" system construction. It is of great significance to the construction of a strong and intelligent power grid.