Monitoring of overhead transmission lines supported by 3G/4G + Mesh combination

Monitoring of overhead transmission lines supported by 3G/4G + Mesh combination

The safe and stable operation of transmission lines is an important guarantee for national economy and livelihood. However, transmission lines have been affected by man-made damage, climate and geological changes, as well as illegal buildings, super-high-growth plants, birds, snakes, and other animal interference, these are the security risks of stable operation of the power grid, which is not conducive to achieving the goal of building a strong smart grid in China.

Transmission Line Features "wireless" is the best solution

In China, the geographical environment is diverse, and the transmission lines have a wide area, ** in the wild, with a high terrain, and complex terrain in mountainous areas (see figure 1 ). The electric power department has a heavy workload for managing and maintaining transmission lines, which is difficult and faces complicated problems. The following is an analysis of the overhead transmission line facilities and the surrounding conditions.

Related Facilities of Overhead power lines

Overhead power lines: towers, foundations, cables, Grounding Devices, wires, lightning wires, fittings, insulators, ladders and nails, signs and ancillary facilities;

Transformer, capacitor, circuit breaker, knife gate, lightning arrester, transformer and ancillary facilities on power line.

Required monitoring Scope

Environment along the line: construction activities, blasting, machine ploughing, drilling, underground mining, and other construction activities, inflammable and explosive facilities, and plants with ultra-high growth in the line protected area; ultra-high machinery;

Tower Foundation: the soil around the foundation is protruding, subsidence, water erosion, or soil extraction; The Foundation is cracked, damaged, sunk, pulled up, water or buried; weathering and cracking of basic protective caps; hidden dangers of retaining walls and slope protection;

Grounding device: the grounding line is not firmly connected to the tower; the grounding line is broken and rusted; the grounding network is exposed, damaged, and rusted;

Tower Body: Tilt, horizontal load bending deformation; rust, cracks, component defects, rust or loose connections; nest, Snake, vine plants on the tower;

Insulator, fittings, and wire accessories: the insulator has serious contamination; the insulator has cracks, damages, or corrosion; the marks of Electric erosion or flashover of the composite insulator; and the glass insulator has the marks of Self-explosion or flashover; corrosion, deformation, wear or crack of fittings; pin defect or removal; Anti-vibration hammer, Rod interval, pressure ring, damping line corrosion or exception; abnormal connection pipe and pre-twisted wire;

Line and ground wire: defective, rusted, Broken Strand, burned; not balanced, there is too tight or too loose phenomenon; line vibration, dancing, mutual entanglement; hanging with foreign body; overheating, deformation, screw looseness, and burns of the tension-resistant drainage clamp; abnormal ADSS and plug-in lines;

Accessories and other facilities: lightning arresters and Their device defects; fault locating and other device defects; line, phase sequence, circuit, tower sign defects or blurred; warning and protection mark defects or blurred; the tower top shows high lights and their devices with defects or failures.

Problems to be Solved for Network Monitoring

From the above analysis, we can see that the transmission department has very clear requirements for the safety of overhead transmission lines. According to China's current construction in this area, the following problems must be solved for its security monitoring system.

Network transmission of video and environmental data;

On-site real-time video data collection and environmental data collection;

Self-supplied power supply problem of Line Monitoring System equipment;

This service is suitable for all-weather field work environments;

Monitoring Management System platform software development issues.

"3G/4G + Mesh" transmission, solar power supply

To meet the needs of the transmission Department, based on the existing transmission network, integrates advanced image processing technology, low-power control technology, 3G/4G communication technology, Mesh Wireless LAN technology, solar energy application technology, data collection and processing technology to build a security monitoring network. The public network wireless (3G/4G) and Mesh Wireless LAN data transmission channels are used to transmit environmental data, alarm data, and video data, real-time online monitoring of the surrounding conditions of overhead transmission lines, towers, and towers. The combination of solar, wind, and energy storage batteries enables uninterrupted power supply around the clock to achieve real-time monitoring. This greatly improves the level of security monitoring for overhead transmission lines.

Alarm and monitoring

1. communication transmission subsystem

Public network communication transmission mode: uses the 3G/4G automatic switch mode. Priority is given to 3G with higher bandwidth for better video image quality. If 3G is not covered, the communication transmission subsystem will automatically switch to the CDMA communication mode. The communication and transmission subsystem adopts a series of advanced wireless communication technologies (Dynamic cross-frequency networking technology, smart power control technology, advanced dynamic route Adjustment Technology, seamless soft switching technology, video optimization technology, and dual-channel intelligence ). combined with technology, multi-level video compression and buffering technology, and smart image fuzzy processing technology ), this ensures that the video images are smooth, clear, and smooth during transmission. In a 3G network environment, a video data stream of up to 25 frames/S at 704x576 pixels is supported.

Wireless Mesh LAN transmission mode: Wireless Mesh Network is a wireless multi-hop Mesh network with self-organizing, self-management, and self-healing capabilities. It features high security, high stability, and wide coverage, high bandwidth, zero charges, flexible networking, and other advantages, is the best transmission mode for Transmission Lines of wireless information highway.

2. anti-false alarm system for microwave intrusion

Using an Advanced Microwave alarm, microwave wavelength is very short, in 1mm ~ Between 1000mm, so it is easy to be reflected by objects. When a microwave signal is reflected by a mobile object, the Doppler effect is generated. That is, the frequency of the reflected microwave signal and the frequency of the sent wave signal will produce a slight offset. In this case, an alarm is triggered, the traditional Infrared alarm mainly uses the infrared thermal effect and photoelectric effect for detection. It is prone to false alarms due to environmental factors such as temperature and light. Microwave alarm is not affected by these factors. Microwave due to short wavelength, penetration strength, glass, wooden boards, brick walls and other non-metallic materials can penetrate, so there is no blind area of detection.

3. frontend Collection Subsystem

Infrared high-speed ball machine + Intelligent Control Server: The Intelligent Control Server is a custom low-power (4-6 W) video encoding device. It mainly implements video analog signal H. 264 encoding compression, and then the video data is transmitted through the wireless network. The camera adopts a custom low-power (daytime Power Consumption ≤ 5 W) infrared high-speed ball machine. The infrared high-speed ball machine is a built-in high-performance digital signal processing (DSP) camera with a zoom lens, it is a high-tech day-and-night monitoring product that integrates universal Speed Control cloud platform, digital decoder and infrared light. It can be quickly located and continuously tracked and scanned to realize comprehensive, blind-spot-free, around-the-clock monitoring in a true sense. It can automatically adapt to changes in the environment light and shade and on-site distance. It adopts full digital control, the design is exquisite, minimizing the reliability between system components and facilitating installation and maintenance.

Dedicated Network infrared high-speed machine: mainly implements H. 264 video encoding compression and video data transmission through wireless networks; power input dc12 V, low power consumption (daytime Power Consumption ≤ 15 W), performance can meet all-weather field monitoring, the shooting distance of the ball machine is-m during the day and 50 m at night. The camera supports 28-fold zoom to adjust the distance. At the same time, the ball machine also has a constant temperature function, working temperature-20 ~ 70 deg C.

4. Front-end Power Supply subsystem: solar power supply unit + Remote Power Supply Intelligent Controller

The front-end Power Supply subsystem uses single crystal solar panels, and the photoelectric conversion efficiency of the Panel reaches 20%. The charging characteristic curve is smooth, which effectively prolongs the service life of the power supply subsystem.

The remote power intelligent controller monitors and manages the front-end power system, including remote control of the power system's working status, alarm analysis, linkage control, and other functions (2 shows ).

5. Background Management Subsystem

The main modules of the background management subsystem include the video management server, storage service, mobile video gateway service, site registration service, SMS cat service, software dog, remote smart power management service, and remote monitoring subsystem.

System Functions

The basic functions of the video surveillance system for power lines and towers are as follows:

Monitoring distance: the visible distance during the day is less than 500 meters, and the operation status of the power transmission line is less than 50 meters at night (result 3 shows );

Monitoring content: monitors the status of power transmission lines and towers in real time, and clearly shows the insulator status. A human face can be seen when someone is working under the tower or someone climbs the tower;

Start by phone: remote control and monitoring system for the bell rings (free of charge) of the mobile phone or on-duty landline, monitoring the transmission line status, and enabling back-to-back video and video recording. You can set a time to automatically close the front-end video;

SMS start: You can use SMS to control the monitoring system, monitor the transmission status, and enable the back-to-back video and video. You can set the time to automatically start and close the system;

Timed start: the video monitoring system of the pole tower is set in advance for a certain period of time, and the front-end video monitoring is automatically disabled after the work is completed within the specified period of time;

Preset Camera position: You can pre-set shooting positions for different angles of the tower to facilitate remote monitoring of the surrounding conditions of the tower from multiple angles. When an Infrared alarm occurs, the monitoring target location is automatically locked and a video is returned;

Photo Taking function: When man-made damage or exceptions occur, you can enable the photo taking function to capture images and transmit them to the background management system or mobile terminal in real time through wireless networks;

Microwave alarm: intelligent controllers are used to automatically analyze alarm behaviors, which can avoid frequent false alerts when small animals and birds go through monitoring points;

Coordinated alarm: When an alarm probe detects a behavior that damages the power facilities or an exception, the front-end collects automatic video recordings and transmits the monitored images to the background monitoring center to trigger an alarm, and automatically send text messages to relevant personnel;

Remote Call warning: When man-made damages occur, the personnel on duty can remotely call for deterrence to prevent damages;

Permission settings: You can set different access control permissions for users. You can use the mobile phone and background management system to modify system parameters to improve system operation security;

Video storage playback: videos are automatically recorded and saved during operation to facilitate data viewing and analysis;

Electronic Map management: on a map, you can mark the location information of the monitoring point of the tower in the wild, and view the Site status of the Point of view directly on the map;

Multiple Remote Monitoring Methods: real-time monitoring of the integrated power video platform, smart phones, remote WEB, and clients.

Different network systems are suitable for different environments

1. 3G/4G Wireless Network

It is applicable to the irregular layout of Monitored Objects on physical locations and sporadic distribution of monitoring points;

Transmission uses the 3G network of the operator, and all monitoring videos of the power tower are collected through the video management server in the monitoring center through the 3G network. The 3G fee must be determined by the standard of the local carrier;

3G communication modules must be configured for each tower monitoring site;

The video management server of the monitoring center is responsible for device management, Video scheduling, alarm management, video management, and device control of all tower monitoring sites. All data streams in the system must be authenticated and forwarded by the video management server;

The video management server in the monitoring center must allocate the wan ip address and map the wan ip address to the Intranet IP address. There is a certain risk in system security;

The system supports Web pages for remote Web user access;

The video of the power tower can be seamlessly connected to the video platform of the Power Integrated Video for unified management.

2. Mesh Wireless Network

It is applicable to the rule layout along the monitored point, such as an overhead transmission line, or the monitored point is concentrated within 5 kilometers;

The maximum line of sight of two adjacent nodes in the Mesh Wireless LAN is 10-15 kilometers. If a node fails, the system automatically searches for adjacent nodes to restore the network, at the same time, the system generates a node network interruption alarm;

Each node in the Mesh Wireless LAN has a signal coverage area with a radius of about 200, which can be used for inspection and other functions;

Transmission uses a self-built Mesh wireless local area network, without the need for fees; each monitoring site video is aggregated to the substation through the Mesh network, the substation transmits monitoring video data to the video management server of the monitoring center through the integrated power data network;

The Mesh relay module must be configured for the substation to automatically switch from the wireless network to the wired network;

The data bandwidth of the tower monitoring point in the wireless LAN is 10Mbps-20Mbps;

The video management server of the monitoring center is responsible for device management, Video scheduling, alarm management, video management, and device control of all tower monitoring sites. All data streams in the system must be authenticated and forwarded by the video management server;

The video management server in the monitoring center is an intranet server. You only need to assign an intranet IP address to access data, which is highly secure;

The system supports Web pages for remote Web user access;

The video of the power tower can be seamlessly connected to the video platform of the Power Integrated Video for unified management.