Distribution network ubiquitous Internet of Things Hong Kong City lights brightly

As night falls, on the coast of the East China Sea, the "Port Connects the World" sign of Ningbo Port is lit up as bright as day, the high-rise buildings in the southern business district are full of busy figures, and the all-electric homestays in the mountains and forests emit the aroma of food but no smoke... The unique splendor of this city at night slowly begins.

Ningbo, Zhejiang Province, is the economic center of the southern wing of the Yangtze River Delta. In 2018, it ranked among the cities with a total economic output of one trillion yuan. With the booming industry and the increasing demand for electricity, higher requirements have been put forward for the guarantee capacity, power supply reliability and power quality of urban distribution networks. As one of the first ten cities in which State Grid Corporation of China carried out the construction of world-class urban distribution networks, after nearly three years of high-quality construction, Ningbo's urban power supply reliability has reached 99.99%, and the rural power supply reliability has reached 99.9601%.

Build a smart distribution area of ​​the Internet of Things to form a "grid map"

The Eastern New City is the new center of Ningbo, and the distribution network of the Eastern New City is also the top priority of the city's distribution network. At 9:48 on October 29, Chen Yujie of Jiangdong Power Supply Station of Yinzhou District Power Supply Company discovered through the distribution network monitoring platform that a low-voltage outgoing line of the No. 4 public transformer in the No. 1 distribution room of the East Yard of the Eastern New City had lost power. The system prompted that the cause of the fault was the burnt low-voltage switch. He immediately contacted the emergency repair personnel to rush to the scene to deal with it.

Since 2017, Ningbo Power Supply Company has promoted the deep integration of advanced technologies such as big cloud, Internet of Things, mobile Internet of Things and artificial intelligence with the distribution network, and built intelligent substations for the distribution Internet of Things.

So far, Ningbo Power Supply Company has completed the construction of 427 distribution IoT smart substations in Yuyao, Haishu, Eastern New Town, Meishan International Logistics Industry Cluster and other areas. Intelligent distribution transformer terminals and low-voltage line monitoring units are installed at all levels of the distribution network nodes to achieve automatic identification of the "distribution transformer-branch-meter box" electrical topology of the substation, full perception of the distribution network status and information integration, forming a "ubiquitous terminal IoT, one map of the power grid".

"After a distribution network failure occurs, the distribution Internet of Things terminals at all levels can accurately analyze the scope of the fault and feed it back to the monitoring platform, greatly shortening the fault handling time. Now, the power supply reliability rate in the smart substation has reached 99.999%, the average annual power outage time does not exceed 5 minutes, and the power supply to important customers has achieved 'zero flicker'." said Zhou Honghui, director of the operation and inspection department of Ningbo Power Supply Company.

In Cixi City, Ningbo, the pilot project of lean management of underground distribution network pipelines based on wireless radio frequency technology provides digital support for the distribution network and promotes the comprehensive "visualization" of the Cixi power grid.

So far, more than 650 kilometers of 10 kV cables in the central urban area of ​​Cixi City have all been equipped with wireless radio frequency technology, and a total of 19,155 electronic tags of various types have been installed. "Once a cable fault occurs, the cable lean platform can automatically determine the cable fault point, automatically send a text message to remind the person in charge of the equipment, and provide cable paths and positioning navigation to help the operation and inspection personnel quickly find the fault point. Using a mobile phone APP to scan the code on site to verify the faulty cable greatly shortens the time to find the faulty cable." said Gao Dongyin, a full-time staff member of the Operation and Inspection Department of Cixi Power Supply Company.

Human-machine collaborative three-dimensional inspection, scientific planning and precise investment

"Satellite positioning is normal, the digital transmission link is normal, the image transmission link is normal, and the night navigation lights are on." On the evening of September 18, employees of the Ningbo Beilun District Power Supply Company operated a small drone equipped with an infrared temperature measuring device to conduct night temperature measurement on the 35 kV Luju line, and compared the drone's thermal imaging data to find fault points with poor contact.

The use of drones to inspect distribution lines is 6 to 10 times more efficient than manual inspections. Ningbo Power Supply Company uses drones to inspect line channels, collects detailed data, builds a real-life 3D platform, and constructs a multi-dimensional fusion, human-machine collaborative 3D inspection system. Currently, Ningbo Power Supply Company is equipped with 98 drones and plans to gradually increase the intensity of drone inspections, so that the distribution line inspection mode will change from manual inspections to drone and manual collaborative intelligent inspections.

On June 8, in the No. 3 switch station of Ningbo International Convention and Exhibition Center, the main venue of the first China-Central and Eastern European Countries Expo, a half-meter-tall intelligent inspection robot "shakes its head" to scan the data and information of the power distribution equipment and monitor the equipment status in real time. During this special power supply period, the intelligent inspection robot carried out infrared detection and ultrasonic partial discharge detection on the power distribution equipment at multiple important sites, identified the switch position status and environmental monitoring of various types of equipment, and realized automatic information analysis and active fault alarm. The intelligent inspection robot is set to an automatic inspection mode every 2 hours, and periodically uploads data to the mobile terminal for reference and analysis by operation and maintenance personnel. During this power supply period, the intelligent inspection robot inspected a total of 184 ring network cabinets and 36 transformers, and found and promptly handled 4 hidden defects.

At present, Ningbo Power Supply Company is equipped with 140 intelligent inspection robots for power distribution networks. According to the importance of power distribution stations, two inspection modes are adopted: "one machine one station" and "one machine multiple stations". Through mobile terminals, operation and maintenance personnel can view the robot's daily inspection data and operate the robot to complete the inspection work of the power distribution room in a targeted manner.

In 2019, the installed capacity of photovoltaic power generation in Ningbo reached 2.229 million kilowatts, and the power generation from January to October was 1.83 billion kilowatt-hours, a year-on-year increase of 32%. With the rapid development of new energy, the ability of distribution networks to ensure the absorption of distributed clean energy and adapt to diversified loads is also urgently needed to be improved. This puts higher requirements on distribution network planning.

In 2018, Ningbo Power Supply Company pioneered the photovoltaic resource assessment visualization platform "Light Woven Network" based on big data applications in China, which innovatively changed the conventional design access management mode of distributed photovoltaics, provided technical support to government departments, new energy enterprises, power supply companies and other parties, maximized the utilization of social resources, and promoted the rapid development of clean energy.

Ningbo Hangzhou Bay New Area is a key area for the construction of the Greater Bay Area, Greater Garden and Greater Channel in Zhejiang Province, and is also one of the national demonstration areas for the application of rooftop distributed photovoltaic power generation. Through the "Light Weaving Network", relevant units can accurately evaluate the photovoltaic resources in various areas of the Hangzhou Bay New Area, comprehensively consider factors such as the local power supply layout and grid acceptance capacity, reasonably arrange the layout and installed capacity of photovoltaic projects, and coordinate the total target of new energy development planning at all levels.

For Ningbo Power Supply Company, the "optical network" provides a basis for grid planning and construction, and avoids redundant grid investment to the greatest extent. Yao Yan, director of the company's development planning department, said that thanks to the precise assessment of the "optical network", the company has avoided building an extra 110 kV substation, 5 to 10 km 110 kV lines and 30 to 50 km medium voltage lines in the 30 square kilometer demonstration area of ​​Hangzhou Bay.

At the same time, Ningbo Power Supply Company also uses planning as a guide to clarify reasonable grid construction goals based on regional functional positioning, development goals, load types and power supply reliability requirements.

At present, 335 of the 414 distribution grids planned by Ningbo Power Supply Company with high standards have been built, and the distribution network structure has been significantly optimized; the load transfer capacity is 92.3%, an increase of 21.5% over 2017, and the flexibility of power grid operation has been greatly improved.

Promote proactive emergency repairs and uninterrupted power supply operations to enhance customer satisfaction