Building a world-class power distribution network to help Hangzhou further improve its energy level

As the night lights come on, citizens flock to the West Lake and check in at the ten "most beautiful autumn roads" in Hangzhou; on the east bank of Qiantang River, the beach is brightly lit, and the 113-hectare Asian Games Village is rising from the ground. Standing at the time node of "post-summit and pre-Asian Games", Hangzhou, known as a "paradise on earth", is accelerating the construction of a world-famous city with unique charm and unique splendor, integrating into the integrated development of the Yangtze River Delta, and creating a strong and active growth pole with both beauty and strength.

Behind the ever-changing urban appearance and booming economy, Zhejiang Hangzhou Power Supply Company has conscientiously implemented the overall deployment of the construction of a world-class distribution network by State Grid Corporation of China, and focused on practicality and effectiveness to create a safe, reliable, high-quality, efficient, green, low-carbon, and intelligently interactive world-class urban distribution network, injecting tremendous momentum into the further improvement of Hangzhou's energy level.

Grid planning

Accurately connect urban development

At the end of 2017, Hangzhou proposed a strategy of embracing the river to create a core development area with Qiantang River as the axis. The strategy of embracing the river is being implemented step by step and becoming a reality, becoming the driving force for Hangzhou to become a world-famous city. Against the backdrop of the city's eastward expansion, Hangzhou's diversified layout of the West Science and Technology Innovation Corridor, the East Smart Manufacturing Corridor, and the Qiantang River Financial Bay has formed a number of new hotspots.

How to make good use of limited resources to build a world-class distribution network to serve urban development plans?

"Hangzhou Power Supply Company has targetedly adopted a distribution network grid planning model that is refined to the power supply unit. It closely tracks details such as planning adjustments and industry entry within each grid, and achieves moderate advancement in distribution network construction through precise investment." said Ye Gangjin, deputy chief engineer of Hangzhou Power Supply Company.

Hangzhou Power Supply Company divides the supply area into 331 power supply grids. With the help of the "Online Power Grid", it integrates urban planning information such as Hangzhou's urban control detailed planning, regional land use nature, land transfer and government project approval, and carries out distribution network planning and benefit evaluation relatively independently in each grid, building a long-term target grid that is accurate to every block and every road.

"In the rapidly developing Hangzhou, there is no final draft for the distribution network planning," said Yang Xuan, a full-time staff member of the Development Planning Department of Hangzhou Power Supply Company. He opened the "Online Power Grid" system, and 56 billion pieces of data such as equipment parameters of the operation and inspection profession, customer project progress of the marketing profession, and meteorological information of the control profession were presented one by one. With the help of the fusion calculation of these data, Hangzhou Power Supply Company updates the investment amount, switch station and distribution transformer location of each grid in real time, and accurately achieves the coordination of grid distribution network planning and grid development through high-frequency iteration.

"In the past, the distribution network planning implemented according to administrative regions was like cooking a big pot of rice, with just a little bit of oil, salt, sauce and vinegar. Now we have changed to stir-frying small dishes, with more precise control over the heat and ingredients," said Yang Xuan.

The Yangtze River Grid is located in the south of Qiantang River and has been the focus of investment in the past decade. Opening the "Online Power Grid", the Yangtze River Grid distribution network planning formed at the end of 2018 reminds: the development of this area is almost saturated, please pay attention to reducing investment and controlling investment inertia. According to the investment plan given by the "Online Power Grid", Hangzhou Power Supply Company plans to invest 5 million yuan in three emerging grids in the south, including Jiangnan, Yongjiu and Zhongxing, to first strengthen the grid structure and ensure the coordinated development of the regional distribution network.

Hangzhou Power Supply Company is currently piloting a time-matching model for the construction of a first-class distribution network and main grid, and promoting the simultaneous construction, commissioning and power supply of four-level grids from 220 kV to 10 kV in newly developed areas, so as to achieve simultaneous recovery of distribution network investment benefits and become a growth point for the power grid companies' own operating benefits.

Smart Upgrade

Build a highly reliable smart distribution network

At 8:29 on November 22, Weng Fanghua, an employee of the Power Supply Service Command Center of Hangzhou Power Supply Company, detected through the dispatching automation D5000 system that a 10 kV outgoing line of the 110 kV Huafeng substation tripped due to a fault. The feeder automation function of the distribution automation OPEN5200 system quickly carried out automatic fault analysis and provided an operation strategy. After confirmation by the duty personnel, it automatically completed the three-step remote control operation and completed the fault isolation within 7 minutes, helping Shiqiao Street Office, drainage company and other customers to restore power supply.

"At present, Hangzhou's distribution network has achieved 100% automation coverage." Liu Hongwei, deputy director of the operation and inspection department of Hangzhou Power Supply Company, said, "This is the foundation for us to build a world-class distribution network."

Liu Hongwei believes that the prerequisite for achieving full coverage of distribution network automation in Hangzhou is the excellent "double-layer perception" capability of the power grid + equipment. By building an automated collection system, Hangzhou's entire distribution network has the ability to automatically perceive its own operating mode, load, and switch status at various locations, and can upload key power grid data to the automation master station at any time. At the equipment level, the "heaven and earth integrated" grid intelligent inspection system is promoted throughout Hangzhou. With the help of intelligent inspection equipment such as intelligent operation and inspection robots, wireless radio frequency identification systems, drones + machine nests, Hangzhou Power Supply Company has achieved accurate collection and real-time analysis of environmental data such as temperature of distribution network equipment, and electrical data such as current and voltage. This makes it possible to accurately formulate differentiated inspection plans and accurately repair equipment with hidden dangers.

In 2019, Hangzhou Power Supply Company migrated nearly 2,400 terminals to the new generation distribution network automation master station system, completed the information access of 3,560 feeders in the city's substations, and realized the centralized analysis of abnormal data in the distribution network and the formulation of repair strategies. In the past year, Hangzhou Power Supply Company has completed 11,200 remote control operations, successfully handled 652 faults, and reduced power outages by 4,000 hours.

In core areas such as Qianjiang Century City and West Lake, Hangzhou Power Supply Company has implemented the "on-site self-healing" distribution network restoration mode, which has enabled customers to "receive power in seconds" in the event of a fault. The company has established a dual-ring distribution network structure and a dedicated communication network, deployed distributed distribution automation terminals, and realized on-site information analysis and judgment. Within seconds, the fault signal of the distribution network positive line is sent to the switch stations on both sides, commanding the disconnection of the fault point switch to achieve instant fault removal.

While promoting less power outages for customers with distribution network faults, Hangzhou Power Supply Company has stepped up efforts to popularize non-stop power supply operations, built a 300 square kilometer non-stop power supply operation demonstration area, and achieved "zero power outage" for planned maintenance in the area. Hangzhou Power Supply Company took the lead in developing and applying non-stop (synchronous) grid-connected technology for 10 kV generators within the company system, and accurately commanded the synchronous phase adjustment of the generator and the power grid through computer instructions to achieve synchronous grid connection. This move successfully solved the problem of "disconnecting before connecting" for generators to the grid.

At present, the reliability rate of Hangzhou's full-caliber power supply has increased to 99.974%, an increase of 56% year-on-year. Next, Hangzhou Power Supply Company will achieve full coverage of 16,000 square kilometers of world-class distribution network before the 2022 Asian Games.

Data Mining

Fault repair is accelerating

At present, the area of ​​Class A and Class A+ supply areas in Hangzhou has reached 936 square kilometers, and the power supply reliability in the area exceeds 99.99%. How to deal with this one in ten thousand probability of power outage? Hangzhou Power Supply Company solves the key problem of "customer power outage" by mining the value of ubiquitous power Internet of Things data.

The source of the data is a smart data collection device integrated into the customer's electricity meter. In 2019, Hangzhou Power Supply Company completed the upgrade of smart data collection equipment for 100,000 customers, increasing the number of smart data collection customers to 200,000.