After taking a nearly five-hour flight to Urumqi and then a three-hour car ride, Jiao Zhen, Secretary of the Party Committee of the State Grid Anhui Extra-high Voltage Company, and his entourage traveled from Hefei, Anhui to the Zhundong Economic and Technological Development Zone in Changji Hui Autonomous Prefecture, Xinjiang, on a "visit".

"After five years, we 'netizens' have finally met in person," said Lü Jianpan, Secretary of the Party Committee of the State Grid Xinjiang Extra-high Voltage Company, with deep emotion.

"The electricity from Xinjiang illuminates our Yangtze River Delta," Jiao Zhen said. The ±1,100 kV Zhundong-Wannan UHVDC transmission project (hereinafter referred to as the "Zhundong-Wannan project") "delivers" electricity over a distance of more than 3,300 kilometers. Not only Anhui but also Shanghai, Jiangsu, Zhejiang and other places have benefited from it.

On January 12 this year, the Guquan Converter Station in Xuancheng, Anhui, the receiving end, has cumulatively transmitted more than 300 billion kWh of electricity to the Yangtze River Delta region. Last year, the power transmission volume of the Changji Converter Station in Zhundong, Xinjiang, the sending end, also reached 300 billion kWh. Recently, the reporter made an on-site visit to the Zhundong-Wannan project to feel the strong momentum of the green and low-carbon development of energy at close range.

Electricity Comes from Afar
Increasingly Rich in Green Elements

In the Wucaiwan Gobi in the Zhundong Economic and Technological Development Zone, power lines crisscross in the air. In the Changji Converter Station, which covers an area of about 415 mu (approximately equivalent to 40 football fields), more than 30,000 pieces of equipment operate day and night, and more than 70 operation and maintenance personnel ensure operation and inspection 24 hours a day. In several wind farms, huge wind turbines stand in rows.

Xinjiang is an important energy production base in China, rich in wind, solar and other resources. At present, it has built three large-scale new energy bases with a capacity of ten million kilowatts and more than ten new energy bases with a capacity of one million kilowatts. The East China region is an important load center in China.

"The converter station receives 200 million kWh of electricity every day, which is equivalent to the electricity generated by 70,000 tons of standard coal. We convert it into 1,100 kV direct current and then transmit it outward," introduced Liang Fuqiang, the operation shift leader of the Changji Converter Station. "If 70,000 tons of coal are transported to Anhui, it will take nearly 1,200 train carriages 15 meters long to be filled, and they can be arranged in a row for 18 kilometers. Now, the green electricity can be transmitted between the two places in 0.01 seconds, and the loss in the whole process can be controlled within 5%."

On September 26, 2019, as the second major channel for "transmitting Xinjiang electricity outward" in China, the Zhundong-Wannan project was officially put into operation. Starting from the Changji Converter Station in the west and ending at the Guquan Converter Station in the east, the project has a total length of 3,324 kilometers and a transmission capacity of 12 million kilowatts. It is a UHVDC transmission project with the highest voltage level, the strongest transmission capacity and the longest transmission distance in the world, which is independently developed and designed by China.

The more than 3,300-kilometer "power highway" is connected by thick wires as thick as an arm and supported in the air by more than 6,000 iron towers with an average height of more than 80 meters and a weight of 180 tons each. In electrical engineering, the transmission lines with an alternating current transmission voltage level higher than 1,000 kV and a direct current transmission voltage level higher than ±800 kV are called UHVDC transmission lines, which can increase power, extend the transmission distance and reduce losses. The Zhundong-Wannan project is the world's first ±1,100 kV UHVDC transmission project and is known as the "Everest of Electricity".

"Now, every second, more than 2,000 kWh of electricity from Xinjiang can light up more than 200 million 30-watt light bulbs in Anhui and even in the Yangtze River Delta region," Jiao Zhen said.

"We have cumulatively transmitted more than 300 billion kWh of electricity, which can meet the annual domestic electricity consumption needs of 133 million households, equivalent to the on-site conversion of 90 million tons of standard coal and a reduction of 255 million tons of carbon dioxide emissions," said Wang Hong, the station master of the Changji Converter Station. Relying on the "infinite wind and solar resources" in Xinjiang, the Changji Converter Station has currently been equipped with new energy power sources with a capacity of more than 7.7 million kilowatts, accounting for more than half.

The Road Runs in the Air
Increasingly Rich in Technological Elements

Entering the converter stations at both ends of the Zhundong-Wannan project is like stepping into a "giant country". Each huge object is dozens of meters high, and the low-end converter transformers, gas-insulated switchgears and other equipment are arranged in an orderly manner.

In the Changji Converter Station, the most eye-catching is the converter transformer that is six stories high. This is the "heart" of the power transmission of the Zhundong-Wannan project. Through two groups of metal coils weighing dozens of tons, the voltage is raised to 1,100 kV, and the alternating current sent by the power plant is converted into direct current and transmitted outward.

"The converter station integrates a number of innovative technologies," Wang Hong said. "We have overcome a number of industry problems, and a number of technologies, systems and equipment innovatively applied have breakthroughs worldwide."

Advanced equipment independently developed like this is quite common in the Zhundong-Wannan project. Since 2014, the State Grid Corporation of China has organized hundreds of units from the power, electronics and machinery industries to carry out joint research on production, education and research, and has successfully developed 15 categories and more than 30 kinds of key DC equipment representing the highest level of similar equipment in the world.

During the interview, it happened to be the annual major maintenance of the Changji Converter Station. The maintenance personnel operated the crane to lift the bushing that is 27 meters long and weighs a total of 7.7 tons, and precisely passed it through the wall for renewal, just like threading a needle. The replaced one is the first domestic ±1,100 kV DC transmission bushing, which has been operating safely for 5 years since it was put into operation.

Looking up, there is a string of "abacus beads" on the wire at the connection with the iron tower. "This seemingly simple string of 'abacus beads' is the special insulator for UHVDC transmission. Previously, it was all imported, and the foreign quotation was as high as 10 million yuan. After localization, the price has dropped to less than one million yuan, and the operation effect is excellent," the maintenance personnel introduced.

More than 3,300 kilometers away, the Guquan Converter Station in Wannan is also undergoing maintenance simultaneously. In this station, which is as large as 1,000 basketball courts, there are more than 6,200 pieces (sets) of equipment operating in real time, and more than 130,000 pieces of various data are generated every day, but there are less than 100 operation and maintenance personnel.

In the intelligent operation and inspection center, the operation status of the equipment and the real-time pictures of the station are clearly displayed on the digital large screen. Jiang Xinfeng, the team leader of the substation operation and maintenance class, clicked the mouse, and a comprehensive analysis report on the operation status of all the current transformers in the station was generated in a few seconds.

"At first, the inspection work almost relied entirely on manpower, and a single inspection took up to 10 hours," Jiang Xinfeng introduced. Now, the Guquan Converter Station has installed 1,524 intelligent cameras, 1,132 environmental sensors and more than 300 sets of online monitoring equipment, which, together with mobile inspection robots, inspection drones and quadruped robots, form a "digital inspection team". "They transmit the data to the intelligent operation and inspection management and control platform, and we can complete the inspection work within 10 minutes without leaving the house," Jiang Xinfeng said.

Activating a Chessboard
Increasingly Stronger Regional Momentum

The Zhundong-Wannan project connects Xinjiang at one end and the Yangtze River Delta region at the other end. Over the past five years, the project has changed the power consumption structure of the receiving end area and also driven the industrial development of Xinjiang.

"The safe and stable operation of the project has driven the accelerated development of a number of upstream and downstream enterprises related to the power grid. Through large-capacity power transmission, the development and outward transmission of Xinjiang's energy bases have been further promoted, effectively relieving the tight power consumption situation in the Yangtze River Delta region. It has expanded the scope of clean energy consumption and promoted the transformation of Xinjiang's resource advantages into economic advantages," said Chen Shoujun, Chairman of the State Grid Xinjiang Electric Power Co., Ltd.

By the end of last year, the annual power transmission volume of the Zhundong-Wannan project reached 68.373 billion kWh, ranking first among the UHVDC projects in China for four consecutive years, accounting for 19% of the total social electricity consumption in Anhui Province in 2024, which is approximately equal to the province's electricity consumption for 69 days.

Yang Lianghu, Deputy General Manager of Anhui Yongchang New Materials Co., Ltd., has a direct experience. In recent years, with the increasing market recognition, the company's production capacity has been gradually improved, and the requirements for power supply reliability have also increased. "In the past, when the power consumption was tight in summer, the enterprise had to give up power for the people, and the production capacity was also reduced accordingly," Yang Lianghu said. In recent years, the situation has improved significantly, and the enterprise's power consumption has not been affected.

The effective guarantee and stable support of electricity have helped Anhui's economic development enter the "fast lane". In 2024, Anhui's manufacturing industry performed remarkably, with the added value of industrial enterprises above a designated size increasing by 9%.

"The entry of Xinjiang electricity into Anhui not only expands the power supply 'pool' of the State Grid Anhui Electric Power Co., Ltd., but also provides reliable electricity for other regions in the Yangtze River Delta," Jiao Zhen introduced. Since its operation, about half of the transmitted electricity of the Zhundong-Wannan project is used in Anhui, and the other half is sent to Jiangsu, Zhejiang and Shanghai, which has strongly promoted the high-quality economic and social development of the Yangtze River Delta region.

"With the support of the Zhundong-Wannan project, Anhui Province has built a UHVDC layout of 'two alternating current and one direct current' and a 500 kV backbone grid of 'four vertical and four horizontal', and is accelerating the upgrading of the Anhui power grid into a center for undertaking external electricity in the Yangtze River Delta, a hub for inter-provincial transmission and a platform for the allocation of green clean energy resources, providing reliable power support for the development of the Yangtze River Delta region," said Huang Xiaoyao, Chairman of the State Grid Anhui Electric Power Co., Ltd.