Sichuan's hydropower transmission volume exceeds 1 trillion kWh

On December 25, the State Grid Sichuan Electric Power Company revealed that as of the current settlement period, the total amount of hydropower transmitted by Sichuan (full caliber) has reached 1009.3 billion kWh, breaking the "1 trillion kWh" mark. Among them, the total amount of hydropower transmitted by Sichuan (full caliber) in 2019 was 128.035 billion kWh.

Since the Sichuan power grid began to transmit electricity to other provinces in 1998, the 1 trillion kWh of clean electricity transmitted by Sichuan in the past 22 years is equivalent to the annual power generation of 10 Three Gorges hydropower stations, which can reduce coal consumption by about 400 million tons, reduce carbon dioxide emissions by about 1 billion tons, sulfur dioxide by about 8 million tons, and nitrogen oxides by about 1.5 million tons, making great contributions to the economic and social development of East my country and Central China, and the prevention and control of air pollution and energy conservation and emission reduction in the whole country. This shows that Sichuan has achieved fruitful results in implementing my country's strategy of transmitting electricity from west to east, and realized the "national optimal allocation of clean energy in Sichuan".

The construction of delivery channels is full of difficulties

According to statistics, the theoretical reserves of Sichuan's hydropower resources reach 145 million kilowatts, and the technically exploitable reserves are 120 million kilowatts. As of November 2019, Sichuan's installed hydropower capacity reached 78.39 million kilowatts, ranking first in the country. Sichuan has naturally become one of the main destinations for the country's west-to-east power transmission strategy.

Making good use of Sichuan's hydropower resources is an important issue facing the national energy development. Since Sichuan's power sources are far away from the power load center, a large number of large-capacity ultra-high voltage and ultra-high voltage transmission projects need to be built. However, the province has a complex terrain, many high mountains and ridges, large surface undulations, and many nature reserves and scenic spots. In recent years, geological disasters have occurred frequently, especially in Ganzi, Aba, Liangshan and other areas rich in hydropower resources, which are located in the transition zone from the second terrace of my country's terrain to the highest first terrace, which has brought huge challenges to the construction of transmission channels.

Take the newly started Yazhong-Jiangxi ±800 kV UHV DC transmission project as an example. "The Sichuan and Yunnan sections of the line we are responsible for pass through the Hengduan Mountains, with complex terrain, diverse climates, and crisscrossing geological fault zones, making construction particularly difficult." Li Wei, deputy commander-in-chief of the State Grid Sichuan Electric Power UHV Construction Command, introduced. In 2019 alone, there were 16 earthquakes of magnitude 3 or above along the line of the project, with the strongest reaching magnitude 6.0. At the same time, the line crosses many places, including highways, railways, Yalong River, Anning River, and 110 kV or above transmission lines 47 times. It passes through the Qionghai-Luoji Mountain National Scenic Area, Luoji Mountain Nature Reserve, and 5 secondary drinking water source protection areas, which also puts extremely high demands on the environmental and water protection work of the project.

It is understood that since the 11th Five-Year Plan, the State Grid Corporation of China has invested more than 100 billion yuan in Sichuan to build hydropower transmission channels. Eight 500 kV power transmission channels have been built in Ya'an, Maoxian, Kangding and other provinces. Three UHV DC transmission lines of ±800 kV Fufeng, Jinsu and Binjin and 500 kV Debao DC transmission lines have been built across provinces, as well as 8 500 kV AC transmission lines, providing a "hardware" foundation for Sichuan power transmission. At present, the maximum transmission capacity of Sichuan power grid across provinces exceeds 30 million kilowatts, ranking first in the country.

Transmission line operation and maintenance pressure is huge

In addition to power grid construction, State Grid Sichuan Power has also made arduous efforts in the operation and maintenance of hydropower transmission channels.

The three UHV DC transmission lines of Fufeng, Binjin and Jinsu, which originate from Sichuan, have large transmission capacity, long transmission distance and complex natural environment. In 2018, the three UHV DC lines of Fufeng, Jinsu and Binjin transmitted 96.2 billion kWh of electricity to the three provinces and cities in East China (Shanghai, Jiangsu and Zhejiang), accounting for 9.25% of the electricity sales of the three provinces and cities, of which Shanghai accounted for 20.7%. Once a line failure occurs, the consequences will be disastrous.

At present, Sichuan Power Grid has become the provincial power grid with the most complex operating environment in the country. Natural disasters such as earthquakes, mudslides, wildfires, floods, ice disasters, thunderstorms, etc. have brought great pressure to the maintenance and emergency repair of the power grid. Sichuan Power Grid has a total of 18 500 kV substations, and more than 6,000 kilometers of lines are located in remote areas such as Gansu, Azerbaijan, and Liang, with the highest altitude of 4,925 meters; the transmission lines pass through about 1,700 kilometers of virgin forests, about 8,700 kilometers of mountainous areas, about 2,000 kilometers of medium and heavy ice areas, about 650 kilometers of wildfire-prone areas, about 6,100 kilometers of mine-prone areas, and about 1,080 kilometers of geological disaster-prone areas.

According to statistics, from 2010 to the present, various natural disasters have caused 589 failures in the operation and maintenance lines of the State Grid Sichuan Electric Power Maintenance Company, 45 towers have been damaged due to earthquakes, landslides, mudslides, etc., and 41 lines have been shut down due to wildfires.

In response to this, State Grid Sichuan Electric Power introduced "Internet +", big data and other intelligent means in its operation and inspection business, and used technologies such as laser radar mapping, three-dimensional modeling, and online monitoring to achieve accurate positioning and early warning. When power outage maintenance can no longer meet the needs of modern power transmission, live working and intelligent robot inspections have been deeply applied to the maintenance site. On June 17, 2019, the installation of visualization equipment for the three UHV DC transmission lines of Fufeng, Jinsu and Binjin was completed, with a total of 2,279 sets of visualization equipment installed, which provided a "clairvoyant" for the monitoring of transmission lines.

Market transactions help Sichuan electricity delivery

In addition to huge investment in "hardware", strengthening and improving "software" is equally important.

As one of the first pilot provinces for the construction of the electricity spot market in the country, State Grid Sichuan Power has fully considered the actual situation such as abundant hydropower resources, large differences in power generation between wet and dry seasons, and complex grid security constraints, deepened the construction of the electricity market, and further promoted the development and consumption of clean energy in Sichuan.

In May 2016, Sichuan Power Trading Center was established. The center cooperated with Beijing Power Trading Center to actively carry out inter-provincial transmission transactions of Sichuan power, overcome the unfavorable factors such as the limited transmission channels of Sichuan hydropower, adapt to the changing market situation, and realize the expansion of the transmission market from single to diversified, the cycle from annual to monthly and short-term within the month, the time period from flood season to normal water season, the mode from long-term agreement to real-time spot, and the channel from extra-high and ultra-high voltage to 220 kV and below "capillaries", making full use of the transmission channel capacity to meet the needs of Sichuan power transmission to the maximum extent.

During this period, the scale of Sichuan power trading marketization continued to increase, and the number of market players increased sharply from 382 in 2015 to more than 2,000 in 2019. State Grid Sichuan Power has precisely implemented policies around direct power trading, retained power and surplus power, innovated trading methods, and enriched trading varieties. Whether in terms of mechanism and system innovation or standardized operation, it has been at the forefront of the national power market construction. According to statistics, from 2015 to 2018, the Sichuan power industry has released a total of 22.3 billion yuan in reform dividends to power users through market-based transactions, and the reform dividends have benefited large industrial users, general industrial and commercial users, and residents' daily electricity consumption. With the expansion of the scale of power market transactions, it is estimated that the reform dividends released in 2019 will exceed 8 billion yuan.

Statistics from the Sichuan Power Exchange Center show that from January to November 2019, Sichuan's market-based electricity trading volume reached 81.9 billion kWh, breaking through 80 billion kWh for the first time, while the figure was only 31.9 billion kWh in 2015.

A new round of delivery channel construction started

However, as the development of Sichuan's hydropower resources moves forward, the current transmission channels are still insufficient.

On December 18, Sichuan Province started construction of major projects in the fourth quarter, among which the Ya'an-Jiangxi UHV DC transmission project has attracted much attention. The total investment of the project is 24.4 billion yuan. It passes through five provinces, including Sichuan, Yunnan, Guizhou, Hunan and Jiangxi. The total length of the line is 1,711 kilometers. It is the first inter-provincial DC transmission channel built in Sichuan Province during the "13th Five-Year Plan" period. It is understood that after the completion and operation of the project, the inter-provincial transmission capacity of the Sichuan power grid will increase by 8 million kilowatts, and the annual transmission capacity will increase by 40 billion kilowatt-hours. At present, more than 2,000 construction personnel have entered the site, and the work of organization and management, construction coordination, and personnel training has been fully started. The construction of the project is progressing in an orderly manner and is scheduled to be put into operation in 2021.