Exclusively Reveals the Past & Present of China’s Ultra-High Voltage (Second Half)

Conquering the “Mount Everest” of electricity, UHV is a “start from scratch” in China.

Since 2004, State Grid Corporation of China has organized dozens of scientific research institutions and universities, more than 200 equipment manufacturing companies, more than 500 construction units, and hundreds of thousands of people to participate in UHV basic research, technology research and development, equipment development, system design, In the work of test verification, engineering construction and commissioning and operation, 310 key technologies have been overcome, and world-class problems such as overvoltage and insulation coordination, electromagnetic environment control, and UHV AC and DC hybrid power grid safety control have been solved.

To determine whether the power grid is safe, countries around the world use simulation calculations as the basis for evaluation. China Electric Power Research Institute has built the world’s most advanced power system simulation platform, which conducts simulations on ultra-large ultra-high voltage AC and DC hybrid power systems including 220 kV to 1,000 kV power grids, 2,258 generators, 35,932 lines, and 11,547 nodes. Panoramic simulation calculations simulated more than 100,000 fault conditions and operating modes, fully verifying the safety and reliability of the UHV power grid.

In 2010, when the “Sanhua” power grid controversy was at a boiling point, the National Energy Commission’s Expert Advisory Committee specially organized experts and academicians to conduct research at the China Electric Power Research Institute. Through simulation calculations and comparison of multiple options, the China Electric Power Research Institute believes that the “Three China” synchronous power grid is not a choice between good and bad, but an inevitable choice for power grid development.

The localization of UHV equipment requires advanced test conditions. At present, China has built an UHV test and research system with the highest voltage level, the most advanced technology, and the most complete functions in the world. It has also relied on independent innovation to successfully develop the single transformer, DC converter valve, and DC converter valve with the highest voltage level and largest capacity in the world. Converter transformers, switchgear with the strongest breaking capacity, and more than 100 items in 21 categories including the first set of UHV key equipment have been domestically produced.

“You don’t know how big the innovation potential is until you are forced to a dead end.” This is how many key equipment of UHV were created. Thyristor is the “CPU” of UHV DC transmission, which determines the transmission capacity of UHV DC. At that time, there were two options: 5-inch and 6-inch. Most opinions believe that “the 5-inch thyristor technology is mature and can be produced domestically, but the 6-inch thyristor has not been produced and used at home or abroad, and it is very difficult to rely on domestic independent research and development.” “At that time, I insisted on using the 6-inch solution, and there were some internal problems within the State Grid Corporation of China. Comrades are actually afraid of difficulties and are worried that they will not succeed. But how can there be such a simple and easy way to achieve international leadership?” Liu Zhenya said when recalling this experience.

Looking at it now, the 6-inch solution was the right choice. The 6-inch thyristor increases the current flow capacity from 3000 amps of the 5-inch thyristor to more than 6000 amps. The Xinjiang Zhundong-Wannan ±1100 kV UHV DC line is 3,324 kilometers long and has a transmission capacity of 12 million kilowatts. In the future, the ±1100 kV UHV DC transmission distance will reach 6,000 kilometers and the transmission capacity will reach 15 million kilowatts.

It is precisely relying on the spirit of innovation that China has formulated the world’s first UHV technical standard system with completely independent intellectual property rights, forming a complete set of technical standards and specifications for UHV AC and DC projects from design to manufacturing, construction, commissioning, operation and maintenance. China’s UHV AC voltage has become an international standard.

The success of UHV has led to a comprehensive upgrade of my country’s electrical equipment manufacturing industry and enabled my country’s UHV to fully “go global.” In 2014 and 2015, the State Grid Corporation of China won the bid for the first and second phases of the UHV DC transmission project of the Belo Monte Hydropower Station in Brazil. Currently, both projects have been completed and are operating safely and stably.

In 2008, Reuters published an article saying that China planned to build an ultra-high voltage power grid by 2020. This plan “surprised Western countries that have been slow to upgrade their old power grids.”

Tikhateev, director of the Russian Federal Institute of Electrotechnical Research and an academician of the Russian Academy of Sciences, shed tears twice after watching China’s UHV results. Although UHV started earlier in the former Soviet Union, China eventually climbed to the peak of world power technology, and it was inevitable to feel disappointed and regretful.

Smog “catalyst”. In 2011, UHV construction truly entered the “fast lane” and was inseparable from a sudden haze.

At that time, the state issued a report stating that the wind power grid-connected installed capacity and power generation in the “Three North” regions of Northeast China, North China, and Northwest China accounted for more than 85% of the country’s total, but the wind curtailment situation was relatively serious. In 2011, wind power curtailment in the “Three North” regions reached 12.3 billion kilowatt-hours, corresponding to a loss of approximately 6.6 billion yuan in electricity bills.

On the one hand, there is sudden smog, and on the other hand, there is a serious waste of clean energy. However, around 2011, the approval of new UHV lines was still unknown.

It was during this period that some people proposed that only UHV DC needs to be developed and UHV AC does not need to be developed, and they opposed the construction of UHV AC “Sanhua Synchronous Grid”.

“AC and DC only have different functions and functions, just like men and women, but with different genders. There is no distinction between advantages and disadvantages.” Liu Zhenya emphasized. In fact, whether domestic or international, AC power grid is the main body. UHV DC is like a 10,000-ton giant ship, and UHV AC power grid is like a deep-water port. To develop a 10,000-ton giant ship, a deep-water port must be built. If only UHV DC is developed and AC is not developed, a “strong direct and weak AC” structure is formed. It is easy for AC faults to cause commutation failure of the DC system, or even multiple DC faults at the same time, leading to large-scale power outages.

In September 2013, the State Council’s “Air Pollution Prevention and Control Action Plan” proposed to strive to achieve negative growth in total coal consumption in the Beijing-Tianjin-Hebei, Yangtze River Delta, Pearl River Delta and other regions, and gradually increase the proportion of external power transmission. On February 12, 2014, the State Council’s executive meeting to study and deploy the strengthening of haze control clearly stated “the implementation of cross-regional power transmission projects.”

On April 18, the first meeting of the new National Energy Commission clearly proposed the development of long-distance and large-capacity power transmission technology and the construction of a number of ultra-high voltage transmission channels. In May, the country proposed to accelerate the construction of 12 key transmission channels in the air pollution prevention and control action plan. The State Grid Corporation of China was responsible for the construction of 11 transmission projects, including 8 UHV projects, all of which were put into operation on December 25, 2017.

In 2018, new infrastructure appeared for the first time at the Central Economic Work Conference, and UHV may be waiting for spring. On September 3, the National Energy Administration prepared an UHV approval plan: 12 UHV projects with a total transmission capacity of 57 million kilowatts.

It is foreseeable that the UHV power grid, which is “connected to the development and utilization of clean energy in the west and the haze control in the east and central part,” will surely receive more and more attention.

UHV, high-speed rail, and 5G are respectively examples of major technological innovations in my country’s three basic industries of energy, transportation, and information and communications. At the beginning of this century, China’s high-speed rail and UHV started almost at the same time. In 2004, the country introduced the “four vertical and four horizontal” high-speed rail plan, and later planned the “eight vertical and eight horizontal” plan. The development of 5G is in full swing.

However, compared with high-speed rail and 5G, there is still a considerable gap in UHV power grid coverage across the country. After more than ten years of development, the “Sword of Damocles” of the UHV power grid’s “strong and weak connections” has been hanging over our heads.

Liu Zhenya believes that the utilization rate of some UHV DC projects is low, either because the power supply construction at the sending end has not kept up and there is not so much power to send, or the construction of UHV AC projects at the receiving end has not kept up, and the power grid has insufficient capacity to accept it. So much power ultimately results in idle and wasted UHV DC transmission capacity. If the AC power grid is not developed, the DC power transmission capacity will also be limited.

From 2009 to now, the two major power grids in North China and Central China still rely on only one UHV AC line to maintain weak interconnection, like an “elephant walking a tightrope.” In desperation, the State Grid Corporation of China built pumped storage power stations and condensers on a large scale to improve the active and reactive power regulation capabilities of the power grid. This can also be regarded as a “self-rescue” to ensure safety.

It is difficult to develop UHV. What is the problem? Is it a technical problem? Zhang Guobao recalled in the book: “The State Grid Corporation of China insists on building ultra-high voltage AC lines and wants to connect the ‘Three China’ (East China, Central China, and North China) power grids. Some people are opposed to the three China power grids. It should be a technical dispute.” Incorporating non-technical factors.”

Is it an institutional problem? Since the founding of the People’s Republic of China, the Ministry of Railways has been one of the most stable ministries, while electric power has been the industry with the most changes in management agencies. It has experienced many changes from the Ministry of Fuel Industry, the Ministry of Water Conservancy and Electric Power, the Ministry of Energy, the Ministry of Electric Power, the Electricity Regulatory Commission, and the Energy Bureau. change. At the end of 1996, the State Electric Power Company was established. After its cancellation in 2002, two power grid companies, five power generation groups, and a number of related power enterprises such as planning and design, equipment manufacturing, and engineering construction were established. There are many mountains on the top, and it is inevitable that there will be a door view.

UHV has been debated for many years. As technical issues are resolved one by one, objections will eventually be attributed to reform. This is a unique “strange circle” in China’s power industry in the past 20 years. Some people even believe that the State Grid Corporation of China has strengthened its power grid monopoly by developing UHV, and that developing UHV AC and synchronous power grids is the “evidence” of strengthening its monopoly.

In fact, strengthening the synchronous interconnection of power grids is an effective means to ensure the security of large power grids. On July 30 and 31, 2012, India experienced continuous large-scale power outages, affecting more than 600 million people. From the analysis of the accident, the Indian power grid at that time was mainly 400 kV, and had not yet formed a national synchronized network. The connection between the five major regional power grids was weak, and the power supply and accident support capabilities were seriously insufficient.

After the accident, India strengthened the national interconnection and unified management of the power grid. In 2013, it built a 765-kV national AC synchronous power grid, which significantly improved its power supply capacity. Since then, there has been no large-scale power outage.

Compared with my country’s “Sanhua” power grid, the power supply range of the Indian power grid is 1.2 times that of the “Sanhua” power grid, and the number and density of the power supply population are 1.7 times and 1.3 times respectively. India achieved nationwide communication networking eight years ago, but the construction of my country’s “Sanhua” power grid is still subject to repeated disputes.

In September 2018, experts from China Southern Power Grid Corporation took the lead in organizing a report “Consultation Opinions on my country’s Future Power Grid Layout Research (2020)”. An insider analyzed: “The report states that ‘UHV AC is generally not used as a power transmission project’ and it is not recommended to build an UHV AC synchronous power grid. Why is it concluded that UHV AC is neither suitable for power transmission nor for networking?” The reason behind it is quite intriguing.”

Due to institutional reasons, technology seems to have its own competition. Let’s look at a set of data: China Southern Power Grid Corporation has successively built four ±800 kV UHV DC lines, three of which use 5-inch thyristors, with a transmission capacity of 5 million kilowatts. The first ±800 kV UHV DC transmission capacity of the State Grid Corporation of China was 6.4 million kilowatts, the second was 7.2 million kilowatts, and was later increased to 8 million kilowatts and then to 10 million kilowatts. It is also ±800 kV UHV DC, but the power transmission capacity is doubled.

Where will the UHV roads be in the future? What historical mission will the new era entrust to UHV? These questions deserve our rational thinking.The carbon neutrality trend is a coincidence or destiny.

On September 22, 2020, my country announced its carbon peak and carbon neutrality goals at the general debate of the 75th United Nations General Assembly, which quickly triggered heated discussions around the world. On the same day, the Global Energy Internet Development Cooperation Organization held an international forum on cracking the climate and environmental crisis and officially released two results, “Cracking the Crisis” and “The Road to Sustainable Development.” Half a year later, on March 18, 2021, the cooperative organization released research results such as China’s carbon peak before 2030, carbon neutrality before 2060, China’s energy and power development plan in 2030, and outlook for 2060, proposing China’s carbon peak. Peak, carbon neutrality roadmap.

The success of China’s UHV development has paved the way for the construction of a global energy Internet. The Global Energy Internet is a platform that uses UHV as the backbone grid to allocate energy globally and promote the implementation of “two substitutions” (clean substitution for energy development and electric energy substitution for energy use). It is a new type of electricity with new energy as the main body. system, and ultimately form a modern energy system that is clean-led, electricity-centered, green, low-carbon, cost-effective and efficient.

United Nations Secretary-General Guterres once said that China’s UHV technology is crucial to the development of renewable energy, and the global energy Internet is the core of achieving sustainable human development and the key to global inclusive growth.

Steven Chu, winner of the Nobel Prize in Physics and former Secretary of the U.S. Department of Energy, believes that related areas where China challenges the U.S.’s leadership in innovation and is developing rapidly include UHV AC and DC transmission.

“Without broadband technology, can the world become a ‘global village’?” Liu Zhenya once said, “The core of sustainable development is clean development. To achieve clean development, we need to develop clean energy on a large scale, and clean energy cannot be transformed into power transmission. Open UHV. Without UHV technology, the global energy Internet would be unthinkable, but now it is actually feasible.”

With the development of the times, UHV is not only a new power transmission technology, but also a new resource allocation platform and a new low-carbon development path. It shoulders multiple missions such as energy transformation and sustainable supply, clean low-carbon and green development, innovation-driven and national rejuvenation, sustainable development and building a community with a shared future for mankind.

Looking back on the past, UHV has promoted my country’s electric power revolution and achieved a major change in the development mode of energy and electric power. Based on the present, my country’s ultra-high voltage power grid is fully constructed and actively promotes the transformation of the world’s energy and electricity. Looking to the future, with the UHV power grid as the core, accelerating the construction of my country’s and the global energy Internet, and promoting the integrated development of the “three networks” (energy, transportation, and information), we will achieve the goals of carbon peak and carbon neutrality and promote the sustainability of human society. Development plays a greater role.