Shulou(Shulou.com)11/24 Report--

This article comes from the official account of Wechat: SF Chinese (ID:kexuejiaodian), author: SF

Whether it is all aspects of life, or production, office work, farming, doing experiments, we all need electricity. Ensuring the use of electricity is a huge livelihood project, and improving the transmission technology, reducing the loss of electric energy in the transmission process and improving the security and stability of power supply are an important part of this livelihood project.

Wen Jing | Wen Jing

The operation of modern society needs basic electricity supply, so as to meet the growing needs of people for a better life; in hot summers and cold winters, we all have to face the rush of electricity peak; for the sake of our earth home, we actively develop a variety of new energy sources to make them more connected to the traditional power grid, until finally completely replace fossil fuels.

Considering the above problems, various countries and regions are making efforts to develop safe, stable, efficient and energy-saving transmission technologies. This article will take an inventory of several promising next-generation transmission technologies.

The electrochemical energy storage system is mainly composed of battery pack, battery management system, energy management system, energy storage converter and other electrical equipment. There are mainly two kinds of control technologies for energy storage converters, namely, follower network control technology and network configuration control technology.

The grid-type energy storage system will output electricity according to the demand of the power grid, which can not provide active synchronous support, so it is difficult to adapt to the high proportion of new energy connected to the grid. On the other hand, the grid energy storage system can not only provide a stable voltage source for the power grid, but also actively stabilize the fluctuation of new energy generation, and has the advantages of strong system inertia, voltage and frequency support capacity. it can also improve the operation stability of the power system and the ability to accept new energy in extreme environments.

In January this year, the field test of the grid-connected performance of the world's first grid-based optical storage system jointly carried out by the Qinghai Institute of Electric Power of the State Grid and China Electric Power Research Institute Co., Ltd. was successfully completed.

In June 2023, the 100 MW / 200 MW hourly design and construction general contract project of Huaneng Laiwu Energy Storage Power Plant, which was built by the Power Construction Nuclear Power Company, realized full capacity connection in Huaneng Shandong Laiwu Power Plant, marking the formal commissioning of the world's first 100 MW decentralized control network independent energy storage power plant.

Flexible DC transmission technology is a new generation of DC transmission technology, which has been fully developed and applied in wind power delivery, power grid interconnection, passive network power supply and long-distance large-capacity transmission and other scenarios. Its transmission capacity has reached the UHV level, which is equivalent to the traditional DC transmission.

Flexible DC transmission can actively construct the network and provide strong supporting capacity for the power grid. However, due to the current capacity of the devices, the transmission capacity of flexible DC transmission can not reach the highest level of traditional DC transmission.

At present, flexible HVDC transmission projects such as Nanhui, Xiamen and Nanao have been completed in China, but due to the technical monopoly of foreign companies, the core components-flexible HVDC matching capacitors have been imported for a long time.

In order to get rid of this dilemma, Liaoning Yijin Electronics Co., Ltd., entrusted by the State Grid Corporation, and Fuxin High-tech Holdings established Jinlang (Fuxin) Capacitor Co., Ltd. in 2020, we will make every effort to tackle the project of flexible HVDC matching capacitors.

In July this year, the flexible capacitor products independently developed by Jinlang (Fuxin) Capacitor Co., Ltd. passed the strict type test of the Electric Power Industry equipment quality Inspection and Test Center of the Chinese Academy of Electrical Sciences, a national authoritative quality inspection institution.

There is also good news in July that the world's first high-voltage (220kV) large-capacity flexible low-frequency transmission project Hangzhou Tingshan-Zhongbu flexible low-frequency transmission demonstration project site, the world's first 72.5kV and 252kV 20Hz low-frequency GIS (Gas Insulated Switchgear) equipment successfully connected to the grid.

At present, this is a flexible low-frequency transmission project with the highest voltage level and the largest transmission capacity in the world. it not only realizes the interconnection between the two load centers of Hangzhou Fuyang and Xiaoshan, but also fully reflects the technical feasibility. it has laid a technical foundation for medium-and long-distance maritime transmission, flexible AC networking in Tibet, new energy access and other new transmission modes.

High temperature superconducting transmission technology is known as the next generation power transmission strategic technology, which is zero loss in theory. However, in order to achieve zero loss, we have to overcome many difficulties.

In January 2021, after four years of tackling key problems, the scientific research team of Shenzhen Power supply Bureau of Southern Power Grid successfully developed the first 10kV 400m three-axis high temperature AC superconducting cable in China. In September of the same year, the cable was officially put into use.

The new superconducting cable is only 17.5 cm in diameter and has a transmission capacity of 43 MVA, which is equivalent to meeting the electricity demand of four trains of 350 km / h high-speed railway at the same time, and its transmission capacity is five times that of conventional cables.

In February this year, the Shenzhen Power supply Bureau of Southern Power Grid announced that the 10kV three-axis high temperature AC superconducting cable successfully passed the high load test, marking another step forward in the application of superconducting normalization engineering.

Gas insulated transmission line (GIL) is a kind of transmission equipment with large capacity, high current and rigidity, which has the advantages of large transmission capacity, low transmission loss, strong resistance to natural disasters, small footprint and friendly electromagnetic environment. It is suitable for the connection between gas insulated metal enclosed switchgear (GIS), overhead lines, cables, transformers and other equipment.

In August 2018, as the first project in the world to adopt UHV AC GIL transmission technology in important transmission channels, the Sutong GIL comprehensive pipeline corridor project was completed. Sutong GIL comprehensive pipe corridor project is one of the large-diameter and long-distance tunnels across the Yangtze River, with a total length of 5468.5 meters, which is the deepest buried and highest water pressure GIL project in China.

In the future, GIL transmission technology can play an important role in power construction, reconstruction and expansion, large-scale new energy access system and hydropower station delivery in economically developed areas.

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