Applying superconductivity technology to power systems, whether from the characteristics of the device or from the characteristics of the system, it is possible to obtain a number of performance superconducting generators and superconducting transformers that are infeasible or difficult to achieve using conventional techniques to provide active and reactive power for the system. The response capacity opens up new ideas for the stability control of power systems. The superconducting energy storage device on the load side can improve power supply quality and provide emergency backup power. However, practical applications of superconducting power still have a number of problems that need to be solved. This requires the further development of technology. At the same time, the development of superconducting force also needs to solve several non-technical issues. 1 Key topics in the science and technology of superconducting force 1.1 Basic issues to be solved in implementing superconducting force Superconductivity must be widely used in power systems. Technology must be studied on four basic issues: economy, technological superiority, compatibility with existing technologies, and safety and reliability. For economic and technological superiority, it should be viewed from two perspectives: it is necessary to consider superconductivity. The economics of superconducting technology in power installations should be emphasized in the introduction of superconductivity technology into the power system. Overall economic efficiency and technical superiority At present, the price of high-temperature superconducting wire is still relatively expensive, and the technical parameters need to be further improved. Therefore, the reality of superconductivity technology in power systems is forecasted internationally: ) 6 paragraphs. The journal will continue to pay attention to the research and development of superconducting force technology at home and abroad, and report the latest research results and developments in a timely manner. I believe that after scientific research. Production operation. With the joint efforts of scientific and technical workers in management and other departments, superconducting technology will play an important role in the future power system with its unique performance. It takes 5 to 10 years for the application to show that the results of Nagoya University's research show that when superconducting cable technology is used in large-scale power grids, although the operating costs of the superconducting cable itself are higher, the high-density transmission of high-capacity power can be used. Improve and optimize the network structure and distribution of power grids in large cities so that the loss of the entire system can be reduced. The other problem is the conventional protection of systems after applying superconducting devices in power systems. 1.6.1 Loss in Superconducting Power Systems Super-protection can also cause superconductor's "quake-absorption problem J. Therefore must be fciSh! System failure. This will seriously affect the reliability of the system's power supply. Even the bookmark1 superconducting device can only operate below the critical temperature, the magnetic field and the The current passing through must not exceed the critical value, otherwise it will lose the superconductivity, that is, the occurrence of quenching.The danger of quenching is huge. First of all, the superconducting device has large power transmission capacity, and serious quenching will lead to insufficient power application. It can be said that it is only just starting that China's wrong home she is involved in the stability of the power system from the power generation to affect the system, followed by quenching after superconductivity The heat generated in the device may damage the superconductor in the device. It may also lead to a rapid expansion of the volume of the cooling medium until the entire device is damaged. (The change of the volume of the main cryogenic cooling media is: 4.2K of liquid helium evaporates, the volume is 8 times larger. After 100K liquid helium gas evaporates, the volume is 530 times larger; after 77K liquid nitrogen evaporates, the volume is 182 times larger, 100K liquid nitrogen evaporates, and the volume is 250 times larger) Thirdly, there are many factors affecting the critical value of superconductors, only from the surface There are three critical values, and three critical values ​​are related to each other, and they are also affected by several factors. For example, the AC loss in the superconductor, the magnetic flux jump mechanical vibration, the cooling stress, etc. may all cause the critical value to decrease. The quench protection of the guiding device is a very complicated issue. Fourth, the quenching will also cause concurrent failures, such as overvoltage and insulation stress, to study the quench protection in the superconducting force system. It should start from three aspects. :1 Beginning with the superconducting wire, a detailed study of the quenching phenomenon is the basis of quench protection. The quench protection of 2 pairs of superconducting devices includes: How to reduce the heat generated after the quench, as soon as possible to transfer the energy within the superconducting device; 3 ensure the safe and stable operation of the power system after the occurrence of the quench, this is a special problem of the superconducting force system, but also makes the superconducting force in the The quench protection has different meanings from the quench protection of general superconductivity technology. It requires us to carry out the dynamic design of the superconducting device based on fully understanding the dynamic characteristics of the superconducting force system, such as the rated current value of the superconducting force device and The operating current value of the protection device should also avoid the operating modes that may cause quenching in the system operation management. 1.6.2 Protection system in the superconducting force system The protection system in the superconducting force system must be completed in addition to the existing conventional system. In addition to the protection task, the quench protection of the superconducting force device and the quench protection of the entire system must be realized.The superconducting current limiter is one of the main protection devices in the superconducting force system, which can not only limit the short circuit in the system. Current, which reduces the requirement for breaker breaking capacity, can also be used as overcurrent protection for other important superconducting devices. The superconducting current limiter's rapid action and controllable operating current value can be introduced into the superconducting current limiter's system protection, which can be considered as the active protection with controllable fault current level. How to coordinate the action of the superconducting current limiter and conventional protection system will be an important research content for the safety protection of the superconducting force system.
2 Some opinions on the development of superconducting force science and technology The gap between China's superconducting force application technology research and foreign advanced countries is greater. The United States, Japan, Russia, France, Germany, Sweden, Britain, Norway and other countries have all developed various types of technologies. Experimental prototypes of superconducting force devices Our research on the characteristics of superconducting physical materials is not far apart from foreign countries, and some are even in a leading position. There are also several research results in general superconducting applications. However, at the Institute of Superconductivity Engineering Huazhong University of Science and Technology, Tsinghua University and other research institutions and universities have begun preliminary research work in the United States, Japan and other countries in the application of superconducting power technology has invested a lot of money. Taking Japan as an example, almost all universities with electrical engineering disciplines are engaged in research on the application of superconducting power technologies to varying degrees. Among them, the results of the University of Osaka Kyushu, Nagoya University, Yokohama National University, and the University of Tokyo are the most significant. Large-scale motor cable manufacturing companies and electric power companies also invested huge sums of money. Toshiba Hitachi Mitsubishi Electric and Fuji Electric Motor Manufacturing Plants, Showa, Sumitomo, Yokogawa, Fujikura and other cable manufacturers, Tokyo Electric Power Co., Chubu Electric Power Co., Ltd., Kansai Electric Power Co., Ltd. Major power companies such as Kyushu Electric Power Co., Ltd. are involved in the research and application of superconducting power.
It should be noted that there is still a vast space for development in the field of superconducting force science and technology. The space superconducting force has not yet been implemented in the real sense. Even in industrialized countries such as the United States and Japan, the superconducting force has been studied so far. The work has basically stayed in the stage of trial production and laboratory research of the stand-alone superconducting force experimental device. We have not mentioned the superconducting force to the subject's height to comprehensively study as long as we lose no time to enter into the trend of scientific and technological progress in superconducting force. It is possible to form independent intellectual property rights to meet the arrival of superconducting force. The implementation of superconducting force has yet to be implemented in all aspects. 2.1 Superconducting force needs national support for superconducting force science and technology Although it has a good application prospect, After all, it is still in the early stages of development. The development of superconducting force at this stage in China is still difficult to achieve immediate results, immediately form a product, occupy the market, get a huge economic return, therefore, the development of superconductivity is inseparable from the national key investment.
The U.S. and Japan’s early research on superconducting power also focused on the application of superconducting forces in the “Sunshine†plan of the “Sunshine†program and the “New Sunshine†project, which were mainly funded by the national investment agencies of Japan's Ministry of International Development and the New Energy Development Agency. With the support of these plans, funds have been set up with the cooperation of a number of research institutes and companies, with the main purpose of developing superconducting generators and related technologies. Super-GM (founded in 1988) is centered on national support. The International Superconductivity Research Center (ISTEC, established in 1991), whose main purpose is the development and research of superconducting magnetic energy storage systems and related technologies, has also provided a great deal of support for other superconducting power devices. We have invested in the research project for the supersonic missile superconducting magnetic energy storage (participation initiative). Table 1 shows the related projects and investment of superconducting power in the SPI program (both high-temperature superconductors) and the DOE investment 50% (data from the Internet) 2.2 Superconducting power needs support from the industry sector. From the industrial field, superconducting power requires both the power industry Situation, but also need to care about a new technology of the mechanical manufacturing industry, and Table 1 main contents of the US spi plan and the investment of superconducting power main technical parameters investment situation million US dollars installation related companies transformer current limiter power cable motor magnetic suspension flywheel energy storage The power sector will realize its real application and development when it fundamentally recognizes its necessity and superiority of technology and economy. Although the basic principles and structures of most superconducting power devices and conventional devices are not much different, due to the special electromagnetics of superconductors The design principle and manufacturing process of the performance and superconducting force device are still the research topics of the manufacturer. Only if the manufactory masters the production technology of the mature superconducting force device will there be a real sense of rejection. Take Japan as an example. Major power companies, several motor cables, and related equipment (such as vacuum cryogenic equipment) manufacturing plants not only actively participated in the joint research of Supei.-GM and ISTEC, which are supported by Japan's MITI or new energy development organizations, but also performed autonomously. Several other research work on superconducting force science and technology, such as Tokyo Electric Power The company and Sumitomo Electric jointly conducted research and development of high-temperature superconducting electric power 000A, 100m). The two sides each invested 50%, a total of 1.8 billion yen (approximately RMB 13.5 million). The author participated in the full closure of the Japanese Nagoya University. Of superconducting superconducting power transmission models (superconducting transformers 6000V, 250A, 5m), the project applies for national research funding 16 million yen, Central Power Corporation supports 20 million yen, Showa Wire and Cable provides superconducting wire It is said that without the support of the electric power industry and the electrician manufacturing industry, the research work on superconducting power science and technology is difficult to develop. The development of China's superconducting power science and technology needs to be actively involved in the power industry and manufacturing plants, and the common challenges are forward-looking. Scientific research topics to form an independent intellectual property 23 superconducting force requires a wide range of disciplines to cross superconductivity The first is the combination of superconducting application technology and the power system. Today's superconducting technology is inseparable from low-temperature and low-temperature technology. It not only provides the most basic operating conditions for superconductivity, but also directly relates to the efficiency and safety and reliability of superconducting equipment. It is whether superconducting technology can be actually applied to the power system. One of the keys. Superconducting power is inseparable from the most important application fields of superconductivity. They rely on each other and promote each other. It is a typical cross-disciplinary and interdisciplinary topic. The development of new superconducting materials and the application of superconducting materials to improve their performance are One of the important foundations of superconducting force. In the application of superconducting technology in the power system, especially the application of superconducting energy storage systems, power electronics is an indispensable technical means. It can be seen that the development of superconducting power needs to include the extensive blending of superconducting physical superconducting materials, cryogenic engineering, power electronics, power systems, automatic control, and mechanical manufacturing, etc. Conversely, the development of superconducting power can not only be triggered in the power industry. The technological revolution can also promote the development of a number of related disciplines. 3 Conclusion In China, due to the extremely uneven distribution of energy resources and energy consumption, high-voltage long-distance transmission of electric power from the west to the east is unavoidable, which makes the stability of the system extremely problematic. With the long-term consumption of electricity and the increasing size of power systems, it has been difficult to meet the requirement of long-circuit short-circuit capacity for circuit-breaker breakers; excessive short-circuit currents have raised higher electromagnetic levels for power devices. Electric and thermal specifications are due to the use of copper-aluminum (AL) as a conductive material, which has a large electrical loss. In large cities, the power consumption density has been increasing, but the transmission channels have become more and more intense. It has been difficult to meet the high density of large cities using conventional technologies. Requirements for large-capacity power transmission Because superconductivity has a resistance of 0 and other superior characteristics, application of superconductivity technology Power system is an effective way to solve these difficulties it will be the power industry and electrical industry technological revolution. We are eager to expect that superconducting force will also become a research hotspot in China's power and electric industries. We hope that through the efforts of scientists and technicians, we will push our superconducting technology from basic theory, basic materials and superconducting power applications to a new one. The level of development has enabled China to be in a favorable position in the 21st-century technological competition between countries.
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