Not long ago, the high-temperature superconducting energy storage system independently researched and developed by the China Electric Power Research Institute successfully achieved grid-connected power compensation in the power system simulation laboratory of the State Grid Corporation of China. This marked a breakthrough in the field of power application technology for high-temperature superconducting energy storage systems. It also aroused people's attention to superconducting power technology and related equipment.

The study of superconducting energy storage is becoming hotter. Related research and development personnel said that the success of this experiment shows that China has independently mastered key technologies such as the construction, integration, control, protection, and practical application of transmission and distribution engineering of the second generation high temperature superconducting energy storage system. The research results have laid a solid foundation for the scientific research, experimental demonstration operation, system analysis and evaluation of superconducting power application technology in the next phase. Earlier, the China Electric Power Research Institute also undertook the "Key Generation Technology Study of the Generation II High-Temperature Superconducting Energy Storage Unit."

According to reports, the high-temperature superconducting energy storage system is a kind of energy storage system that can realize energy-electricity conversion. It can directly store electromagnetic energy without resistance loss, and it does not need energy conversion during power transmission. It has fast response and high power density. As well as the advantages of high efficiency, it can realize real-time large-capacity energy exchange and power compensation with the power system, and plays an important role in improving the power quality, power supply reliability, and dynamic stability of the power grid.

In addition, the power scale and energy storage scale of the superconducting energy storage system can be very large, and it has the advantages of high system efficiency, simpler technology, no rotating mechanical parts, no dynamic sealing problems, and the like. Superconducting energy storage technology plays an active role in transient power quality management of transmission/distribution systems, improvement of transient power quality, transient stability of power grids, and emergency power accidents, and thus has broad application prospects.

Great Wall Securities analysts believe that superconducting energy storage is one of the research directions for important domestic smart grid related technologies, but due to reliability and economic constraints, commercial applications are still relatively far. At present, the energy storage method of domestic wind and energy storage projects is mainly based on lithium batteries, supplemented with sodium-sulfur batteries and liquid-flow battery storage.

Industrialization is the key In fact, the application of superconducting technology is not limited to energy storage systems. Superconducting cables, superconducting current limiters and other related equipment have all achieved a certain degree of development. In general, the superconducting force device can minimize losses and achieve efficient use of electrical energy. In April of this year, China’s first superconducting substation, which can significantly increase the reliability and safety of power supply, was built and operated safely in Baiyin, Gansu Province. The substation has integrated various superconducting force devices such as superconducting energy storage systems, superconducting current limiters, superconducting transformers, and three-phase AC high-temperature superconducting cables.

Some experts believe that it will take a long time for the superconducting technology to truly realize industrialization. However, there are different opinions in the industry. Industry analyst Tang Xiaobin believes that superconducting technology has entered the stage of industrialization. Superconducting current limiters, superconducting filters, and superconducting energy storage in high-temperature superconductors are expected to be the first to be applied.

It is understood that the superconducting current limiter can limit the short-circuit current and protect the power grid when the power grid is short-circuited. Compared with other methods of limiting the short-circuit current, superconducting current limiters have the advantages of not changing the original design and equipment and greatly reducing the energy consumption of operation.

It is estimated that compared with a 500 kV air-core reactor, the superconducting current limiter will save 2 million yuan in electricity bills and save more than 5 million yuan in the transformation of original equipment. The market for superconducting current limiters is estimated at 60 billion yuan.

In addition, high-temperature superconducting cables are also an important aspect of superconducting technology in the field of electric power applications. It uses a high-temperature superconducting material with no resistance and high current density as a current-carrying conductor. It has the advantages of large current carrying capacity, low loss, and small size. The transmission capacity of a superconducting cable with the same cross-sectional area will be 3-5 times higher than that of conventional cables. The Joule heat loss of the cable body is very small. Although in the AC operating state, it also has a certain loss, but as long as the superconducting cable exceeds a certain length, even taking into account the low-temperature cooling and terminal power consumption, the transmission loss will be reduced by 50% than conventional cable -70 %.

Some experts once said that taking China's grid transmission loss as a percentage of the generating capacity of 7%, if all superconducting power cables are used, the transmission loss of the power grid can be reduced to about 3.5% or less, and the benefits are obvious.

Tang Xiaobin believes that the first and second generation HTS materials have their own advantages. In terms of cost, the current first-generation costs are 1/3 of the second generation, but the second generation has the potential to fall below the first generation. In the field of application, except for the second generation of superconducting motors, the two materials in other application areas are basically the same.

Advantages Obvious problems to be solved Experts have told reporters that there are some limitations in current conventional power equipment and power systems, which has stimulated the industry's testing and development of superconducting power equipment.

According to reports, the development trend of China's power system is that the capacity of the power system is getting bigger and bigger, and the power grid is developing toward a very large scale. With the continuous expansion of the power grid capacity and scale, the short circuit capacity of the power system is increasing, which poses a great threat to the safe and stable operation of the power system. At present, there is no effective current limiting device in the transmission system. Starting from the structure and operating mode of the power grid to reduce the short-circuit current, its cost is very expensive. Superconducting force devices have significant advantages in this regard.

According to industry insiders, the efficiency of conventional power systems is limited by basic conductive materials such as copper and aluminum, and it is very difficult to further increase them. As China's power demand increases, the total network loss will further increase. This also requires superconductivity technology to break through this limitation.

In addition, the conventional electrical equipment covers a large area, and densely populated large and medium-sized cities are the load centers. As the demand for electrical energy continues to increase, so does the demand for power grid construction. The contradiction between urban land tension and power supply difficulties also needs superconductivity technology to crack.

At present, there are many scientific research institutes in the country that are working hard on superconducting power technology and have made gratifying achievements. For example, superconducting cables have been researched during the "Ninth Five-Year Plan" period and various kinds of high-temperature superconducting cables have been developed. Various types of superconducting power equipment have been developed prototypes, some products enter the demonstration test operation stage. However, according to the reporter's understanding, the application and industrialization of superconducting power technology still faces some problems that need to be solved.

Experts from the Institute of Electrical Engineering of the Chinese Academy of Sciences stated that the application and industrialization of the superconducting force technology faced three problems in brief: First, the critical temperature of superconducting materials needs to be improved; second, the price of superconducting materials is still relatively High, some are several tens of times higher than conventional materials, and hundreds of times; Third, the preparation of cryogenic refrigeration systems used in superconducting technology is still relatively complicated, and the maintenance free life of refrigerators is short. At the same time, the low-temperature and high-voltage insulation technology, real-time detection technology, integration technology, and the matching and coordination operation with conventional systems of superconducting power equipment also need further study.