The future development trend of high-voltage electrical appliances

With the advancement of science and technology, high-voltage electrical appliances adopt high-tech, adopting new principles, new processes, and new media, and are brewing a new generation of high-voltage electrical appliances. Their development trends are as follows:

1Combination and complete set-up To meet the needs of small size, small footprint, high performance, and high reliability, various combinations of electric appliances and complete sets of electric appliances have emerged. In addition to switch cabinets, FC cabinets, and multi-layer cabinets, there have been combinations of load switch fuses, high voltage contactor fuses (for FC cabinets), load switches, drop fuses, and arrester combinations, as well as arresters and disconnectors. , various combinations of voltage and current transformers, etc. have been developed into advanced types of combined devices, such as CGIS, GIS, and all-substation combinations such as prefabricated substations (including transformers) High and low voltage electrical box change).

2 Large Capacity and High Parameters Due to the rapid growth of electricity consumption in modern life, the electricity consumption of industrial and agricultural industries has increased, and the formation of high-voltage and large-capacity power grids has required the rapid increase in the capacity and various parameters of high-voltage electrical appliances. At present, the rated current of the main power transmission and distribution equipment has been increased from 1000 A to 2500 A to 4000 A, and the short-circuit current has been increased from 16 to 20 kA to 31.5 to 50 kA, or even higher. The number of single-pole breaks in 550kV circuit breakers has been reduced from 4 to 2, and single-faults are being developed. If China's main power transmission and distribution voltage can't be rapidly increased, then the demand trend of China's power grid for large-capacity and high-parameter high-voltage electrical appliances will not cool down (higher transmission voltages can unlock some sub-distribution voltage ring networks to reduce these Short-circuit current in the power grid).

3 Electromechanical integration (intelligent) As the development of computers, sensor technology and the improvement of power grid automation, the demand for intelligent functions of high-voltage electrical appliances is more urgent. The combination of strong electrical equipment and advanced weak current technology can significantly expand the function of high-voltage electrical appliances and provide better conditions for power grid automation, remote control, and on-line detection. Large-sized, heavy-weight, single-function traditional electromagnetic relay protection devices, electrical instruments, and control devices will be replaced by multi-functional computers and sensors.

4 Less maintenance-free products With the high-voltage electrical products using a large number of SF6 and vacuum and other excellent insulating medium and arc extinguishing medium, as well as the production process based on advanced high-tech (such as CAM, etc.) implementation, the product overhaul cycle can be extended to In 10 years, even the product is maintenance-free over the lifetime. Moreover, with the development of electronics and information technology, online detection technology has become more practical, and the use department has made it possible to realize the transformation from troubleshooting to maintenance. Operation and maintenance will also be implemented with few people, high efficiency, safety and reliability. The next decade will be a time when there will be relatively little development and maintenance-free products, and will gradually occupy a certain position in the power system.

5 Select phase separation and closing circuit breakers With the development of high-voltage, large-capacity power grids, excessively high closing over-voltages and large short-circuit currents of the system are detrimental to the safety and reliability of the power system. The selection of circuit breakers for phase-locked no-load lines is possible today with the rapid development of electronic control technology. Selecting the phase-closed no-load line can minimally limit the closing over-voltage, which is very important for the UHV power grid to reduce the insulation level and improve the technical and economic level. The breaking of large short-circuit currents (especially more than 50 kA and larger asymmetrical currents) imposes a heavier burden on the breaking of the high-voltage circuit breaker. If it is possible to automatically select the favorable phase (that is, the short arc time and the small half-wave), it can be switched off. Improve the breaking capacity of high voltage circuit breakers and improve the safety and reliability of power systems. Therefore, the use of advanced electronic control technology to achieve high-voltage circuit breaker phase separation, closing, is one of the development direction of high-voltage circuit breakers.

6 Oil-free switch electrical appliances In the high-voltage electrical appliance industry, oil has been used as an insulating medium and arc extinguishing medium for more than 100 years. It has also been widely used in transformers and switches. However, the oil medium is a kind of flammable and explosive material, and the operation and maintenance are inconvenient. With the rise of SF6 and vacuum switches in switchgears, the use of oil switches has been decreasing (oil switches are no longer used at 363kV and above). It can be said that oil-free is a development trend of switchgear, and it is also an important equipment policy.

However, the oil switch is more economical and has rich experience. Therefore, in the next 10 years, there will still be a certain proportion in the medium and high voltage switches.

The above is only a recent development of switching electrical appliances. There are also some mid- to long-term development of switchgear, such as superconducting switches, static electronic switches (non-mechanical switches), high-environmental switches, etc. Due to technical and economic limitations, it is difficult to have substantial start-up and development in the near future.

7 Integration trend of various professions In the 50s to 70s of the 20th century, various specialties of power transmission and transformation equipment, such as transformers, switches, surge arresters, transformers, and secondary control protection and measurement systems, etc., have a clear division of labor and a clear distinction between professions. The fields do not interfere with each other. Nowadays, with the advent of GIS, CGIS, electromechanical switchgear, and prefabricated substations, the specialized fields of power transmission and transformation equipment, strong and weak power industries have been tightly kneaded together and it is difficult to separate them. Therefore, the high-voltage electrical professional must not only adapt itself to the development trend of integration of various professions, penetrate each other, and break down professional barriers, but also should penetrate and merge with electronic technologies, computers, and secondary systems. In short, we should have a clear understanding of the above listed trends of high-voltage electrical appliances, especially for manufacturers engaged in high-voltage electrical business should adapt to market trends, re-adjust the professional configuration, to moderately develop products with technical reserves, to meet the new The arrival of a generation of high voltage appliances.