1. Combination and complete set In order to meet the needs of small size, small footprint, high performance and high reliability, various combined electrical appliances and complete sets of electrical appliances have appeared. In addition to switch cabinets, FC cabinets, and multi-layer cabinets, load switch-fuse combination capacitors, high-voltage contactors-fuse combination appliances (for FC cabinets), load switches, drop fuses, and arrester combinations, as well as arresters, Various combinations of disconnectors, voltage and current transformers, etc., have been developed into advanced types of complete sets of equipment, such as inflatable cabinets (C-GIS), fully enclosed combined electrical appliances (GIS), and fully substation combinations such as pre-installed substations (Including transformers and box transformers for high and low voltage appliances).
2. Large capacity and high parameters Due to the rapid growth of electricity consumption in modern life, the increase of electricity consumption in industry and agriculture, and the formation of high-voltage and large-capacity power grids, the capacity of high-voltage electrical appliances and various parameters need to be increased rapidly. At present, the rated current of main power transmission and distribution equipment has been increased from 1000A to 2500A to 4000A, and the short-circuit current has been increased from 16-20kA to 31.5-50kA, or even higher. The number of single-pole breaks for 550kV circuit breakers has been reduced from four to two, and single-breaks are being developed. If China's main power transmission and distribution voltage cannot be quickly increased, then China's power grids will not reduce the temperature of high-voltage electrical appliances with large capacity and high parameters (higher transmission voltages can unlock some ring networks of subordinate distribution voltages to reduce these Short-circuit current of the power grid).
3. Mechatronics (intelligence) Due to the development of computer and sensor technology and the improvement of grid automation, the demand for intelligent functions of high-voltage electrical appliances is more urgent. The combination of high-voltage equipment and advanced weak-current technology can significantly expand the functions of high-voltage electrical appliances, and provide better conditions for grid automation, telecontrol, and online detection. Large-scale, heavy-weight, single-function traditional electromagnetic relay protection devices, electrician instruments, and control devices will be replaced by multifunctional computers and sensors.
4. Fewer, maintenance-free products. With the high-voltage capacitor products using a large number of SF6 and vacuum and other excellent insulation medium and arc extinguishing medium, as well as the implementation of production technology based on advanced high technology (such as CAM, etc.), the product maintenance cycle can be extended. By 10 years, even products are maintenance-free. And with the development of electronics and information technology, online detection technology is becoming practical, and the use department has the conditions to realize the transformation from fault maintenance to condition maintenance. Operation and maintenance will also be implemented "less people, efficient, safe and reliable." The next ten years will be a period of great development from fewer, maintenance-free products, and will gradually occupy a certain position in the power system.
5. Phase selection and closing circuit breakers With the development of high-voltage and large-capacity power grids, the system's excessively high closing over-voltage and large short-circuit current are unfavorable to the safety and reliability of the power system. The selection and closing of no-load lines for circuit breakers is possible today with the rapid development of electronic control technology. The phase-selection closing no-load line can minimize the closing overvoltage, 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 current (especially in the case of more than 50kA and large asymmetric current) has a heavy burden on the opening and closing of high-voltage circuit breakers. If the favorable phase can be automatically selected (that is, shorter arcing time and small half-wave), it can be broken. 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 selection and closing, is one of the development directions of high-voltage circuit breakers.
6. Oil-free switchgear 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 been widely used in transformers and switches. However, the oil medium is a flammable and explosive substance, and it is inconvenient to operate and maintain. With the rise of SF6 and vacuum switches in switch appliances, 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 switch appliances, and it is also an important equipment policy.
However, oil switches are relatively economical and have rich experience in use. Therefore, in the next 10 years, there will still be a certain proportion in medium and high voltage switches.
The above are just the recent development of switching appliances. There are also some medium and long-term development of switching appliances, such as superconducting switches, static electronic switches (non-mechanical switches), high environmental protection switches, etc., due to technical and economic constraints, it is difficult to start and develop in the near future.
7. Convergence of majors In the 1950s and 1970s, majors of power transmission and transformation equipment, such as transformers, switches, arresters, transformers, and secondary control protection measurement systems, etc., had a clear division of labor and a clear boundary The areas of expertise do not interfere with each other. Nowadays, with the emergence of GIS, C-GIS, mechatronics switchgear and prefabricated substations, the majors of power transmission and transformation equipment, the specialties of strong and weak electricity, have been tightly combined together and difficult to separate. Therefore, the high-voltage electrical appliance specialty should not only adapt itself to the development trend of the integration of various specialties, penetrate each other and break the professional barriers, but also infiltrate and integrate with electronic technology, computers, and secondary systems. In short, we should have a clear understanding of the development trends of the above-mentioned high-voltage electrical appliances. Especially for manufacturers engaged in high-voltage electrical appliances, we should adapt to the market trend, readjust professional configuration, and appropriately develop products with technical reserves to welcome new ones. The arrival of a generation of high-voltage electrical appliances.
Conclusion: In terms of high-voltage capacitors, SG6 technology, vacuum technology, combined technology, etc. have been applied to the product structure, and basically achieved "oil-free". The introduction of shell production lines, vacuum epoxy casting and injection molding equipment, machining centers, etc. have appeared in the process. At present, through market research and high-voltage electrical equipment market transaction rates, and customer feedback, domestic equipment of voltage levels of 500KV and below has been able to meet domestic needs, and its technical parameters have approached or reached the state's advanced level.