With the advancement of science and technology, high-voltage electrical appliances have adopted high technology, new principles, new processes and new media, and a new generation of high-voltage electrical appliances is being brewed. The development trends are as follows:
1. Combined and complete sets In order to meet the needs of small size, small footprint, high performance, and high reliability, various combined electrical appliances and complete electrical appliances have appeared. In addition to switch cabinets, FC cabinets, and multi-layer cabinets, load switch-fuse combination appliances, high-voltage contactor-fuse combination appliances, load switches, drop fuses, and arrester combinations, as well as arresters, disconnectors, voltages and currents Various combinations such as transformers have been developed into advanced types of combined complete sets of devices.
2. Large capacity and high parameters Due to the rapid increase 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 must be rapidly increased. 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 increased quickly, then China's power grid demand for high-voltage electrical appliances with large capacity and high parameters will not cool down.
3. Mechatronics 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 strong electrical 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, electrical instruments, and control devices will be replaced by multifunctional computers and sensors.
4. Fewer, maintenance-free products. With the high-voltage electrical products using a large number of excellent insulation media such as SF6 and vacuum and arc extinguishing media, as well as the implementation of production technology based on advanced high-tech, the product maintenance cycle can be extended to 10 years, and even The product is maintenance-free for life. And with the development of electronics and information technology, the online detection technology has become practical, and the use department has the conditions to realize the transformation from fault maintenance to condition maintenance.
5. Phase selection and closing circuit breakers With the development of high-voltage and large-capacity power grids, the system's excessively high closing overvoltage 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 reducing the insulation level and improving the technical and economic level of the UHV grid. 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 breaking of the high-voltage circuit breaker. If the favorable phase can be automatically selected (that is, shorter arcing time and small half-wave), it can 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.
The convergence trend of various specialties During the 1950s and 1970s, various specialties of power transmission and transformation equipment, such as transformers, switches, arresters, mutual inductors, and secondary control protection measurement systems, etc., had a clear division of labor, clear boundaries, and specialized fields. Do not disturb 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, are tightly kneaded 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, they should adapt to the market trend, readjust professional configuration, and appropriately develop products with technical reserves to welcome new The arrival of a generation of high-voltage electrical appliances.