Analysis of the current situation of SF6 load switches in China

According to the forecast, the final statistical load of the industrial park will reach 599MW, with a calculated load of 452MW. The existing power grid cannot meet the requirements for increasing electricity consumption. For this reason, the distribution network planning of the park has been readjusted. The introduction of a 20kV medium voltage distribution network in the industrial park has reduced the planned 10kV substations from 4 to 2, and the number of public switch stations from 18 to 9. As a result, the construction of the park's power grid is expected to save investment of 149 million yuan, save land resources of 6000m2, and highlight the advantages of using 20kV
The test line was operated with no load on March 20, 2008, and with load starting from March 21
Comparing the enterprise standard of Jiangsu Electric Power Company with the national standard, it can be seen that the power frequency withstand voltage specified in the enterprise standard is higher than the value specified in the national standard (GB)
According to GB/T11022-1999 (Common Technical Requirements for High Voltage Switchgear Standards), for 24kV, the rated short-term power frequency withstand voltage (1 minute, effective value) is specified as 50kV (general value) and 60kV (inter break), while the enterprise standard of Jiangsu Electric Power Company (Technical Specification for 20kV Distribution Equipment) specifies the rated short-term power frequency withstand voltage of 50 (65) kV (to ground) and 64 (79) kV (inter break) for 24kV. If the test is conducted according to the required values in parentheses, it is obvious that the voltage resistance level of the switchgear has been improved. The enterprise standards of Jiangsu Electric Power Company have become the technical requirements for switchgear in terms of usage conditions, main technical parameters, functional design, structure, performance, installation, and testing
Therefore, for switch manufacturing enterprises, it is necessary to design, manufacture, and test 24kV switchgear according to the requirements of power enterprise standards. To implement electricity enterprise standards higher than national standards. Due to the existing experience in manufacturing 12kV and 40.5kV switchgear in our country, it is not technically difficult to manufacture 24kV switchgear. However, 24kV equipment is not an amplification of 12kV equipment or a reduction of 40.5kV equipment, but requires re research, redesign, remanufacturing, and retesting in order to develop 24kV switchgear that meets regulations
7 About 24kV switchgear

The 20kV power grid should be equipped with indoor and outdoor switchgear with a rated voltage of 24kV. Due to the promotion of 20kV distribution in China, most of the existing 20kV power grids in China use mature switch equipment technology from abroad. ABB, Siemens, Schneider and other companies have long manufactured 24kV switchgear, such as ABB's ZXO type inflatable cabinets, Safeplus ring main cabinets, Schneider's SM6 ring main cabinets, Siemens's 8DC11 inflatable cabinets, Areva's M24, FBX ring main cabinets, etc., which are commonly used in the 20kV power grid of Suzhou Industrial Park. In the 20kV distribution network used in the Nanfen area of Benxi, Liaoning, the 24kV switchgear and other circuit breakers are products of Areva. The column mounted recloser load switches and drop switches used on the line are all produced by ABB. Foreign electrical manufacturing companies such as Schneider held 20kV technical exchanges and seminars in Huai'an, Jiangsu and Nanjing on April 2 and 22, 2008, recommending the company's continuously improved and perfected 24kV switch products
Generally speaking, gas insulated switchgear is commonly used for indoor equipment in urban areas, such as box type gas insulated switchgear (C-GIS), ring main unit (RMU), vacuum circuit breakers, current limiting fuses, load switches, etc. Pole mounted switches are commonly used on outdoor circuits, such as pole mounted circuit breakers, reclosers, sectionalizers, load switches, drop fuses, etc
The construction of a 20kV distribution network brings business opportunities to domestic production enterprises. Many enterprises have seized this opportunity and vigorously developed a series of 24kV switchgear, especially manufacturing enterprises in Jiangsu Province. Jiangsu Power Company has launched pilot promotion work for 20kV voltage levels in 13 cities throughout the province
Yangzhou Beichen Electrical Equipment Co., Ltd. has timely developed three types of 24kV switchgear, including 24kV switchgear, 24kV vacuum circuit breakers, and 24kV outdoor pole mounted SF6 load switches. After receiving the type test report from Xi'an High Voltage Electrical Appliance Research Institute on January 19, 2008, the company received an order for 24kV switchgear worth 550000 yuan signed with the customer
For example, Jiangsu Dongyuan Electric Appliance Group seized the opportunity of State Grid Corporation to promote 20kV distribution voltage, vigorously developed 24kV switchgear, and held a promotion meeting for the new series of 24kV switchgear products in Suzhou on March 13, 2009, providing users with a detailed introduction to the technical key and characteristics of 24kV switchgear products. The 24kV switchgear developed by the company includes VED-24 fixed sealed pole type high-voltage vacuum circuit breaker, ZW32-24 outdoor pole mounted vacuum circuit breaker, HZF-24 outdoor load switch, HXGN-24 ring main cabinet, KYN28-24 (P) programmable movable metal enclosed switchgear, YB-24 prefabricated box type transformer, etc
Some people estimate that for general power supply users, the investment increase in high-voltage switchgear and transformers caused by 20kV power supply will not exceed 20%
The promotion of 20kV distribution voltage brings development opportunities for the development of new 24kV switchgear in the high-voltage switch manufacturing industry. We should seize these opportunities and win the market early through early development

Translated from: China Switching Network