40.5kV air-insulated switchgear.
40.5kV air-insulated switchgear, once reflected the company's strength, called some small manufacturers to discourage high-end products, but now it has become no threshold, all manufacturers can produce products, from cabinets, components, insulation, mechanical accessories, etc. can be bought everywhere, 1 minute 95kV power frequency withstand voltage, 185kV lightning impulse withstand voltage does not seem to be a problem, why is this happening? Is it an excellent result of technological progress and industry development?
40.5kv early switchgear are 1818mm wide, 3600mm deep fixed equipment, the distance between copper bars is more than 400mm, in the 90s with the introduction of foreign vacuum circuit breaker switchgear, a 1200mm wide, 2600mm deep, 2400mm high miniaturized switchgear came to China, the foreign voltage level is 36kv, the power frequency withstand voltage is 70kv, the lightning impulse withstand voltage is 170mm, it can be seen that there is still some gap with the domestic standard insulation voltage, There are different solutions for this.
One is for 405kV is tailor-made for the Chinese market, such as some foreign-funded enterprises have optimized the design to meet the insulation voltage requirements of China when entering China, such as ABB ZS32 completely according to our 405kV insulation voltage design, foreign 36kV switchgear is ZS20 is only 900mm wide, increasing the bus spacing, and the unique design of the contact box. The distance between the main bus bars of TAMCO company is increased, the contact box is redesigned, and the ring-CT doughnut current transformer worn at the back of the L-PDS contact box is replaced by epoxy casting block current transformer cast by epoxy resin casting block current transformer in the rear of the L-PDS contact box, and the epoxy solid sealing of the connection between the bus bar and the CT truly meets the requirements of domestic standards. General Electric (GE) company adopts American technology, uses American standard 38kV vacuum circuit breaker, insulation voltage up to 200kV, with electric field shielding equalizing contact box and wall sleeve, so that the insulation performance of the whole switchgear is very good. GE, Tamco, ABB 40The 5kV switchgear is 1200mm wide, which has become the mainstream of the industry and is widely used in chemical, metallurgical and municipal infrastructure.
There is also a solution is excellent domestic enterprises, the use of imported circuit breakers, their own design of 1200mm wide switchgear, such as Changzhou Pacific and other enterprises, the use of their own technical advantages, combined with the advantages of foreign switchgear mechanical operation, interlocking and other advantages, redesign the leading electrical circuit system, increase the insulation distance, design to meet the requirements of domestic standards 405kV mid-mounted circuit breaker switchgear.
Subsequently, the West High Court organized outstanding enterprises in the industry to jointly develop ZN85 vacuum circuit breaker and KN61 floor circuit breaker switch cabinet with a width of 1400mm.
After this, 405kV switchgear has sprung up. 1400mm wide, and later 1600mm wide, it can really be said that the insulation is not good, and the size is to make up. Make full use of the unique insulating medium of air, increase the size of insulators, creepage distance, etc., it doesn't matter if the switch cabinet is big, cheap is the king, and then it has entered the road of development of the zg characteristic electrical industry with high standards, low standards and high requirements, and various manufacturers can do it, and product performance is no longer the main factor to sell. Simple, low-cost and repetitive, large equipment footprint, high infrastructure costs, short equipment life, high material consumption, and large environmental damage are not conducive to long-term sustainable green and low-carbon development.
The development of the industry requires high-performance, miniaturized and long-life products, such as the 550mm wide 12kv central cabinet, which can handle 40The 5kv 1200mm wide switchgear is the level, which is more conducive to green, low-carbon and sustainable development.