Regarding KYN28A center-mounted cabinet and ring network cabinet, these are two concepts. Both of them are switchgear, and switchgear can be categorized according to application, insulation method, structure type and so on.
KYN28A
center-mounted cabinet is based on the product structure, center-mounted cabinet is an air-insulated metal-enclosed withdrawable circuit breaker switchgear, is relative to the floor-standing (Floor Standing) circuit breaker switchgear, floor-standing circuit breaker trolley on the ground to move, directly inserted into the interior of the switchgear, advancing or swinging into the working position. Center-standing cabinet structure is compact, make full use of space, circuit breaker trolley in the middle of the front of the switchgear cabinet, the lower space can be installed voltage transformer trolley or surge arrester trolley and other auxiliary functions of the trolley. And the center (Mid-Mounted) switchgear circuit breaker trolley is placed in the middle of the front of the switchgear up and down, from the bottom of the cabinet has a certain distance, circuit breaker trolley in and out of the switchgear cabinet needs to be through the transfer trolley, that is, the circuit breaker is first pulled out in the transfer trolley, and then with the transfer trolley with the movement, if you need to overhaul, and sometimes need to be lifted from the circuit breaker from the transfer trolley down to the ground for overhauling, and the Floor-mounted type is not required.
The generation of the middle type is the result of the miniaturization of vacuum circuit breaker, before the floor type switchgear using frame structure, by the installation of the foundation is not flat, the ground is not flat caused by the deformation of the switchgear, the floor type circuit breaker trolley inserted to move out of the switchgear cabinet is very difficult, more importantly, due to the deformation, resulting in the trolley contacts and the switchgear bus bar static contacts are not good in the middle of the contact is not good, so that the heat is big, and even burned out of the switchgear cabinet. The center-mounted switchgear cabinet, on the other hand, adopts wall-mounted guide rails, so that the circuit breaker moves within the guide rails, reducing the influence of cabinet deformation and ensuring good contact.
Center-mounted cabinet is mainly used for industrial and mining enterprises, urban and rural power supply, belongs to the primary power distribution equipment, rated current 630-5000A, short-time withstand current 25-50kA, that is, generally used for the main power distribution, can be used in the air-insulated center-mounted switchgear cabinet (AIS, trolley-type vacuum circuit breaker), can also be used in the gas-insulated stationary switchgear cabinet (C-GIS, the use of isolation, grounding three-station switch + fixed vacuum circuit breaker). Generally the primary distribution is the main distribution, and the main distribution comes out to the distribution, which is the secondary distribution.
Ring network cabinet
is from the application point of view. Ring network is a power supply, belongs to the secondary power distribution, two into a hand in a ring form, the ring on both sides of the connection of a group of power supply, open-circuit operation, when a section of the equipment, cable failure, it is only necessary to disconnect the fault on both sides of the switch, the other ring can be operated normally to ensure the continuity of power supply. Ring network application general current 630A, short time withstand current 20kA, there are load switchgear for ring opening and closing, load switch + fuse combination appliance / circuit breaker for outgoing transformer protection.
Air-insulated switchgear, gas-insulated switchgear, solid-insulated switchgear can be used for ring network power supply, typical ring network cabinets have air-insulated type, that is, the use of SF6-type load switches are installed inside the cabinet, in and out of the line connecting the copper rows, fuses or circuit breakers are installed in the air, cables are also connected to the ordinary cable nose, typically Schneider’s SM6, the use of the popularly known as ” Typical is Schneider’s SM6, which uses SF6 load switches commonly known as “King Bastard Shell”, the general cabinet width is 500mm, and the circuit breaker cabinet width is 750mm. another type of ring network cabinet is gas fully insulated, i.e., the load switches, busbars, fuse sockets, or circuit breakers are all mounted inside the stainless steel box filled with SF6 gas, the main busbar is connected by side connectors or solid busbars on the top, and the external cable connection is made by the European standard sleeve and cable accessories, so the high-voltage belt line is connected by the copper row, fuse or circuit breaker. The external cable connections are made with European standard bushings and cable accessories, so the high-voltage energized circuits are completely isolated from the air environment and are not affected by the environment. Solid-insulated ring main unit adopts isolation, grounding three-position switch + vacuum load switch/circuit breaker, high-voltage energized parts are completely sealed inside the solid insulator, in addition to isolation, grounding break is closed to the air, and the outside world does not come into contact with, not affected by the environment.
Gas-insulated ring network cabinet due to the conductive circuit circuit is completely sealed, so it is more small and compact, such as the same 630A 20kA, the use of the center cabinet is generally 800mm wide x 1400mm deep x 2200mm high, while the ring network cabinet only needs 350mm wide x 750mm deep x 1750mm high.