1. Understanding of distribution box (cabinet)
GCK, GCS, MNS are low-voltage draw-out switchgear; GGD, GDH, PGL are low-voltage fixed switchgear; XZW integrated distribution box; ZBW box-type substation; XL, GXL low voltage distribution cabinet, construction site box; JXF electrical control box; PZ20, PZ30 series terminal lighting distribution box; PZ40, XDD (R) meter metering box.
Second, the role of low-voltage distribution cabinet
(1) Easy to reasonably configure the power supply.
(2) When the line fails, it is conducive to controlling the fault range and convenient to quickly find the fault point and eliminate it in time.
(3) It is easy to arrange line maintenance in pieces, without a large area of power failure.
(4) The distribution cabinet is convenient to place a variety of protective equipment such as fuses (fuses) to prevent short circuit, air switches to prevent overload, etc.
Third, the composition of low-voltage distribution cabinet
(1) The distribution cabinet mainly includes: terminal, various tool switches, protection equipment (air switches, fuses, etc.), measuring equipment (voltmeter, ammeter, frequency meter, etc.) Measuring equipment (active and reactive power meters).
(2) There are many types of low-voltage distribution cabinets, and the components are very different, taking the power cabinet as an example, from top to bottom: knife switch, current transformer, air switch, and each branch circuit breaker. If the power load is directly controlled, there are contactors, thermal relays and branch current transformers under the branch circuit breaker. Of course, there are ammeter, voltmeter, voltage conversion switch, indicator light.
Fourth, the content of each distribution cabinet model
GGD Low voltage distribution cabinet: G-- low voltage distribution cabinet; G-- fixed installation, wiring; D-- power cabinet;
GCK low voltage distribution cabinet: G-- cabinet structure; C-- extraction type; K-- Control center;
GCS low-voltage distribution cabinet: G-- closed switchgear; C-- extraction type; S-- Senyuan Electrical system;
MNS low-voltage switchboard: It is manufactured according to the technology transferred by ABB.
Five, GGD, GCS, GCK, MNS distribution cabinet difference
GGD is better than the other three, it is fixed, and GCK,GCS,MNS are drawer type switchgear, each of their outgoing unit is independent, the loop will not affect each other.
GCK is a very old cabinet type in China, and the strength of the profiles used at that time was poor, and the operating mechanism was not too flexible.
Most of the products produced now absorb the advantages of GCS cabinets. It is obviously different from GCS and MNS in that its main busbar is placed on the top of the cabinet.
GCS is a new generation of drawer type switchgear designed by Senyuan Company with reference to ABB's MNS cabinet type in the mid-1990s, the main structure is similar to MNS, and the main bus line is placed behind. Different from MNS, the drawer module uses the 20mm module commonly used in China (MNS is 25mm); Drawer adopts the propulsion mechanism, the operation is more convenient and flexible.
MNS cabinets can be operated on both sides, with a maximum of 36 circuits (1/4 drawer) in a single cabinet and 22 in a GCS. The material used in the MNS cabinet is aluminum-zinc plate, which is fully assembled and does not require post-treatment (galvanized).
The horizontal busbars of MNS and GCS are separated from the front left drawer unit and the front right cable room by a partition, and their vertical busbars are assembled in a flame-retardant plastic function board for greater reliability. The difference is that GCS can only have a minimum of 1/2 drawer, MNS has 1/4 drawer, MNS drawer has an interlocking mechanism, and GCS only has the switch itself.
The difference between GCK is that the horizontal bus is traditionally located on the top of the cabinet, the vertical bus has no flame-retardant plastic function board, the cable outlet can be the rear outlet, or it can be made into the right cable room outlet, but the drawer propulsion mechanism is different from GCS and MNS, which is relatively simple.
6, GGD, GCS, GCK, MNS switchgear use
(1) Fixed cabinet
GGD is a fixed cabinet, the fixed cabinet is not said modulus (only drawer cabinets or fixed dividing cabinets are expressed in modulus, this will be discussed later), GGD AC low-voltage switchgear has the advantages of reasonable mechanism, easy installation and maintenance, good protection performance, high breaking ability, the disadvantage is that the loop is less, the unit can not be arbitrarily combined and covers a large area, can not contact the computer.
(2) Chest of drawers
GCK, GCS, MNS are chests of drawers, when it comes to chests of drawers, we must first understand a concept, that is, modulus E, modulus E= there are two values, one is 20mm, one is 25mm. At present, the body of the drawer cabinet is generally processed with two kinds of profiles, one is KS profile, the E = 20mm of this profile; The other is C profile, E = 25mm.
Because the cabinet height is 2200mm, the effective height of the drawer (that is, the height of the drawer) is 1800mm, so the GCK of these two profiles can be loaded with 9 layers of drawers, because 8E (E=20) = 160, 8e (E=25) = 200 are less than the effective height of 1800.
Take E=25 as an example...
8E/4=200/4(meaning a 200 high space with 4 drawers and a width of 150)
8E/2=200/2(meaning that the space of 200 high is arranged with 2 drawers and the width is 300)
8E= Drawer height is 200 and width is 600
12E= Drawer height is 300 and width is 600
16E= Drawer height is 400 and width is 600
20E= Drawer height is 500 and width is 600
24E = Drawer height 600 width 600
1) GCK switch cabinet
GCK cabinet dimensions:
Width: 400/600/800/1000/1200mm
Depth: 800/1000mm
Height: 2200/2300mm
However, it should be noted that when the rated current of the main bus is 6300A, the main bus system is a double-layer bus system, the cabinet height is 2300mm, and the other cabinet heights are 2200mm.
When the rated current of the main bus is 5000A and below, the effective height of the functional unit can be accommodated by the GCK complete set of equipment is 72E(E=25mm), and the maximum outlet circuit can be arranged with 9 layers and 1 unit (8E). When the rated current of the main bus is 6300A, the effective height of the functional unit can be accommodated by the GCK complete set of equipment is 64E(E=25mm), that is, the maximum 8-layer 1 unit outlet circuit can be arranged. The functional units of the same cabinet can be all drawer installation or fixed installation, or mixed installation. The minimum height modulus of the functional unit chamber is 6E or 8E.
When 6E is the minimum height module, 12 functional unit drawers can be assembled at the installation height of 72E.
When 8E is the minimum height module, 9 functional unit drawers can be assembled at the installation height of 72E. Drawer unit standard loop design is available in 9 specification grades: 8E /4, 6E/2, 8E /2, 6E, 8E, 12E, 16E, 20E, 24E.
Fixed division unit standard loop design is available in 4 specification levels: 6E, 8E, 16E, 24E.
There are three kinds of drawer loop propulsion mechanism: XJG8(H1) hand-operated propulsion mechanism, XSL hand-pulled propulsion mechanism, XJG8(H2) hand-operated electric special propulsion mechanism.
2) MNS switch cabinet
MNS system frame adopts C-shaped skeleton, standard modulus E=25mm; MNS cabinet dimension (high) x width x deep mmx600 1000/1200 mmx400/600/800/2200/800/1000 mm drawer components standard specification for 8 e/e / 4, 8, no. 2, 4, 6, 8 e e e, 12, 16, 20, 24 e e e e.
Note: Four 8E/4 or two 8E/2 components can be installed horizontally in a 600-wide unit chamber with a height of 8E (200mm). However, individual components of 4E, 6E, 8E, 12E, 16E, 20E, 24E require a 600mm-wide unit chamber with the height of the component being the size required by the component specification.
3) GCS switchgear
The frame of GCS is assembled by E=20mm KS profiles;
GCS tank dimension (high x width x deep) 2200 mmx400 MMX / 600/800/1000/1200/800/1000 mm drawer units high modulus is 160 mm, divided into 1/2 unit, 1, 1.5 units, 2 units, 3 units five dimension series.
In fact, no matter what kind of cabinet is used, the conventional design considers the installation of beautiful and convenient, it is impossible to completely plug a cabinet full, low-voltage switchgear choose fixed separation plug switchgear, you can roughly refer to the following:
Circuit breaker: Frame air circuit breaker should be used for switches with capacity of 1000A and above, and plastic-case circuit breaker should be used for switches with capacity of 800A and below.
Low-voltage output switchgear cabinet: the height of the low-voltage distribution cabinet is generally 2.2 meters, and the effective height of the circuit breaker is 1.8 meters. The height of the circuit breaker with different capacities is as follows:
① Molded case circuit breaker below 250A: 200mm, occupying 8E space, that is, a drawer space;
(2) 400A, 630A molded case circuit breaker: 400mm, occupying 16E, that is, two drawer space;
(3) 800A plastic-case circuit breaker: 600mm, occupying 24E, that is, three drawer space;
④ Low voltage switch cabinet MCCB installed number (reference) :
⑤ For 800A moulded case circuit breaker, 3 can be installed in 1 cabinet;
For 400A, 630A molded case circuit breaker, 1 cabinet can be installed 4;
7 For 250A and below molded case circuit breakers, 1 cabinet can be installed 9.