1. Overview
MNS is a frame structure Low voltage switch cabinet MNS products have gathered many design concepts, with more reasonable structure and superior functions. The system is suitable for various intelligent control switchgear systems. MNS frames have been designed and manufactured for many modern midpoint control system MCC cabinets and power distribution cabinet systems, proving that MNS cabinets have high safety, technical performance and operational reliability. The frequency conversion cabinet of Beijing Tiantuo Sifang Technology Co., Ltd. is mainly MNS cabinet type.
MNS series low-voltage switchgear system is applicable to all occasions for power generation, distribution and use, such as utilities, power plants, refineries, oil drilling platforms, ships, manufacturing, sewage treatment, buildings, residential buildings, etc.
2. Service conditions
a. Altitude: no more than 2000m;
b. Ambient temperature: upper limit 40 ℃, lower limit - 15 ℃;
c. Relative humidity: the daily average value is not more than 95%, and the monthly average value is not more than 90%;
d. Seismic intensity: no more than 8 degrees;
e. There is no danger of fire explosion, no severe vibration, chemical corrosion and other seriously polluted places.
3. Main technical data
3.1 Main technical parameters
| | | Three phase AC | direct |
| Rated voltage | Rated insulation voltage U1/V | one thousand | one thousand and five hundred |
| | Rated working voltage Ue/V | six hundred and ninety | seven hundred and fifty |
| | Rated pulse voltage Uimp/k | eight | |
| | Overvoltage level | Ⅲ | |
| | class of pollution | three | |
| | Rated frequency/Hz | 50~60 | |
| | | a bus or bus bar | Branch bus |
| Rated current | Rated current Rated working current Ie/A | six thousand and three hundred | two thousand |
| | Rated peak withstand current Ipk/kA | two hundred and twenty | one hundred and sixty-five |
| | Rated short-time withstand current Icw/kA | one hundred | eighty-six |
3.2 Structural parameters
| Structural characteristics | parameter |
| Recommended height H (mm) | two thousand and two hundred |
| Recommended width B (mm) | 600、800、1000、1200 |
| Recommended height T (mm) | 600、800、1000、1200 |
| Modulus E (mm) | twenty-five |
| Protection grade | IP00-IP54 |
4. Structural characteristics
The frame structure adopted by MNS is highly flexible. Once the structure is assembled, it does not need to be repaired. It is compact and saves the cabinet volume. Different standard components can be installed in the frame to meet various use requirements. Because the whole system, including the electrical structure, adopts the combined design, which can meet the requirements of various elements and different working environments, and achieve the corresponding protection level.
The design and materials of MNS can prevent the occurrence of fault arc to a large extent. Even if a fault arc occurs, it can be extinguished in a short time. MNS cabinet can be divided into three mutually isolated units: bus compartment, device compartment and Cable The chamber, structural design and materials used can also prevent arc damage to a large extent. Even in case of accidental arc, the arc is largely confined to the area where the arc occurs. The plastic material used does not contain CFC or halogen, and has flame retardant and self extinguishing characteristics, enabling users to repair and debug the cabinet in a short time.
4.1 Frame structure
The basic parts of the frame are all equipped with a C-type frame with modular holes at 25 mm intervals. All the frame parts are maintenance free. Because of the 25 mm modular hole system, the frame structure can be assembled into various types of cabinets without special tools. The C-type frame design is suitable for front operating, back-to-back independent and multiple assembled switchgear.
As required, the frame structure can be divided into the following compartments: device compartment, bus compartment and cable compartment. The device compartment is equipped with equipment components, and the MNS cabinet can be equipped with the following components: drawer unit, plug-in component and fixed component.
The main bus and branch bus are installed in the bus compartment. The branch bus is completely sealed in most functional boards. The multi-function board has the function of anti arc. Together with the bus, it can reach the protection level of (IP20) impact resistance without a partition. In the open structure, more cabinets can be installed with dual bus systems. The multi-function partition board has the function of anti arc, It is also used as the isolation between the device compartment and the bus compartment.
The cable compartment is the connecting wire and accessories (cable rack, cable connector, parallel wire, wiring duct, etc.) between incoming and outgoing cables (both upper and lower incoming and outgoing wires are acceptable) and bus bars.
4.2 Drawer unit design
The draw out drawer of MNS series switchgear separates the main circuit elements from the auxiliary circuit elements, effectively preventing the spread of faults. The drawer operating mechanism has been changed from the original double mechanism mutual cooperation to a single mechanism, reducing the cooperation error between mechanisms, making the mechanism operation more flexible. At the same time, locks are added on the drawer panel to improve the operation safety, All panels have been improved to improve the strength and protection level of the whole structure. The structural standard modulus of the draw out assembly is E=25mm. The draw out assembly consists of the assembly itself and the assembly installation chamber. The standard specifications are 4E, 8E/4, 8E/2, 8E, 12E, 16E, 20E~24E. Four 8E/4 or two 8E/2 can be horizontally arranged in a 600mm wide device chamber, forming a height of 8E: 200mm. The operation of the main switch is realized by the handle installed on the instrument panel, which has electrical and mechanical functions. The electrical interlocking adopts a 2-open and 2-close microswitch. The position of the switch handle is described as follows:
Working position - main switch is closed and components are locked;
Main switch opening - the main circuit is open, the control circuit is still connected, and the components are locked;
Test position - the main circuit is opened, the control circuit is still connected, and the components are locked;
Draw out position - both main circuit and control circuit are disconnected;
Isolation position - the component is withdrawn 30mm away, the main circuit and control circuit are disconnected, and the component is locked. The operating handle is used for opening, test and isolation of the main switch Padlock As safety protection, 3 padlocks can be added for more.
For 4E, 8E, 12E, 16E, 20E and 24E components, a 600mm device chamber is required for a single component. The height of the component is the size of the component door The special instrument panel for opening is used to install metering, operating and indicating devices. The operating handle has the mechanical interlock function of the agricultural production system, and the position description of the operating handle of the components:
Working position - the component is locked, the main switch can be operated, and the upper switch is opened. The handle can only be turned to the test position;
Test position - the main circuit is opened, the control circuit is still connected, and the components are locked;
Draw out position - both main circuit and control circuit are disconnected;
Isolation position - the main part is pulled out 30mm away, the main circuit and control circuit are disconnected, and the components are locked.
4.3 Flexible bus system
The main bus is horizontally installed and arranged at the back of the cabinet, which is divided into upper and lower layers. The double bus system is arranged at the upper and lower layers respectively, and the single bus system is arranged at the upper or lower layers. The bus section size of the two layers can be different. The bus system can also be installed at the front, middle and rear of the cabinet top as required. Space is reserved at both ends of the bus. If it needs to be expanded in the future, the bus can be directly connected without change.
The rated current of the main bus is up to 6300A, and the rated current of the branch bus is up to 2000A. The bus adopts high-quality copper bus, and the main bus is insulated with heat shrinkable sleeves to improve safety performance. The bus support parts are made of special materials in the form of standard parts, which have better insulation, firmness and heat resistance, and can meet the dynamic and thermal stability requirements of the system. The connection between the main bus and the branch bus adopts special copper column connection, which can effectively increase the contact surface and reduce the contact resistance.
4.4 Unique multi-function partition board
In the withdrawable or fixed and withdrawable hybrid design switchgear, the distribution bus (branch bus) is installed in the insulated multi-functional partition board. As the isolation between the device compartment and the bus compartment, the multi-functional partition board, together with the entire bus system, can meet the requirements of the electrical resistance protection grade (IP20) without adding a partition. The multi-functional partition board is composed of Special materials It is made of and has the protection function of anti fault arc. Once a fault occurs, it can quickly prevent the spread of the fault arc and limit the fault to a lower limit, that is, the fault arc will not affect the adjacent withdrawable components. When the arc is extinguished, the drawer assembly still has the operation function after cleaning. The position of the components with the mechanical interlock of the agricultural production system in the cabinet has not changed, even in the isolation position, there is no fault trace on the surface of the cabinet.
