MNS low voltage withdrawable switchgear

◎Overview

MNS low-voltage withdrawable switchgear is a combined low-voltage switchgear (hereinafter referred to as the device) assembled by standard modulus. This device is suitable for power supply and distribution systems with AC 50(60)Hz and rated working voltage of 690V and below. Control of power generation, transmission, power conversion and power consumption equipment.

The device complies with the national standards of EC439.DE660 and GB7251.1 (low-voltage switchgear and control equipment) and has passed the “3C” compulsory product certification.

 

◎Features

Compact design: accommodates more functional units in a smaller space. Up to 36 8E4 drawer units can be installed.

The structure is versatile and flexible in assembly: C profiles with a modulus of 25 mm can meet various structural forms, protection levels and operating environment requirements.

It adopts standard module design: it can form standard units such as protection, operation and conversion, and users can choose assembly as needed. More than 200 kinds of assembly parts can be used to form different frame structures and drawer units.

High safety: a large number of high-strength flame-retardant engineering plastic components are used to effectively enhance the protection and safety performance, with anti-arc design and personal safety for operators.

High technical performance: The main parameters reach the level of contemporary international technology.

Convenient assembly: no special complicated tools are required, and the entire series is standardized.

The plate is made of cold plate or aluminum-zinc plate, and the cabinet is maintenance-free.

Equipment updates are easy to improve.

 

◎Normal use environmental conditions

The ambient air temperature is not higher than +40 ° ° C, not lower than -10 ° C, and the average temperature within 24 hours is not higher than +35 ° C.

Atmospheric conditions: air is clean, relative humidity is not more than 50% at a maximum temperature of +40 ° C, and a relatively large relative humidity is allowed at a lower temperature, such as 90% at +20 ° C, but due to temperature changes Moderate condensation may occur by chance.

For indoor use, the altitude of the place of use shall not exceed 2000m.

The device is suitable for transportation and storage processes at the following temperatures: between -25 ° C and +55 ° C, in a short time (not exceeding 24 h)

Up to +70 ° ° C, the device should not be subject to any irreparable damage at these extreme temperatures.

If the above conditions of use cannot be met, it should be resolved by the user and the manufacturer.

When the device is used in offshore drilling platforms and nuclear power plants, a separate technical agreement shall be signed.

 

◎Basic parameters

Rated insulation voltage AC 690/1000V

Rated working voltage AC 400690V230/400V

Rated frequency 50 (60) Hz

Main busbar maximum working current 6300A

Vertical busbar maximum operating current 1000A

Main bus short-time (s) withstand current (RMS) 100KA

Main bus short-time withstand peak current (maximum) 250KA

Vertical busbar short-time withstand current 50KA

Vertical busbar short-time withstand peak current (maximum) 125KA

Protection level|P30, P40, P54 (when ordering | P54 protection level, you must contact the manufacturer in time).

 

◎Cabinet structure

The basic structure of the switch cabinet is composed of C profile assembly. The C profile is made of a steel plate with a mounting hole of E=25mm as a modulus, and all the shelves and the inner partition are galvanized and passivated. The surrounding door panels and side panels are electrostatically sprayed. The cabinet is divided into three compartments, namely the horizontal busbar compartment at the rear of the cabinet, the functional unit compartment on the left side of the cabinet front, and the cable compartment on the right side of the front of the cabinet.

The horizontal busbar compartment is separated from the functional unit compartment by a functional board made of flame-retardant foamed plastic, and the cable compartment is separated from the horizontal busbar compartment and the functional unit compartment by a steel plate.

In addition to the standard side outlet scheme, there is also a rear outlet scheme, which is designed to reduce the width of the switchgear cabinet. The main busbar of the rear outlet switchgear is horizontally installed at the top of the switchgear cabinet, the rear half of the cabinet is a cable compartment, and the ingress and egress cables are connected from the cable compartment of the cabinet. The front side of the switchgear is the device compartment and the functional unit of the switchgear is installed. The system design moves the cable compartment on the side of the switchgear cabinet to the rear half cabinet, which greatly reduces the arrangement width of the switchgear cabinet to further meet the space layout requirements of the substation.

The feeder cabinet is 600mm wide and 1000mm deep. The top is an independent main busbar compartment, which is isolated from the device compartment. The total height of the front unit is 72E (E=25mm). It is separated from the rear cable compartment by the multi-function board. It makes full use of the installation space of the switchgear, compact structure and flexible unit configuration. The rear cable compartment has a door for easy installation and maintenance.

The width of the incoming line is determined by the frame current of the incoming unit. The recommended width is 600800/1000mm and the cabinet depth is 1000mm.

 

Switch cabinet dimensions

Height: 2200m

Width: 600, 800, 1000mm

Deep: 600, 800, 1000mm

 

Withdrawable component

Standard component specifications: 8E/4, 8E/2, 4E, 8E, 12E, 16E, 20E, 24E.

 

(1) 8E/4, 8E/2 withdrawable components

 

The 8E/4 and εE/2 draw-out assembly structures include instrument panel, insulation side panels, rear cover with cable terminations, and one or two 20-pin control line terminal mounts. 8E/2 can be used with two different requirements. 20-pin terminal.

 

A knockout hole is provided on the instrument panel for mounting metering, operation, and display devices. The main switch (generally the motor switch with fuse or circuit breaker operation is realized by the handle mounted on the instrument panel, the handle has electrical and mechanical interlock function, the electric interlock uses a micro-opening normally closed contact Switch to complete.

 

After the operation handle is pressed inward, it can be moved from the O position to the | position. The operation handle can be used to open, lock and test the main switch in three positions for safety protection. Up to 3 locks can be added.

 

(2) 4E, 8E, 12E, 16E, 20E, 24E withdrawable components

 

The 4E to 24E withdrawable components include instrument panels, insulated back panels, front cover panels, metal side panels, and wireway slots.

 

The hinge assembly door provides the convenience of replacing components from the front (such as replacing fuses) without the need to extract components. When the component is in the working and test position, only the tool (such as a screwdriver, double lock) can be used to open the front door. When the component is in the isolated position, it can be equipped with a double lock.

 

The front cover has an opening for mounting the instrument panel, and the instrument panel remains in place when the front cover is opened and closed. The instrument panel is provided with knockout holes to mount metering, operating and indicating devices. The operating handle has an electrical and mechanical interlock function, and the electrical interlock is implemented with a micro switch that normally opens a normally closed contact.

 

Switch handle position description

丨Working position - main switch closed, control loop is on, component is locked

○Opening position - the main switch is open, the control loop is not connected, the component is locked

Isolation position - twitch 3σmm distance, the main circuit and control loop are disconnected, complete isolation, three locks can be added

Test position - the main switch is opened, the control circuit is connected, the components are locked, and three locks can be added.

↑↓Extraction position - the main circuit and the control circuit are disconnected

When the operator pulls out the drawer in the “↑↓” position, the switch handle will automatically jump to the “O isolation position, and the drawer is locked at the position of 30mm to prevent the drawer from being pulled off at one time due to excessive force. Go to the "↑↓" extraction position and you can completely pull out the drawer.

 

 

◎Busbar system

The switchgear can be configured with two sets of main busbars installed in the rear busbar compartment of the switchgear. The two sets of busbars can be installed in the upper or lower part of the cabinet. According to the requirements of the incoming line, the upper and lower sets of busbars can be made of different or the same cross-section materials. Both can be powered separately or in parallel, or as a backup power supply.

The distribution busbar (vertical busbar) is assembled in a flame-retardant plastic function board to prevent arc-induced discharge and prevent human contact, and is connected to the main busbar through a special connecting piece.

There are separate PE protective conductors and N neutral conductors in the cabinet, which run through the entire unit. The neutral busbar N and the protective busbar PE are mounted in parallel at the lower portion of the functional unit compartment and vertically in the cable compartment. The insulator is separated from the N line and the PE line.

 

◎Security system

Each cabinet is provided with a flame-retardant plastic functional partition, which is installed between the main bus room and the functional unit compartment. Its function is to prevent the accident caused by the arcing and busbar short circuit caused by the failure of the switch element, and adopts strict Isolation measures.

The upper and lower drawers are separated by a galvanized metal bottom plate with ventilation holes. The smaller 8A4 and 8E/2 drawers are surrounded by flame-retardant engineering plastic parts, so there is strong insulation between adjacent circuits.

A variety of plastic components are used in the cabinet to support the live parts. These components are halogen-free and have leakage-proof properties.

 

◎Drawer type

Available in five standard sizes, based on 8E (200mm) height

8E4: 4 drawer units in 8E height space.

8E2 assembles 2 drawer units in 8E height space

8E: Assemble 1 drawer unit in 8E height space.

16E: Assemble 1 drawer unit in 16E (400mm) height space.

E24: Assemble 1 drawer unit in 24E (600mm) height space.

The five drawer units can be assembled in a single cabinet or in a mixed assembly. The maximum number of drawer units in a single cabinet is shown in Table 1.

The total height of the functional unit compartment is 72E.

In the same device, the general arrangement of functional units is that the small functional unit is on the upper and the large functional unit is on the lower.

 

 

◎Electrical and mechanical interlocking of drawers

The drawer unit has a reliable mechanical interlock that is controlled by the operating handle and has a clearly accurate closing, test, extraction and isolation position. To enhance safety and security, the operation handle can be positioned with a padlock, and up to three locks can be added.

After the drawer unit is in place, it must strictly follow the operation shape function and its position action. If it is forcibly operated, it will easily damage the structural parts. Please pay attention when using the user.

 

◎Installation, use, maintenance

The dimensions and installation of the device are shown in Figure 3.

When the device arrives at the destination, first check that the package is complete. If the device is not installed immediately, store it in a dry and clean place.

The device is recommended to be installed off-wall and the installation base plane is required to be flat.

After the cable is connected, the bottom of the device should be closed to prevent small animals from climbing into the cabinet and causing a short circuit accident.

After installation or adjustment, the following inspections and tests are required before putting into operation.

(1) Check whether the installed electrical equipment and control wiring are in accordance with the factory drawings.

(2) Manual operation of various switches should be flexible, no abnormalities and stuck.

(3) Check whether the mechanical interlocking mechanism and the electric interlocking device are correct and reliable, and should meet the system requirements.

(4) Check whether the insulation resistance of the main circuit and the control circuit meets the specified requirements.

(5) Check whether the electrical equipment installed in the device is good and meets the technical requirements of the electrical itself.

(6) Check if there is any foreign matter inside the device and whether the mounting screws of each component are loose.

 

◎Withdrawal MCC operation instructions

(1) The bottom of the drawer should be correctly inserted into the guide before it can be pushed into the cabinet. Otherwise, the drawer will be damaged or the drawer will not be pulled out.

(2) The symbol marks and functions on the 8E/4 and 8E/2 drawer panels are shown in Figure 1. The arrows from the breaking position "○" to "|" in the figure are indicated as follows: first push the operating handle inward and then the handle Rotate from "O" to "", you don't need to push when you return, just turn the handle from "" to "○", and let go, the handle will pop up automatically.

(3) The symbol mark and function on the 8E~24E drawer panel are shown in Figure 2. When the handle reaches the working position "|", the mechanism releases the mechanical lock on the main switch. At this time, the main switch can be closed and opened, when the main switch After closing, the handle of the interlock mechanism cannot be operated.

(4) There is a small hole in the lower right corner of the symbol mark. This is the unlocking mechanism of the door. The operation process is as follows: When the drawer is in the working position, if the door is to be opened, use a screwdriver to insert the screwdriver and move the lock downward to open the door.

 

◎Transport and storage of the device

The device is not allowed to pour and suffer from severe vibrations.

When the device is hoisted after unpacking, the transport gusset should be used, and the angle between the two steel ropes is 120°. If a forklift, roller or crowbar is used, it is not allowed to be carried out directly on the undercarriage of the device.