MNS type low-voltage withdrawable complete switchgear

MNS type low-voltage withdrawable switchgear (hereinafter referred to as switchgear) is currently one of the more advanced low-voltage withdrawable switchgear equipment in China. This product is used in three-phase AC frequency 50Hz, rated insulation voltage and working voltage 380 (400) V.660V, rated current 5000A and below for power supply systems. It can be used in power plants, substations, industrial and mining enterprises, buildings, hotels, airports, docks, and broadcasting and television communication centers to control power generation, transmission and distribution, energy conversion, and energy consumption equipment, and to compensate for reactive power on its main busbar through capacitor compensation cabinets.

Model meaning

① Standard module type

② Low pressure

③ Switching and distribution equipment

Usage environment

● The ambient air temperature shall not exceed+40C, not be lower than -5C, and its average temperature shall not exceed+35C within 24 hours.

● Atmospheric conditions, clean air, and relative humidity not exceeding 50% at maximum temperature of+40C. Higher relative humidity is allowed at lower temperatures, such as 90% at+20C. However, temperature changes should be taken into consideration as there may be occasional moderate condensation.

● This device is suitable for transportation and storage processes at temperatures ranging from -25 ° C to+55 ° C, and can reach+70 ° C in a short period of time (not exceeding 24 hours). Under these extreme temperatures, the device should not suffer any irreparable damage and should be able to function normally under normal conditions.

● If the above usage conditions cannot be met, it should be resolved through negotiation between the user and the manufacturer.

● When this device is used on offshore oil drilling and production platforms and nuclear power plants, a separate technical agreement should be signed.

Product features

The MNS system adopts an advanced framework structure design, mature technology, compact structure, flexible assembly, and can form standard units for protection, operation, conversion, control, adjustment, measurement, indication, etc. It has a high degree of flexibility, and drawers can also be exchanged with each other. Its structural design can meet the requirements of various inlet and outlet schemes, including upper inlet and outlet, upper inlet and outlet, lower inlet and outlet, and lower inlet and outlet. Different standard components can be installed inside the cabinet to meet various usage requirements. The entire system adopts a combination optimization design, with strong universality, high standardization, convenient maintenance, and safe and reliable operation.

technical parameter

Bus system

The switchgear can be equipped with two sets of main busbars, installed in the rear busbar compartment of the switchgear. Two sets of busbars can be distinguished and installed in the upper or lower part behind the cabinet. According to the needs of the incoming line, the upper and lower sets of busbars can be made of different or the same cross-sectional materials. Both can be powered separately, in parallel, or as backup power sources.

The distribution busbar (vertical busbar) is assembled in a flame-retardant plastic functional board, which can prevent discharge caused by arcs and prevent human contact. It is connected to the main busbar through special connectors.

There is an independent PE grounding system and N neutral conductor inside the cabinet, which run through the entire device and are installed at the bottom and right side of the cabinet. Each circuit grounding or neutral connection can be connected nearby. The installation of the entire busbar system is shown in Figure 1. All frame structural components are connected with self tapping screws, which has high grounding reliability. The neutral busbar and neutral protection busbar are installed parallel to the lower part of the functional unit compartment and vertically in the cable compartment. If the N line and PE line are separated by insulators, the N line and PE line are used separately. If the two are short circuited with conductors, they form PEN lines.

Protective grounding system

The protection circuit of the device consists of two parts: a separately installed PE wire (or PEN wire) that runs through the entire length of the arrangement and a conductive structural component.

The metal structural components in the device, except for the exterior doors and sealing plates, are all galvanized. At the connection points of the structural components, they are carefully designed to withstand a certain short-circuit current.

Security protection system

Each cabinet is equipped with one or a group of flame-retardant plastic functional boards, installed between the main busbar room and the electrical room. Their function is to effectively prevent accidents caused by arcing and short circuits between the switch components and the busbar due to faults, and strict isolation measures are taken.

There is a galvanized metal bottom plate with ventilation holes between the upper and lower drawers for isolation. The smaller 8E/4 and 8E/2 drawers are surrounded by flame-retardant engineering plastic parts, so there is a strong insulation isolation effect between adjacent circuits. Multiple plastic components are used inside the cabinet to support the live parts. These components are required to be halogen-free and have CTI300 or higher anti leakage performance.