low voltage distribution cabinet product introduction

low-voltage distribution cabinet refers to a complete set of electrical equipment used to receive, distribute, control, protect and monitor electric energy in the ac power system with rated voltage of 1000v or less. it is a key hub connecting transformers and terminal electrical equipment, and is widely used in various fields such as industry, commerce, civil buildings, infrastructure, etc, it can be called the "heart" and "vein" of modern power system ".

i. core functions and functions

1. electric energy distribution: the electric energy from transformer or superior power supply is distributed to each electric power area, floor or specific equipment through different branches.
2. circuit control: through circuit breaker, contactor and other components, the on and off operation of the circuit is realized, which is convenient for equipment start and stop and line maintenance.
3. safety protection: when overload, short circuit, leakage and other faults occur in the circuit, the power supply can be cut off automatically and quickly to protect the lines and equipment from damage and prevent electrical fire and personal electric shock accidents.
4. monitoring and metering: real-time monitoring of power parameters (voltage, current, power, electric energy, etc.) through instruments (such as voltmeter, ammeter, power-factor meter) and intelligent devices, provide data for energy management and fault diagnosis.
5. improve power quality: reactive power compensation is carried out through built-in capacitor banks to improve power factor, reduce line loss and improve power utilization efficiency.

ii. main product classification

according to its structure, use and leading technical standards, low-voltage distribution cabinets are mainly divided into the following categories:

1. fixed distribution cabinet
· features: all electrical components (such as circuit breakers, isolating switch, etc.) in the cabinet are fixed installation, with simple structure, low cost and convenient maintenance.
· application: it is suitable for occasions where the power load is relatively stable, circuit quantity is not much, and frequent operation and replacement are not required, such as light-duty vehicle rooms and power distribution rooms in residential areas.
2. draw-out/drawer type distribution cabinet
features: the main electrical components (such as circuit breakers and contactor) in the cabinet are installed in the drawer that can be extracted. when a circuit fails, the faulty drawer can be quickly pulled out, replaced with a spare drawer, and the power supply can be restored immediately, which has extremely high power supply reliability and flexibility.
· application: widely used in occasions requiring high continuity of power supply, such as data centers, hospitals, large industrial plants, high-rise commercial buildings, etc.
3. intelligent distribution cabinet
features: this is the development direction of modern power distribution system. based on the draw-out or fixed structure, the intelligent power monitoring system is integrated. through communication module (such as modbus, profibus, ethernet), the data of various intelligent instruments and circuit breakers are uploaded to the background monitoring software to realize remote monitoring, data recording, fault warning, energy management and automatic control.
· application: all modern buildings and factories that require intelligent and refined management.

iii. main components

a typical low-voltage distribution cabinet usually consists of the following parts:

· cabinet structure: shell and skeleton, providing protection level (such as ip20 and ip30) to protect internal components from dust, moisture and accidental contact.
· bus system: including horizontal bus and vertical bus, is the conductor that carries and distributes the main current, usually made of copper or aluminum row.
· functional unit:
incoming line unit: main switch, usually frame circuit breaker (acb).
· power distribution unit: each branch circuit usually adopts molded case circuit breaker (mccb) or miniature circuit breaker (mcb).
· compensation unit: reactive power compensation cabinet (capacitor bank).
control unit: control motor and other equipment through contactor, relay, etc.
· protective electrical appliances: circuit breakers, fuses, leakage protector, etc.
measurement and indication unit: current/voltmeter, indicator light, intelligent integrated instrument, etc.
secondary circuit: all connecting wires of control, measurement, signal and protection circuit.
iv. main technical parameters
when selecting low-voltage power distribution cabinets, the following key parameters should be paid attention:
· rated working voltage: such as 400v, 690v.
· rated insulation voltage: for example, 800v.
· rated work current: rated current of main bus, such as 630a, 1000a, 2500a, etc.
· short-term withstand current (icw): the thermal effect value of short-circuit current that can withstand within a specified time (such as 1 second) is the key index to measure the dynamic thermal stability of the cabinet, such as 50ka and 80ka.
· protection level (ip code): for example, ip20 (protection against solid foreign matters greater than 2.5mm) and outdoor ip54 (dustproof and splash-proof).
· overall dimensions: dimensions of height, width, and depth.
v. selection suggestions
1. clear requirements: according to the load nature, power supply reliability requirements, budget and other factors, determine whether to choose fixed or draw-out type and whether intelligent functions are needed.
2. calculation parameters: the load calculation and short-circuit current calculation are carried out by professional electrical engineers to determine the required key parameters such as rated current and breaking capacity.
3. select brands and models: within the budget, give priority to brands with good reputation, stable quality and guaranteed after-sales service.
4. consider scalability: reserve some space and margin for possible future capacity expansion.
vi. summary
low voltage distribution cabinet is an indispensable basic electrical equipment in modern society. from lighting up the electric meter box of a room to the huge power distribution center that drives a factory to run, it has its shadow. choosing a set of low-voltage distribution system with reasonable design, reliable quality and stable operation is the basis for ensuring safe production, improving energy efficiency and realizing intelligent management.