The Main Components And Functions Of Low-voltage Distribution Cabinets

First, the main components of low-voltage distribution cabinet

The low-voltage distribution cabinet is mainly composed of incoming cabinet, outgoing cabinet, capacitor cabinet, and metering cabinet.

Incoming cabinet: Also called power receiving cabinet, it is a device used to receive electrical energy from the power grid (from the incoming line to the busbar). Generally, it is equipped with circuit breakers, CT, PT, isolating knives and other components.

Outlet cabinet: Also called feeder cabinet or power distribution cabinet, it is a device used to distribute electrical energy (from the busbar to each outgoing line). Generally it is also equipped with components such as circuit breakers, CT, PT, isolating knives.

Bus contact cabinet: Also called bus break cabinet, it is a device used to connect two sections of bus (from bus to bus). Bus connection is often used in single-bus segmented and double-bus systems to meet users' choice of different operating modes The requirements or guarantee the selective removal of load in the event of a fault.

PT cabinet: Voltage transformer cabinet is usually installed directly on the bus to detect the voltage of the bus and realize the protection function. Inside are mainly installed voltage transformers PT, isolation knives, fuses and arresters.

Isolation cabinet: It is used to isolate the bus bars at both ends or to isolate the power receiving equipment from the power supply equipment. It can provide a visible endpoint for the operator to facilitate maintenance and repair operations. Because the isolation cabinet does not have the ability to interrupt and connect the load current, the handcart of the isolation cabinet cannot be pushed and pulled when the circuit breaker matched with it is closed. In general applications, it is necessary to set the interlock of the auxiliary contact of the circuit breaker and the isolated handcart to prevent misoperation by the operating personnel.

Capacitor cabinet: It is also called compensation cabinet. It is used to improve the power factor of the power grid, or reactive power compensation. The main components are parallel capacitor groups, switching control loops and fuses. With electrical appliances. It is generally installed in parallel with the incoming cabinet, and one or more capacitor cabinets can be operated in parallel. After the capacitor cabinet is disconnected from the power grid, because the capacitor bank needs a period of time to complete the discharge process, you cannot directly touch the components inside the cabinet, especially the capacitor bank; within a certain time after power failure (according to the capacitor bank Depends on the size of the capacitor, such as: 1 minute), re-closing is not allowed to avoid over-voltage damage to the capacitor. When doing the automatic control function, we should also pay attention to the reasonable allocation of the switching times of each group of capacitor banks to avoid damage to one group of capacitors, while other groups rarely switch.

Metering cabinet: It is mainly used for measuring electrical energy (kWh), and it is divided into high voltage and low voltage. It is generally installed with isolation switch, fuse, CT, PT, active watt-hour meter (traditional meter or digital electric meter), Power meters, relays, and some other auxiliary secondary equipment (such as load monitors, etc.).

Second, the role of low-voltage distribution cabinet

The low-voltage power distribution cabinet has a rated current of 50Hz AC and a rated voltage of 380v. The main function is to distribute power and distribute the voltage across the transformer to each power unit for power and lighting distribution in the low-voltage power distribution system. Use. The product has strong breaking ability, good dynamic and thermal stability, flexible electrical scheme, convenient combination, strong series and practicality, and novel structure.

1.Easy to configure power reasonably

2. When the line fails, it is helpful to control the fault range and it is convenient to quickly find the fault point and eliminate it in time.

3. It is convenient for arranging the line for maintenance without fragmentation.

4. Various protection devices such as fuses (fuses) to prevent short circuit, air switches to prevent overload, etc. are conveniently placed in the distribution cabinet.