A brief introduction: distribution cabinet details, as well as a variety of applications

Switch cabinet:

A complete set of power distribution device assembled from primary equipment and secondary equipment according to a certain line scheme is used to control and protect lines and equipment. It can be divided into fixed type and manual type, and can be divided into high voltage switchgear (fixed type and manual type) and low voltage switchgear (fixed type and drawer type) according to the incoming and outgoing line voltage level. The structure of the switchgear is generally similar, mainly divided into bus room, circuit breaker room, secondary control room (instrument room), feeder room, and there is generally steel plate isolation between the rooms.

Internal components include: bus (bus bar), circuit breaker, conventional relay, integrated relay protection device, metering instrument, isolation knife, indicator light, grounding knife, etc.

Divided from the perspective of application

1. Incoming cabinet:

Also known as the receiving cabinet, is used to receive electrical energy from the power grid equipment (from the incoming line to the bus), generally installed with circuit breakers, CT, PT, isolation knife and other components. The outlet cabinet is also called the feed cabinet or distribution cabinet, which is used to distribute electrical energy equipment (from the bus to each outlet), and is generally installed with circuit breakers, CT, PT, isolation knife and other components.

2. Bus liaison cabinet

Also known as the bus breaking cabinet, is used to connect two sections of the bus equipment (from the bus to the bus), in the single bus segment, the double bus system is often used in the bus connection to meet the requirements of users to choose different operating modes or to ensure that there is a choice of cutting load in the case of failure. The PT cabinet voltage transformer cabinet is generally installed directly on the bus to detect the bus voltage and realize the protection function. Inside the main installation of voltage transformer PT, isolation knife, fuse and lightning arrester.

3. Isolation cabinet

It is used to isolate the bus at both ends or to isolate the power receiving equipment and the power supply equipment, and it can provide the operator with a visible endpoint to facilitate maintenance and overhaul operations. Since the isolation cabinet does not have the ability to break and switch on 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 circuit breaker auxiliary contact and the isolation of the interlock, to prevent the operator's misoperation.

4. Capacitor cabinet

Also known as the compensation cabinet, is used to improve the power factor of the power grid, or for reactive power compensation, the main device is a group of parallel capacitor banks, switching control circuits and fuses and other protective appliances. It is generally installed side-by-side with the incoming cabinet, and one or more capacitor cabinets can be run side-by-side. After the capacitor cabinet is disconnected from the power grid, because the capacitor bank takes a period of time to complete the discharge process, it is not possible to touch the components in the cabinet directly by hand, especially the capacitor bank; Within a certain period of time after power failure (depending on the capacity of the capacitor bank, such as 1 minute), it is not allowed to re-close, so as to avoid overvoltage damage to the capacitor. When performing the automatic control function, it is also necessary to pay attention to the reasonable allocation of the switching times of each group of capacitor banks, so as to avoid the situation that one group of capacitors is damaged while the other groups are rarely switched.

5. Measuring cabinet

It is mainly used for measuring electricity (KWH), and there are high and low voltage points, generally installed with isolation switches, fuses, CT, PT, active power meters (traditional meters or digital meters), reactive power meters, relays, and some other auxiliary secondary equipment (such as load monitoring meters).

6. GIS cabinet

Also known as the closed combination electrical cabinet, it is the circuit breaker, isolation switch, ground switch, CT, PT, arrester, bus and other closed combination in the metal shell, and then with good insulation performance and arc extinguishing performance of the gas (generally with sulfur hexafluoride SF6) as the phase and ground insulation measures, suitable for high voltage grade and high capacity grade power grid. Used for distribution and control.