Classification of switchgears

From an application point of view, the switchgear can be divided as follows:

1. Incoming line cabinet: also called power receiving cabinet, it is the equipment used to receive electrical energy from the power grid (from the incoming line to the bus). Generally, components such as circuit breaker, ct, pt, isolating knife, etc. are installed.

2. Outgoing cabinet: also called feeder cabinet or equipment used to distribute electric energy (from the bus to each outgoing line). Generally, components such as circuit breaker, ct, pt, isolating knife, etc. are also installed.

3. Busbar connection cabinet: also called busbar breaking cabinet, it is used to connect two sections of busbar equipment (from busbar to busbar). Bus connection is often used in single-bus section and double-bus system to meet the user's requirements for selecting different operating modes or to ensure selective load removal in the event of a fault.

4. pt cabinet: voltage cabinet, which is generally installed directly on the bus to detect the bus voltage and realize the protection function. Mainly install pt, isolating knife, fuse and arrester inside.

5. Isolation cabinet: It is used to isolate the busbars at both ends or to isolate the power receiving equipment from the power supply equipment. It can provide a visible end point for the operator to facilitate maintenance and repair 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 or pulled when the circuit breaker matched with it is closed. In general applications, it is necessary to set the interlock between the auxiliary contact of the circuit breaker and the isolated handcart to prevent misoperation by the operator.

6. Device cabinet: also called compensation cabinet, which is used to improve the power factor of the power grid, or for reactive power compensation. The main components are protective electrical appliances such as groups connected in parallel, switching control loops and fuses. Generally installed in parallel with the incoming cabinet, one or more capacitor cabinets can be operated in parallel.

After the capacitor cabinet is disconnected from the power grid, since the capacitor bank needs a period of time to complete the discharge process, it is not possible to directly touch the components in the cabinet, especially the capacitor bank. Within a certain period of time after the power is cut off (depending on the capacity of the capacitor bank, such as 1 minute), re-closing is not allowed to avoid damage to the capacitor due to overvoltage. When performing automatic control functions, 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 on and off.

7. Metering cabinet: It is mainly used for metering electric energy (kWh), and it is divided into high voltage and low voltage. Generally, isolation switches, fuses, ct, pt, active watt-hour meters (traditional meters or digital meters), reactive watt-hour meters, relays, and some other auxiliary secondary equipment (such as load monitors, etc.) are installed.

8.gis cabinet: also known as closed combined electrical cabinet. It is a closed combination of circuit breaker, isolating switch, grounding switch, ct, pt, arrester, bus bar, etc. in a metal shell, and then use a gas with good insulation and arc extinguishing performance (usually sulfur hexafluoride sf6) as the interphase and Insulation measures to ground. It is suitable for high-voltage and high-capacity power grids for power distribution and control.