Composition and Function of Incoming Cabinet, Outgoing Cabinet, Metering Cabinet, PT Cabinet and Contact Cabinet

In the complex power system, incoming cabinet, outgoing cabinet, metering cabinet, PT cabinet, contact cabinet and isolation cabinet are like precise gears, working together to ensure the stable transmission and distribution of power. Lets take a closer look at their composition and role.

1. Incoming Cabinet

The incoming line cabinet is generally composed of high voltage disconnecting switch, vacuum circuit breaker, current transformer, voltage transformer, lightning arrester, grounding switch, etc.

For example, the high voltage disconnector is used to provide obvious disconnection points to ensure safety; the vacuum circuit breaker can quickly cut the circuit during failure.

As the entrance to the power system, receive the high voltage power supply, such as 110kV or 35kV power supply, and introduce it into the substation or distribution room.

Protect the input power supply. When short circuit or overcurrent faults occur, the vacuum circuit breaker will trip quickly to prevent the fault from expanding and protect the safety of equipment and personnel.

Through the current transformer and the voltage transformer, the current, voltage and other parameters of the input power supply can be monitored to provide data for the operation monitoring of the power system.

2. Outgoing Cabinet

The outgoing line cabinet mainly includes vacuum circuit breaker, disconnecting switch, current transformer, grounding switch, relay protection device, etc.

Distribution of electricity from the substation or distribution room to each electrical equipment or lower distribution room. For example, providing power to factory production lines, lighting and air-conditioning systems in shopping malls.

Protect the outgoing circuit. When the outgoing circuit fails, the relay protection device acts quickly, trip the vacuum circuit breaker, and cut off the faulty circuit.

Using the current transformer and other equipment, it can monitor the outlet current in real time, so as to find the overload and other abnormal conditions in time.

3. Metering Cabinet

The metering cabinet is usually composed of high-precision voltage transformer, current transformer, multi-functional electric energy meter, etc.

Accurate measurement of electricity consumption is made to provide a basis for the settlement of electricity charges between power supply departments and users. For example, electricity meters record the electricity consumption over a certain period of time.

Voltage transformer and current transformer convert high voltage and high current into low voltage and small current suitable for the measurement of electricity meters, ensuring the accuracy of measurement.

4. PT Cabinet

The PT cabinet is mainly equipped with voltage transformer, fuse, lightning arrester, etc.

Change high voltage to low voltage to provide suitable voltage signal for measuring instrument, relay protection device, etc. For example, the 10kV, voltage to 100V, easy to voltmeter, power meter and other instrument measurement.

Monitor the voltage of the system, and issue an alarm when the voltage is abnormal, to ensure the stable operation of the power system.

5. Contact Cabinet

The contact cabinet is mainly composed of disconnecting switch, circuit breaker, etc.

It is used to connect two segments of bus to realize power switching and mutual backup.

For example, when one section of bus needs to be repaired or faulty, the load can be transferred to another section of bus through the contact cabinet to ensure the continuity of power supply.

In normal operation, the contact cabinet can distribute the power supply reasonably according to the load situation to improve the reliability of the power system.

Practical Application Cases

Assuming a distribution room in a large factory, the incoming cabinet receives 10kV power supply from the superior substation and monitors the parameters of the input power supply through the current transformer and voltage transformer. The outgoing cabinet distributes the electric energy to the electrical equipment of each workshop, such as motor, lighting, etc. The metering cabinet accurately measures the electricity consumption of the plant, so as to settle the electricity charges with the power supply department. The PT cabinet provides the appropriate voltage signal for the factory voltmeter and power meter, and monitors the system voltage. When a workshop of the factory needs to conduct equipment maintenance, the power supply of the workshop can be disconnect through the isolation cabinet to ensure the safety of the staff. If one section of the factory bus fails, the contact cabinet can transfer the load to another section of the bus to ensure the normal production of the factory.

In short, incoming line cabinet, outgoing cabinet, metering cabinet, PT cabinet, contact cabinet and isolation cabinet in the power system, together to provide stable and reliable power supply for our production and life. A deeper understanding of their composition and role will help us to better understand and maintain the power system.