The function of high-voltage switchgear cabinets

The high-voltage switchgear compartment divides the main electrical circuit into several units. And the circuit breakers, disconnectors, current transformers, voltage transformers, as well as protection, control and measurement equipment of each unit are centrally assembled in a single integrated cabinet!
According to the requirements of the electrical wiring diagram, when selecting the required functional units, there are multiple functional units. In power plants and substations, the distribution devices formed after installation are called high-voltage complete distribution devices.
High-voltage complete power distribution equipment can be classified into metal enclosed type, metal enclosed armored type, metal enclosed box type and sulfur hexafluoride enclosed combined type according to their structural characteristics.
According to the installation method of circuit breakers, they can be classified as fixed type and drawer type.
It can be classified as outdoor type or indoor type according to the installation location.
It can be classified according to the rated working voltage. There are high-voltage complete distribution equipment and low-voltage complete distribution equipment.
All current high-voltage switchgear assemblies and high-voltage switch cabinets now possess the five-prevention interlock function! This function prevents incorrect tripping or closing of circuit breakers, incorrect pulling or closing of disconnectors with load, incorrect hanging of grounding wires or closing of grounding switches while live, incorrect closing of circuit breakers with grounding wires, and prevention of entering live compartments. The five-prevention interlock function is typically achieved through mandatory mechanical locking mechanisms between circuit breakers, disconnectors, grounding switches, and the cabinet doors. Alternatively, it can be realized through electromagnetic locking mechanisms.
The function and requirements of a circuit breaker are that it must have sufficient operating power, high reliability, rapid operation during opening and closing, and also a free-tripping device.
The inspection of the circuit breaker includes the positions of opening and closing. It should be consistent with the actual operating conditions at that time! Check that the supporting insulator has no cracks or discharge sounds, the support plate, and the cleanliness of the insulator. The grounding of the circuit breaker is in good condition, there is no overheating at the connection parts of the leads, and the sag of the leads is appropriate.
Abnormal operation of circuit breakers and their handling. If any abnormal phenomenon occurs during the operation of the circuit breaker, the on-duty personnel should promptly eliminate it. If it cannot be eliminated in time, it should be reported to the superior leaders and recorded accordingly in the operation log and the equipment defect log.
If the on-duty personnel discover any defect in the equipment that endangers the safe operation of the power grid and cannot be eliminated without power-off, they should promptly report to the superior leaders, and at the same time, inform the power supply department and the dispatching department and apply for power-off for handling.
The bushing has severe damage and discharge phenomenon, the SF6 gas is severely leaking, an operation lockout signal is issued. The three vacuum circuit breakers are making crackling sounds indicating vacuum damage and cannot be reliably closed. After closing, there is a noise. The closing core does not return to the initial position and the closing trip device is stuck. The circuit breaker operates, after tripping, the on-duty personnel should record the time when the fault occurred and immediately conduct accident and special inspections. Determine whether there is any fault in the circuit breaker itself. If the circuit breaker malfunctions during the fault trip, even if the power supply is successful or not, a detailed inspection of the circuit breaker’s appearance should be carried out. When the circuit breaker malfunctions during the fault trip, it should be isolated from the system and kept in its original state before restoring the power supply to the system and re-energizing. Only after the cause of the action and the defect are identified and eliminated can the circuit breaker be put back into operation.