Do you know how to maintain vacuum circuit breakers?

Vacuum circuit breaker maintenance is very important, it is to ensure the service life of the circuit breaker and the key to long-term stable operation, maintenance mainly includes daily inspection, regular maintenance, troubleshooting and special site management. Please follow the maintenance points:

• Appearance inspection

Check the vacuum circuit breaker body can not have the phenomenon of abnormal noise, burnt smell or discharge, the interrupter room vase can not have cracks or oxidation discoloration.

Observe that the contact cover has no cracks, the contact is in good contact condition, and the over-travel indicator shows normal.

Connection and fasteners

Confirm that there is no heat or discoloration at the connection between the vacuum circuit breaker and busbar, and that the connection bolts are tightened without loosening.

Check all fixing bolts, transmission cylinders and other moving parts and apply lubricant if necessary.

• Maintenance of operating mechanism

Check whether the spring energy storage mechanism is in the state of energy storage, and the opening and closing indication is consistent with the actual operation.

The rotating part should be flexible and free of jams, and the parts with serious wear should be replaced in time.

• Cleaning and insulation maintenance

Regularly clean the internal vacuum circuit breaker and conductive part of the dust, use a dry cloth dipped in alcohol to wipe the insulating parts, to avoid the insulation degradation caused by water washing.

It needs to be tested to replace the desiccant in the nonlinear resistor bottle to ensure it is sealed.

• Component Replacement and Inspection

Detect the main contact reset spring, non-linear resistor sheet and other key components, and replace them in time when abnormal.

When the operating mechanism is seriously worn (e.g., spring jamming), it needs to be adjusted or replaced.

Calibration of performance parameters

Regularly measure the contact resistance of movable and static contacts (≤80μΩ), and mechanical parameters such as opening and closing speeds and simultaneity should meet the requirements of the manual.

When the operating environment is poor (e.g. wet, dusty), shorten the inspection period to 1/5 of the mechanical life; when operating frequently, the interval between two inspections should not be more than 1/5 of the mechanical life.

Temporary maintenance requires stopping operation, and insulation test and mechanical test after repair.

• Troubleshooting

When poor insulation and discharges are found, work needs to be stopped immediately for repairs.

After the short-circuit fault current exceeds the specified number of times (e.g. 20 times 20kA), the vacuum insulation unit (VI) needs to be replaced.

Operation times ≤ 20,000 times (below 31.5kA) : Routine inspection once a year.

Close to the mechanical life: Shorten the inspection cycle to 1/5 of the mechanical life.

Harsh operating environment: Take the lower limit of the maintenance cycle.

Replacement of some parts (such as the arc extinguishing chamber) requires professional qualifications and equipment.

Regularly record the maintenance situation and establish equipment files.

Through the above systematic maintenance measures, the service life of vacuum circuit breaker can be effectively extended to ensure the stable operation of the power system.