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Precautions for safe operation of capacitors

The safe operation of capacitors is a problem that every technician must pay attention to. The problems encountered in the operation can not be handled blindly by technicians. Learning the corresponding processing methods and steps can avoid many problems. Let’s take a look at the precautions for safe operation of capacitors.

Under normal circumstances, the parallel capacitor should be put into or out according to the power factor of the line and the voltage level. When the power factor is lower than 0.9 and the voltage is low, it should be put into the capacitor bank; when the power factor approaches 1 and there is a trend, the capacitor group should be exited when the voltage is high.

When the operating parameters are abnormal and exceed the operating conditions of the capacitor, the capacitor bank should be exited. If the three-phase current of the capacitor is significantly unbalanced, it should also be out of operation.

The file found that the capacitor connection point was severely overheated or even melted, the porcelain casing was severely flashed and discharged, the casing was seriously expanded and deformed, and the capacitor or its discharge device issued a serious abnormal noise, and should be withdrawn from operation.
The precautions for safe operation of capacitors are as follows:

1. Under normal circumstances, when the whole station is powered off, first open the switch of the capacitor, then pull the switch out of each way; under normal circumstances, when the whole station resumes power transmission, first close the switch that appears in each way, and then close Switch on the capacitor line.

2. After the power failure of the whole station, the switch of the capacitor should be opened.

3. After the capacitor circuit breaker trips, it must not be forced to send power; after the fuse is blown, the fuse cannot be replaced before the cause is found.

4. Whether it is a high voltage capacitor or a low voltage capacitor, it is not allowed to brake with residual charge. Otherwise, a large current surge may occur. Discharge at least 3 minutes before the capacitor is reclosed.

5. For inspection and repair needs, after the capacitor is disconnected from the power supply, the worker must use a special discharge load that can be manually discharged before the worker approaches, regardless of whether the capacitor is equipped with a discharge device.

When the total capacity of the high-voltage capacitor bank does not exceed 100kvar, it can be protected and controlled by the downtime fuse; when the total capacity is 100~300kvar, the load switch protection and control should be adopted; when the total capacity is 300kvar, the vacuum circuit breaker or open circuit should be used. Protection and control.

When the total number of low-voltage capacitor banks does not exceed 100kvar, AC contactor, knife switch, fuse or knife fuse switch can be used for protection and control; when the total capacity is above 100kvar, low-voltage circuit breaker protection and control should be adopted.


Post time: Aug-27-2018
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