How to prevent film capacitor failure? What should I pay attention to?

In the process of using film capacitors, even high-quality film capacitors will have some minor problems over time. Therefore, understanding the preventive measures for capacitor failures can effectively increase the service life of film capacitors.

1. Abnormal operating conditions should be dealt with in time. If abnormal conditions such as bulging, joint heating, and serious oil leakage (leakage) of the parallel capacitor are found during operation, it must be taken out of operation. Vicious accidents such as fuel injection, fire, explosion, etc. should be carried out immediately for power outage inspection to find out the cause of the accident and deal with it, and then replace with a new capacitor to continue operation.

2. Strictly control the operating voltage. The operating voltage of the parallel capacitor must be strictly controlled within the allowable range. That is, the long-term operating voltage of the parallel capacitor must not be greater than 10% of its rated voltage. Too high operating voltage will greatly shorten the life of the capacitor. As the operating voltage increases, the dielectric loss of the parallel capacitor will increase, which will increase the temperature of the capacitor, accelerate the aging speed of the capacitor insulation, and cause premature aging, breakdown and damage to the insulation in the capacitor. In addition, under the action of excessively high operating voltage, the insulating medium inside the capacitor will undergo local aging. The higher the voltage, the faster the aging and the shorter the life.

3. Install fuse protection. Each single capacitor should be equipped with fuse protection. The rated current of the fuse must not be greater than 1.3 times the rated current of the capacitor to be protected. This can prevent a certain capacitor from failing due to failure. Removal in time caused group explosion accidents.

4. Correctly select the throw (cut) switch and disconnect the parallel capacitor, due to the arc action between the static and moving contacts of the switch, it will cause the operating overvoltage, except that the capacity of the throw (cut) switch should be selected more than the parallel connection In addition to the capacity of the capacitor bank is about 35% larger, it must be a circuit breaker with high insulation recovery strength between contacts, low arc reignition, and good arc extinguishing performance.

5. Control the operating temperature. Under normal circumstances, it is generally required that the temperature of the hottest spot of the shunt capacitor housing should not be greater than 60°C. Otherwise, the cause must be found out and processed.

6. Strengthen patrols, inspections, and maintenance of parallel capacitors should be checked regularly, at least once a quarter, mainly to check whether there is dust and other dirt in the capacitor casing, porcelain bushing, mounting bracket, etc., and clean it carefully . When checking, pay special attention to whether the connection of each connection point is firm and loose; whether the shell is bulging, seeping (leaking) oil, etc. If the above phenomenon is found, the capacitor must be taken out of operation and handled properly.

7. Choose a good film capacitor manufacturer, deal with problems in time, product quality, whether the price is appropriate, etc.