Preventive measures for Fault of Capacitor(II)

Strictly control operating voltage

The operating voltage of shunt capacitor must be strictly controlled within the allowable range. That is, the long-term operating voltage of shunt capacitor must not be greater than its rated voltage value of 10.If the operating voltage is too high, it will greatly shorten the service life of the capacitor.With the increase of operating voltage, the dielectric loss of shunt capacitor will increase, which will increase the temperature of capacitor, accelerate the aging speed of capacitor insulation, and cause premature aging and breakdown of internal insulation of capacitor. In addition, under the effect of too high operating voltage, the insulation inside the capacitor will age internally, the higher the voltage is , the faster it ages and the shorter the life is.

If the long-term operating voltage of shunt capacitor is higher than 20 of its rated voltage, the service life of shunt capacitor will be about 0.3 times that of normal condition.

Therefore, the rated voltage should be reasonably selected according to the actual situation of the local power grid operation voltage, so that the long-term operating voltage should not be greater than 1.1 times of the rated voltage value of the capacitor. Of course, the actual operating voltage is too low, because the output of the shunt capacitor reactive power is directly proportional to the square of its operating voltage.If the operating voltage is too low, the reactive power output of the capacitor will be reduced, and the task of reactive power compensation will not be completed. Therefore, in actual operation, we must try to make the operating voltage of shunt capacitor keep at 95 and 105 of its rated voltage for a long time, the maximum operating voltage must not be greater than 110% of its rated voltage.