What is the upper limit of operating temperature for power filter capacitors?

As a common reactive power compensation device, power filter capacitors are easily affected by various factors in practical use, among which temperature factors have a significant impact on the service life and operating status of capacitors.

Now the question is, what is the maximum temperature allowed for the operation of power filter capacitors? How should we view the temperature range? Come and learn!

What is the impact of temperature on power filter capacitors?

Under normal circumstances, the higher the operating temperature and ambient temperature of power filter capacitors, the shorter their service life will be. If the temperature rise of the capacitor is fast, it may directly shorten the lifespan of the capacitor by half for every 8 ℃ rise.

There are many factors that can cause the operating temperature of power capacitors to be too high, such as environmental temperature exceeding the allowable range, long-term overvoltage and overcurrent operation, ignoring system harmonics, etc., which need to be noted and avoided.

Operating temperature range of capacitors

Ensuring that power filter capacitors operate at the specified ambient temperature can effectively reduce equipment failure rates and extend the actual service life of capacitors. So, how should we view the allowable operating temperature specified for each capacitor?

In fact, the nameplate of each power capacitor will indicate that the four letters A, B, C, and D are usually used to represent the maximum operating temperature, and the four letters represent the maximum operating temperature separated from the minimum allowable operating temperature. As shown in the figure, the allowable operating temperature range for capacitors is -25 ℃~40 ℃.

The letters represent temperature:

A=40℃

B=45℃

C=50℃

D=55℃

If the capacitor operates within the allowable temperature range for a long time, its actual service life can reach more than 10 years; If the actual operating temperature of the capacitor remains around the limit value for a long time, it may directly cause the capacitor to fail to function properly.

Therefore, when using power filter capacitors, it is best for enterprises to monitor their operating temperature and ambient temperature in real time. If approaching the limit value, certain ventilation and cooling measures must be taken, or the relevant capacitors must be directly removed.