Please teach: how to determine the automatic reactive power compensation capacitor capacitance low value should be changed, there is no requirement below how much should be changed?

There are many ways to judge, the following gives you a brief introduction to a few:

1, capacitance measurement method: the use of capacitance meter measurement, the measured capacitance and rated value comparison, the general allowable error range of +5% ~ -10%

2, power flow measurement method: the use of a clamp meter to measure the capacitor's output current (it is best to use a harmonic analysis of the function of the clamp meter) and then compared with the rated current. Rated current comparison, this way the error is larger, the general allowable current error of 10% ~ -10%

3., empirical comparison method, for stable loads can be determined by the number of segments into the capacitor. If the number of segments increases, it indicates that the capacitor may have decayed. (This method does not have the standard of judgment)

For the attenuation of the capacitor should be replaced in a timely manner, otherwise it will cause harmonic amplification, resonance may occur, thus affecting the stable operation of the system.