This is wrong solution to the problem that may cause damage.
Originally Posted by ptonsparky
The problem that you mean is harmonics. When you have harmonics (such as from VFDs), at certain point the the capacitor reactance (1/impedance) will be the same in negative sign as the transformer's. The result is that the capacitor and transformer branch impedance is infinity. The harmonic distortion, which acts as current source, goes on the infinity impedance to create infinity voltage (in theory, in real life it is no infinity). This cause the voltage to increase and the capacitors to blow up. If you use higher rated capacitors, that can withstand the higher voltage, the next component to go is the transformer itself. In the better case, it belongs to the POCO and you will only have long downtime. In the other case, you have to buy a new one.
In such cases, or to my recommendation in any case of using capacitors, use detuned reactors to prevent this issue.
Last edited by iwire; 04-25-10 at 06:39 AM.
Reason: removed link
Certified engineer, PowerQualityDoctor