Detuned Capacitor Banks or LC Passive Filters?

[Anonymous user]

Please help me to correctly define the following statements:

1. When we speak of detuned capacitor banks, I understand that we refer to banks of capacitors with reactors at the input, such that the "LC set" makes the system's resonance frequency move to values smaller than the harmonics present.

2. When we speak of LC passive filter tuned to a certain frequency, I understand that we refer to an LC filter designed so that it does not pass the components of that frequency.

Thanks in advance.

[sesa90709 · Accepted solution]

 Hi , 

 your are right  in caps banck with DR , the goal of DR is to block harmonic current circulation so  the LC is set to be below the lowest harmonic rank  (generally the H5 in industrial application). it is why we propose  in our components catalogue DR at 210Hz , 190Hz or 135Hz 

While in passive filter the goal is exactly the reverse . The LC is set on the 250Hz  (for a passive filter H5) in order to "attract" all harmonics current from one non linear laod and avoid that this harmonics in current create voltage distorsion due to source impedance. Passive filter is normally reserved for devices solution ( eg 1 passive filter for 1 non linear load)   This is not recommend to installed passive filter at system level. 

Thierry Bravais System Expert Power Quality