SOFIA Voltage-Controlled Harmonic Filter

Classic harmonic filters are based on the series connection of a capacitor and an inductor. The circuit has a fixed tuning frequency at which the filter has its lowest impedance and thus the greatest suction. Failure to optimally design such a system will result in high losses and thus unnecessary costs for energy and possibly cooling measures.

SOFIA® on the other hand is an actively controlled harmonic filter with automatic impedance control. For this purpose, the device has several capacitors that are automatically switched on and off depending on the harmonic level. This allows the tuning frequency to be varied and the filter current to be kept almost constant over a wide range.

However, not only changes in the harmonic level can be taken into account by switching the stages, but also changes in the mains frequency as well as age- and temperature-dependent changes in the installed capacitors. This increases the service life of the device and saves costly measures to adapt to the new conditions in the network.

SOFIA® already saves costs during the planning stage, as individual design is not necessary. The device is immediately ready for use and reacts independently to changes in the system. SOFIA® is voltage-controlled, therefore no on-site current transformers are required and the function is also guaranteed in meshed networks with harmonic generators distributed over the entire network.