Active filters are used to mitigate harmonics and balance 3-phases and neutral current with result of :Unloading lighting equipment from harmonics and thus increasing equipment lifetime. Unload the neutral wire from Heavy Harmonic Current. Harmonic Current in the neutral cause heavy heating & overloading of the euipment.
Harmonic Filter
Harmonic is defined component of periodic wave whose frequency is integral multiple of the fundamental frequency. Non liner load such as rectifier, inverter, variable speed drive, furnaces create harmonics.