GE’s portfolio of active filters include the GEMActive™ and Maxsine™ filters. They effectively cancel harmonics by dynamically injecting out of phase harmonic current. Installation of the active filters will allow for compliance with IEEE 519 – 1992 recommended harmonic limits. Reduced harmonic levels results in improved electrical network reliability and reduced operating costs. Nuisance tripping of protective devices and nuisance clearing of fuses due to harmonic heating effects is greatly reduced.
Overheating of motors, transformers, switchgear and cables is also reduced which increases their life expectancy and reduces maintenance costs. For new installations, over-sizing of distribution equipment to reduce harmonic susceptibility can be reconsidered.
GE’s active filters reduce current distortion that, in turn, reduces voltage distortion. Unlike passive devices, these filters are easy to install and cannot be overloaded. When required harmonic compensation exceeds capacity, the filters will simply supply its maximum continuously. Multiple units can be connected in parallel to increase compensation.
Closed-loop control allows for high accuracy and self-adaptive harmonic control. GE’s active filters determine the harmonic compensation required by using current transformers to measure the network current. The control logic removes the fundamental frequency component (50 or 60 Hz) from this waveform. The remaining waveform is then inverted and the filter fires its IGBTs to inject this waveform on to the network to compensate for the harmonics. The result is a waveform with greatly reduced harmonic content as seen by the upstream electrical system.