Harmonic studies are performed to determine harmonic distortion levels and filtering requirements within a facility. Field measurements and computer simulations are used to characterize variable frequency drives (VFDs) and other nonlinear loads and simulations are then performed to determine the filter specifications and effectiveness. The installation of Passive or Active Harmonic filters will significantly alter the frequency response of the power system. An evaluation of the harmonic voltage and current limits, (e.g., IEEE Std. 519) is completed to determine the effectiveness of the proposed filter installation.
The potential for harmonic distortion problems is dependent on two important factors:
The combination of these two factors determines whether or not a harmonic problem will exist at a particular bus. It is also possible for harmonic problems to occur at buses remote from the harmonic source if local resonances exist. If capacitors are applied at any locations that have large variable frequency drives, the potential for resonance problems must be considered carefully.
A harmonic study evaluates these concerns.
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