In power supply systems based on alternating current (AC) – such as the main power distribution network from electric utilities – non-linear loads can feed some amount of power back into the wiring. This feedback typically occurs in the form of harmonics: multiples of the frequency of the original AC wave. Harmonics need to be eliminated from a power circuit by a harmonic filter to prevent them from causing voltage distortions and excessive currents in grounding connections. A harmonic filter consists of a power capacitor connected in series with a tuning reactor, with both of them placed between the power line and ground. The parameters for a harmonic filter depend on the electrical circuit in which harmonic elimination needs to happen. PAActual = arccos(PF) PADesired = arccos(0.97) KVAR = LD x (tan(PAActual) - tan(PADesired)) C = KVAR / ((KV)^2 x 2 x Pi x F x 0.001) Replace KV by the power line’s voltage in kilovolts, and F by the power line’s frequency in Hertz. X = 1 / (2 x Pi x F x C) Writer Bio
