Filters
of harmonics
liabilities
Passive harmonic filters for variable speed drives Inomaxtech
Passive harmonic filters are commonly used at the input of electric motor drive systems operated with IGBT-based variable speed drives. Its purpose is to mitigate the amount of harmonic distortion produced by the variable speed drive (VSD/VFD).
If this harmonic distortion is not addressed, it can further distort the power grid or cause damage to nearby equipment. The IEEE-519 standard establishes a voltage and current distortion limit below 5% for electrical systems. In different industries and establishments with high usage of electronic equipment, mains voltage distortion is becoming an increasing problem. Grid voltage distortion levels have become so bad in these areas that utility providers have begun to measure the amount of distortion coming from variable speed drives. If the measured harmonic levels do not meet the utilities' standard, they will issue a fine or cut off the power supply to the site.
Effects of harmonics
1,The possibility of amplification of some harmonics as a consequence of series and parallel resonance.
2, The reduction in the efficiency of energy generation, transportation and utilization systems.
3, The aging of the insulation of the network components and, as a consequence, the reduction of power
4, Distortion of electronic measuring and control elements such as instrumentation or medical equipment
But, what are harmonics in electrical networks?
Non-linear loads such as: rectificators, inverters, variable speed drives, furnaces, etc; absorb non-sinusoidal periodic currents from the network. These currents are formed by a fundamental component of frequency 50 or 60 Hz, plus a series of superimposed currents of frequencies, multiples of the fundamental, which we call ELECTRICAL HARMONICS, which generate significant technical and economic costs. The result is a deformation of the current, and as a consequence of the stress, it leads to a number of associated side effects.
