Harmonics Mitigation

What’s Harmonics?

A pure sinusoidal voltage is a conceptual quantity produced by an ideal AC generator built with finely distributed stator and field windings which function in a uniform magnetic field. Winding distribution and magnetic field both are variable in a working AC time relationship deviates from the ideal sinewave function.

The distortion at the point of generation is very small (about 1% to 2%), but nonetheless it exists. Because this is a deviation from a pure sinewave, the deviation is in the form of a periodic function, and by definition, the voltage distortion contains harmonics.

Major Equipment that gets affected due to System Harmonics

  • Electric Motors
  • Transformers
  • Capacitor Banks
  • Cables
  • Neutral

Cause of Harmonics:

Due to continuous increase of non-linear load, electrical system gets polluted due to increase of harmonics level. This will become one of the leading reasons for system premature failure. Second nuisance relay tripping will also lead to output loss.So, this is important to do the timely study of system harmonics level to avoid such intangible losses.

Equipment’s that may be responsible to generate system harmonics are

  • Variable Frequency Drive (VFD)
  • UPS
  • SMPS
  • LED Lights
  • Electronic Ballast

Adverse impact of harmonics over system

  • Malfunctioning activity of sensitive electronics
  • Premature aging of electronic equipment’s
  • Nuisance tripping of relay and circuit breakers
  • Failure of capacitor bank
  • Puncture of electrical cables due temperature rise
  • Burning of motor rotor winding

How to get rid of System Harmonics?

First, we have to know the existing system harmonics and for that we have do the assessment study. If the system harmonics limits are as per prescribed IEEE-519 then no need to worry.

Harmonics Mitigation Solution :

  1. Active Harmonics Filter(AHF)
  2. Passive harmonics Filter(PHF)

Benefits Of Harmonics Removal

  1. AHF/PHF minimize the harmonics in the electrical system & improve the power flow quality.
  2. Harmonics filters improve energy efficiency that increase the asset life.
  3. Filters helps to make optimum utilization of supply.
  4. It also helps in reduction in maintenance amount.
  5. It improves the power factor.
  6. AHF helps to optimize the power bills.
  7. Filter helps to maintain the system health and also improve aging of system.
  8. Harmonic filter also helps to avoid the additional APFC panel cost.
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