Problems Caused By Harmonics In Electrical Plants
Linear & Non-linear loads
Harmonics are not available in an electrical system having linear elements fed by a source having
purse sinusoidal wave shape at fixed amplitude and frequency. However, non-linear loads such as
power electronic elements increasing parallel to advanced technology withdraw harmonic currents
over the source and pollute the source. Electrical systems with intense harmonics experience
various problems arising from harmonics.
Problems generally caused by the wave shape distortion are;
 Source voltage wave shape distortion
 Efficiency loss in transmission and distribution depending on RMS current increase on
lines
 Failures in compensation systems
 Overheating in electrical engines and transformers
 Difficulties insulation levels of equipment’s
 Increased losses in the system
 Having faulty works in protection and control systems
Condensers:
 linear circuit elements
 condensers in a system having distortion loads, harmonic currents and harmonic voltages
are considerable affected from harmonics.
 Frequency
Engine and Generators
 Overheating
 Copper losses increase due to harmonic currents and iron losses increase due to harmonic
voltages
 cause noisy and vibrated operation of the machine
Transformers
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Increased frequency shall cause increased loss (PI controller)
Harmonics cause noise, abrasion and mechanic difficulties on transformers
transformer sizing. K-factor
magnetic core of transformers reaches saturation
Switching Elements and Fuses
 faulty operations on switching elements.( RMS currents increasing)
 Failures occur electromagnetic induction coil used by circuit breakers (high frequency )
Cable and Busbar
 Conductor losses increase due to skin effect and conductors expose to mechanic
difficulties and vibrations.
 Overheating