Power Quality · 6 min read · Published 2026-07-17 · Updated 2026-07-17
Harmonics are unwanted frequency components in electrical systems, commonly caused by non-linear loads such as drives, rectifiers, UPS systems and power electronics.
Why harmonics occur
Non-linear loads draw current in pulses instead of smooth sine waves. This distorts current and sometimes voltage waveforms, creating harmonic components that can affect transformers, cables, capacitors and sensitive equipment.
Common symptoms
Transformer overheating
Capacitor bank failure
Neutral overheating
Breaker nuisance tripping
Drive or control malfunction
Poor power quality readings
How to control harmonics
A power quality study should measure total harmonic distortion and identify the source. Active harmonic filters or passive filters may be selected depending on load profile, harmonic order, current level and system design.
