Which statement best describes harmonics mitigation in LV systems?

• A. Use larger cables only
• B. Only reduce nonlinear loads
• C. Filtering and proper sizing of equipment are common mitigation methods
• D. Rely on insulation testing

Answer: (C)

Harmonics mitigation in LV systems centers on reducing distortion by managing how harmonic currents flow. The most effective and common approach is to use filtering and proper sizing of equipment. Filtering—through filters or line reactors—attenuates or diverts harmonic currents at problematic frequencies, lowering current and voltage distortion and protecting equipment. Proper sizing ensures transformers, cables, and switchgear have enough impedance and rating to carry harmonic content without overheating or creating dangerous resonance, which helps keep power quality within limits.

Using larger cables alone doesn’t remove harmonics, since the distortion stays in the waveform even if conductors are bigger. Relying on insulation testing doesn’t address harmonic distortion, as that testing focuses on insulation integrity, not power quality. Reducing nonlinear loads can help, but isn’t always practical, so filtering combined with correct equipment sizing is the standard, effective strategy.