Harmonic distortion is a broad, complex power quality issue with significant economic impacts for electric utilities and end-users. Distorted current waveforms from end-user loads create excessive heating for utility transformers and capacitor banks, leading to premature equipment failures.

Distorted utility voltage can cause customer equipment misoperation or damage, reduce motor performance, and cause benign loads to draw harmonic currents. An overview of harmonics and power quality is given here.