Pumping: Harmonic Mitigation Techniques

Many of today's loads are nonlinear and are constantly switching diodes and capacitators. Variable frequency drives also have diodes that convert AC power into DC before it creates the variable frequency power that controls the motor. These nonlinear devices introduce harmonic currents and voltages to the utility supply. However, most systems are not designed to operate in such conditions.

Harmonic distortion results in additional system and component losses that affect, at the very least, transformers, distribution equipment, and cabling. For example, increased eddy current losses caused by typical harmonic currents require current de-rating factors of 7% to 10% in some transformers and up to 21% for systems that have high harmonic currents. Utilities can fine customers that introduce these excessive harmonics into the grid to make up for the additional power generation. This listicle will provide a snapshot of the most common methods for mitigating harmonics and allows you to consider the pros and cons of each.