Which statement best summarizes the overall impact of harmonic currents on a power system?

Which statement best summarizes the overall impact of harmonic currents on a power system?

• A. They only affect motors
• B. They can cause nuisance tripping, reduced power factor, and penalties
• C. They only affect transformers
• D. They are always beneficial

Answer: (B)

Harmonics distort both current and voltage in a power system because non-linear loads draw current in abrupt bursts instead of a smooth sine wave. That distortion doesn’t stay confined to one piece of equipment—it travels through the network and shows up as extra heat, inefficiencies, and unexpected behavior elsewhere. This makes the statement about nuisance tripping, reduced power factor, and penalties the best description. Distorted current can cause protective devices to trip or operate oddly, even if the real load isn’t that high. The waveform distortion also lowers the true power factor because the current is no longer in phase with the voltage in a purely resistive sense, increasing apparent current and losses. Utilities and facilities may impose penalties when harmonic levels exceed agreed limits, reflecting the broader quality and efficiency impact on the system. Harmonics don’t affect only motors or only transformers, and they aren’t beneficial in any sense. They influence the whole electrical network, especially with modern non-linear loads, so attributing their impact to a single device would miss the bigger picture.

Harmonics distort both current and voltage in a power system because non-linear loads draw current in abrupt bursts instead of a smooth sine wave. That distortion doesn’t stay confined to one piece of equipment—it travels through the network and shows up as extra heat, inefficiencies, and unexpected behavior elsewhere.

This makes the statement about nuisance tripping, reduced power factor, and penalties the best description. Distorted current can cause protective devices to trip or operate oddly, even if the real load isn’t that high. The waveform distortion also lowers the true power factor because the current is no longer in phase with the voltage in a purely resistive sense, increasing apparent current and losses. Utilities and facilities may impose penalties when harmonic levels exceed agreed limits, reflecting the broader quality and efficiency impact on the system.

Harmonics don’t affect only motors or only transformers, and they aren’t beneficial in any sense. They influence the whole electrical network, especially with modern non-linear loads, so attributing their impact to a single device would miss the bigger picture.