The Hidden Dangers of Harmonics: Why Low or Moderate Levels Near Resonance Can Be More Harmful Than High Harmonics: 

There's a common belief that high harmonic levels are always the most dangerous, while low or moderate harmonics cause minimal impact. However, this view is misleading and doesn't accurately reflect the risks posed by harmonic distortions. The truth lies in how harmonics interact with the system’s resonance frequency.

Low or Moderate Harmonics, Close to Resonance: Low or moderate harmonics can be far more dangerous when their frequency aligns with the system’s resonance. The resonance amplifies their effects, causing voltage spikes, overheating, and equipment damage.

High Harmonics, Far from Resonance: High harmonics can cause inefficiency and gradual equipment wear, but the risk of sudden failure is low as long as they are not near the system’s resonance frequency.

The bottom line is simple: It’s not just the magnitude of the harmonics that matters, but their relationship to the system's resonance frequency. While high harmonics can cause inefficiency, low or moderate harmonics can be far more damaging if they resonate with the system, potentially leading to catastrophic system failures.

To safeguard against the risks of harmonics and resonance, it’s crucial to monitor both harmonic levels and resonance frequencies and install appropriate protective measures.