Harmonics and Power Quality: Harmonic Filtering in Switchboards
Harmonics are distortions in the mains current and voltage waveform caused by nonlinear loads (such as frequency inverters, LED drivers, UPSs, and computers). They are one of the most significant power quality problems in modern installations.
Why are harmonics harmful?
High harmonic levels lead to overheating of conductors and transformers, excessive current in the neutral conductor, shortened capacitor lifespan, and malfunctions in sensitive equipment.
THD (Total Harmonic Distortion)
THD, a measure of power quality, indicates the ratio of harmonic components to the fundamental component. Standards (e.g., IEEE 519) recommend specific THD limits at the facility’s connection point.
Harmonic Solutions in Panels
- Reactor compensation: Protects capacitors from harmonic resonance.
- Passive harmonic filters: Suppress specific harmonic orders.
- Active harmonic filters (AHF): They suppress harmonics with high efficiency by measuring them in real time and injecting countercurrent.
Devpan designs harmonic filtering and compensation panels based on power quality analysis. See our low-voltage panels page for more information on our products.
Frequently Asked Questions
What are harmonics?
Harmonics are distortions in the mains current and voltage waveforms caused by nonlinear loads, and they degrade power quality.
What is THD?
THD (Total Harmonic Distortion) is a value that indicates the ratio of harmonic components to the fundamental component and measures power quality.
How are harmonics filtered in electrical panels?
Harmonics can be suppressed using reactor-based compensation, passive harmonic filters, and active harmonic filters (AHF).
