Executive Summary:Active Harmonic Filters (AHFs) actively eliminate harmonics and correct Power Factor, while Line Reactors passively limit harmonic amplitude but degrade power factor and risk resonance. For demanding applications requiring low THD (<5%), AHFs are the superior solution despite higher initial cost.

Key Differences Summary Table:

Detailed Feature Comparison:

1. Core Function & Technology:

• AHF:An advanced electronic device using IGBTs and a digital controller. Monitors load current, calculates specific harmonics (e.g., 5th, 7th), and injects opposing currents to actively cancel harmonics at the source. Dynamically corrects power factor.
• Line Reactor:A passive inductive component (coils on a core). Adds impedance that increases with frequency, attenuating harmonic current amplitude flowing back to the source. Inherently worsens power factor.

2. Harmonic Mitigation Performance:

• AHF:Actively eliminates harmonics, achieving very low THD levels (typically <5%), ensuring compliance with standards (e.g., IEEE 519) and protecting sensitive equipment.
• Line Reactor:Passively limits harmonic current amplitude, typically achieving only a 30-50% reduction in THD. Residual THD is often still significant.

3. Power Factor (PF) Impact:

• AHF:Corrects poor PF by dynamically supplying leading or lagging reactive power (kVAR) without causing resonance. Improves overall power quality.
• Line Reactor:Degrades PF by adding inductive reactance (lagging kVAR). Requires additional capacitor banks for PF correction, which introduces resonance risks.

4. Resonance Risk:

• AHF:Very low risk. Does not create low-impedance paths and actively counters/dampens system resonances. Inherently safer.
• Line Reactor:Significant risk. Alters system impedance, potentially shifting resonance frequencies closer to problematic harmonics (especially if capacitor banks are present). Requires detailed harmonic studies to avoid dangerous conditions.

5. Voltage Stability:

• AHF:Prevents voltage drop associated with harmonic currents.

Line Reactor: Causes a fundamental frequency voltage drop due to its series impedance.

Conclusion: AHF is the Superior Solution for Harmonic Mitigation

While line reactors are simpler, cheaper upfront, and suitable for basic attenuation, motor protection (dv/dt reduction), and short-circuit current limiting, AHFs are fundamentally superior for effective harmonic reduction and power quality enhancement:

• Effectiveness:AHFs eliminate harmonics, achieving drastically lower THD (<5%) than reactors which only limit them (residual THD often 30-50%).
• Precision:AHFs target specific harmonics; reactors offer only non-selective broadband reduction.
• Power Quality:AHFs simultaneously correct power factor; reactors degrade it, creating a new problem.
• Safety & Stability:AHFs avoid resonance risks inherent with reactors near capacitors and prevent voltage drop.
• Compliance:AHFs ensure reliable compliance with harmonic distortion standards (e.g., IEEE 519).

Therefore, for environments with significant harmonic distortion requiring low THD levels, compliance, or protection of sensitive equipment, the Active Harmonic Filter is the superior and more effective technology. Line reactors are often only a partial or preliminary solution. Choose AHF for demanding harmonic mitigation needs.

Media Contact
Company Name: Shanghai Intone Power Co., Ltd.
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Phone: +86 13603058851
Country: China
Website: https://www.intonepower.com/