Active Harmonic (Power) Filter

Delta’s PQC Series APF can perfectly mitigate harmonic current, and suppress harmonic voltage caused by the harmonic current. When the APF capacity is sufficient and background harmonic voltage is low, the APF ensures excellent compensation performance at full load condition, as below:

• THDu (Total Harmonic Distortion of Voltage) < 3%
• THDi (Total Harmonic Distortion of Current) < 5%
• PF (Power Factor) ≥ 0.99 (improves both leading and lagging PF)
• Neutral Current Attenuation Ratio ( [^IN(Before) - ^IN(After)] / ^IN(Before) ) >95%

APF Actual Compensation Performance

Application:Textile Industry
Non-linear Loads: Variable Frequency Drive (VFD).
Compensation Result: Current harmonic distortion (THDi) was reduced from 32.5% to 2.9%

Current waveform and spectrum are recorded by Fluke 435, as below.

Current Waveform

Current Spectrum

Application: Foundry Industry
Non-linear Loads: Electric Welder
Compensation Result: Current harmonic distortion (THDi) was reduced from 70% to 4.4%, load imbalance was reduced from 102% to 6.1%.

Current waveform and spectrum are recorded by Fluke 435, as below.

Current Waveform

Current Spectrum

Application: Automobile Industry
Non-linear Loads: Thyristor driven heater
Compensation Result: Voltage harmonic distortion (THDu) was reduced from 5.5% to 1.3%.

Voltage waveform and spectrum are recorded by Fluke 435, as below.

Voltage Waveform

Voltage Spectrum