Active Harmonic Filter

Jan 08, 2019

Overview of Active Harmoinc Filter

Active Harmonic Filter(AHF) is a perfect comprehensive solution to power quality problems such as harmonic wave, reactive power, and 3 phase load unbalance. AHF is connected in parallel in power grid, to detect the harmonic wave in real time, generate the reverse-phase compensation current through the converter, and dynamically filter the harmonic wave. The operation of AHF is unaffected by power grid structure and load type, and it will not produce harmonic oscillation with the system, thus perfectly realizing harmonic wave control of various loads. AHF can also realize dynamic reactive compensation, and control the capacitor switching, to improve the power factor. Meanwhile, Active Harmonic Filter has the function of controlling the 3 phase load current unbalance, thus comprehensively solving various power quality problems with power grid.

Principle of Active Harmoinc Filter

Key Features of Active Harmonic Filter

Multifunctional: Harmonic, reactive power and imbalance compensation
High harmonic filtering rate: Up to 98%
Excellent reactive compensation: High speed, Precise (-0.99≤PF≤0.99), Step-less, Bi-directional (capacitive and inductance) compensation
Excellent imbalance correction: Both negative and zero sequence, mitigates neutral current
Wide input voltage & frequency range, adapts to tough electrical environments
Low thermal loss (≤3% of rated AHF kVA), efficiency ≥ 97%
High stability: Infinite impedance to grid, avoids harmonic resonance problems
Flexible application: Modular design, embedded in standard or customized cabinet
Easy installation and maintenance: Plug-in installation for AHF module replacement and expansion
Wide capacity range: 30A~600A for a single cabinet, up 10 cabinets in parallel
Environmental adaptability: -10~50°C temperature, compatible with diesel generator
Complete protection: Grid Over/Under voltage, AHF over current, over temperature, and more. All faults are recorded in the event log, which is convenient for failure analysis

Typical Application of Active Harmonic Filter

Harmonics occur usually as follows,

◆Overheating of transformers and conductors

◆Generator instability

◆Capacitor failure

◆Nuisance tripping of fuses and circuit breakers

◆Damage to or failure of sensitive electronic equipment including drive failure

◆Telephone interference

◆Motors experiencing overheating, audible noise and reduced service life

◆High energy costs

◆Downtime and loss of production due to equipment instability.

AHF Modular Datasheet

Number of phases (system input)	3-phase 3-wire or 3-phase 4-wire
Rated frequency	50/60Hz
Rated voltage	400 V ±20%
Response time	<5ms
Harmonic mitigation performance	2^nd to 50^th harmonic
Filter Efficiency	>97%
Total harmonic current distortion THDi	<5%
Reactive power compensation Rate	>0.98(inductive and capacitive compensation)
3 phase unbalance compensation effect	<5%
Active Loss of system	<3%
Inverter topology	IGBT
Controller	DSP+FPGA
Current transformer placement	Mains side or load side
Communication interface	Modbus Protocol,RS485
Rated current of Modular	30A	50 A	75 A	100 A	150A
Weight	30kg	30kg	35kg	40kg	45kg
Self-protection	Yes
Over heat protection	Yes
Over/under voltage protection	Yes
Over/under frequency protection	Yes
Noise level	<60 dB (depending on load situation)
Relative humidity	<95% non-condensing
Temperature	-20 ~70°C
Cooling type	Air cooling
Dimensions cabinet	440 mm × 641 mm × 230.5mm (w × d × h)
Mounting	Wall-mounted or Rack mounted
Ambient conditions	<1000m; Up to 4000m with derating 1% per 100m
Protection class	IP20
Certification	ISO9001,Type Test Report
	EN 50178:1997/IEC50178:1997
Design standards	EN61000_6_2(2005)/EN55011,Group1,ClassA
	IEC61000_6_2(1999)/CISPR11,Group1,GlassA
	EN50091-3/IEC62040-3/AS62040-3(VFI SS 111)