Active Harmonic Filter (LIEBERT AF3)
Generation Active Harmonic Filter. State-of-the-Art active filter, that dynamically cleans up Harmonics and improves Power Factor, for all types of electrical installations. It has dynamic control features and has no resonance effects, no reactive power circulation, no passive components.
FEATURES – 32 bit, DSP control Employs high speed IGBTs in power circuit Closed loop active filter with source current sensing High attenuation up to 96% of individual harmonics Programmable selective harmonic elimination PF compensation, leading as well as lagging Load balancing PF can be programmed from 0.7 to unity Selection between PF and harmonic compensation Remote monitoring and diagnosis Self current limiting, under overloading condition Automatic current limit modification with respect to ambient temperature Helps compliance to IEEE 519 IEC / EN 62040 - 2 category C3 User friendly PC interface
BENEFITS TO CUSTOMER- Safe and reliable AC electrical distribution systems Overloading and overheating of the neutral conductor cancelled Nuisance tripping of protection circuit breakers avoided Improved power quality Reduction of the THD v Cancellation of the voltage potential on the neutral conductor Increased lifetime of AC distribution system equipment Over-sizing cables, transformers and other AC distribution equipment avoided Compliance of installations with harmonic standards ensured Improved power factor Lower energy expenses/bills
AREAS OF USE
Due to the higher costs in direct comparison with passive filter solutions, active filters are mainly used in the following cases
In systems in which no, or only limited, additional capacitor power may be installed (power factor close to 1) Clearly defined harmonic level (THD-U) e.g. critical production with long process chains (chemical industry semiconductor production) High neutral conductor currents (e.g. 3 harmonic) Unsymmetrical load on networks High dynamic of the harmonic distortion and reactive power Highest harmonic distortion or weak grids
TYPICAL AREAS OF APPLICATION
Oil, gas and steel industry Welding machines Water treatment USV systems, computer centres Cement and automobile industry (computer and network connections) Paper industry Banks and data centre Tooling machines, drive technology frequency converter, servo applications, DC drives, DC supplies) Elevator industry, tunnel supplies (ventilation).
AF3 - Next Generation Active Filter
Liebert AF3 latest technology to eliminate harmonic injected into the mains supply by non linear loads, as well supplies inductive power demanded by the load, so as to correct input power factor to near unity.
Current harmonic elimination is achieved by sensing load current& extracting harmonic current signal. This and the reactive current signal, together are used to generate a reference for the controlled current source connected at the PCC(point of common connection) of source and load. This results in mains supplying only real power for the load and reactive & harmonics being sourced from the AF3.This is carried out dynamically,so that any change in the load pattern or its nature is immediately responded without any manual intervention.
In the following example first figure shows the recorded input current waveform of a six pulse thyristorised rectifier.
Bottom figure shows considerable improvement in the waveform due to AF3 connected in shunt.
One is with only harmonic correction and the other is with power factor & harmonic correction.
APFC Panel
We are engaged in offering a quality range of APFC Panels. These products are acknowledged for their attributes such as sturdy construction, trouble-free operations, reliability and durability. In electrical power networks, ranging from the industrial electricity network through to office buildings,system perturbation occur when operating electrical and electronic loads. We refer to network perturbation when the original “clean” sine wave of the voltage or current changes.
Detuned APFC Panel
Use of both capacitive and inductive devices in distribution systems leads to resonance phenomena, resulting in extremely high or low impedance values. These variations in impedance modify current and voltage in the distribution system
Performance Results
Features :
Modular type Very small foot print Advanced controller with FUZZY logic Easily scalable MODBUS, PROFIBUS connectivity PF compensation, leading as well as lagging Load balancing Remote monitoring and diagnosis Self current limiting, under overloading condition Helps compliance to IEEE 519 User friendly PC interface Main Purpose: Saving Cost
• Correct and flawless functioning
• Long operating life (>8 years)
• Safe operation Modern requirements: Power Quality
• Mitigation instead of amplification of harmonics
Benefits Elimination of reactive power drawn from power utilities Reduced electricity costs Reduction of harmonic voltage and current distortion Avoidance of resonance Lower investment for new equipment (KVA release). Stabilizing line voltage, power supply Overall improvement of power quality Longer service life of APFC & equipments. Reduced maintenance cost. Lower failure risk for production equipment
Dynamic APFC Panel
For use with rapid and high load changes
Dynamic PFC systems are particularly used in applications with rapid and high load changes. These are automatically regulated systems for central compensation in low voltage distribution boards or for group compensation of sub-systems.De-tuned PFC systems for use in applications with non-linear loads i.e. harmonic loads.There are various designs tailor-made to suit your individual application.
Advantages:
Improved power quality i.e. high inrush currents from power capacitors are avoided The lifespan of PFC systems is increased The safety of the full system is significantly increased
(i.e. damages due to defective contactor and as a result of exploding capacitors are avoided) Extremely rapid regulation of the power factor and therefore consequential reduction of reactive
power costs and kWh losses Voltage stabilisation (e.g. network support during the start-up phase for large motors) Improved utilization for energy distribution (transformers, cable, switch gear etc.) throug the elimination of power peaks Process times can be shortened (e.g. welding)
Typical applications Automobile industry (welding machines, presses...) Elevator systems and cranes Start-up compensation for larger motors Drilling rigs in oil production Wind power plants Welding Steel production Plastic injection moulding units Fishing boats
Real Time Power Factor Corrector (RTPFC)
Dynamic PFC systems are particularly used in applications with rapid and high load changes. In such cases, conventional PFC systems are not fast enough to follow the load changes which means that these systems are either under compensated or overcompensated.
Electromechanical contactors are not suitable for these types offrequent switching cycles. If contactors or capacitor contactors are still used in such applications, the contactors are worn out very quickly and this can lead to significant safety risks for the whole system. Dynamic PFC systems avoid this problem with the help of semiconductors. Semiconductors gently connect thecapacitors to the network i.e. without network perturbations and capacitor stresses.
32 bit, DSP control 
