3-PH Harmonics & Line Filtering


1. What is the use of harmonic filter?


The Line Loss Pro approach to countering harmonics is a special application of balancing passive neutral line filtering. The filter uses inductive components to block large neutral line current harmonics and divert the energy of those harmonics to a dissipative resonant tank filter.  The resultant neutral current has components of much higher frequency but also of much lower magnitudes that incite far less wasteful input filtering activity on the part of other equipment sharing the same neutral bus.

2. What is an active harmonic filter?


An increasing number of loads are non-linear, introducing harmonics into the power grid and thus significantly impairing the power quality. LineLossPro is an active harmonic filter that effectively reduces the unwanted harmonics.


3. How does a harmonic filter work?


The harmonic filter is built using a unique patented filter device. Unlike passive neutral filters that install in series with distribution panel neutral busses, the Line Loss Pro filter connects in parallel with the distribution panel bus bar, and thus does not require disconnection of the neutral bus for installation.  This special design allows Line Loss Pro to help customers install harmonics-mitigating filters while facilities are connected and operational.


4. What are harmonics in electrical power systems?


Harmonics are a distortion of the normal electrical current waveform, generally transmitted by nonlinear loads. Switch-mode power supplies (SMPS), variable speed motors and drives, HVAC unit, refrigeration equipment, LED lighting, machinery operated by motors,  personal computers, fax machines, battery chargers and UPSs are examples of nonlinear loads.


5. What are common problems caused by Harmonics?


Overloading the Neutral Conductors:
The three-phase system consists of three individual phase conductors and a neutral conductor. If all the phase conductors carry the same current, the phase currents tend to cancel one another out provided there is a balanced load. This balanced load makes it possible to reduce the size of the neutral conductor. Unfortunately, switched mode power supplies used in computers have a very high third-harmonic current. While harmonic currents cancel out on the neutral wire, the third harmonic current is additive in the neutral. In buildings with a large number of installed personal computers, the neutral wire can carry much higher currents than the wire was designed to accommodate, creating a potential fire hazard.


6. What is meant by phase distortion?


In signal processing, phase distortion or phase-frequency distortion is distortion, that is, change in the shape of the waveform, that occurs when a filter's phase response is not linear over the frequency range of interest, that is, the phase shift introduced by a circuit or device is not directly proportional to ...


7. What are the effects of harmonics?


Harmonic is multiple of the fundamental frequency and it can be voltage and current in an electric power system are a result of non-linear electric loads. ... Harmonics in power systems result in increased heating in the equipment and conductors, misfiring in variable speed drives, and torque pulsations in motors.



8. How the harmonics are generated?


Harmonics are created by electronic equipment with nonlinear loads drawing in current in abrupt short pulses. The short pulses cause distorted current waveforms, which in turn cause harmonic currents to flow back into other parts of the power system.


Harmonics are electric voltages and currents on an electric power system that can cause power quality problems. Because equipment and machinery can malfunction or fail in the presence of high harmonic voltage and/or current levels, harmonic distortion has become a growing concern for facility managers, users of automation equipment, and engineers. While the presence of harmonics won't make it impossible for a factory or office to operate, the degree of impact depends on how much the power system can withstand and how susceptible the equipment is to harmonic distortion.




Harmonics are created by electronic equipment with nonlinear loads drawing in current in abrupt short pulses. The short pulses cause distorted current wave-forms, which in turn cause harmonic currents to flow back into other parts of the power system. Harmonics are especially prevalent when there are many personal computers, laser printers, fax machines, copiers, or medical test equipment, fluorescent lighting, uninterruptible power supplies (UPSs), and variable speed drives all on the same electrical system.

Harmonics degrade the level of power quality and its efficiency, particularly in a commercial building or industrial facility. In general, most buildings can withstand nonlinear loads of up to 15% of the total electrical system capacity without concern. If the nonlinear loads exceed 15%, some non-apparent negative consequences can result.