PURESINE Three Phase Passive Harmonic Filters from EMIS - A popular choice of VFD manufacturers

BENGALURU, India - Oct. 5, 2021 - PRLog -- Harmonic Distortion and its impact

Harmonics are current and voltage waveform distortions in power supply. Harmonics occur in integer multiples of the fundamental (supply) frequency - 50 Hz in India/Europe, 60 Hz in North America.

There are several nonlinear equipment sources that can potentially trigger harmonics in the line, affecting all other connected devices. These devices include rectifiers, inverters, electronic starters and battery chargers, home appliances, SMPS, office automation devices and so on. Since such devices are a dominant part of our industrial and home environment, harmonic distortions are inevitable. Therefore, necessary corrective action has to be taken at the design level itself.

Total harmonic distortion (THD) is a measurement that tells you how much of the distortion of a voltage or current is due to harmonics in the signal. THD should typically(not always) be as low as possible. The acceptable threshold of THD is under 10%, and varies according to the application. The total harmonic distortion for voltage and current are represented as THvD and THiD respectively.

Harmonic distortion may impact power quality in several ways:

• Distorts the sine wave shape of the fundamental on the grid. Increased Harmonics increases the phase angle difference between Voltage and Current.
• As the grid has protection equipment, harmonics may give false triggers.
• Increases heating losses, torque pulsations
• Affects life of the equipment connected to the grid
• Can cause overheating, resulting in a potential fire hazard
• Can result in irregular fuse operation, capacitor failure, electronic equipment malfunction, flickering lights and telephone interference
• Voltage Harmonics with high peak values can weaken insulation in cables, windings and capacitors
• Current Harmonics in motor windings can create Electromagnetic Interference (EMI)

Use of Harmonic Filters - simple and effective

Active harmonic filters are very effective for systems that have multiple loads, but are expensive, complex and space consuming. On the other hand, Passive harmonic filters offer a rugged, inexpensive, low maintenance option. They are typically L-C filters installed in a shunt arrangement on the line side of the inverter. They are tuned to resonate at a single frequency or through a band of frequencies. They could be tuned somewhat below the 5th harmonic, which is the largest component of harmonic distortion. A significant amount of 7th harmonic distortion will also be absorbed. Additional filters tuned to higher order harmonics may also be used.

PURESINE Three Phase Passive Harmonic Filters from EMIS

Three Phase Passive harmonic filters (https://www.emisindia.com/three-phase-passive-harmonic-fi...) from EMIS are designed and manufactured to provide an economical and sturdy solution for harmonic mitigation in power systems. These filters effectively maintain THID 5% in compliance with current and voltage requirements of IEEE 519.