Objectives of Harmonic Filtration

There has been much discussion and interest in recent years on the subject of Harmonics under ambit of network power quality.

More and more frequently, industrial and commercial users are finding they have to deal with the problem of "polluted power.

Many seminars and awareness programs have been conducted to effectively deal with the problems of harmonics. Lot has been done but still there are gaps in knowledge of harmonics in network and methods to effectively deal with them.

Some significant problems because of high harmonic distortion are as follows :

  • Overload and failure of capacitor banks used for Power factor correction .The capacitors are subjected to an overload and their lifetime is drastically reduced.
  • Overload and failures of Motors; Reduced motor life, inability to fully load motor.
  • Low efficiency of transformers and cables- The user transformers, wires and loads are affected by this increase in current, which leads to increased I2R losses and eddy current losses in transformer. This reduces the capacity of transformer resulting into economic loss as well. Apart from this transformer may also be subjected to excessive overheating and saturation. This will shorten the life of transformer. When transformer fails, the cost of loss of productivity during emergency repair time far exceeds the replacement cost of transformer itself.
  • Malfunctioning and failure in computers, microprocessor, solid state controlled and other Electronic equipment.
  • High voltage distortion shall also be encountered when shifting from mains to emergency generator as they offer high impedance than supply transformer.
  • Tripping of protection switchgear and relays without apparent reason.
  • Large current in neutral wires of power distribution system. This is a real fire hazard as usually phase wires are only protected by circuit breakers or fuses.
  • Poor power factor: As mentioned earlier the harmonic current caused by non-linear loads do not carry any real power (KW) even though they do increase the volt amperage (KVA). This lowers the power factor at (Pf=KW/KVA) the main distribution transformer.
  • Over heating in fuses resulting in false blowing and in some cases because of resonant condition result in burning of HRC or even fuse base because of resonant conditions. False / spurious operations of breakers, which may lead to variation in other characteristics.
  • Low efficiency of UPS- Reduction of power generated by UPS.
  • Interference in communication networks.

Therefore harmonic studies assume great significance to understand network power quality and negative impact they can have on network. NECPL can offer continuous studies from 24 hours to many days by high end waveform and PQ recorders so that to comprehensively understand harmonics during various load cycles and their impact on network devices.

We can offer high quality PQ studies for short durations, 24 hours to many days by high end waveform and PQ recorders so that to comprehensively understand harmonics, voltage flicker, Voltage fluctuation (Sags & Spikes), power factor issues during various load cycles of plant / office and their impact.

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