18 June 2011

Harmonics Distortion effect in Power System

Harmonics distortion:

Harmonic Distortion in power system increasing everyday due to increase in the use of non linear loads such as wave rectifiers,Static VAR compensators, and other solid state controlled devices. Some of the sources of harmonic currents in household appliances includes the electronic components we use like computers, printers, telecom equipment, micro ovens, UPS systems  and other electronic loads will increase the flow of harmonic currents. In industries use of variable frequency drives and other power electronic equipments such as rectifiers, inverters enhances the flow of harmonic current.

Problems due to Harmonic distortion:

Problems due to the harmonics include increase in the winding temperature of the transformers, over heating of motors, line conductors, neutral conductors, and mis operation of relays results in unwanted tripping of circuit breakers, mis operation of power electronic devices. Harmonics effect on induction motors includes increase in the core loss, reduction in the torque, increase in skin effect, damages to the motor insulation and much more. Some of the disadvantages due to harmonics on power system is already discussed

Methods to control harmonics distortion:

  • Filters: Adding  filters to block the harmonic currents from entering in to the system where we need to protect the sensitive equipments from harmonics (power electronic equipment)
  • Modify  frequency response of the system by introducing inductors and filters in to the system
  • Isolating the equipment from power system which is producing more harmonics distortion.


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