06 March 2013

Harmonics Disadvantages in Power System

Sources of Harmonics:

Several sources of harmonic currents that may be found on electrical power distribution networks are listed below:
  • Variable speed motor drives
  • Rectifiers
  • Arc furnaces
  • Wielding equipment
  • Uninterrupted power supplies
  • Switching mode power supplies
  • Compact fluorescent lamps
  • Electronic ballasts

Disadvantages of Harmonics:

Harmonics degrades the performance of power system. Some of the disadvantages of harmonics in the power distributed network are listed below:
  • The harmonics flowing in the distribution network downgrade the quality of the electrical power supply. There can have several negative effects on the operation of the power system
  • Increased losses on the distribution system due to increase in the effective rms current
  • Over-load in neutral conductors due to cumulative increase in the third harmonics created by the single phase loads
  • Overloads, vibration and premature ageing of the generators, transformers and motors as well as increase in the noise level
  • Overloads and premature ageing of the power factor correction capacitors
  • Distortion of the supply voltage that can disturb the operation of the sensitive loads
  • Disturbances in the communication networks and telephone lines
  • Resonance between the supply inductance and capacitance of the power factor correction capacitors

No comments: