Abstract:
The use of non linear loads is increasing day by day. This
increasing use of non linear loads has created more distortions in current
and voltage waveforms. This increased power quality disturbances has
lead to various optimizations techniques and filter designs. Harmonic
distortions are the major cause for power quality problems.
The harmonics in distribution systems come from transformers or
satiable reactors, are furnace, welding machines, florescent lamps,
rotating machines and power electronics devices. In general, the non
linear loads in which the relationship between the voltage and current is
not constant. It is considered that there is no risk of harmful perturbation
from 5 to 10% above 10%, problems will certainly occur.
Equipments can be affected by the harmonics like transformers
with increase of losses , risk of overheating , noise and even insulation
stress problems .cables that can heat too much due to as Kelvin effect
above 400HZ. Induction relays and meters that are permutated by
harmonic torques incorrect tripping and readings.
The solutions that can be used to improve the power factor and to
protect the capacitors are either de-rate the capacitors or using detuning
reactors, and also by using harmonic filters.
This thesis presents the definitions of harmonic, generation, causes,
effects on electrical power system and elimination.
