Research On Infiuence Solutions Of Power Losses Caused By Harmonic In Low Voltage Distribution Network

Harmonics have always been a problem with industrial loads, but now more and more consumer and commercial power loads are cropping up as sources of harmonic currents. The effect of harmonic wave on power loss in low voltage power distribution network can not be neglected anymore, in addition to the power quality, the impact on distribution network loss should also not be underestimated.In AC systems, only the fundamental power is useful. Harmonic power in the grid is not doing any useful work, and ultimately as heat diffuse, therefore the essence of harmonic power is "network loss". Harmonic wave current can also result in neutral wire overloading, its thermal effects can lead to overheating of transformers and rotating electric motors, accelerate aging of insulating material, thereby reducing the service life of the device, increase fixed costs of distribution networks.This paper described the basic concept of harmonic and the main definition of harmonic; briefly analyzed the harmonic voltage distortion, current distortion in low voltage power distribution system and domestic-overseas standards for the amount of different orders of harmonic current, the principle of harmonic generation for traditional harmonic source(transformer and electric motors) is analyzed, the characteristics of main harmonic sources in residential and commercial electricity is investigated and analyzed, the measured value of harmonics in some common used operational equipment and corresponding current harmonic distortion rate are proposed; The harmonic contents in residential and commercial electricity are measured in situ, on the basis of analyzing of measurement results, the harmonic contents of different orders, the total distortion rate of current and harmonic losses are calculated, according to the residential and commercial electricity price in Shandong Province, the distribution network loss due to harmonics is obtained. Finally, based on the calculation results and electric power utilization characteristic for different users, the proper filtering is selected. The aim of this article is attaching the importance to power distribution network loss for appropriate organizations, meanwhile it also provides very good reference for power supply corporation and electricity power users to control harmonic wave and formulate plans to reduce network loss.