The Causes And Treatment Measures Of Qingdao Power System Harmonics

This article introduces the basic concept of power quality and the 6 indexes (frequency, harmonics, deviation, unbalance factor, fluctuation and flicker) of measuring the power quality. The commonly mathematical methods used in power quality analyzing such as discrete Fourier series, are elaborated.Through on-the-spot and online measurements of different substations and transmission lines of Qingdao power grid and bases on the analysis of the data acquired, this article studies the power quality conditions of Qingdao power grid. Based on comprehensive analysis of the power quality, the main factors that influence the power quality of Qingdao power grid are found. Among these factors, rectification load, low-voltage electrical equipments and electric arc furnaces are main harmonic source loads, which directly influence the harmonic distribution and power quality in Qingdao power grid. And as a result, the electrical equipments can be damaged easily. In addition, electrified rebuilt of Jiao Ji railway is under construction. After the operation of this railway, harmonic condition in power grid will be deteriorating. Based on the analysis of the power quality of Qingdao power grid, methods presented by this article will be meaningful to improve the power quality of Qingdao power grid.