Analysis of harmonics in the power supply networks of electric welding equipment of alternating voltage

Electric arc welding is widely used in construction and engineering for rigid connections of metal elements. Substantial nonlinearity of dynamic voltage-current characteristics of electric arcs in such equipment is a source of distortion in current and voltage sinusoids at the points of other electric receivers parallel joints. The voltage fluctuations from the nominal value result in changing luminous flux of bulbs, while current higher harmonics result in additional losses in electric motors. However, the problem of electric welding equipment influence on power lines wasn’t paid proper attention to. Therefore, this work is to research electric arc equipment influence on power lines in order to find out the values and the spectrum of higher harmonics, and the prevailing amplitudes dynamics of change. In this paper the results of experimental researches of harmonics spectrum in electrical circuits of electric arc welding machine of alternating voltage that it generates during the technological process and the main energy parameters, that influence negatively on the power supply networks of 0,4/0,23 kV. Analyzing the results of the measurements we come to the conclusion that if the load factor is about 35% the power coefficient of the welding machine is 0,46, that is rather low. Such a result is economically disadvantageous since high reactive power results in a significant increase of active power losses in the elements of power supply. That’s why reactive power compensation as well as higher harmonics filtration are necessitated