Experimental Study On Intermedicate Frequency Power Supply Harmonic

Harmonics is harmful substances in the power system andone kind of energypollution in power system.Not only the pollution of power would be caused,grid stable of harmonic would be line influenced,but also a certain pollution will produce on electronic equipment,leading to the electronic equipment can not be operated normally.Moreover,the harmonic also has considerablely harmful to the human body,seriously harmful to human health.Yuchai casting center is one of the main production base of the company,the main production is the blank such as diesel engine cylinder block,cylinder head,and a total of 5 sets of medium frequency induction furnace was set up in it.In the foundry industry,the medium frequency induction furnace by using the whole circuit system generates most harmonic known as the harmonic source.In order to minimize the adverse effects of harmonic,ensure the quality of products,reduce the costs of production,the experimental investigations of harmonic controlling has been studied on the casting center gridsystem by using dynamic wattles compensation device combined with passive filters,the main research results are as follows:1.After Harmonic controlling the 110kV three-phase voltage unbalance and long time flicker value of casting center under the normal operation of intermediate frequency furnace load shallly meet the national standards.2.After Harmonic controlling,each harmonic current of power grid point of common coupling injected by casting center hade all meet the national standard of power quality under the normal operation of intermediate frequency furnace load,and there was also a large margin at the same time,each harmonic current size were 2 times,4 times,8 times,3 times.3.After Harmonic controlling,the total harmonic distortion(THDu)as well as each harmonic rate of the casting centers 110kV bus voltage at point of common coupling had meet the power quality national standards on voltage under the normal operation of intermediate frequency furnace load,and also had a lot of margin.4.The harmonic current exceed the standard and the problem of low power factor of the casting center had been completely solve,leading to maximize the improvement of thesecurity,stability of power grid and the economic benefit of enterprise...