High Quality Power Supply Scheme In Large Scale Industrial Enterprises

The requirements of power quality for imported equipment and precision instruments are more stringent in large-scale industrial enterprises.A considerable impact on supply voltage will be made when electric furnaces,rolling mills and other non-linear,impact loads running in enterprises.For example,supply voltage will appear harmonic,amplitude fluctuations,three-phase imbalance and other issues.With fast development of power electronic technology,there are more and more methods to solve these problem.Power electronic equipment connects with supply line in series or in parallel.In accordance with different control strategies,power supply quality could be advanced in different way.It is also a difficult problem of general interest about coordination and optimization of control strategy,by which means,several equipment coordinate with each other.On the basis of discuss in dynamic voltage restorer,this paper studies the high quality power supply for sensitive equipment,electric furnace equipment and rolling mill equipment,which are three important loads in large-scale industrial enterprises.Firstly,this paper introduces conventional topology of dynamic voltage restorer,then analyzes the advantages and disadvantages of two conventional compensation schemes.Aiming at the requirement of sensitive devices in power quality and power supply reliability,an interleaved parallel scheme is proposed.In order to identify the availability of the new scheme,three types of compensation schemes are compared with each other by simulation.Secondly,through the analysis of the load characteristics of the electric furnace and the topology of the traditional electric furnace transformer,many shortcomings have been found,such as complex and unreliable voltage regulator winding,cumbersome relay protection device,frequent action of tap-changer and much difficulty in maintenance.A novel electronic voltage regulating furnace transformer is mentioned.In this way,tap-changer will be removed or greatly decreased,output voltage will be continuously regulated,and power reliability or quality will be remarkably increased.Finally,according to the impact of the rolling mill equipment,a suitable control method for rolling mill equipment is proposed based on topology of electronic voltage regulating transformer.Installing energy storage device in addition,it will be possible to achieve the aims of eliminating active power and reactive power fluctuation and improving the power quality.