The Harmonic Study Of Variable Frequency Speed Control Drive System In Petroleum Enterprises

Frequency conversion technology as a mature energy-saving technology,due to its excellent energy saving and automatic production control effect has been widely applied in petroleum enterprises.But the inverter will produce harmonic in the work,which will cause serious harm to electric power system,device load and power quality.Therefore,it is necessary to study harmonic Influence on power quality and energy consumption of variable frequency drive system.This paper studies principle and energy distribution of the variable frequency drive system.By analyzing the production of the harmonic and its influence on the variable frequency drive system.selected a series of harmonic parameters for evaluating the variable frequency drive system,including 9 parameters of the Input side and 11 parameters of the output side,such as the Harmonic voltage distortion rate,Harmonic current distortion rate,Three phase voltage imbalance and so on,in total 20 harmonic parameters.determine the parameters of the test method and calculation method.The testing methods and calculating methods of various parameters are also determined.The operation of the variable frequency drive system is simulated on the energy consumption test bench of the variable frequency drive device,test and measure a lot of experimental data.According to the calculation method of the parameters determined,Lab View software is used to compiling the calculation program to calculate the relevant parameters.Analysis the influence of frequency and motor output torque on the efficiency of inverter,efficiency of motor,efficiency of variable frequency drive device and various harmonic parameters.Meanwhile,the influence of harmonic parameters on inverter efficiency,motor efficiency and variable frequency drive device efficiency are analyzed.On this basis,determine the harmonic evaluation index of the variable frequency drive system,including 7 indexes of the Input side and 4 indexes of the output side,such as the Harmonic voltage distortion rate,Harmonic current distortion rate and so on,in total 11 harmonic indexes.According to the research results,set up an index system of energy efficiency evaluation for variable frequency drive system,including inverter efficiency,motor efficiency and variable frequency drive device efficiency and above 11 harmonic evaluation indexes.The oil enterprises can use the above evaluation index system to evaluate the energy efficiency level of the variable frequency drive system and reasonable use of frequency converter according to demand,to achieve the purpose of saving energy and reducing consumption.