Research On The Influence Of Electrified Railway Harmonic On Electric Energy Metering

With the development of electrified railway,especially the operation of newly build high-speed railway,the operation mileage of electrified railway is increasing,and the consumption of electric power is increasing.Electrified railway is a special user in the power system.The power quality problem is more complex than the ordinary user.The electrified railway load has the characteristics of large power,asymmetry and nonlinearity,which have put forward higher requirements for power supply capacity of the power system.In the process of power system power supply,electric energy measurement plays a vital role in the system.It is the basis for electricity and railway departments to settle the electricity bill.The accuracy of the electric energy measurement is related to the economic benefits of both sides.This paper studies the characteristics of electrified railway power quality,makes the difference of electrified railway and ordinary users clear,and analyses the impact of connection type of traction transformer,traction characteristics,measuring point position and other factors on the measurement accuracy of load power.Then,by analyzing the working principle of the electric energy metering device,the influence of harmonics on the accuracy of voltage transformer,current transformer and electric energy meter is studied,and the influencing factors are identified.The simulation models of voltage transformer,current transformer and electric energy meter are built up.Than the simulation results are combined with the measured data,and the results are compared with the theoretical analysis results.Finally,in the MATLAB/Simulink platform to build a model of the traction power supply system,simulating the actual working condition,put the model of voltage transformer,current transformer and power meter,electric energy metering device model in the boundary of power system and the traction power supply system.By changing the running state of the load to analyses the accuracy of measurement results and obtain the error size of the various metering device results,at the same time,the results of the measured data of power substation and traction substation are compared with those of simulation.