| Smart electricity meter is an impprtant part of the advanced measurement system of smart grid,and its measurement accuracy is the basic requirement of reliable,economical and efficient operation of smart grid.Moreover,the accuracy of smart energy meters is directly related to the economic benefits of the three:power generation enterprises,transmission and distribution enterprises and power users.With the increase of distributed energy and the common use of electric equipment(such as electric arc furnace and electrified railway),more and more power loads in smart grids exhibit dynamic characteristics.Published research literature indicates that the smart electricity meter currently used by the grid company does not necessarily meet the measurement requirements under dynamic load conditions,even some may cause serious test errors.Therefore,what are the magnitude of measurement errors of the smart meter that is widely used under dynamic conditions?What are the reasons for generating dynamic errors?These problems need to be solved urgently.However,the current international standards,national standards and verification procedures related to smart energy meters do not include the measurement accuracy test items of the meters under dynamic power conditions,and the corresponding dynamic error test methods are also lacking.The quality inspection of the on-site smart meter is still based on the measurement data under the steady state power conditions of the laboratory.This paper studies the dynamic error test method of electric energy meter under complex dynamic load condition and the error source based on dynamic model.The main contributions are as follows:1.An OOK(On-Off Key)dynamic error testing signal model and a TDLE(Testing Dynamic Load Energy)sequence of dynamic load power of smart electricity meter was established.Then,the dynamic error test method under OOK signal testing was proposed.Based on the analysis of two TDLE excitation modes and three dynamic power test modes were given.The problem of how to measure the errors of smart electricity meter under dynamic conditions was solved.2.The whole system model of the smart electricity meter was built.Moreover,the dynamic measurement performance of the electric energy meter was defined.Four models were established firstly by mechanism analysis including voltage channel model,current channel model with gain feedback control of programmable gain amplifier,active power measurement module model and energy measurement module model Then the signal transmission relationship between the units was integrated and the whole system model of the smart electricity meter was established.It provides a theoretical basis for analyzing the sources of dynamic errors of electric energy meters.3.The error effects of each unit on active power and active power were analyzed based on the whole system model of the smart electricity meter Moreover,error sources of the meter were analyzed.The power errors caused by PGA(Programmable Gain Amplifier)response lag were analyzed in theory and simulation.The dynamic errors of the power measurement unit were analyzed under synchronous and non synchronous sampling.The dynamic power error models of RMA(Rectangle-MA)and TMA(Trapezium-MA)filters were established.Then the influence of the parameters of the power measurement unit model on the active power measurement was analyzed4.The SDPA(Segmented Dot Product Accumulation)algorithm for dynamic measurement of smart electricity meter was proposed.The implementation of CIC(Cascade Integrator Comb)decimation filter contributes to improve the efficiency and dynamic measurement performanc of the electric energy meter. |
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