Research On Modeling And Key Techniques Of Truncated M-sequence Dynamic Testing Signal

In recent years,with the continuous development of smart grid construction,the dynamic loads with complex random characteristics in power system are continuously increasing,which lead to serious impacts on the energy metering characteristics of smart electric meters.According to statistics,in 2017,the electricity consumption of the whole society was 6.3077 trillion kWh,and the electricity consumption of heavy industry reaches 3.6113 trillion kWh.Therefore,how to correctly test and evaluate the dynamic measurement characteristics of smart electric meters attracts extensive attention from researchers in related fields all over the world.Firstly,this paper introduces the research status of dynamic load characteristics analysis in power system and the dynamic error test of smart electric meters,and elaborates the importance of establishing dynamic error testing signal model of smart electric meters with the random fluctuation characteristics of actual dynamic loads.Secondly,this paper analyzes the average,variance,autocorrelation function and probability density function of the instantaneous current and instantaneous power random signals from the dynamic loads spot acquisition of the electrified railway,moreover,the m-sequence dynamic testing signal model is established with random characteristics of the actual dynamic loads.Based on the impact of dynamic testing signals on the smart electric meter dynamic metering performance,the truncated m-sequence dynamic testing signal model is established.Aiming at the electric energy value tracking problem of the dynamic testing signals in the smart electric meter dynamic error test,the electric energy value traceability formula of the dynamic testing signal is deduced and the dynamic error calculation formula is given.Thirdly,part of the hardware circuit for generating the dynamic testing signals is designed and the related software programs of MCUs and FPGA/CPLD are wrote.The synchronous testing method is designed for the whole cycle testing problem of dynamic testing signals,and an evaluation of the measurement uncertainty during the smart electric meter dynamic error test is performed.Finally,in this paper,the dynamic error testing device named HE5025 of smart electric meter is developed.The dynamic error testing scheme of smart electric meter is designed and the testing system is built.The m-sequence dynamic testing signal is used to test the dynamic error of smart electric meters produced by different manufacturers in the country.The experimental verification of the truncated m-sequence dynamic testing signal is performed.The testing results show that the dynamic testing signals studied in this paper are reasonable and effective,in other words,they can be applied to test and evaluate the dynamic measurement characteristics of smart electric meters.