基于小波分析的智能电能表动态测试信号模型与误差分析

Dynamic test signal model and error analysis of smart electricity meter based on wavelet analysis

针对电能表动态误差测试问题,文章采用小波分析对采集到的加热炉负载等三种实际工况信号进行了分解,提取了时域及时频域的特征,从幅值和频率两个维度总结提取了包括幅值变化、低频稳态、高频稳态、高频暂态在内的四类测试信号,能够全面表征多种动态信号的特性,并且采用薄板样条插值建立了包络信号,幅值上升、下降、中断、谐波、间谐波、冲击的七种单一测试信号模型,在搭建好的动态信号测试平台上实验并分析了单一测试信号的参数对误差的影响,结果表明幅值变化和包络、间谐波对电能表计量误差影响较大。通过单一测试信号的参数调整以及多种信号的复合进一步建立了复合测试信号模型,可逼近现实工况信号,遍历各种工作模态,对采集到的激光切割机负荷进行误差预测与补偿,模型预测误差的结果验证了复合测试信号模型的正确性,可为电能表动态误差研究提供依据。

Aiming at the problem of dynamic error testing of electricity meter,firstly,this paper adopts wavelet analysis to decompose the collected signals of three actual working conditions,such as heating furnace load,extracts feature in the time domain and in the time-frequency domain.Four kinds of test signals,including amplitude variations,low frequency steady state,high frequency steady state and high frequency transient,are summarized from the two aspects of amplitude and frequency,which can comprehensively characterize the characteristics of various dynamic signals.And the thin plate spline interpolation is used to establish seven single test signal models,including the envelope signal,amplitude swell,sag,interruption,harmonic,interharmonic and impulse.The influence of parameters of the single test signal on the error is analyzed on the established dynamic signal testing platform.The results show that the amplitude variation,envelope and interharmonic have great influence on the metering error of electricity meter.Then,the test signal model of composite signal is further established by parameter adjustment of single test signal and compound of multiple signals.Various working modes and conditions of dynamic load can be approximated to carry out error prediction and compensation for the load of laser cutting machine.The results of model prediction error verify the correctness of the composite test signal model,which can provide a basis for the study of dynamic error of electricity meter.