Research Of Electricity Measurement Equipment In Aberration Signal Onditions Based On Lifting Wavelet Transforms

Modern power grid access a lot of new type of electrical equipment such aselectric locomotives, electric arc furnace, frequency control devices have beenconnected to the grid, these loads have the characteristics of nonlinear and strongimpact, so that the signal of the low pressure side of the grid become seriousaberration. However, the energy meters we are using now which are designed basedon traditional power theory, and regardless of the Nonlinear,and the impact load,thisis very unreasonable. The traditional energy meters would cause less measurement,took economic losses to the power company. These distortion signal feed back to thepower grid, made the power quality decline, which can cause serious safety accidentsin production, if these signals can not be accurately measured, the responsibility ofcourse can not be traced. Developed specifically electric energy meter for thesenonlinear, impulsive load signals, which has scientific significance, as well ascommercial value and social value.This paper studied a electric energy measuring technology under the condition ofdistortion signal, designed a electric energy metering device for nonlinear, impulsiveload.Firstly, the paper create a mathematical model of the grid signal and the complexelectrical signal is divided into steady-state distortion signal and transient distortionsignal, then,paper extract the typical characteristics from the complex signal anddescribe the complex signal with mathematical. on this basis, paper analyze girdpower flow and research reasonable plan of the energy measurement,under theconditions of the distortion signal.Secondly, the paper simulate lifting wavelet transform to use MATLAB software.then, discuss wavelet transform sub-band measurement of electrical energy andchoose reasonable wavelet decomposition, by comparing use of different wavelets toanalyze the accuracy of the distortion signal. based on this, paper proposed db4asenergy measurement wavelet basis function. paper also analyze and simulate differentcharacteristics signal throungh lifting wavelet. verified to improve the accuracy ofthe wavelet energy measurement, and through comparing the first generation waveletcomputation time, to enhance the superiority of the wavelet in real-time measurement.Finally, be aimed to the preamplifier circuit of the power meter have the problem of limited bandwidth, low overload ability, the frequency leaks and unable to measurethe impact load energy accurately, We designed the Electric Energy MeasuringSystem based on lifting wavelet transform, and provided the software and hardwaredesigning. In order to meet the information processing speed requirements of thelifting wavelet transform. In order to improve the processing speed and computingprecision.We selected A/D+DSP+MCU structure. The MCU is used to the systemcontrol,and the TI’s floating-point DSP is used to carried out the power calculation.The article also gives the overall system software design, flow charts and descriptionsof each subroutine.