Energy Metering System Harmonic Study

The electric energy is the main energy of the national economy and people's lives. It plays a very important role in the development of the country. Electric measurement involves the tripartite economic benefits of power plant, power supplier and power user as well. It is also important bases for calculating many technical specifications. At present, wide applications of non-linear loads distort electric current & voltage wave from sine wave. The harmonic effect on electric measurement is focused in all level research fields. On the base of the existing research achievements of this subject, this dissertation made a study of harmonic problem in electric energy measurement system.Structures of induction electric energy meter and electron electric energy meter are introduced in chapter two, and operation principles are specially explained in detail. The error of two meters is also analyzed under the condition of the distortion wave, with measurement principle. At the same time, a performance comparison is made between the two measurement meters.Applying the theory of instantaneous reactive power, chapter three put forward three-phase basic frequency rotate transform theory with moving average filter and set up detection model of three-phase basic wave power. Single-phase circuit was also introduced about basic wave detection method. By the k-multiple frequency rotate transform, k time harmonic can be separated. Chapter four focused on simulation of the model with C language and MATLAB. Proving the correctness of model, filter method was also compared through simulation. Simulation experiments were carried on, and harmonic influence upon electric energy measurement is analyzed to prove the content mentioned in chapter two.In chapter five, the hardware & software design was expatiated for a harmonic metering device to realize standard digital energy metering function. The design in this dissertation utilized circuits to sample the data of both voltage and current, ARM to rotate transformation data to get the values of basic wave & harmonic voltage and current, and algorithm to get the power of basic wave & k time harmonics. The hardware and software development adopted blocking design method. The hardware included: pre-posed circuit, sampling circuit, ARM circuit and display circuit. The software included: main procedure, MAF sub-procedure and power algorithm sub-procedure.