Effect Of Harmonics On Power Measurement

With the broad application of the electric and electrical technology in the industry branches and the power apparatuses, the number of non-linear loads is much more and more, and the capacity of them is biggish, in addition, with the extensive use of electric traction engines and large-scale equipments of steel rolling, a mass of harmonic is injected into the power system, which pollutes the power system and produces the waves of voltage and current to be aberrant serious. Electric energy is main energy source of country economy and people's life, electric energy metering relates to the three sides of power generation, power supplier and power user. Under the condition of marketing economy, improving the accuracy of electric power metering is of most importance. So, studying the influence of harmonic to electric energy metering deeply is very necessary.The importance of electric energy measurement is explained at first in economic settlement and the technical indicator calculating, at the same time, the fact that the universality and serious harm of harmonic in the power system is described in the paper. It indicated the important meaning of study of harmonic. Through consulting a large number of domestic and foreign materials, the structure and working principle of induction and electron electric energy meter are introduced. And then the reason of electric energy meter registration error is explained. It points out the irrationality of electric energy measurement under current electric energy measuring standard through the expression formula of the electric energy consumed by linear loads and non-linear loads, and introduces a new measuring way, which is attested feasibly and rationally by the simulated experiment.Derive formulas of harmonic power measurement by using the principle of the Fast Fourier Transform (FFT).The harmonic energy and harmonic factors of the 10KV supply and three-phase half-wave rectifier composing system are calculated by modeling with the MATLAB/SIMULINK tools, which certificated the new measuring way introduced in this paper to be true by comparing the calculation results with the theoretical analyzed conclusion.