The Research Of Harmonic Measurement Of Power System Based On DSP

In recent years, the capacity of harmonic in the power system have largely increased and waveform distortion of electric power become more and more serious because of the adoption of direct current transmission and gentle alternating current transmission, the fast development of the electrification railway, and large quantity application of power electronic equipment in chemical engineering, metallurgy, coal…etc. All of these have a worst influence to the running of power system. The harmonic measurement is a main basis in the study of harmonic problems. It will be very necessary to prevent the harmonic bane and to assure the safe running of power system with the accurate capacity of harmonic measured in real time.After analyzing the severity of the harmonic problem and some related harmonic standards, this paper put forward a method that realizes harmonic detection based on TMS320F2812, the paper also present the feasibility and advantage of the method. According to this, the author had primarily completed two works as follows.The first, the selection of the harmonic analysis algorithm is the key to complete the harmonic measurement. After analyzing harmonic measurement principle, the paper compared some current method using in harmonic analysis and discussed their advantages and disadvantages. At the same time, the paper pointed out that the methods based on FFT in common use to deal with the harmonic measurement have the frequency spectrum leak and the precision of harmonic results calculated by this method is not high. After analyzing in detail the reason of frequency spectrum reveal and the characteristic of various window functions, the paper in succession points out to adopt the window of Blackman- Harris is a superior selecting for FFT algorithm based on cosine-window and interpolation for harmonic analysis in power system. The B-H window can largely reduce mutually interference error of the integral harmonic and the non-integral harmonic. At the same time for getting the more accurate result, a kind of two-interpolation computation harmonic parameter is put forward, and the paper also bring forward related harmonic computation formula with realizing steps. An example of algorithm...