Development Of Network Harmonic Analyser Based On Fast Foutier Transform

In the power systems, the harmonic produced by various harmonic sources has contaminated the power systems, and affected the entire power systems setting. Either from guaranteeing electrical power systems and power supply systems secure and economic running or from guaranteeing the equipment and person's security, it is urgent necessary to monitor and limit the harm influence generated by the harmonic pollution.With the progress of the harmonic arithmetic, the instruments for harmonic analysis have become more and more. In recent years, much work has been done on researching the two aspects in foreign and home, but it still exists some shortcoming. Although foreign instruments are very precise, the price is generally too high; most of the homemade instruments are not very precise and have not complete function. This paper refers to the related national standard and the domestic and foreign similar products technical specification and the practical application requirement, base on the existing harmonic analyzer, develops a new analyzer which bases on FFT harmonic arithmetic in software and DSP chip in hardware. It has many merits, just as the high precision, the complete function, the low price and so on.Firstly we study FFT harmonic arithmetic and carry on massive simulations experiment with Matlab to this arithmetic, then analysis the precision of this arithmetic and forecast the feasibility of this system.Secondly we design and realize the analyzer's hardware architecture. It include the selection of SCM for controlling, the program for controlling; the selection of DSP for data processing, the arithmetic researching and programming, the designing of the analyzer's related circuit, RAM and PLC. At last we carry out on the site measurement. Referring the result we analysis the error resource, find out the way to reduce it and make sure the precision rank of the analyzer.The research results of this paper have practical significance and broad market prospect in the electrical power system.