Harmonic Detecting And Measurement Of Electric Power Based On DSP

With the development of electrical industry, the burden and demand of electrical power increase rapidly, harmonic detection becomes an important topic in power system. A harmonic detecting system with high precision is proposed in this paper.Firstly, detailed analysis and comparison are done about normal-used harmonic detecting algorithms. A harmonic detecting algorithm with high precision based on DFT is proposed, and simulations are also done to prove the validity of proposed algorithm.Active power filter (APF) is a new type of power electronics devices used for harmonics reduction and var compensation, and is widely used in power quality condition of power system. Because APF runs at very high voltage and current in the power distribution networks, the effective monitoring of running state is quite significant to the power safety and harmonics disposal effect.Great deals of embedded processors have been appearing since 1980', which makes it possible to construct highly integrated real-time data processing system for dedicated application. As the background work of this paper, the harmonic detecting system developed by the author adopted a special embedded processor that is adept in digital signal processing, which is named as DSP, in order to fulfil the requirement of harmonic detection object. Based on DSP, this harmonic detecting system is expanded with signal regulating circuit, data sampling circuit, communication module and human-machine interface.Thanks to the complex functions of harmonic detecting system, the technique of embedding ASM subroutines into C program is adopted in the programming of system software. The system software is developed in the manner of modularization, so that the adjusting of the function is made very flexible. In help of the real-time interrupt mechanism, continuous rapid signal sampling, as well as contemporary data analysis, display and record is achieved. In virtue of reasonable software stack settings, C program is entitled to call up ASM functions, which optimizes the performance of DSP. Finally, the experiment result has proved that the harmonic detecting system has fulfilled all the technical requirements. Detailed error analysis of the experimental results is also given.