Research On Power Quality Detection Based On DSP

Electric energy is wildly used in people's life,its application has been one of the most important symbols of national development and comprehensive nation power. With the development of the power electronics technology, kinds of non-linear loads are greatly applied. Therefore, it gradually deteriorates the power quality of electric grid. To promote the safe and stable operation of the power system, there is an urgent need for the monitor of parameters of electric power quality.In this paper, the concept of power quality, some related national standards and the situation of academic research and industry development of power quality monitoring technology have been introduced in detail. Then the harm of harmonic and kinds of general analysis methods applied in inharmonic monitoring have been discussed. Based on the national standards on electric power quality, a novel power quality monitor system has been designed. From the view of both the hardware and software, the designed methods and operation mechanism have been analysis.The data acquisition module are designed based on the hardware of TMS320F2812, voltage sensor series VSM025A, current sensor series CS040G and industrial LCD monitors LR080AR/D. the data processing module are consisted by the communication module and HCI module. And it accomplishes the principle of power quality detection system design and production of experimental apparatus. The design of hardware focuses on the data collection, in order to ensure the measured current and voltage to reach the range of collection system, a signal conditioning circuit is applied to modify it, which is constituted by mutual inductor and OPAMP. The keyboard is used to achieve the function of data inputting and command transmission, and the displaying part is designed based on the Large-scale dot-matrix LED.In this system, the software are mainly applied for the work of system initialized configuration, the programming of A/D transfer, the programming of FFT, data analysis and data transmission. However, it would be better to implement FFT algorithm with C language, and further improvements can be made by twiddle factor pre-storage, bit reverse algorithm and stages of butterfly. And then, the N point real signal is divided into two parts such as odd sequence and even sequence, which can be used to form an N/2 point complex signal sequence. The result of FFT can be applied to form an N/2 point complex signal sequence; therefore, the FFT calculation efficiency could be promoted. Moreover the calculations based on FFT and method of symmetrical components of values as follows are accomplished: harmonics, root mean square of phase voltage and line voltage as well as phase current, frequency, Positive sequence voltage, Negative sequence voltage, and Zero sequence voltage. Finally, A LCD driver program is designed to display all the results.Based on our designed system and other related experimental instruments and tools, the entire system are tested and the reached power quality parameters are as following:spectrum, RMS phase voltage, line voltage rms value, positive sequence/negative sequence/zero sequence voltage, frequency, phase voltage waveform. The result of test and the analysis of error indelicate that the software and hardware operated correctly, which can achieve the desired task.