Microcomputer Detection Of Voltage Fluctuation And Flicker

With the development of power electronic technology, much nonlinear, impactive and imbalance load emerges in power system. As a result, power quality has deteriorated. The problem of voltage fluctuation and flicker, one issue of power quality, becomes more and more serious. To solve the problem and improve power quality, effective supervision and exact measurement is primary. However, compared with voltage deviation, unbalance of three phases, harmonics and frequency deviation, fluctuation and flicker are more complex to be detected, its research is relative to scarce, and the measuring devices are much less. Hence, some further research on measuring voltage fluctuation and flicker has been done in the paper.The basic concepts and character values of voltage fluctuation and flicker are introduced firstly, and then the common methods of suppress the voltage fluctuation are discussed. Further more, the process of extracting voltage fluctuation signal and calculating flicker values is analyzed, and the principle of detecting voltage fluctuation and flicker is detailed. By analyzing and comparing the features of the methods and devices in existence, a new digital detection method is present. It is capable of detecting the value of both the fluctuation voltage and the fluctuant power. The proposed method accords with the national new standard promulgated in 2000, and is consistent with the method of detecting flicker recommended by IEC. Compared with the traditional methods, the new one can be realized more easily and save the cost of device effectively. With the help of MATLAB language, the simulation results verify the feasibility and effectivity of the proposed method.Based on the new method, a digital meter of detecting voltage fluctuation and flicker is implemented with Single Chip Microprocessor. Some novel techniques and devices, such as Programmable Peripheral Device, technique of memory page, and the Chinese character menus of LCD, are adopted in the meter. All of them simplify the system hardware, improve the reliability, satisfy human-computer interface, and reduce the cost.