Study And Realization Of Voltage Fluctuation And Flicker Measuring Method

Voltage fluctuation and flicker is an important power quality problem. It is caused mainly by fluctuating load, for example, electric arc furnace, rolling mill, electric locomotive, electric welding, etc. in power supply system. Voltage fluctuation will affect the normal operation of sensitive loads, seriously endanger the safety of equipment, or cause huge economic losses; Voltage fluctuation also causes flashing lights, makes people's visual discomfort and fatigue, even irritability and generates unbearable emotions, thus reducing the work efficiency and quality of life.In order to suppress voltage fluctuation and flicker, and improve power quality, we must first measure the voltage fluctuation and flicker so that understands its severity. Therefore, this article studies deeply the measurement method of voltage fluctuation and flicker, and on this basis designs a kind of detection device of voltage fluctuation and flicker based on DSP.This paper simply introduces the revelant basic theory of voltage fluctuation and flicker, systematicly elaborates the detection method of voltage fluctuation. IEC flicker measurement method is studied by MATLAB simulation. The calculation process of this method is more complex, and it is difficult to achieve in the digital detection device. FFT-based flicker measurement method omits the more complex filter design of IEC method, which simplifies the calculation process, easily realized digitally. So this paper uses this flicker measurement method and studies it deeply.The implementation of voltage fluctuation and flicker detection device includes hardware design and software design. For hardware, the hardware structure using TMS320C5402 DSP(digital signal processor) chip as the core component is designed. It mainly includes analog signal changing and conditioning unit, signal acquisition unit, DSP core unit, memory unit, communication unit, the man-machine interface unit, etc. For software, FFT-based flicker measurement method is selected, and the voltage fluctuation and flicker measurement software is designed by using the integrated development environment CCS and mixed C and assembly language programming. The software mainly includes system initialization subroutine, A/D sampling subroutine, the voltage RMS calculation subroutine, voltage fluctuation calculation subroutine, FFT subroutine, the instantaneous flicker sensation calculation subroutine, short-term flicker value calculation subroutine, long-term flicker value calculation subroutine, etc. The article also prepares the linker command files(.cmd files) to allocate the DSP memory space, and the target code is generated and debugged by using the integrated development environment CCS.The detection device ultimately realizes voltage fluctuation and flicker measurement, and the way to reduce the errors is found through calibration and error analysis.