Research On Measuring Method Of The Voltage Fluctuation And Flicker

As a result of nonlinear, impact and imbalance loads, the power quality could be significantly reduced. The voltage fluctuation and flicker is one problem of power quality. And it becomes more and more serious. When voltage fluctuation occurs, the sensitive loads and ultra-sensitive loads can't work well. And if the voltage fluctuation is very serious, there will be a great immeasurable loss caused by it. Flicker will cause light glitter, television images distorted and visual fatigue of human.In order to solve the problem of voltage fluctuation and voltage flicker and to improve the power quality, the effective supervision and exact measurement is primary. So I choose this task, the measuring method of voltage fluctuation and flicker, for further study. And based on this method, a inspection device has been made.The basic concepts of voltage fluctuation and flicker are introduced in detail. The reason of causing voltage fluctuation and the common methods of mitigating the voltage fluctuation are also discussed. The principle of examining voltage fluctuation signal and the method of calculating the value of voltage flicker are elaborated systematically. By analyzing and comparing the features of the measuring method, a digital detection method which is good at real-time property is selected to use in this device. The selected method accords with the national standard issued in 2000, and it is consistent with the principle of IEC recommended flicker meter.The design of this device contains two parts. One is hardware design, and the other is software design. The components of this device mainly include, a PC, a data acquisition card, voltage sensor, etc. The software of this device is completed by the soft of virtual instrument-LabVIEW which is a graphic-based programming language. According to its functions, the software of this device can be divided into two parts, the initialization subprogram and the circulation subprogram. The circulation subprogram is composed of data acquisition subroutine, the R.M.S. values calculation subroutine, voltage fluctuation and P_st values calculation subroutine, and P_lt calculation subroutine. The device is realized...