Development Of An Impulse Voltage(Current) Measurement System Based On Virtual Instrument Technology

In electrical power system, electrical equipment during operation may suffer fromnatural lightning overvoltage and instantaneous large current, in such a case, theequipment insulation is easy to be damaged, which threatens the stability of power grid. Inorder to test performance and tolerance of the equipments under impulse voltage (current),simulated natural lighting impulse voltage and high current，which are generated byimpulse voltage (current) generators, are needed. And in order to obtain the mainparameters of the impulse waveforms for further research, an impulse measurementsystem is needed.In related IEC standards, specific introduction and definitions for the impulses aremade and methods are introduced for calculating some parameters of the impulses underspecial conditions. Nevertheless, in practical application, some problems, during researchand design of the impulse measurement system discussed in this paper, still need to besolved. To solve these problems, researches were done and effective methods areproposed，for instance，effective methods were proposed to determine the terminal point ofwaveform beginning flat part and the chopping instant of a chopped lighting-impulse.Standard theories were introduced for base curve fitting and K (f)factor digital filterdesign. Moreover, some difficulties also appeared about the impulse measurementsoftware and its included programs design. To cope with these difficulties, awell-performing impulse measurement system is designed based on Virtual Instrument (VI)technology and the programs are designed by LabVIEW.The software, the core of the measurement system, has passed the accuracy test byIEC standards and the uncertainty of the measurement results is also calculated.