Based On Parameter Identification To Measuring The Capacitive Current

When the distribution network occurssingle-phase ground, impaired point flows capacitive current. With the city development, distribution network continue to expanding, making the distribution network to ground capacitive current also increased, leading to the impaired point are prone to producing intermittent arcing ground, causeing excessive amplitude arc grounding overvoltage. If the arc overvoltage durats long time and affects a large area, it may lead to insulation breakdown, the failure expanding. In order to avoiding the expansion of the accident, the neutral point of distribution network need to installe arc suppression coil. Measuring capacitive current is the important parameters of installation of arc suppression coil, determining. Petersen Coil capacity and processing Coil tuning. Therefore, this article mainly research on how to accurately measure the distribution network capacitive current.For low-voltage distribution network capacitive current measurement model, The sym metrical components method was utilized to analyze the symmetric Systems. The relationship between capacitance, insulation resistance and system zero-sequence voltage and branch zero sequence current were invetigated. Quantitative estimates was obtained for the distribution ca pacitive current measurement. In this thesis, Least Squares Parameter Identification method w as utilized to investigate the identification of ground capacitance and insulation resistance and obtained the ground capacitance and insulation resistance of each branch as well as the curre nt system. The simulation results showed that this method was reliable and effective when the system is symmetrical.For asymmetric three-phase power system analysis impact of parameter identification method of capacitive current measurement. Theoretical analysis shows, zero-sequence signal used to detecting capacitive current contains a 50 Hz frequency signal. In order to guarantee the asymmetry parameter identification method for system identification precision capacitive current. Using the optimized method to design a band-pass digital FIR Filter.Paper gives measurement methods to asymmetric system. First, measuring the system zero-sequence voltage and zero-sequence current of each branch signal. Then the measured signal is taken advantage of filters designed for signal processing. Gain ground capacitance and insulation resistance of an identification by least squares. It is measured capacitance to ground current and insulation resistance of the current size. The simulation results shows, to asymmetric system detects parameter identification also accurate, reliable and effective...