Research On Dual Adjustable Arc Extinguishing Coil And Fault Line Detecting Method

With distribution network extending and increasing of apply more cable,the system capacitance current is increasing. Neutral earthing via arcextinguishing coil system is preferable to make sure to put out arc insingle-phase earthing fault. The paper introduces a new arc extinguishingcoil—dual adjustable auto compensable arc extinguishing coil which bases onanalyzing kinds of arc extinguishing coil merits and demerits.The paper analyzes operation state of neutral earthing via arc extinguishingcoil system. It educes normal operation state. It deduces the single-phaseearthing fault current and gets fault current expression. The paper sums up theauto-tune mode of existing arc extinguishing coil, whose merits and demerits areanalyzed.The designed structure of dual adjust arc extinguishing coil isautotransformer and switched capacitor with adjusted short impedance.Switched capacitor is the coarse adjustment and adjusted short impedance is thefine adjustment. It can realize widely continuous and high accurate fastadjustment. It discusses the structure and establishes the equivalence circuit andmathematic model. The designed parameter is quantitative deduced. On the baseof the analyzed result we choose capacity of capacitor and thyristor. Model ofarc extinguishing coil is simulated by used MATLAB/Simulink in various adjustcase. The simulation proves that the merits of the new arc extinguishing coil iswidely adjusting range, well linear character, and little harmonic pollution,highly compensating accuracy, etc.The paper researches on the fault line detecting and analyzes the problemand the shortage of existing fault line detecting method and offers modifiedthree arc extinguishing coil system detecting method include wavelet analyzedmethod, active component method and first semi-wave method. The proposedmethod using fusion policy detects with the previous three methods. It isvalidated in neutral earthing via arc extinguishing coil system. The experimentproves the method using fusion policy can preferably resolve single-phaseearthing case.