Research On Rural Distribution Network Of Smart Meters Dedicated SPD Based On Homemade Rogowski Coil

For the problem of lightning through the power, signals lines and other ways to the town grid smart meter system,analysis of damage ways and means by lightning towards rural smart meter system,exploration of rural distribution network lines and meter box installed in the farmhouse, comprehensive analysis of agricultural distribution network especially the lightning surge of smart meters. For peasant household electric meter grounding can’t meet the requirements, even without a grounded should be online road and table to isolate and equipotential principle design of electric meter in the special pertinence of lightning protection technology measures such as the SPD.For power frequency leakage current of Insulators and lightning impulse current monitoring issues,using electromagnetic induction principle to design a flexible induction coil,raised in the middle of the coil plus a tap, so that one coil can be measured simultaneously in two different frequency and amplitude range of current,which tap measuring insulation leakage current, all coils measure lightning current.Through experimental comparison:using 8/20us lightning current impulse comparison test.The average error of measured value and the standard current shunt is about 1.51%;The average error of measurement of Insulation leakage current and the standard current shunt is about 1.03%.Experimental results and theoretical analysis matched that coil design method has some practical value when detecting insulation leakage current and the lightning current.For multi-level signal surge protection section with the problem of fitting in smart meters,researching on BNC type protection circuit consisting of gas discharge tubes, resistive or inductive, Transient Voltage Suppressor.The protection circuit which takes different decoupling resistor and decoupling inductor values is used to impulse discharge experiments by using Haefely PSURGE 6.1 surge generator. Current flowing via GDT and TVS tested by two developed Rogowski coils to analyze working process from beginning to end and TVS diode power consumption. Experimental results show that the decoupling resistor, inductor values will affect the residual voltage, but as resistance or inductance changes, the impact of residual voltage will gradually decrease. Furthermore,theoretically proposed to further reduce the residual voltage by way of the decoupling resistor in series with an inductance value in order of magnitude μH.Another surge protection for power supply section presents a single chip varistor, double pills in parallel, series single chip varistor gas discharge tube of the three design schemes, surge generator circuit for the use of 8/20μs impact, in which zinc oxide varistor series of gas discharge tube is worthy of study and promote the use, series tests showed that the gas discharge tube leakage current decrease obviously, after impact resistance voltage amplitude are also greatly increased; Two pieces of pressure-sensitive resistors in parallel use, need to select pressure-sensitive voltage similar resistance, to achieve the purpose of flow.