The Coupling Principle And Impedance Matching Research Of The Clamp Inductive Coupler On Medium Voltage Distribution Network Carrier Communication

Most of the urban distribution networks are cable lines,and there is a wide application space in the carrier communication of medium-voltage distribution network cable lines on the clamp inductive coupler.The medium voltage cable line is mostly a three-core cable,and each phase of the core wire is covered with a shielding layer.The carrier signal can be coupled to the three-phase cable core and coupled to the shielding layer through the clamp inductive coupler.The analysis of coupling principle and the improvement of coupling efficiency is a technical difficulty in its popularization and application.This paper is to study the coupling principle and impedance matching of card inductive coupler.The topic selection has important theoretical significance and engineering application value.In this paper,based on the structure of the clamp inductive coupler and the structural characteristics of the cable line,the coupling mechanism of the clamp inductive coupler is analyzed.The mathematical model of the clamp inductive coupler is derived by using the Rogowski coil method.And ansoft electromagnetic simulation software and laboratory tests are used to verify the correctness of the mathematical model of the coupler.Based on the coupler mathematical model,the effects of coupler magnetic ring air gap,magnetic ring relative magnetic permeability,winding turns and coupler frame size to the coupling efficiency of the cable side are analyzed.Finally,the equivalent T-type circuit of the coupler mathematical model is used to carry out the Smith circle impedance matching and the impedance matching circuit of the normalized Chebyshev bandpass filter,and the matching effect is verified by simulation.The simulation shows that the matching circuit based on the normalized Chebyshev filter network can achieve better power matching in the narrow band range of the 50-500 kHz band.