Channel Modeling And Characteristic Analysis Of Power Line Communication In Distribution Network

A reliable,economic,flexible and elastic information communication network is the prerequisite for the realization of intelligent control and management of the distribution network.With the development of the urban distribution network,its structure is becoming increasingly complex,the complementary communication mode of “wireless+wired” is one of the development directions of future distribution network communication technology.Power line carrier communication(PLC)technology uses the existing power line as the communication channel,it has natural network channel advantages and flexible application,it can adapt to the complex structure of the distribution network with multiple branches and multiple loads and have become an important supplement to wireless communication.At present,most of the urban medium-voltage distribution networks are hybrid networks composed of cable lines and overhead lines,the coupling mode and transmission characteristics of carrier signals on cable lines and overhead lines are quite different.Therefore,establishing the carrier channel model of the hybrid medium-voltage distribution network and analyzing the transmission characteristics of the carrier signal in the hybrid mediumvoltage distribution network have important theoretical significance and practical value for the planning,design and promotion of PLC in the power Internet of Things.Firstly,through the loop analysis method,the calculation method of the unit length parameter of the 7-conductor model of the armored buried cable of the medium voltage distribution network is obtained.Considering that the buried cable is a 5-conductor model in actual operation,the parameter calculation method of the buried cable 5-conductor model is obtained by the Gaussian elimination method.Secondly,The input impedance method of PLC channel modeling for hybrid distribution network is proposed.This method combines the structural characteristics of the distribution network,divides the distribution network into different types of network branches,and gives the calculation method of the input impedance matrix of various branches,The chain parameter matrix of the transmission line and the input impedance matrix of each node can be obtained The voltage vector of any node in the network is obtained,and the PLC channel modeling of the hybrid distribution network is realized.Teirdly,The BLT method of PLC channel modeling for hybrid distribution network is proposed.This method solves the voltage vector of any node in the network by listing the total propagation matrix and node scattering matrix of the distribution network,and realizes the modeling of the PLC channel of the hybrid distribution network.The modeling method is not restricted by network topology and line types,and has strong adaptability and portability.And considering that the BLT channel modeling method has the problem of excessive BLT equation order in practical application,combined with the input impedance method,an improved BLT method is proposed,which can effectively reduce the order of the BLT equation.Finally,based on the realization of PLC channel modeling,further study the line length,number of branch networks,branch network distribution,cable shielding layer and armor layer grounding resistance,PLC equipment coupling mode,reactive power compensation in the medium voltage distribution network.The equipment analyzes the influence of the PLC signal transmission characteristics of the hybrid power distribution network,and provides a reference for the practical application of the PLC technology of the hybrid power distribution network.