Low-Voltage Distribution Network Topology Identification Method Based On Broadband Power Line Carrier Channel Characteristics

Accurate network topology is the foundation for supporting low-voltage distribution network to carry out line loss management,electric larceny prevention work and network transformation.It is of great significance for the distribution network to reduce power loss and save energy,and to improve the intelligence and information level of low-voltage distribution network.However,in the construction of the actual low-voltage distribution network,the increase in power load and the change of power facilities have caused the problems of untimely update of the topology information of low-voltage distribution network and the inconsistency of the topology file with the actual situation.Therefore,topology identification of low-voltage distribution network is urgently needed.In view of the high installation,operation and maintenance cost of the current signal injection method of low-voltage distribution network topology identification,and the difficulty of practical application of the data analysis method,considering the advantages of broadband power line carrier communication technology and the broad prospects for its application in remote meter reading systems,this paper proposes a new type of low-voltage distribution network topology identification method based on broadband power line carrier communication channel characteristics.Firstly,a low-voltage power line channel model is established and the channel characteristics are analyzed based on this.Analyze the frequency selective attenuation characteristics of the low-voltage power line channel,and introduce the notch frequency point,so as to derive the calculation method of the branch length based on the frequency selective attenuation;analyze the average channel attenuation of the topologies of different complexity,and propose the frequency response peak fitting and decomposition of the complex simplifies the calculation of the length of the complex branch line step by step to the calculation of the length of the non-branch line,thereby deriving the line length calculation method based on the average channel attenuation.Secondly,the topology identification method of complex low-voltage distribution network is proposed.Based on mathematical morphology,the frequency response of the T-branch channel is simulated to extract the peaks to fit the frequency response of the corresponding non-branched channel,and then based on the channel characteristics,the topology identification process of the T-branch line is proposed;based on the singular value decomposition,the frequency response of the complex branch channel is decomposed,and the frequency response of each T-branch channel is extracted,and then based on the channel characteristics and the T-branch line topology identification method,the topology identification process of the complex branch line is proposed;combined with the actual low-voltage distribution network characteristics,the identification method based on the above two topologies,propose the flow of low-voltage distribution network topology identification method.Finally,an experimental platform was built with real objects in a laboratory environment to verify the method.Using power lines,signal generators,spectrum analyzers and other equipment to build a power line test network,verify the correctness of the topology identification methods of T-branch lines and complex branch lines;using an analog master station and a centralized power line carrier communication function,a low-voltage distribution network topology identification experiment platform was built by the power converter,smart meters,and carrier nodes.By simulating a typical low-voltage distribution network topology,the correctness of the low-voltage distribution network topology identification method proposed in this paper was verified.The experimental results show that the method proposed in this paper can not only accurately identify the topology of low-voltage distribution network,but also calculate the length of each section of the line,which has very good practical value and promotion significance.