Design Of Partial Discharge Monitoring Terminal For Power Cables Based On NB-IoT

With the rapid development of science and technology,people’s life and production have been inseparable from electrical energy.Cable as one of the main power transmission equipment,its working state directly affects the reliability of power supply.Insulation aging or damaged cables are prone to partial discharge,which accelerates insulation damage and eventually leads to more serious power supply accidents,resulting in huge economic losses.The partial discharge signal of cable can reflect the damage degree of cable insulation to a certain extent,so it is of great significance for the partial discharge of cable to improve the stability of power system.Through the research and analysis of the existing cable partial discharge monitoring terminal monitoring principle and implementation method,this paper designs a partial discharge online monitoring edge agent terminal based on pulse current method.This paper first analyzes the causes and development process of cable partial discharge and the characteristics of the existing cable partial discharge monitoring terminal,and determines the feasibility and significance of the terminal design combined with the research status.Then,according to the functional requirements of the terminal,the hardware and software of the terminal are designed.This paper designs a hardware platform with FPGA as the core and A / D conversion and data transmission modules to realize the functions of local discharge signal acquisition,processing and transmission.On the basis of hardware platform,the program design of cable partial discharge signal acquisition,distribution parameters,end extraction of characteristic fingerprint parameters and data upload based on narrowband Internet of Things are completed.Finally,three kinds of discharge models were designed using cross-linked polyethylene.The terminal test was completed by building a partial discharge test platform,and the partial discharge pattern recognition was completed using the reverse propagation neural network for the terminal data.By comparing the recognition results of the signal extracted by the terminal and the original discharge signal processing,the results show that the monitoring terminal designed in this paper can effectively complete the acquisition and processing of partial discharge signals.Based on the hardware and software design of the cable partial discharge signal monitoring terminal,this paper proposes a method of end-side processing high frequency signal,that is,high frequency partial discharge signal for statistical parameter analysis.Terminal extraction and uploading replaces the traditional design method of transmitting the whole partial discharge signal with a small amount of characteristic parameters that can characterize the partial discharge mode,which can greatly reduce the amount of data required for subsequent storage and processing,and has important significance for the design of intelligent monitoring terminals such as Internet of Things.