Fault Detection In Complex Writing Networks Based On The Broadband Quasi-orthogonal CPPM Signal

Cable network is the main carrier for the transmission of electrical energy and information in various large-scale complex systems and equipment.With the continuous improvement of equipment automation level,the topology of cable network becomes more and more complex.Due to the insulation aging of cables,installation and operation environment and external forces,cable network faults are difficult to avoid.Accurately locate and identify faults in cable network can quickly eliminate faults and minimize the damage caused by cable network faults.In order to achieve accurate positioning and identification of cable network faults,this paper uses multi-path wide quasi-orthogonal Chaotic Pulse Position Modulation(CPPM)and distributed detection strategies to detect cable network faults.The main contents of the research are as follows:1.This paper describes the application background of cable networks and the causes and types of faults in cable networks.By enumerating common methods of cable network fault detection and analyzing and comparing these methods,the author proposes the use of CPPM signals as detection signals in combination with distributed detection strategies to detect cable network faults.2.This paper analyzes the transmission characteristics of the cable.Based on the ABCD matrix,the author carries on the channel modeling to the cascading cable network and the branch cable network respectively,finally he verifies the correctness of the model through simulation examples.3.The author introduces the generation process of CPPM signal,and theexperimental results show that the signal is of good quasi-orthogonality.The CPPM signal can be used for distributed diagnosis and online detection of cable networks.What's more,when the measurement range reaches 850 m,the relative error is less than 2.3%.4.The author sets up an experimental platform,using CPPM signal as a detection signal combined with time-domain reflection detection principle and distributed multi-point detection technology to respectively achieve unambiguous positioning and impedance mismatch measurement of Y-type and Double-Y type cable network branch faults.The experiment verifies that this method can achieve the online detection of cable networks.5.The author analyzes the detection principle of the time domain transmission method,sets up an experimental platform,uses the CPPM signal as the detection signal in combination with the time domain transmission method and distributed multi-point detection technology to achieve the unambiguous positioning and impedance mismatch measurements of the fault location of the branch position and trunk position of the Double-Y cable network.