It improves the detection of electrical faults related to degradation of insulation. The third method, called RART (Reflectrometry combined with a time reversal process), is also based on the principle of reflectometry and time reversal. It allows the characterization of aging of electrical cables. The second method, called TRR (Time Reversal Reflectometry), is based on the principle of reflectometry and time reversal. It improves fulat's location and the detection of singularities on cables regardless their lengths. The three methods can briefly described as follows : - The first method, called "adaptive correlation", provides a new algorithm to compensate signal's dispersion. Another barrier, the detection of soft faults, represents currently a major issue of wire diagnosis because the amplitude of soft faults signatures is very small and sometimes noisy or masked by the proximity of higher pulses. First barrier, the phenomenon of signal dispersion in cables makes the detection of faults and of cable aging difficult or imprecise. Each of these methods circumvents one or more of the barriers encountered during this research's duration. In this respect, three new methods for wire diagnosis have been studied and developed to improve and ease the detection and location of soft wire faults. Improvements in measurement and treatment are necessary to overcome the limitations of these methods. Generally, these methods are appropriate to detect and locate hard faults but soft faults are virtually transparent to them because this kind of fault has very low electrical consequences. Among them, reflectometry methods are widely used and easily embeddable. Several methods have been developed to test the status of cables.
Therefore, the knowledge of the state of wire networks and particularly the detection of their faults is important. Current practices show that a significant number of failures and malfunctions of these systems come from faults in wired links and not from electrical devices. However, the reliability of these systems is partially based on the reliability of electrical networks. The use of electric cables in electrical systems has been significantly increasing over the last decades. The importance of ABCD matrix modelling in trans-mission line theory and its indisputable advantages over other tools are presented and discussed in this paper. Indeed, the authors claim that most of the transmission line results which are usually obtained by other means can more easily be produced when nothing more than the ABCD matrix model is used. 1,3,4,8 The concepts of image impedance and ABCD matrix can be used as an alterna-tive approach to the modelling of the two-wire transmission line, although the oper-ational advantages and capabilities of the ABCD matrix model as a convenient tool for solving almost all problems related to the transmission line are not fully stressed. Several physical interpretations can be obtained from the solution of these equations. Partial differential equations for voltage and current along the line are traditionally derived from an elementary line section of length Dx using the distributed param-eter model for a two-wire transmission line. Some standard examples of transmission lines are analysed through the use of ABCD matrices and a case study of a balun network is presented. Therefore the consideration of frequency-dependent parameters can be carried out in a simple way compared with the time-domain. An important advantage of this approach is that the transmission line modelling arises naturally in the frequency domain. The aim of this note is to show that all the behaviour of a two-wire transmission line can be directly derived from the application of ABCD matrix mathematical concepts, avoiding the explicit use of differential equations.
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