This paper presents a novel wavelet-based fault-location scheme for aged cable systems when synchronized digital fault recorded data are available at the two terminals of each cable. The proposed scheme estimates the fault location in multiend-aged cable systems using the theory of wavelet singularity detection as a powerful signal processing tool. The arrival of the first and second voltage traveling waves at both ends of the power cables can be identified reliably. The developed wavelet processing scheme is applied on the modal coordinates instead of the phase coordinates. The proposed scheme has the ability to eliminate the impact of the change in the propagation velocity of the traveling waves on the fault-location calculations. This will help solve the problem of cable changing parameters, especially the change of the relative permittivity of the cable with age. The method is valid even with faults that are very close to busbars. Characteristics of the proposed fault-location scheme are analyzed by extensive simulation studies using Alternative Transients Program/Electromagnetic Transients Program. The results indicate an accepted degree of accuracy for the suggested fault locator.

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A k t r r t A digital algorithm for the protection of parallel "fuloo linea bar beea implemented on a 16-bit dngle board co(~pp1c1: It haa been tested on a physical model codsting of two rpchtoMwu " i connected through a double circuit lirre. Tbe algorithm is baaed on comparing magnitudes of amcats of two prnllel linea Details of the experimental set-up rab tbe d t s of oa-line tests for various oparriag conditions arc prerented A procedure to adjua tbe relay setting8 adapcively is d m iacorpontsd The resulk? illustrate the succwful opardoa of the algorithm in detecting faults on parallel lines.