We have demonstrated that frequency domainreflectometry (FDR) can locate the position ofdegradation or abnormality in a cable with theassistance of inverse fast-Fourier transform (IFFT).Although it is easily understandable that this FDRIFFTmethod can be applied for a location attempt of acable with more than one abnormality, we have notdemonstrated this so well experimentally. Therefore, weheated two different positions on a coaxial cable of 31.5m insulated with low-density polyethylene using twoheating chambers with an effective chamber width ofaround 45 cm set at positions 19.7 and 24.7 m from thecable end connected to the analyzer. As a result, it isclearly indicated that the two positions can be located ifwe heated there only by 10°C.In addition, the two positions at which the cableenters and goes out of the heating chamber can berecognized clearly. This means that the FDR-IFFTmethod we are developing exhibits a good spatialresolution in a way that the two positions with a mutualdistance of 45 cm are clearly recognizable.
展开▼
