Abstract:In this paper, we propose a method to reduce the blind spot based on signal processing that indicates the minimum length of a cable under test in the time-frequency domain reflectometry without using an extension cable or adding a new high-speed hardware component. The time-frequency domain reflectometry adopted the proposed method can be achieved with not only a simple modification of the previous system but also a simple technique based on signal processing. The experimental results show that the proposed method allows us to estimate fault distance on the cable with high spatial resolution. Keywords: time-frequency domain reflectometry, blind spot, spatial resolution, fault detection Classification: Science and engineering for electronics Technol., vol. 8, pp. 1278Technol., vol. 8, pp. -1283Technol., vol. 8, pp. , 1990. OTDR with high-spatial resolution for short haul applications," IEEE Photon. Technol. Lett., vol. 9, pp. 1140-1142 Y. J. Shin, E. J. Powers, T. S. Choe, C. Y. Hong, E. S. Song, J. G. Yook, and J. B. Park, "Application of time-frequency domain reflectometry for detection and localization of a fault on a coaxial cable," IEEE Trans.

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Abstract:In this paper, we propose a diagnostic method for insulated power cables based on wavelet energy. The power cable has the degradation problem because of the thermal stress and the electric stress and the risk increases with aging time. Thus, we need to know the aging condition for the power cable. The cable aging condition can be verified by using the wavelet energy because the attenuation constant is increased by the cable aging. That is, the wavelet energy decreases as the cable aging condition deteriorates. To confirm the effectiveness of the proposed method, the real experiments are carried out for four types of the old cables with the different aging times.

Abstract:In this paper, an impedance change localization method for a live underground XLPE cable with a straight joint using the time-frequency domain reflectometry (TFDR) is proposed. To inject the reference signal to the live cable, an inductive coupler is used. Thus, the characteristics of the cable and the coupler are analyzed and the reference signal is designed to fit for the characteristics of the coupler and the cable. The on-voltage experiment using the TFDR is performed to localize the impedance change of cable. As a result, the accuracy of the TFDR for the on-voltage cables is proved. Keywords: fault localization, inductive coupler, on-voltage experiment, time-frequency domain reflectometry Classification: Electronic instrumentation and control Instrum. Meas., vol. 41, no. 6, pp. 762-767, Dec. 1992. References