Diagnosis of cables in nuclear power plants using joint time-frequency domain reflectometry

Abstract

In this paper, a new methodology which is referred as joint time-frequency domain reflectometry (JTFDR) is proposed to detect and to locate faults of control and instrumental cables in nuclear power plants. Since this method considers information both in time and frequency domain at the same time, we use a linearly increasing Gaussian envelope chirp reference signal as an incident signal which has a adjustable time duration and frequency bandwidth together. After calculating the time-frequency cross-correlation function with two distribution signals, we can determine the fault distance using time delay between the peak of the incident and reflected signals in the cross-correlation. The usefulness of the proposed method in nuclear power plants is verified by the experiments. Experimental results show that JTFDR can be the reliable method for diagnosis of control and instrumentation cables in the nuclear power plants.