Non-Intrusive Cable Fault Diagnosis Based on Inductive Directional Coupling

Abstract

This paper presents and applies an inductive directional coupling technology based on spread spectrum time domain reflectometry (SSTDR) for non-intrusive power cable fault diagnosis. Different from existing capacitive coupling approaches with large signal attenuation, an inductive coupling approach with a capacitive trapper is proposed to restrict the detection signal from transmitting to power source and to eliminate the effect of the power source impedance mismatch. The development, analysis, and implementation of the proposed approach are discussed in detail. A series of simulations and experiments on cables with different fault modes are conducted, along with comparison of existing capacitive coupling, to verify and demonstrate the effectiveness of the proposed method.

Cable Monitoring Using Broadband Power Line Communication

“…Time variation, which may occur due to interference, has also been identified. Article [32] describes the possible detection of cable fault diagnosis by spread spectrum time domain reflectometry (SSTDR), which is a non-intrusive method. The authors test their idea using a simulation, and then experiment on a short cable that is approximately 20 m long.…”

Current Only-Based Fault Diagnosis Method for Industrial Robot Control Cables

“…Until now, the efficiency of reflectometry-based methods for cable diagnostics has been demonstrated [8][9][10][11][12][13][14]. In particular, time-frequency domain reflectometry (TFDR) [12,13] proves the robustness of fault diagnosis in a variety of conditions because it utilizes information in time and frequency domains.…”

“…In addition, because automated machines in the factory floor are not easily accessible, additional equipment is not preferable when conducting diagnosis. Therefore, all the diagnosis methods that require additional equipment [8][9][10][11][12][13][14][15] are not preferable. In addition, the automation machines in manufacturing lines work round the clock; therefore, using an offline diagnostic approach with no online diagnostic capability is not preferable.…”

“…(1) Only three-phase currents are used. Therefore, additional sensors, signal generators, and signal inducing devices are not required, making the method cost efficient, whereas the other methods [8][9][10][11][12][13][14] need additional devices to generate a reference signal and to inject the reference signal into target cables. For example, an arbitrary waveform generator is used to create the designed reference signal in [8][9][10][12][13][14].…”

“…In [11], a network analyzer is used to inject sinusoidal waves into the target cable and to measure the reflected waveforms. For signal injection, an inductive coupling device is used in [9], whereas others [8,10,[12][13][14] utilize three-way connectors, such as T-connectors, and directional bridges. (2) No manual feature extraction with prior knowledge and mathematical values of cable parameters is required, whereas reflectometry based methods need physical cable parameters, such as the information of cable length, to design an incident signal by adjusting signal bandwidth, center frequency, and time duration.…”