In this study, it was investigated that the possibility of electrical discharge pulse sound for new inspection technologies
instead of hammering test. Electrical discharge pulse sound was applied for hammering sound and sensor by using sound
detection was applied for optical fiber vibration sensor. The numerical analysis result using the FEM and the experiment
result along with the single pulse discharge was compared. As the result, it was estimated that the generation factor of the
elastic wave was same as the current duration. These results become possible to estimate the propagation characteristic
of elastic wave. Evaluation of electrical discharge sound for hammering test by using optical fiber sensor was
investigated. Defect shape and scale was estimated from comparison with detected waveform by using optical fiber
vibration sensor and simulated waveform. As the results, it was considered that electrical discharge sound was available
for hammering test.
This paper describes some experimental results on a fundamental phenomenon of the single pulse discharge. The single pulse discharge phenomenon was measured by using the optical fiber sensor, piezoelectric sensor and current transducer. In order to investigate the generation factor and propagation characteristic of acoustic emission (AE) by single pulse discharge in oil, the voltage across the gap, the discharge current and the displacement velocity were measured. Detected the signals using the optical fiber sensor and piezoelectric sensor have been compared with each other. As the results, optical fiber sensor was more resist than piezoelectric sensor in an electromagnetic noise. It is likely that the optical fiber sensor was more useful than piezoelectric sensor for AE detection with electromagnetic field. In order to investigate the relationships between the single pulse discharge phenomena and the detected AE signals, numerical analysis by using finite element method (FEM) was adapted. The numerical analysis result using the FEM and the experiment result along with the single pulse discharge was compared. As the result, it was estimated that the generation factor of the AE wave was the 1μs duration force. The signal detected by the optical fiber sensor has a good agreement with the signal from the FEM one. It is found that optical fiber sensor can detect the displacement velocity with wide band. Moreover, it was considered that frequency response of the optical fiber sensor is approximately flat. The optical fiber sensor was effective in analysis of AE source.