Detection of electric treeing of solid dielectrics with the method of acoustic emission

Abstract

The paper presents results of research of electrical treeing of solid dielectrics with the method of acoustic emission (AE). The study was performed with an alternating voltage of 50 Hz in the range up to 21 kV (RMS) on methyl polymethacrylate or crosslinked polyethylene samples. They were of cuboidal shape of the dimensions 25 × 10 × 4 mm. One of the cuboid sample walls of the dimensions 25×4 mm was covered with a conducting paint. On the opposite wall, a surgical needle of T-25 type was screwed. The distance between the electrodes (the needle and the wall covered with a conducting paint) was in the range 0.5-2.0 mm. Registered signals were denoised with wavelet transformation method and then there were analyzed. The following parameters were analyzed: a sum and rate of acoustic emission counting, a sum and rate of acoustic emission events, RMS value of the electric signal leaving the converter. Spectrum and spectrogram were also analyzed. It was found that AE signals are generated during electrical treeing of solid dielectrics. Values of chosen parameters increased their values when the process begins. There are also some dominant frequencies ranges, different for different kinds of dielectrics, connected with the treeing.

Effect of Polycyclic Compounds Fillers on Electrical Treeing Characteristics in XLPE with DC-Impulse Voltage

“…Research presented a lot of methods to analyze the electrical treeing process. The acoustic emission method and artificial neural networks were used in the detection of the treeing process [11,12]. In addition, imaging techniques such as transmission electron microscope (TEM), scanning electron 2.…”

Inhibition of Rejuvenation Liquid on Trees in XLPE Cables under Switching Impulse Voltages

“…The tree growth mechanism in XLPE cables has long been a subject of research [3][4][5][6]. Researchers tried to detect the signals which are generated during the treeing process and studied the acoustic emission method and artificial neural networks in the detection of the electrical treeing [7,8]. Some novel approaches are also applied to develop a better understanding of electrical treeing [9].…”

Formation of asperities on electrode surfaces of high-voltage vacuum insulation systems by striking microparticles

“…State analysis, design optimization, and life prediction of electrical equipment are important operational issues [1][2][3]. In case of high voltage insulation systems in analyzes often complex computational algorithms are used [4][5][6]. In investigations of the properties of vacuum insulation systems, the authors indicate that if the voltage exceeds a certain level, irreversible changes occur in the system [7].…”