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ABSTRACT: The behavior of a water droplet on a silicone rubber plate was observed with a high-speed camera under ac voltage application. It was confirmed that a water droplet vibrated and that a remarkable deformation from the original droplet form occurred at the mechanical resonance frequency. Vibration frequency of an uncharged water droplet was double the frequency of the applied voltage. On the contrary, in the case of an artificially charged droplet, vibration frequency was the same with that of the applied voltage. A macroscopic mechanical model was devised, to which the experimental data were well correlated. Flashover voltage via the water droplet was also measured. Lower flashover voltage was obtained at the mechanical resonance frequency.
IEEE Transactions on Dielectrics and Electrical Insulation 05/2010; · 1.09 Impact Factor
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ABSTRACT: Observations and analyses have been conducted on the behavior of water droplets deposited on the surface of polymer insulators. As an index to characterize the repellency of water droplets on the polymer surface, the contact angle was measured for different situations. Experiments were conducted to see the behavior of water droplets of different volumes and their size distribution on silicone rubber. Electric field strength calculation was performed to analyze the effect on water droplets. Finally, effects of the Maxwell stress and the Coulomb's force were compared, to conclude that, even if there is some true charge on the water droplet, the Maxwell stress is predominant.
IEEE Transactions on Dielectrics and Electrical Insulation 03/2009; · 1.09 Impact Factor
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ABSTRACT: A novel real-time observation system has been developed. It is
capable of simultaneously recording visual partial discharge arcs and
leakage currents on insulator surfaces under wet-contaminated conditions
during a 2-h test. Since this system uses a video recording system uses
a video recording system, the discharges and currents can be reproduced
repeatedly even at a slowed-down speed. To permit simultaneous recording
and accurate data processing of leakage currents, a personal computer is
also employed. It was found that the sampling frequency of 1.0 kHz was
satisfactory for the recording of the leakage current. Another function
of the computer is to exhibit the contours of insulators to be tested in
a dark room so that the locations where the arcs stay can be clearly
identified. Tests by the clean fog procedure confirmed the good
performance of the system at the time of the design. Some experimental
results and the applicability of this system are discussed
IEEE Transactions on Electrical Insulation 01/1991;
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ABSTRACT: A description is given of the basic results of an investigation
into DC contamination flashover phenomena of suspension insulators. A
novel real-time system was developed that was capable of observing the
partial discharge arcs visually and the leakage current quantitatively.
Insulators were tested and the leakage current was analyzed, with the
result that the effectiveness of the system was confirmed
Properties and Applications of Dielectric Materials, 1988. Proceedings., Second International Conference on Properties and Applications of; 10/1988
