Parameters Affecting the Velocity of Sound in Transformer Oil

Howells, E.; Norton, Edward T.

doi:10.1109/tpas.1984.318719

Cited by 34 publications

(17 citation statements)

References 1 publication

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“…, the time delay ( Δt ), from appearance of arc power peak upon arc ignition to the appearance of first pressure peak of

P_{oi l_{High}}

, is 175 μs. This time delay Δt shows that the pressure wave propagated from the position between electrodes to the pressure transducer (distance: 0.255 m) at sonic speed (about 1420 m/s at 20 °C) in the insulating oil, which was resulted by arc derived bubble formation. In addition, when the sonic speed in all test cases was calculated based on Δt and the distance from the position between electrodes to the pressure transducer (0.255 m), the resultant average experimental sonic speed is 1420 m/s (standard deviation 68 m/s).…”

Section: Liquid Phase Pressure Rise Phenomenonmentioning

confidence: 99%

Pressure Rises Due to Arc Under Insulating Oil in Closed Vessel—Relationship between Bubble Behavior and Pressure Rises

Tadokoro

Kotari

Ohtaka

et al. 2016

Elect Comm in Japan

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SUMMARY When a fault arc occurs in oil‐filled electric power equipment such as transformers in transmission and distribution systems, it generates a flammable gas and a dynamic pressure rise that may trigger an explosion. The purpose of this fundamental study is to investigate the effects of the arc under electrical insulation oil on pressure rises in a closed vessel containing air and oil. In particular, this paper is intended to investigate the relationship between the pressure rises and the generated bubble behavior by the arc. The pressure rises in both air and oil are measured under experimental conditions involving an arc current ranging from 2.3 kA to 8.9 kA, an arc duration of 10 ms or 100 ms. Experimental results show that the behavior of a bubble affects the pressure rises in the air and the oil as low‐frequency pressure oscillation comparatively.

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“…, the time delay ( Δt ), from appearance of arc power peak upon arc ignition to the appearance of first pressure peak of

P_{oi l_{High}}

Section: Liquid Phase Pressure Rise Phenomenonmentioning

confidence: 99%

Pressure Rises Due to Arc Under Insulating Oil in Closed Vessel—Relationship between Bubble Behavior and Pressure Rises

Tadokoro

Kotari

Ohtaka

et al. 2016

Elect Comm in Japan

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“…One thing that is interesting about this mathematical model is that sound velocity during signal flight from PD to acoustic sensors is considered to be constant. Acoustic signal velocity is largely dependent on transformer oil temperature [30,31], meaning that oil temperature is also considered to be constant. From the perspective of physics, thermo dynamics of fluids, transformer construction etc.…”

Section: All-acoustic Non-iterative Pd Location Methodsmentioning

confidence: 99%

“…From the perspective of physics, thermo dynamics of fluids, transformer construction etc. this approximation is enormous [31][32][33]. Nevertheless, reported experimental results for this method are considered to be acceptable for practical use [22].…”

Section: All-acoustic Non-iterative Pd Location Methodsmentioning

confidence: 99%

“…However, for many practical purposes, including the research which is the subject of this article, the approximation taking into account only transformer oil temperature is sufficient [12]. Typical correlation between sound velocity and transformer oil temperature is taken from [31] and shown in Fig. 3.…”

Section: Sound Velocity Dependence On Transformer Oil Temperaturementioning

confidence: 99%

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Algorithm for calculating influence of power transformer oil temperature change on the accuracy of allacoustic non-iterative partial discharge localization

Poluzanski¹,

Kovačević²,

Nikolić³

2018

FME Transaction

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“…Appraising the speed of the wave in the oil on about 1200 m/s [7], it results from intervals between signals in averaging phase characteristic (Fig. 3b) that difference of propagation path should be a rank of 1.3 m and above 7 m. Characteristics presented in Figs.…”

Section: Analysis Of Properties Characteristic For Ae Signalsmentioning

confidence: 99%

Analysis of Properties Characteristic for Acoustic Emission Signals Recorded On-Line in Power Oil Transformers

2011

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Investigation results of properties characteristic for acoustic emission signals recorded in two selected power oil transformers are presented. Signals were put to the filtration, whereas components coming from partial discharges have been left. The calculations concerned: phase-time characteristics, averaging phase characteristics, averaging short time Fourier transform spectrograms, amplitude distributions of signals, values of acoustic emission descriptor with acronym ADC. On the ground of calculated basic characteristics and maps of ADC descriptor three areas have been selected on lateral walls of transformer tanks. Acoustic emission signals recorded in these areas were analyzed from the point of view how is influence of propagation path on these properties.

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Parameters Affecting the Velocity of Sound in Transformer Oil

Cited by 34 publications

References 1 publication

Pressure Rises Due to Arc Under Insulating Oil in Closed Vessel—Relationship between Bubble Behavior and Pressure Rises

Pressure Rises Due to Arc Under Insulating Oil in Closed Vessel—Relationship between Bubble Behavior and Pressure Rises

Algorithm for calculating influence of power transformer oil temperature change on the accuracy of allacoustic non-iterative partial discharge localization

Analysis of Properties Characteristic for Acoustic Emission Signals Recorded On-Line in Power Oil Transformers

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