Study of high frequency transient overvoltage caused by cable-transformer quarter-wave resonance

2021 ◽  
Vol 197 ◽  
pp. 107295
Author(s):  
Paul Akiki ◽  
Alain Xémard ◽  
Charlotte Trouilloud ◽  
Jean-Luc Chanelière
Keyword(s):  
High Frequency ◽  
Wave Resonance ◽  
Quarter Wave ◽  
Transient Overvoltage

Determination of voltage distribution on winding of transformer by state variable method

2021 ◽  
Vol 15 (1) ◽  
pp. 85-94
Author(s):  
Thanh Bao Doan ◽  
◽  
Quoc Vu Pham ◽  
Trung Duy Pham ◽  
◽  
...  
Keyword(s):  
High Frequency ◽  
Voltage Distribution ◽  
Voltage Fluctuations ◽  
State Variable ◽  
Maximum Value ◽  
Lightning Impulse ◽  
Overvoltage Protection ◽  
Negative Impacts ◽  
Transient Overvoltage

A transient overvoltage incident at the transformer terminal generates high-frequency voltage fluctuations that have negative impacts on the transformer. These oscillations may cause damage to the insulation of transformers. These problems are heavy, difficult to restore, and repair. Therefore, overvoltage protection for the transformers is essential. This paper pointed out that the interleaved disk winding has a larger capacitance than that of continuous disk windings. Therefore, the use of interleaved disk winding has the effect of making the voltage distribution on the winding wheels more even and increasing the overvoltage resistance of the transformer. In addition, the value of the voltage at each position of the winding when lightning impulses on the transformer terminal and the voltage distribution on the interleaved disk winding at the time when the lightning impulse has maximum value are also presented in the article. On that basis, the effectiveness of using the interleaved disk winding method in the transformer will be analyzed in detail.

Millimeter-wave absorption properties of BaTiO3/Co3O4 composite powders controlled by high-frequency resonances of permittivity and permeability

2018 ◽  
Vol 6 (47) ◽  
pp. 12965-12975 ◽  
Author(s):  
Wei Tian ◽  
Ruoyang Ma ◽  
Jian Gu ◽  
Zongrong Wang ◽  
Ning Ma ◽  
...  
Keyword(s):  
Millimeter Wave ◽  
High Frequency ◽  
Composite Powders ◽  
Absorption Properties ◽  
Wave Absorption ◽  
Wave Resonance ◽  
Permittivity And Permeability ◽  
5 Ghz

Millimeter-wave resonance of permittivity–permeability-contributed double absorption peaks in BaTiO3/Co3O4, exhibiting RL of ∼−40 dB and a bandwidth of 5 GHz around 35 GHz.

Design of Triggering Device for VFTO Measurement System

2012 ◽  
Vol 516-517 ◽  
pp. 1759-1764
Author(s):  
Gong Chang Yue ◽  
Yu Rong Jia ◽  
Jia Xi He ◽  
Wei Dong Liu
Keyword(s):  
Measurement System ◽  
High Frequency ◽  
Measuring Process ◽  
Pass Filter ◽  
High Pass Filter ◽  
Power Frequency ◽  
Gas Insulated Substation ◽  
Disconnect Switch ◽  
Transient Overvoltage ◽  
High Pass

Very fast transient overvoltage (VFTO) can be generated during the operation of disconnect switch (DS). Especially in ultra high voltage (UHV) gas insulated substation (GIS), VFTO is a threat to the safety of the power system equipment. It is very important to measure VFTO waveforms accurately. VFTO waveforms are comprised of high frequency voltage superimposed on the power frequency voltage in source side of DS and high frequency voltage superimposed on step-wise voltage in load side. How to trigger oscilloscope to acquire data is a big problem in measuring process. According to the features of VFTO waveforms, new triggering device consisting of a high pass filter is designed. The output of measurement sensor is used as the input of the high pass filter, and the output of the high pass filter is used to trigger oscilloscope. When the DS is not operated, there are no signals output from the high pass filter and the oscilloscope is waiting for trigger. After the operation of DS, the high frequency signals will pass the filter to trigger oscilloscope to acquire data. The device can guarantee the oscilloscope to complete a data acquisition properly.

Synthetic Jet Actuator Cavity Acoustics: Helmholtz Versus Quarter-Wave Resonance

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Tyler Van Buren ◽  
Edward Whalen ◽  
Michael Amitay
Keyword(s):  
Acoustic Resonance ◽  
Synthetic Jet ◽  
Cavity Resonance ◽  
Synthetic Jet Actuator ◽  
Acoustic Cavity ◽  
Wave Resonance ◽  
Cavity Resonances ◽  
Quarter Wave ◽  
Cavity Acoustics ◽  
The Impact

The impact of cavity geometry on the source of acoustic resonance (Helmholtz or quarter-wave) for synthetic jet type cavities is presented. The cavity resonance was measured through externally excited microphone measurements. It was found that, for pancake-shaped cavities, the Helmholtz resonance equation was inadequate (off by more than 130%) at predicting the acoustic cavity resonances associated with synthetic jet actuation, whereas a two-dimensional quarter-wave resonance was accurate to 15%. The changes in the geometry (cavity diameter, cavity height, and orifice length) could alter the cavity resonance by up to 50%, and a finite element solver was accurate at predicting this resonance in all cases. With better knowledge of the phenomena governing the acoustic resonance, prediction of the cavity resonance can become more accurate and improvements to current prediction tools can be made.

High-frequency fatigue testing machine with quarter-wave magnetostrictive vibrator

1969 ◽  
Vol 1 (4) ◽  
pp. 428-429
Author(s):  
G. S. Pisarenko ◽  
P. F. Kul'bashnyi
Keyword(s):  
High Frequency ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Quarter Wave

Nonlinear interaction of electrostatic surface waves in a semi-infinite plasma. Part 2. Time-dependent solutions to the coupled mode equations

1981 ◽  
Vol 26 (2) ◽  
pp. 231-252 ◽  
Author(s):  
V. Atanassov ◽  
E. Mateev ◽  
I. Zhelyazkov
Keyword(s):  
Surface Waves ◽  
Nonlinear Interaction ◽  
High Frequency ◽  
Low Frequency ◽  
Density Perturbation ◽  
Time Dependent ◽  
Opposite Case ◽  
Coupled Mode ◽  
Wave Resonance ◽  
Parametric Approximation

The coupled mode equations which govern the nonlinear interaction of three electrostatic high-frequency surface waves and a low-frequency density perturbation are analysed considering time-dependent solutions only. We show the existence of a filamentation instability in the static limit for the low-frequency density perturbation. In the opposite case (density perturbation close to the lowfrequency surface wave resonance) we arrive at a decay instability where only surface waves take part. The parametric approximation (growth rate and threshold) as well as the nonlinear evolution of both types of instabilities are studied.

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