Results 151 to 160 of about 1,321 (185)

Soil ionisation under lightning impulse voltages

IEE Proceedings - Science, Measurement and Technology, 2004
Experiments have been carried out to study soil ionisation and the variation of the critical ionisation gradient against the soil resistivity. Compared with relevant experimental results of other researchers a satisfactory convergence has been proved. An accurate estimation of the critical ionisation gradient has been achieved, of the order of 200 kV/m,
I.F. Gonos, I.A. Stathopulos
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Treeing inception of xlpe at lightning impulse voltage

European Transactions on Electrical Power, 1992
AbstractThis paper deals with investigations of the treeing inception of polyethylene insulation under lightning impulse voltage. The experimental results of investigations with XLPE samples in a needle‐plane arrangement will be presented and the influence of various parameters will be discussed.
K. Rittner, G. Borner
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Lightning Impulse Breakdown Characteristics of Frozen Soil

IEEE Transactions on Power Delivery, 2008
The impulse characteristics of frozen soil are the fundament for the lightning protection design of the overhead transmission lines in frozen soil environments. In this paper, the conductivity and lightning impulse breakdown characteristics of the frozen soil were experimentally studied, and those key factors influencing the impulse breakdown ...
null Jinliang He, null Baoping Zhang, null Peng Kang, null Rong Zeng, null Bo Zhang   +4 more
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Development of lightning electromagnetic impulse simulator on buildings

2010 Asia-Pacific International Symposium on Electromagnetic Compatibility, 2010
In this paper, we report the development of lightning electromagnetic impulse simulator on buildings. This simulator is linked with the counting code VSTL (Virtual Surge Test Lab.) based on the FDTD (Finite Difference Time Domain) method being developed by Central Research Institute of Electric Power Industry.
Hajime Uchida, Yoshiaki Mori, Nobusato Kobayashi, Shinji Yanai, Tetsuo Endo, Yuichi Takahashi, Kaname Yonezawa, Teruo Idogawa, Masaaki Sato, Shuji Higashi   +9 more
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Development of the lightning measure technique and applications using lightning electromagnetic impulse simulator

2012 International Conference on Lightning Protection (ICLP), 2012
We have developed the electromagnetic impulse simulator by FDTD method (Finite Difference Time Domain Method), in order to analyze the situation of current diversion and the effects of electromagnetic field in the building by lightning strikes. Also we have experimented using the 1/4 scale model of a 3-story building. The situation of current diversion
Teruo Idogawa, Yuichi Takahashi, Kaname Yonezawa, Masaaki Sato, Hajime Uchida, Nobusato Kobayashi, Tetsuo Endo   +6 more
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Impulse Impedance Measurements of Lightning Protection Earthings

2019 IEEE PES GTD Grand International Conference and Exposition Asia (GTD Asia), 2019
Lightning protection earthing systems should be tested at currents with time parameters similar to those of lightnings. A method and definition of a measured value of impulse impedance are introduced. The impulse impedance was determined by a quotient of voltage drop on the tested earthing to a value of current in measure circuit. The usefulness of the
T. Horchue, W. Tangtheerajaroonwong, S. Wojtas, M. Woloszyk   +3 more
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Influence of measuring cable on lightning impulse parameters

Electronics and Communications in Japan, 2010
AbstractThe influences of coaxial measuring cables on waveform parameters have been neglected in lightning impulse measurements. This is partly because the tolerable uncertainty for determining the front timeT1in the reference measuring system is 3% and the induced influence due to using a long measuring cable is expected to be much smaller than the ...
Shuji Sato, Toshihisa Yamaguchi, Seisuke Nishimura, Shota Nishimura   +3 more
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Nonlinear Interpretation Technique for Lightning Impulse Test

IEEE Transactions on Power Delivery, 2015
The nonlinear interpretation technique is proposed to detect the fault in transformer windings during the impulse test. To prove feasibility of the proposed technique, 90-MVA 220/110-kV, 250-MVA 500/275/33-kV transformers, and a 22-kV interleaved winding are used.
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Tests with High Lightning and Switching Impulse Voltages

2014
Lightning impulse (LI) over-voltages and switching impulse (SI) over-voltages are caused by direct or indirect lightning strokes or by switching operations in electric power systems, respectively. They cause transient stresses to the insulations, much higher than the stresses due to the operational voltages.
Wolfgang Hauschild, Eberhard Lemke
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Lightning Impulse Ageing of HV Cable Insulation [PDF]

, 2009
Lightning impulses can lead to accelerated ageing of extruded cables. Electrical behaviour of a dielectric material when experiencing a lightning impulse is different to that for DC or power frequency applied voltages. Pre-designed shaped HDPE material samples have been manufactured using a mould tool. The samples then have been electrically aged using
Dao, N L, Lewin, P L, Swingler, S G
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