Results 251 to 260 of about 799,107 (315)

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
exaly   +3 more sources

Impulse Impedance of Grounding Grids

IEEE Transactions on Power Apparatus and Systems / Technical Operations Committee, 1980
A method and an empirical formula to calculate the inductance of square grounding grids fed at either centre or one of the corners is presented. Empirical formulae for the effective area and impulse coefficient for centre fed and corner fel square grids are determinel.
B Thapar
exaly   +3 more sources

Discussion of Measurement Methods of Impulse Grounding Impedance

2018 34th International Conference on Lightning Protection (ICLP), 2018
The grounding device is very important for lightning protection. However, it is difficult to measure the impulse grounding impedance because the impulse generator is cumbersome and dangerous compared with the device for power frequency test. At the same time it is difficult to generate a lightning current with a suitable waveform due to the inductance ...
Jinjiang He
exaly   +3 more sources

Impulse Impedance Measurement Methodology in Space Restricted Locations

2019 International Symposium on Lightning Protection (XV SIPDA), 2019
This paper presents the analysis results of field measurements of ground resistance and impulse impedance. First, the Current Derivative Method is presented, whose objective is to obtain the RLF steady-state ground resistance value from the transient impedance curve $Z(t)$.
A Raizer
exaly   +3 more sources

The Use of the Impulse Impedance as a Concise Representation of Grounding Electrodes in Lightning Protection Applications

IEEE Transactions on Electromagnetic Compatibility, 2018
Based on measured and simulated results, the features of the first-return-stroke impulse grounding impedance are analyzed to show that, in a vast class of lightning protection applications, using this parameter yields results very similar to those ...
Silverio Visacro
exaly   +3 more sources

Online Monitoring of the Cable Insulation State Based on the Impulse Impedance Spectrum

IEEE Transactions on Instrumentation and Measurement
The rapid development of power systems has raised the requirements of the online monitoring of cable insulation performance. Considering that a signal extracted using traditional online monitoring technology is weak and vulnerable to environmental ...
Pengfei Meng, Tengfei Li, Kai Zhou
exaly   +3 more sources

Measurement of Impulse Grounding Impedance in Frequency Domain

2010 International Conference on Intelligent System Design and Engineering Application, 2010
Impulse grounding impedance cannot be described as an absolute index, because it depends on the characteristic of the impulse current waveform, soil structure type and grounding system configuration, etc. This paper presents a test system to measure the impulse grounding impedance directly in time domain, moreover, calculated and defined in frequency ...
Wu Guangning
exaly   +2 more sources

Impulse Impedance of Buried Ground Wire

IEEE Transactions on Power Apparatus and Systems, 1980
The performance of ground electrode under impulse currents must be known if problems concerning lightning protection and transients under ground faults are to be accurately analysed. This paper deals with such performance and establishes a simple analytical expression to determine the impulse impedance of a buried ground wire to a short impulse ...
R. Verma, D. Mukhedkar
openaire   +3 more sources

Impulse impedance of rectangular grounding grids

IEEE Transactions on Power Delivery, 1992
In an earlier work B.R. Gupta and B. Thapar (1980) presented the results of investigations and empirical formulae to evaluate the impulse impedance of square grounding grids. In the present work, the authors extend those investigations to the rectangular grounding grids.
B.R. Gupta, V.K. Singh
openaire   +2 more sources

Coronary input impedance during cardiac cycle as determined by impulse response method

American Journal of Physiology-Heart and Circulatory Physiology, 1987
The coronary arterial system was characterized by its input impedance determined in systole and diastole from impulse response functions in five dogs. The impulse response technique was verified on a known hydraulic system. A second confirmation was obtained on the circumflex artery: reflected pulses were correlated with site of reflections generated ...
G A, Van Huis, P, Sipkema, N, Westerhof
openaire   +3 more sources