Results 111 to 120 of about 7,881 (155)

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 ...
Bo Zhang, Jinjiang He, Sen Wang, Jian Zhang, Zhizhong Li, Wei Li   +5 more
exaly   +2 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 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 $Z(t)$.
Adroaldo Raizer
exaly   +2 more sources

A reduced-scale experimental study of tower impulse grounding impedance

2017 1st International Conference on Electrical Materials and Power Equipment (ICEMPE), 2017
Lightning withstand level of the transmission line is directly affected by the value of the tower impulse grounding impedance. While it's difficult to obtain the tower impulse grounding impedance accurately as its nonlinearity under impulse current. Therefore the study of the tower impulse grounding impedance characteristics is significant to lightning
Hui Cao, Zheng Zhao, Jiangtao Li
exaly   +2 more sources

Impulse Impedance and Effective Area of Grounding Grids

IEEE Transactions on Power Delivery, 2021
High values and uneven distribution of the transient ground potential rise (TGPR) at grounding grid conductors in cases of lightning can disrupt the system safety and reliability. To assess the transient performance of grounding grids under lightning currents, a parametric analysis was performed with a computer simulation of 13,978 cases of time-domain
Leonid Grcev, Blagoja Markovski
openaire   +1 more source

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   +2 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   +1 more source

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

IEEE Transactions on Instrumentation and Measurement
Zhirong Tang, Kai Zhou, Pengfei Meng
exaly   +2 more sources

Characterization of human joint impedance during impulsive motion

Journal of Electromyography and Kinesiology, 1993
The objective of the present work is to make use of the limited existing information on human joint impedance and to supplement and refine it synthetically, by means of simulation. A modular concept was applied to the construction of a joint model. The basic module was an individual revolute joint which was constrained by four resistive elements.
M, Batman, R, Seliktar
openaire   +2 more sources

Reflection of impulses as a method of determining acoustic impedance

The Journal of the Acoustical Society of America, 1984
An impulse technique has been developed which allows investigation of the reflection of acoustic transients at different angles from an impedance boundary. From measurements of the direct and reflected impulses, the complex surface impedance has been calculated from the ratio of the corresponding Fourier components.
A. J. Cramond, C. G. Don
openaire   +1 more source