scholarly journals CN Tower current wavefront parameters

2021 ◽  
Author(s):  
Elvir Burnazovic
Keyword(s):  
Statistical Analysis ◽  
Power Lines ◽  
Lightning Protection ◽  
Lightning Current ◽  
Negative Current ◽  
Multiple Stroke

This work is focused on the establishment of comprehensive statistics concerning the characteristics of the lightning current measured at the CN Tower during five years (1992-1996). Negative lightning currents are characterized with two distinguished impulses: short risetimes’ impulses, and impulses with substantially larger risetimes and larger current peaks in comparison with fast impulses. The slower negative current impulses were found to occur either in single stroke flashes or as first strokes in multiple stroke flashes, suggesting that they may belong to downward-initiated lightning to the CN Tower. The statistical analysis illustrates that there is a substantial difference in current wavefront parameter of ordinary negative fast wavefront impulses and those for slow wavefront negative impulses. The obtained statistics are very important for building lightning protection means against direct strikes to power lines, substation and communication equipments, as well as against lightning occurring in their vicinities.

scholarly journals Analysis of Arc Processes in Multi-chamber Arrester for Lightning Protection at High-voltage Overhead Power Lines

2017 ◽  
Vol 4 (2) ◽  
pp. 124-128 ◽  
Author(s):  
Iu. V. Murashov ◽  
V. Ya. Frolov ◽  
D. Uhrlandt ◽  
S. Gortschakow ◽  
D. V. Ivanov ◽  
...  
Keyword(s):  
Discharge Chamber ◽  
Three Dimensional ◽  
Plasma Temperature ◽  
Power Lines ◽  
Lightning Protection ◽  
Computational Domain ◽  
Transient Model ◽  
Electromagnetic Processes ◽  
Model Equations ◽  
Overhead Power Lines

Nowadays multi-chamber arresters are widely distributed as devices of lightning protection of overhead power lines. A mathematical modelling of processes in the discharge chamber of multichamber arrester is necessary to carry out in order to improve its breaking capacity. A three-dimensional mathematical transient model of thermal, gas-dynamic and electromagnetic processes taking place in the discharge chamber of multi-chamber arrester is presented in the article. Basic assumptions, model equations, a computational domain and the boundary conditions are described. Plasma turbulence is taken into account. The results of the calculation i.e. distributions of plasma temperature and overpressure in the discharge chamber at different time points are shown. The analysis of the results was carried out. It is shown that the presence of cavities in the electrodes design promotes electric arc extinction in the discharge chamber of multi-chamber arrester.

scholarly journals Calculation of lightning surges on the high voltage lines. Case of 220 kV line: Ngo -Brazzaville in Congo

2017 ◽  
Vol 6 (1) ◽  
pp. 13
Author(s):  
Rodolphe Gomba ◽  
Alphonse Omboua
Keyword(s):  
Power Lines ◽  
Protective Equipment ◽  
Worst Case ◽  
Lightning Strikes ◽  
Lightning Current ◽  
Wave Forms ◽  
Lightning Discharges ◽  
Voltage Wave ◽  
High Level ◽  
Insulation Coordination

The importance of line Ngo-Brazzaville (220 kV, 207 km) requires operators to avoid cuts that can increase the risk of instability. We see it is quite rare that a storm that occurs in areas crossed by this line will not cause triggering. Note that due to lightning discharges are the main causes of unscheduled outages of Congo's power lines; we ignore this during the peak values of voltage wave forms that result. In regions with high level keraunic like Congo, reducing insulation failures due to lightning is a concern in the management of overheads lines. This article clarifies the peak values of the voltages that can be achieved on the network in order to build the operators as to the precautions on the insulation coordination of protective equipment related to lightning. For these calculations surge of atmospheric origin (case of lightning), we considered the bi-exponential function and Heidler function for modeling the wave of the lightning current. This methodology led us to specially treat the effects of direct lightning strikes that constitute the worst case because they generate most destructive shock wave that indirect lightning strikes.

Online Condition Monitoring of Line-Insulator Leakage Currents

2006 ◽  
Vol 5 (1) ◽  
Author(s):  
Ibrahim A. Metwally ◽  
Saif AR Sumry ◽  
Saif SH Al-Harthy
Keyword(s):  
Statistical Analysis ◽  
Condition Monitoring ◽  
Pollution Monitoring ◽  
Power Lines ◽  
Monitoring Systems ◽  
Leakage Currents ◽  
Distribution Lines ◽  
Recorded Data ◽  
Overhead Power Lines ◽  
Petroleum Development

This paper introduces some field analyses of the wooden pole fire reports and online condition monitoring recorded data for line insulators of 33kV and 132kV overhead power lines of Petroleum Development Oman (PDO). From the statistical analysis of PDO pole fire reports, it was found that PDO southern directorates had higher number of pole fires during May-September 2004. Pole fires mostly occur for single poles of 33kV distribution lines close to graded roads, where the most common burning locations are at crossarm fixation and at ground foundation. Pollution monitoring systems provide very useful information which can be used to predict the pole fire events.

scholarly journals Numerical Study of Lightning Protection of Wind Turbine Blade with De-Icing Electrical Heating System

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 691
Author(s):  
Yang Zhao ◽  
Xi Wang ◽  
Qibin Zhou ◽  
Zhenxing Wang ◽  
Xiaoyan Bian
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Numerical Study ◽  
Heating System ◽  
Wind Turbine Blade ◽  
Electrical Heating ◽  
Electromagnetic Transients ◽  
Lightning Protection ◽  
Lightning Strikes ◽  
Lightning Current

In order to solve the problem of icing on the surface of wind turbine blade, a heating system that includes a carbon fiber net (CFN) and power cables is proposed recently. When lightning strikes at the blade with a de-icing heating system, the blade and its heating system are more easily damaged due to the overvoltage between the lightning protection system (LPS) of the blade and the heating system. In this paper, the models of a wind turbine blade with the de-icing heating system are established by Alternative Transients Program/Electromagnetic Transients Program (ATP–EMTP) and the accuracy of models is verified through an experiment. With these models, the influence of lightning current, surge protective devices (SPDs) and earthing resistance of wind turbine are analyzed by calculating the voltage between the down-conductor of the LPS and the heating system. The results show that the voltage is positively correlated with lightning current amplitude and negatively correlated with the front time of lightning current. SPDs are quite useful to reduce the voltage, and an optimal installation scheme of SPDs is obtained by simulation. It is noted that voltage decreases slightly with the increasing earthing resistance with the optimal installation scheme of SPDs.

Simulation of Secondary Equipment Lightning Protection in EHV Substation Based on ATP

2014 ◽  
Vol 543-547 ◽  
pp. 514-517
Author(s):  
Hong Bo Li ◽  
Lin Niu ◽  
Nan Nan Gao ◽  
Jie Zhan ◽  
Pei Li ◽  
...  
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Lightning Protection ◽  
Earth System ◽  
Secondary System ◽  
Frequency Signal ◽  
High Frequency Signal ◽  
Lightning Current ◽  
Grounding Grids ◽  
The One

By analyzing the two lightning accidents happening to a 500kV substation situated in the lightning-prone northeastern Guangdong Province, I conclude as follows, there should be some problem in the equipotential earthing of the secondary system of this substation. Specifically, the existing potential difference in the secondary equipment gave rise to the meltdown of it which finally caused the accident. In the context,I build the one-point earthing parallel system simulation model according to ATP graphic pretreatment program, then by using slope-ramp simulation I study the lightning current which leaked into the grounding grids of the substation.In conclusion, the application of high frequency signal mixed low frequency signal earth system in the secondary system and the equipotential bonding is key to preventing accidents.

Analysis on Lightning Electromagnetic Fields

2013 ◽  
Vol 401-403 ◽  
pp. 350-353 ◽  
Author(s):  
Pi Cui Zhang ◽  
Wei He ◽  
Liu Ling Wang ◽  
Li Feng Ma
Keyword(s):  
Electromagnetic Field ◽  
Spatial Distribution ◽  
Electromagnetic Fields ◽  
Maxwell Equations ◽  
Practical Significance ◽  
Lightning Protection ◽  
Perfect Conductor ◽  
Fundamental Theory ◽  
Lightning Current ◽  
The Earth

t is generally needed to know precisely spatial distribution of lightning electromagnetic fields in the lightning protection measurements. Therefore, the research on the lightning electromagnetic field is of practical significance. In this paper, the Maxwell equations were used to calculate and analyze the spatial distribution of lightning electromagnetic fields surrounding lightning current. And the expressions of lightning current electromagnetic fields were deduced under the assumption that the earth was under the condition of perfect conductor. The spatial distributions of the components of lightning electromagnetic fields have been plotted by Matlab. The results would provide fundamental theory for the research of lightning electromagnetic field and lightning protection measurements.

Statistical Analysis and Modeling of Noise on 10-kV Medium-Voltage Power Lines

2007 ◽  
Vol 22 (3) ◽  
pp. 1433-1439 ◽  
Author(s):  
Zheng Tao ◽  
Yang Xiaoxian ◽  
Zhang Baohui ◽  
Nucleus H. Xu ◽  
Feng Xiaoqun ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Power Lines ◽  
Medium Voltage
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