Induction Lightning Current System Design

2014 ◽  
Vol 1030-1032 ◽  
pp. 1314-1317
Author(s):  
Pin Cui Zhang ◽  
Wei He ◽  
Long Zhang ◽  
Ping Lu
Keyword(s):  
Theoretical Basis ◽  
Important Implication ◽  
Current System ◽  
Lightning Discharge ◽  
Lightning Protection ◽  
Discharge Process ◽  
Current Waveform ◽  
Waveform Data ◽  
Lightning Current ◽  
Test Circuit

Lightning protection plays a significant role in modern communication system and other electric instrument. The study of lightning current waveform has important implication for lightning protection, but the direct measurement of lightning current is too risk. So the induction lightning current waveform surveying arises at the historic moment. Depending on the capacitance of the simulated lightning discharge process based on the protel designed test circuit using self-made roche induction coil, the lightning current waveform had been simulated in the paper. Finally, by testing the system, we got a series of waveform data, and it is concluded that the characteristics of the induction lightning current under different pressure. These results would provide the theoretical basis for lightning protection.

scholarly journals Direct Lightning Current Measurements in Southeastern Brazil I. Current Waveform

1997 ◽  
Author(s):  
M. Lacerda ◽  
O. Pinto Jr. ◽  
I.R.C.A. Pinto ◽  
J.H. Diniz ◽  
A.M. Carvalho
Keyword(s):  
Southeastern Brazil ◽  
Current Waveform ◽  
Lightning Current

The Study of Inner EM Environment in the Helicopter under the Influence of Lightning Strikes

2014 ◽  
Vol 912-914 ◽  
pp. 860-864
Author(s):  
Yan De Wang ◽  
Cheng Gao ◽  
Fei Guo ◽  
Yan Xin Li
Keyword(s):  
Simulation Analysis ◽  
Current Waveform ◽  
Lightning Strikes ◽  
Lightning Current ◽  
Numeric Simulation ◽  
Environment Characteristic

Numeric simulation of the whole aircraft is conducted in the CST MICROSTRIPES workshop which is based on the theory of TLM. The current waveform is defined according to the standard of SAEARP5412. The EM environment inside the helicopter is analyzed when the lightning strikes on the middle of the helicopter vertically. The lightning current moves along the aircraft to the back, then travels to the middle along the line. Simulation analysis demonstrates that the method can effectively simulate the indirect lightning effect, and shows the EM environment characteristic inside the helicopter.

scholarly journals Lightning discharge process based on short-baseline lightning VHF radiation source locating system

2012 ◽  
Vol 61 (6) ◽  
pp. 069202
Author(s):  
Cao Dong-Jie ◽  
Qie Xiu-Shu ◽  
Duan Shu ◽  
Xuan Yue-Jian ◽  
Wang Dong-Fang
Keyword(s):  
Radiation Source ◽  
Lightning Discharge ◽  
Discharge Process ◽  
Short Baseline ◽  
Locating System

scholarly journals Selected Issues of Safe Operation of the Railway Traffic Control System in the Event of Exposition to Damage Caused by Lightning Discharges

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5808
Author(s):  
Renata Markowska ◽  
Zofia Wróbel
Keyword(s):  
Control System ◽  
Power Systems ◽  
Traffic Control ◽  
Lightning Discharge ◽  
Lightning Protection ◽  
Current Standard ◽  
Protection Measures ◽  
Railway Traffic ◽  
Protective Devices ◽  
Traffic Control System

Lightning discharge becomes a serious source of interference and damage for electronic and electrical power systems. Safe and reliable operation of railway traffic control systems requires proper protection against the effects of lightning. However, the current standards on lightning protection, PN-EN/EN/IEC 62305, do not cover railway objects. Moreover, there are no other standards or recommendations dedicated to the railway. The paper is an attempt to apply the procedure of lightning risk management according to PN-EN 62305-2 to select the proper protection measures in railway objects. A case study for the signal box with installed relaying and digital stations of the railway traffic control system is analyzed. The analysis comprises calculations based on the current standard PN-EN 62305-2:2012 but including the issues specific to railway traffic control. The risks of lightning losses have been calculated for two cases: without lightning protection measures and with protection measures proposed to decrease the risks below the tolerable values. The results show that a practically effective solution to reduce the risks is applying surge protective devices with proper characteristics. Another way is replacing unshielded incoming lines with shielded ones of given shield bonding way, and supplementing it with surge protective devices when necessary.

scholarly journals De-noising the CN Tower lightning current signal using short term Fourier transform-based spectral substraction

2021 ◽  
Author(s):  
Mohammed Jahirul Islam
Keyword(s):  
Fourier Transform ◽  
Spectral Subtraction ◽  
Current Signal ◽  
Current Waveform ◽  
Transmission Tower ◽  
Subtraction Method ◽  
Short Term ◽  
Lightning Current ◽  
Spectral Subtraction Method ◽  
Current Derivative

The CN Tower is a transmission tower and it is not unexpected that recorded lightning current signals be corrupted by noise. The existence of noise may affect the calculation of current waveform parameters (current peak, 10-90% risetime to current peak, maximum steepness, and pulse width at half value of current peak). But accurate statistics of current waveform parameters are required to design systems for the protection of structures and devices, especially those with electrical and electronic components, exposed to hazards of lightning. Since more electrical devices are used nowadays, lightning protection becomes more important. So to determine accurate statistics of current waveform parameters, the interfering noise must be removed. In this thesis we describe a technique for de-noising the CN Tower lightning current by modifying its Fourier Transform (FT) where a simulated current waveform (Heidler function) is used to represent the lightning current signal.The limitations of Discrete Fourier Transform (DFT) for removal of non-stationary noise signals, including the noise connected with CN Tower lightning current signals and its properties are discussed. The Short Term Fourier Transform (STFT) is explored to analyze non-stationary signals and to deal with the limitations of DFT. Last of all, an STFT-based Spectral Subtraction method is developed to denoise the CN Tower lightning current signal. In order to evaluate the Spectral Subtraction method, a simulated current derivative waveform ( obtained by differentiating Heidler function) is artificially distorted by a noise signal measured at the CN Tower in the absence of lightning. The Spectral Subtraction method is then used to de-noise the distorted waveform. The de-noised waveform proved to be very close to the original simulated waveform. A signal-peak to noise-peak ratio (SPNPR) of the CN Tower lightning current signal is defined and calculated before and after the de-noising process. For example, for a typical measured current derivative signal, the SPNPR before de-noising is 7.27, and after de-noising it becomes 151.30. Similarly for its current waveform (obtained by numerical integration) the SPNPR before de-noising is 20,16 and it becomes 361.39 after de-noising. Statistics of current waveform parameters are obtained from the de-noised waveforms. The Spectral Subtraction method is also applied for de-noising the electric and magnetic field waveforms generated by lightning to the CN Tower which enables the calculation of their waveform parameters.

scholarly journals Evolution Characteristics during Initial Stage of Triggered Lightning Based on Directly Measured Current

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 658
Author(s):  
Zefang Chen ◽  
Yang Zhang ◽  
Yanfeng Fan ◽  
Jingxuan Wang ◽  
Dong Zheng ◽  
...  
Keyword(s):  
Lightning Discharge ◽  
Ground Level ◽  
Current Data ◽  
Discharge Process ◽  
Measured Current ◽  
Critical Range ◽  
Initial Stage ◽  
Evolution Characteristics ◽  
Triggered Lightning ◽  
Initial Process

The initiation of a leader is an important lightning discharge process, but how an upward positive leader (UPL) initiates is still not fully understood. The evolution characteristics of a UPL during its initial stage was systematically studied based on directly measured current data of 14 triggered lightning events in 2019. It was found that the initial stage of triggered lightning can be divided into two types: a single initial process form and a multiple initial process form, with percentages of 64.29% and 35.71%, respectively. Compared with the former, the latter usually lasts longer, and the corresponding lightning is often triggered under a lower ground-level quasi-static electric field. In each initial process, precursor current pulses (PCPs), PCP clusters and initial precursor current pulse (IPCPs) are typical current waveforms, and the pulse durations and transferred charges of PCPs increase linearly with time. However, in the multiple initial process form, the pulse durations and transferred charges of PCPs will reduce significantly after each previous initial process and then continue to increase in the following initial process. In each initial process, when the pulse duration and transferred charge of a PCP increase to a certain extent, PCP clusters and IPCPs begin to appear. For the emergence of PCP clusters, the average values of the threshold are 3.48 μs and 19.53 μC, respectively. For the occurrence of IPCPs, the corresponding values are 4.69 μs and 27.23 μC, respectively. The average values of pulse durations and transferred charges of IPCPs are larger than those of PCP clusters. Compared with adjacent PCP clusters, IPCPs contain more pulses, with a critical range of 6–7. IPCPs also last longer, and have a critical range of 138–198 μs.

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.

scholarly journals V. A comparison of photographic and electrical studies of the discharge process

1938 ◽  
Vol 166 (924) ◽  
pp. 56-75 ◽  
Keyword(s):  
Space Dimension ◽  
Lightning Discharge ◽  
Third Space ◽  
Two Dimensions ◽  
Discharge Process ◽  
Photographic Method ◽  
Electric Moment ◽  
The Third ◽  
Electrical Studies ◽  
Dimensions Of Space

The photographic method of studying the lightning discharge by means of the Boys camera has the unique advantage of giving direct information concerning events in the discharge in two dimensions of space and one of time and could be extended if necessary to include the third space dimension. The luminous events which it records are, however, secondary processes, and the primary movements of electrical charge which cause them can only be inferred by an application of ideas gained from the laboratory study of the passage of electricity through gases. The direct study of these primary electrical processes involves the observation of the electric field during the discharge by means of a cathoderay oscillograph. Studies of near lightning by this method have recently been reported by Appleton and Chapman (1937). The method gives information concerning the total electric moment of the cloud charges and requires to be compared with the photographic data before its results can be interpreted in terms of the charges themselves and their movements.

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