Characterization of measured lightning electric fields observed in Malaysia

This paper presents a characteristic of lightning electric fields. The lightning electric fields captured by two parallel plats sensor and the characterization for preliminary breakdown pulse (PBP) and first return stroke (RS) were studied. A total of 207 data were recorded and 10 data are selected and been utilized in this paper accordingly. In PBP signal data, time before return stroke, ending time and maximum peak of PBP were analyzed. The time duration between the PBP and the occurrence of RS was obtained as 0.64 ms and 2.61 ms and then compared with results from other researchers. For RS signal data, slow front time, deviation time, RS peak, time to peak, zero crossing time and 10% to 90% rise time were evaluated meticulously and the results were discussed accordingly. Moreover, the statistical correlation between electric field zero times and corresponding rise times was studied

The electric field effect on angles of copper-type down-conductor

This paper is to study the effect of electric field on an angle variation of copper down-conductor due to voltage and current transient. Down-conductor which informs of numerous material, shape and dimension are mandatory for diverting the lightning current from air termination system to the grounding system in sheltered building. Hence, a numerical analysis method is applied emulating the comprehensible and particular model according to ordinarily used in the manufacturer’s datasheet specification. A rigorous assessment in term of electric fields was reviewed in comparison with the critical breakdown value of air for a crucial study. Later, a foremost angle is proposed for the installation of down-conductor in order to achieve a reliable protection system

On the behavior of lightning return stroke current incidence to tall towers

The return stroke current in the case of a lightning strike on a tall structure is affected by different tower and channel parameters such as the velocity of the return stroke current, the height of the observation point along the structure, the lightning channel and the reflection coefficients at the top and bottom of the structure. This paper will consider all these factors in the behaviour of the return stroke. The current wave shapes at different heights along tower and channel were modeled and the simulated current at tower top was compared to the corresponding measured current. Moreover, the effects of reflection factors and other important parameters on the values of current peak were considered and the results were discussed accordingly

Consideration of lightning current along a tall structure in the presence of horizontal arrangement grounding

The evaluation of the behaviour of lightning current along a tall structure is becoming an important issue when considering the lightning protection equipment required along a tall structure. This behaviour is affected by the element of the ground reflection factor which has a correlation between the impedance of the ground and the tower. The impedance of the ground is considered for a horizontal grounding arrangement while the impedance of the tower is assumed to be constant. Hence, the ground reflection factor can be given a variable value, whereas most of the existing literature assumes a constant value. When a constant value is entered into a calculation field, an inaccurate result is computed.In this paper, the lightning current along a tall structure under varying values of ground reflection factor and including the effect of the presence of a horizontal grounding arrangement has been considered and the results discussed accordingly. Modelling of the lightning return stroke current along a tall structure was undertaken by entering the calculated variable value of the ground reflection factor. The results indicated that a variable value of the ground reflection factor causes different peak values of the current and wave shape of the lightning current for different positions along a tall structure

Modelling of lightning current in the case of striking to a tall structure

Lightning current is an important parameter that has to be considered. The different behaviour of lightning current depends on the way the lightning strikes either as a direct or indirect lightning strike. In this paper the modelling of the current as a result of a direct strike of lightning on a tall structure is considered. A few of up-to-date on current models, current functions, reflection factors, the return stroke velocity (RSV), the general equation representation of this case are reviewed. Also, through MATLAB software, the results of a case study are generated. The results show a good agreement with the measured values. In addition, the behaviour of the lightning current is evaluated at different heights of the lightning channel with respect to the top and bottom of a tall structure. Also, the lightning current at the top and bottom of the tall structure are observed for different values of the reflection factor. The results show that the peak of the lightning current along different heights of the channel with respect to the top and bottom of a tall structure decreases with increasing height of the channel. Also there is a time delay during the initial time period. Furthermore, the lightning current at the bottom of a tall structure has a high value of peak current and has an attenuation wave shape of current that compares with the lightning current at the top of the tall structure. As a result, this paper may provide benefit in evaluating the electromagnetic (EM) field since the behaviour of the lightning current on a tall structure is known

Effect Of Lightning Impulse Current On The Grounding System Model

The main purpose of the grounding system is to protect human, electrical appliance and building from electrical shock due to lightning or another form of electricity that hazardous. Therefore, to achieve this goal, the fundamental part must be taken into account. In this paper, a different 3-D orientation of concrete has been designed using Comsol software to analyze the performance of the electric potential of the injected impulse in different cases and position of grounding system modelled. In this study, few grounding systems was modelled, which consist of Full concrete, Three-quarter concrete, Half concrete and A quarter concrete to analyse the electric potential of the injected lightning impulse current to the performance of the grounding system modelled. From the result obtained, full concrete was chosen as the best orientation of concrete to be employed at the grounding site. This is because, full concrete has the lowest electric potential value compared to the other cases and position of concrete

Characterization preliminary breakdown in the measured lightning electric fields

In this study, characterization of measured electric fields due to lightning channel was done. Likewise, previous studies on this case were reviewed and discussed accordingly. Furthermore, preliminary breakdown was done in detail and it was indicated on the real measured electric fields and the results were discussed. The behavior of preliminary breakdown signal was observed. This study shows that it will be easier to design filtering of the preliminary breakdown. The result show compelling agreement with theoretical predictions and significant improvement over previous effort by Clarence and Malan, Weidman and Krider and Rakov, et al. the work presented here has profound implications for future studies of Preliminary Breakdown and may one day help solve the problem of designing protection level for Electrical Engineers. The results show that the occurrence of PBP is in between 2 to 10 milliseconds before return stroke as agreed with Clerence and Malan

Characterization of lightning-generated electric fields and development of automated measuring system for cloud-to-ground lightning in Malaysia

Lightning flash produces electric discharges naturally into atmosphere which somehow result in negative consequences especially to power, electronic and communication systems. Hence, the knowledge of such characteristic is crucial to be obtained to fulfil the task of mitigating lightning problems that may occur. Furthermore, most studies regarding this were done in the temperate and sub-tropical regions manually which time consuming for analysing a timeframe purposes. This is due to the reason that an automated system is not available in the present market. Thus, this study is aimed to produce an automated measuring system for cloud-to-ground in Malaysia in order to reduce the analysed time. Measurements of the generated electric fields were done using parallel plate antenna system from May to October 2013 at Universiti Putra Malaysia, Serdang, Selangor, Malaysia, where the measurement site has a geographical coordinate of 2°59'19.9"N latitude and 101°43'29.8"E longitude. It is known that Malaysia is generally a tropical climate country with maximum monsoon rain occurring from October to December due to southwest monsoon and inter monsoon period. This thesis presents the characteristics of cloud-to-ground lightning generated vertical electric field waveforms recorded in Malaysia using Automated Characterisation of Lightning Electric Fields–Center of Electromagnetic and Lightning Protection (ACLEF-CELP). A total of 142 return strokes of negative lightning and 34 return strokes of positive lightning were found during the measurement period, and with preliminary breakdown pulses. The main purpose of this study includes characterisations of 12 and 4 types criteria to be considered for return stroke and preliminary breakdown pulses, respectively. Analysis of the measured cloud-to-ground lightning data is done using Matlab software which is used to analyse the data and serves as a database. It is found that, the initial peaks of electric field and its derivative for first return strokes are larger than those for the subsequent return strokes for both positive and negative return strokes. Data were analysed using ACLEF-CELP system and compared to another set of data with a similar climate condition. Both manual and automated data were compared and it is found that they are compatible with each other. Also, comparison of overall results with published data such as from Sri Lanka, Sweden, Germany, Japan and United States of America shows that several electric field and its derivative parameters are affected by geographical region. The ACLEF-CELP system could reduce analysis time where cloud-to-ground lightning data could be easily characterized with increment of efficiency. This is important specially when dealing with numerous data such as from a cloud-to-ground lightning

A new source of renewable energy from lightning return stroke : a small scale system

A new source of renewable energy from lightning return stroke is an issue which gives a high impact on the environment. This project investigates the behavior of hydrogen gas produced in water by using a Tesla coil. The behavior of the Tesla coil is investigated using a liquid impulse resistive probe. The liquid impulse resistive probe was calibrated by using a recurrent surge generator to identify the probe ratio by using a 500-volt low pulse generator as well as a high voltage impulse generator. The electrolysis method was used to investigate the production of hydrogen gas. A DC generator was used as the source for preliminary tests. Variations in the distance between the two electrodes had been investigated. The conductivity of water due to the hydrogen gas presence was measured. The production of hydrogen gas was observed to increase with the duration of the voltage applied. The amount of hydrogen is also dependent on the height of the carbon electrodes immersed in water. The production of hydrogen gas had also been investigated by using a high voltage pulse source, namely a Tesla coil, to represent a lightning impulse in a small scale system. Results are promising but more work, such as using a more powerful Tesla coil is required to actually generate hydrogen using an impulse source. Hydrogen gas can be converted into electrical energy if it is combined with a fuel cell. This method of energy regeneration can be a potential as a renewable energy source