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Mehrdad Mokhtari
Universiti Teknologi Malaysia
Computer Science & IT Electrical & Electronics Engineering

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Integration of Frequency Dependent Soil Electrical Properties in Grounding Electrode Circuit Model Mehrdad Mokhtari; Zulkurnain Abdul-Malek; Chin Leong Wooi
International Journal of Electrical and Computer Engineering (IJECE) Vol 6, No 2: April 2016
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (15.881 KB) | DOI: 10.11591/ijece.v6i2.pp792-799

Abstract

The effect of frequency dependent soil properties on the impedance and transient response of the grounding electrode was investigated. The frequency dependent soil models as proposed by Scott, Smith-Longmire, and Visacro-Alipio were critically reviewed. A novel method was proposed to integrate the frequency dependent soil electrical properties in the circuit model of grounding electrode. To validate the application of the method in circuit model, the voltage responses of the grounding electrode obtained by the circuit and electromagnetic models were compared. The voltage responses obtained by the circuit and electromagnetic models were in excellent agreement in terms of voltage peaks and wave shapes. The differences between voltage peaks obtained by the circuit and electromagnetic models were found less than 1%.
Statistical Analysis on Preliminary Breakdown Pulses of Positive Cloud-to-Ground Lightning in Malaysia Chin-Leong Wooi; Zulkurnain Abdul-Malek; Noor Azlinda Ahmad; Mehrdad Mokhtari; Behnam Salimi
International Journal of Electrical and Computer Engineering (IJECE) Vol 6, No 2: April 2016
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (13.982 KB) | DOI: 10.11591/ijece.v6i2.pp844-850

Abstract

This aim of this paper is to study the preliminary breakdown pulses (PBP) of positive cloud-to-ground (+CG) lightning flashes in Malaysia. There is a difference in PBP characteristics when a comparison is made between positive and negative flashes. To the best of the authors’ knowledge, this is the first time the PBP characteristics preceding positive lightning in Malaysia are reported. This study was carried out in Johor Bahru, Malaysia using a broadband antenna system during a monsoon period (Oct-Dec, 2012). It is found that the PBP for +CG lightning is much more complicated compared to the positive cloud-to-ground (–CG) lightning since only negative PBP trains are usually present in the –CG lightning.  Out of 21 analyzed positive flashes, four types of PBP trains were identified according to their initial polarities. These are negative PBP (20%), positive PBP (15%), PBP with polarity reversal (10%), and PBP with irregular polarity (15%). The balance 40% of flashes are without any PBP. The effect of geographical region may also cause the observed differences in the cloud discharge processes including the types of PBP. More studies are needed to determine the relationship between the return stroke and PBP.
Co-Authors Behnam Salimi Chin Leong Wooi Chin-Leong Wooi Noor Azlinda Ahmad Zulkurnain Abdul-Malek