Ali I. El Gayar
Universiti Teknologi Malaysia

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AC Interference on Gas Pipeline due to Phase to Ground Faults in Overhead Transmission Line Ali I. El Gayar; Zulkurnain Abdul-Malek
International Journal of Electrical and Computer Engineering (IJECE) Vol 6, No 3: June 2016
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (889.583 KB) | DOI: 10.11591/ijece.v6i3.pp1363-1370

Abstract

The purpose of this research is to investigate the severity of voltages induced on gas pipeline installed in parallel to a 115 kV overhead transmission line. The overhead transmission line (OHTL) is configured as a single-circuit. One of the phases exposed to single phase to ground fault. Transmission of high voltage along the same right of way (ROW) with metallic conductor may possibly introduce interference on metallic conductors such as gas pipeline (GPL) due to power frequency voltage as well as due to phase faults and switching phenomena. Two main approaches were used to compute the induced voltages, namely the method of moment (MOM), which is based on electromagnetic field theory, and circuit based method. The simulation considers the length of OHTL and GPL are 30 km and 10km respectively. The pipeline buried at 1 m underground in homogenous earth structure with various soil resistivites ranged from 10 to 1000 Ω-m. The transmission line consists of 150 towers and 200 m span length. The separation distance between the GPL and OHTL is varied from 5 to 100 m. The phase to ground fault current changed from 0.5 to 10 kA. Several observation points are made throughout the corridor, to examinant the induced voltages at different locations. The result show that, the soil resistivity, separation distance, and fault current had significant effect on pipeline induced voltage. In case of the observation points lying on the soil or on the outer surface of the pipeline coating, the induced voltage increased, when the soil resistivity increase, as expected. In case of the observation points placed inside the pipeline metal, and the pipeline is well coated, the induced voltage will decreased, when the soil resistivity increase.
Conductive and Inductive Coupling between Faulted Power Lines and Buried Pipeline by Considering the Effect of Soil Structure Ali I. El Gayar; Zulkurnain Abdul-Malek; Mohammed Imran M; Chin Leong Wooi; Ibtihal Fawzi Elshami
Indonesian Journal of Electrical Engineering and Computer Science Vol 5, No 3: March 2017
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v5.i3.pp656-660

Abstract

The AC total interference of faulted power lines to gas pipelines sharing the same right of way, which may pose a threat to operating personnel and equipment, was studied. The main advantage of this work is to determine the effects of different soil structures on the induced voltage for various soil resistivities. Two main approaches were used to compute the induced voltages, namely the method of moment (MOM), which is based on electromagnetic field theory, and the circuit based method, which uses the circuit grounding analysis to compute the conductive interference and the circuit based models to compute the inductive interference. A 10-km-long parallel pipeline-transmission line model was developed. The soil resistivity was varied, and the induced voltages obtained from both approaches were compared. Soil resistivity and soil structure are important parameters that affect the AC interference level. The results of the study show that the earth potentials and the metal GPRS are independent. Higher soil resistivity causes the tower ground resistance to increase, thus making the shield wire’s attractiveness as a fault current return path to increase, which in turn forces the induced net EMF and the cumulative GPR in the pipeline to reduce.