| 1. |
- Arevalo, Liliana, et al.
(författare)
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Attachment process of the discharge of competing grounded electrodes - Experimental observations and modeling
- 2021
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Ingår i: 2021 35th International Conference on Lightning Protection (ICLP) and XVI International Symposium On Lightning Protection (SIPDA). - : IEEE. - 9781665423465
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Konferensbidrag (refereegranskat)abstract
- The lightning attachment discharge process theory is based on studies of the physics of the discharge obtained from high voltage laboratory tests. The process of propagation of positive and negative discharges has been studied independently and then the gathered information has been used to understand and explain the lightning attachment development. In this paper, an experimental set-up is built to describe the dynamic behavior of positive and negative discharges. Electrodes of different dimensions placed at different distances are used as grounded electrodes and a high voltage electrode is subject to negative switching impulses. Test results allow to identify different stages of the dynamic process of attachment of the discharge between a downward negative discharge and a positive upward leader discharge. The principles of physics of discharge for positive and negative polarities are used to model the laboratory test measurements. The model can reproduce in an accurate manner majority of the dynamic processes of the discharge. In addition, statistical results of the effect of nearby and competing upward discharges is obtained.
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| 2. |
- Roman, Francisco, et al.
(författare)
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10/350 µs Lightning Impulse Current Behavior of a Conductive Fabric
- 2021
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Ingår i: 2021 35TH INTERNATIONAL CONFERENCE ON LIGHTNING PROTECTION (ICLP) AND XVI INTERNATIONAL SYMPOSIUM ON LIGHTNING PROTECTION (SIPDA). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781665423465
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Konferensbidrag (refereegranskat)abstract
- Lightweight Portable Lightning Protection Shelters require the use of new materials capable of supporting the high current densities associated with lightning currents. In this paper, 30 x 30 cm(2) conductive fabrics samples are subjected to 10/350 mu s lightning current impulses. This experimental work, performed at the HV lab of Uppsala University, is aimed at understanding the transversal pattern of scratches or striations observed in conductive fabrics in previous experiments performed at the HV lab of Universidad Nacional de Colombia with 8/20 mu s lightning impulse currents. Striations were recorded with both a still camera and a fast-recording camera, while the samples current was measured. Additionally, the withstand current density of the tested conductive fabrics was obtained.
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| 3. |
- Wooi, Chin-Leong, et al.
(författare)
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Observations of X-rays in 4-meters long laboratory sparks under positive lightning impulse
- 2021
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Ingår i: 2021 35TH INTERNATIONAL CONFERENCE ON LIGHTNING PROTECTION (ICLP) AND XVI INTERNATIONAL SYMPOSIUM ON LIGHTNING PROTECTION (SIPDA). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781665423465
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Konferensbidrag (refereegranskat)abstract
- In this paper, the observation of X-rays in 4-meters long laboratory sparks is presented for the first time. In this study, a total of 20 standard positive lightning impulse voltages (1.2/50 mu s) with measured peak voltages between 3.0 to 3.2 MV were applied across 4-m long horizontal air gap of sphere-sphere configuration with 50-cm spheres. The results show that most of the X-ray emission were detected at about 12 mu s after the applications of the lightning impulse voltage during the rising part of the voltage or at around the peak of the voltage. Compared to previous shorter gaps studies, the longer air gaps seem leads to a delay in X-ray occurrence time. X-rays appeared at about 1-2 mu s after the applications of lightning impulse voltage which is slightly delayed compared to some of the previous shorter gap's studies. This study also finds an increase in the X-ray emission rate and deposited energies of Xrays in the case of higher applied peak voltages. Higher applied peak voltages seemed to change the X-rays appearance time as well. Additionally, multiple peaks X-rays pulses were observed near to the peak of the voltage in this study.
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