Citation

Ong, Chang Shen (2023) Integrated approach for lightning risk assessment of high voltage Air-Insulated switchgear substations. Masters thesis, Multimedia University.

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Abstract

Outdoor high-voltage (HV) air-insulated (AIS) substations provide transmission and distribution of power to the public. Therefore, it is important that the HV AIS substations are equipped with the lightning protection systems to prevent dangerous events and outages due to lightning strikes. Although power utility companies have applied their preferred lightning protection methods which are mostly outlined in IEEE 998, there is still a high number of incidents of fires and power outages in substations due to lightning strikes each year. Besides that, this lack of a systematic approach also makes it difficult for practitioners to justify the adequacy of their preferred lightning protection methods. Therefore, calculating the lightning risk values in a probabilistic way via the risk assessment process described in IEC 62305-2 can be a viable alternative. For the risk assessment to be carried out according to the standard, a list of assumptions has been made regarding the substations as building structures. Based on IEC 62305-2, the risk values of loss of a human life (R1) and loss of service to the public (R2) for the outdoor HV AIS substations can be calculated and compared to the tolerable risk values (RT). Besides that, the risk assessment will be complemented by a proposed integrated process by including specific inputs regarding the substation characteristics. In this research, five outdoor HV AIS substations with different characteristics such as voltage systems, basic impulse level (BIL), lightning flash density, and striking distances, have been selected for lightning risk assessment. A list of significant risk factors has been identified and compiled, followed by a list of ambiguous risk factors. These significant ambiguous risk factors such as fire load function (rf), environmental factor (CE), LPL class, and other governing factors have been analysed and discussed. Consequently, in addition to having high values for the actual flash density and the lightning collection area of the substations, it is found that the selection of risk factors with a high probability may exceed the tolerable risk in some cases. For the purpose of correlating the results with the ambiguous risk factors, the adjustments in selection to the significant risk factor have been made in successive iterations. These risk factor adjustments can be used to predict the probable consequences by considering the actual adjustment of safety measures in designs. Thus, the lightning risk assessment process for the outdoor HV AIS substations has been successfully integrated by incorporating the substation characteristics, the assumptions made, and the findings of significant ambiguous risk factors.

Item Type:	Thesis (Masters)
Additional Information:	Call No.: TH9057 .O54 2023
Uncontrolled Keywords:	Lightning protection
Subjects:	T Technology > TH Building construction > TH9025-9745 Protection of buildings Including protection from dampness, fire, burglary
Divisions:	Faculty of Engineering (FOE)
Depositing User:	Ms Nurul Iqtiani Ahmad
Date Deposited:	07 Feb 2024 06:34
Last Modified:	07 Feb 2024 06:34
URII:	http://shdl.mmu.edu.my/id/eprint/12074

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