Search

This study determines the voltage across insulators after a direct lightning strike to an overhead ground wire on a 24 kV pole structure for different grounding distances of overhead ground wire, to calculate the maximum ground resistance required to avoid disruption of the distribution line system using ATP-EMTP software. The results show that when a 40 kA lightning current, the average lightning current in Thailand, strikes a 24 kV pole structure, the maximum ground resistance should not exceed 4 Ω for a 40 m grounding distance of overhead ground wire, based on an existing critical insulator flashover of 205 kV. However, because the average ground resistance in Thailand is approximately 10 Ω, this study proposes increasing the insulation level from 205 kV to 300 kV to reduce the likelihood of power outage. The cost-effectiveness of such an investment is assessed in terms of net present value (NPV), internal rate of return (IRR), profitability index (PI), and discounted payback period (DPP) using existing economic tools. Results show that when the critical insulator flashover is increased from 205 kV to 300 kV for a 40 m grounding distance of overhead ground wire, the project is likely to have a DPP of 15.12 years, NPV of 143,321.87 USD, IRR of 12%, and PI of 1.15. On the other hand, grounding distances greater than 40 m for overhead ground wire result in negative NPV, although the back flashover rate can be reduced by 1.51–5.71% with grounding distances of 80–200 m compared to the situation in the absence of grounding. [ABSTRACT FROM AUTHOR]

This article proposed a computer-based simulation approach to estimate touch and step voltages due to a lightning strike at a mass rapid transit railway station. A purely resistive circuit model of a station lightning protection, and earthing & bonding system is formed in MATLAB/Simulink with Yaek Nonthaburi 1 passenger station of MRT purple line in Bangkok, Thailand as a case study. The simulation investigated the consequence of a lightning strike at four different locations on the roof of the station and examined whether or not the lightning protection system met the standard requirements. The results showed the touch voltages, step voltages and body currents in a steady state together with the impact on the human body standing in the station. The simulation can guarantee the effectiveness of the proposed model, and also proved that the lightning protection system of the station is able to conform to the standard and there is no harm for the passenger in the station. [ABSTRACT FROM AUTHOR]

This article presents a five-year performance review of an early streamer emission (ESE) air terminal lightning protection system for a large scale PV power plant in Thailand. The comparison effect of a Franklin lightning protection system and the ESE lightning protection system was analyzed for the PV power plant. The ESE lightning protection system was selected to be implemented in the PV power plant. The capacity of the PV power plant studied was 8 MWp on an area of 150,000 square meters in the Nong Ya Plong district, Phetchaburi province, Western Thailand. A Franklin lightning rod type was also designed to be implemented in this PV power plant. The Franklin lightning rod type comprised 122 pieces but the ESE lightning rod type consisted of only 11 pieces. The conceptual design of the Franklin rod type followed the standard of the Council of Engineers, Thailand, and the ESE lightning rod type followed the NFC17102 standard of France. The estimated cost of installation was a key comparison to select the lightning protection system; the total installation cost of the Franklin lightning rod type was USD 197,363.80 and the ESE lightning rod type was USD 44,338.06. The lightning system was applied to the lightning arrester in the power plant to provide good protection, in which the balance of the pole to the mounting position is required to optimize the system performance. The result of the simulation also showed that the shading effects of the Franklin rod type were greater than the ESE rod type. The installation cost of the Franklin lightning rod type was 4.45 times more expensive than the ESE lightning rod type. Therefore, the ESE lightning protection system was selected to be implemented in the PV power plant. From the recorded data of the five-year performance of the ESE lightning protection system (2016–2020), there were three occurrences of a lightning strike on the PV power plant. The ESE lightning protection system effectively protected and prevented the lightning strike to the PV power plant. This study can help and support with the selection of a lightning system for the protection of large scale PV power plants in the future. [ABSTRACT FROM AUTHOR]

In this paper, we apply the Failure Modes, Effects, and Criticality Analysis (FMECA) approach to the criticality and risk analysis of the efficiency, safety/reliability, environment, and financial criteria of the high voltage transmission line. In the efficiency analysis, the weighting-scoring method and analytical hierarchy process are applied to obtain the line renovation index, which is interpreted as efficiency severity. The safety/reliability severity relates to the system impacts are caused by failure of the equipment and the system. The environmental severity takes social impacts and pollution into consideration. The financial severity involves the cost of spare parts and maintenance costs, which are interpreted as the financial severity of the lines. Twenty practical transmission lines in Thailand with actual data for 115, 230, and 500 kV were studied. The transmission line components are divided into eight components including the conductor, conductor accessories, insulator, steel structure, foundation, lightning protection system, tower accessories, and right-of-way. The severity and criticality of the components and transmission lines are analyzed and plotted in criticality matrices based on four criteria. This criticality matrix is presented at four different levels including very low, low, medium, and high risk, as represented by four color bands: green, yellow, orange, and red, respectively. The results show that three 115 kV lines are the first priority for short-term reconstruction planning because of their unacceptable condition and high risk in terms of safety/reliability and financing. Recommendations for maintenance strategy and risk mitigation are proposed for the utility according to the utility's actual criticality. Ultimately, maintenance planning of the transmission system can be effectively managed with higher reliability, a lower risk of failure, and a lower cost of maintenance. [ABSTRACT FROM AUTHOR]