Effects of Lightning Channel Equivalent Impedance on Lightning Performance of Overhead Transmission Lines

Datsios, Zacharias G.; Mikropoulos, Pantelis N.; Tsovilis, Thomas E.

doi:10.1109/temc.2019.2900420

Cited by 57 publications

(19 citation statements)

References 28 publications

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“…In fact, the resistance of the lightning discharge channel at the stage of the main discharge does not remain constant, decreasing as the lightning current increases. In most calculations, the resistance of the lightning discharge channel is recommended to be considered equal to 400 Ω, 1000 Ω [11] or infinite. Computation of lightning performance indicators of overhead transmission lines with a lightning channel equivalent impedance equal to infinity leads to a certain overestimation when calculating the number of lightning outages caused by lightning strikes to phase conductors.…”

Section: Methods Of Researchmentioning

confidence: 99%

Alternative evaluation of voltage at top of transmission line tower stricken by lightning

Trotsenko

Dixit²,

Brzhezitsky

2021

TAPR

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The object of the research is a circuit that simulates a lightning strike to a tower of 220 kV power transmission line, taking into consideration the reflection of a current wave from 10 nearest towers. Computation of the voltage arising at the top of the stricken tower is necessary further to determine the lightning performance of transmission line by various methods. For Indian conditions, the average number of lightning strikes to this power line per 100 kilometers per year is about 77, which is a fairly high figure. As a rule, for the tasks of lightning protection, the lightning current is approximated by some analytical expression. In most cases, such expressions are various combinations of exponential functions. However, the waveform of real lightning currents on oscillograms differs significantly from the waveform attributed to them and approximated by relatively simple exponential expressions. For a more detailed study of transient processes caused by thunderstorm activity, there is a need to use oscillograms of real lightning currents when modeling. The problem of determining the voltage at the top of the stricken transmission line tower was solved using circuit simulation. To simulate the lightning current, digitized oscillograms of real lightning currents with peak values of –5.256 kA and –133.586 kA were applied. The article shows that the proposed approach gives a more accurate and visual representation of the transient process at the top of the stricken tower than the approximation of the lightning current by simple exponential expressions. Applying a simplified exponential description of the lightning current leads not only to a simplification of the nature of the transient process at the tower top, but also to an underestimation of the results to 8.8%. The selection of the equivalent circuit for the power line towers also affects the result. Representation of towers in the equivalent circuit with lumped inductances leads to slightly higher values compared to application of surge impedances in the circuit. In this case, the smaller the current amplitude, the greater the difference (8.6 % in the domain of low currents and 1.9 % in the domain of high currents). Since this leads to some reserve during the computations of lightning performance, it is recommended to use an equivalent circuit with lumped inductance for a transmission line tower. The conducted research contributes to the development of methods for calculating the lightning performance of power lines and extends the scope of application of circuit simulation programs.

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Section: Methods Of Researchmentioning

confidence: 99%

Alternative evaluation of voltage at top of transmission line tower stricken by lightning

Trotsenko

Dixit²,

Brzhezitsky

2021

TAPR

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“…Research studies related to insulation coordination of TLs require accurate modeling of string insulator flashover to help in calculating the fast-front surges resulting from shielding-failure flashover or back-flashover of TLs. The TL insulator flashover process can be characterized using the integration method [30], volt-time curve [30,31] or by employing leader development models [32][33][34]. The volttime curve, which is used in this work, is one of the most accurately used flashover criteria [15].…”

Section: Modeling and Simulationsmentioning

confidence: 99%

“…The impedance connected in parallel with the current source is the surge impedance of the lightning channel. The estimated values of the surge impedance of the lightning channel from limited experimental and computed data range from several hundred ohms to a few kilo-ohms [31,37].…”

Section: Lightning Strike Modelmentioning

confidence: 99%

Evaluation of the Transient Overvoltages of HVDC Transmission Lines Caused by Lightning Strikes

et al. 2022

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High-voltage direct-current (HVDC) transmission systems are considered an outstanding solution due to high electrical losses emerging from long-distance transmission. However, HVDC transmission lines (TLs) are vulnerable to lightning strikes. In this work, the Yunnan-Guizhou 500 kV HVDC transmission system is used as a case study to evaluate the impact of lightning strikes on DC-TL overvoltages, as no research studies have been conducted to assess the lightning transient behavior of DC-TLs. A comprehensive investigation of the 500 kV DC-TL transient performance during lightning strikes is performed, taking into account different technical aspects that have not been studied in detail by previous researchers. Additionally, analysis of the back-flashover phenomenon has not been conducted well in previous work, and results on the effect of changing the lightning strike current peak and tower grounding resistance on shielding-failure flashover are quite limited. The distributed-parameter model is used to represent the DC-TL using the electromagnetic transients program (EMTP), considering real parameters of shielding wires and DC towers to study the lightning impact in the case of back-flashover and shielding-failure phenomena. Lightning strike is applied to the shielding wire, and the impact of increasing the peak value of lightning current is investigated on the back-flashover occurrence. Moreover, the influence of tower grounding resistance variation on the transient overvoltages across the tower body and back-flashover phenomenon is evaluated. From the simulation results, increasing the lightning current peak and grounding resistance results in higher overvoltages across the tower body, which increases the probability of back-flashover. Additionally, the shielding failure of the TL is assumed, and the variation impact of the lightning current peak and grounding resistance on shielding-failure flashover is investigated. The results show that the impact of the lightning current peak has a more significant impact than the grounding resistance in the case of shielding-failure flashover.

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“…e impedance of the lightning strike channel was 400 Ω parallel to the current source. e 400 Ω value of the lightning strike channel is a typical value used in literature; however, it is more appropriate for higher lightning currents as analyzed in [29]. Using a higher value, such as the 1000 Ω value proposed in [30], would considerably influence the obtained results.…”

Section: Model Of Lightning Currentmentioning

confidence: 99%

Lightning Protection Improvement and Economic Evaluation of Thailand’s 24 kV Distribution Line Based on Difference in Grounding Distance of Overhead Ground Wire

Sestasombut

Ngaopitakkul

2021

Mathematical Problems in Engineering

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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.

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Effects of Lightning Channel Equivalent Impedance on Lightning Performance of Overhead Transmission Lines

Cited by 57 publications

References 28 publications

Alternative evaluation of voltage at top of transmission line tower stricken by lightning

Alternative evaluation of voltage at top of transmission line tower stricken by lightning

Evaluation of the Transient Overvoltages of HVDC Transmission Lines Caused by Lightning Strikes

Lightning Protection Improvement and Economic Evaluation of Thailand’s 24 kV Distribution Line Based on Difference in Grounding Distance of Overhead Ground Wire

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