Effects of agricultural fires on the performance of overhead transmission lines

Fonseca, Johanna; Tan, Ai Lee; Silva, R.P.; Monassi, V.; Assuncao, L.A.R.; Junqueira, W.S.; Melo, M.

doi:10.1109/61.53071

Cited by 45 publications

(21 citation statements)

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“…The particle size of carbon black varies from 0.2 to 5 microns, and it has a certain conductivity. They form granular chains and bridge parts intermittently, so that the gap insulation strength decreases rapidly [11]. In addition to small carbon black particles, vegetation combustion also produces large-scale ash.…”

Section: Introductionmentioning

confidence: 99%

Two Dimensional Axisymmetric Simulation Analysis of Vegetation Combustion Particles Movement in Flame Gap under DC Voltage

Zhou

Xiong

et al. 2019

Energies

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In recent years, extreme high temperature weather occurs frequently, which easily causes forest fires. The forest fire is prone to the trip accident of the transmission line. Previous studies show that charged combustion particles cause electric field distortion in the gap below the transmission line, and trigger discharges near the conductor area. The motion and distribution characteristics of combustion particles in the gap have an important influence on the discharge characteristics. Therefore, the size and morphology of combustion particles are analyzed through combustion experiments with typical vegetation. The combustion particles are mainly affected by the air drag force, electric field force and gravity. The interaction and influence of temperature, fluid, electric field and the multi-physical field of particle motion are comprehensively analyzed. A two dimensional (2D) axisymmetric simulation model is established by simplifying the flame region. According to the heat release rate of vegetation flame combustion, the fluid temperature and velocity are calculated. Combined with the fluid field and electric field, the forces on particles and movement are calculated. The results can provide a basis for the analysis of the electric field distortion, and further study the discharge mechanism of the gap under the condition of vegetation flame.

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Section: Introductionmentioning

confidence: 99%

Two Dimensional Axisymmetric Simulation Analysis of Vegetation Combustion Particles Movement in Flame Gap under DC Voltage

Zhou

Xiong

et al. 2019

Energies

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“…Many researchers have studied the gap breakdown characteristics under forest fire conditions . The withstand voltage of transmission line insulation under fire conditions was calculated as 35 kV/m by Fonseca . West and MacMullam placed the wood crib under two phase test line to study the gap insulation strength .…”

Section: Introductionmentioning

confidence: 99%

Study on the breakdown characteristics of the transmission line gap under forest fire conditions

Ruan

Huang

et al. 2014

Int. Trans. Electr. Energ. Syst.

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Summary With the fast development of China's power grid construction, many transmission lines' corridors are inevitable across mountain with luxuriant vegetation. The occurrence of forest fires under transmission lines may lead to power interruptions, seriously affecting the stability of the grid operation. The characteristics of fire‐induced flashovers are analyzed by statistical data of 220–500‐kV lines trips in recent years. The line trip out rate caused by forest fires varied according to seasons and climate. The fire‐induced flashover is much more serious than lighting trips. AC and DC voltage discharge tests of transmission line gap under different fire conditions are carried out by using wood crib fire. Test results indicate that: the gap's insulation strength under fire conditions is reduced to about 20% of that under pure air; the values of breakdown voltage have been decreased about 30% after alkali metal added; the gap breakdown under DC voltage has obvious polarity effect, and the flame shape and leakage current waveform are different under positive DC voltage and negative DC voltage. The analysis of gap breakdown mechanism under fire conditions shows that temperature, flame conductivity and ashes are main factors. Their combined effect significantly reduces the gap's insulation strength. Copyright © 2014 John Wiley & Sons, Ltd.

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“…Occurrence of wildfires under transmission lines has caused a great number of power outages in many countries (Fonseca et al, 1990). In South African high voltage network, wildfires are responsible for almost 15% annual power outages (Bekker and Hoch, 2002).…”

Section: Introductionmentioning

confidence: 99%

Wildfire plume electrical conductivity

Mphale

Heron

2007

Tellus B: Chemical and Physical Meteorology

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Wildfires are weakly ionized gas. The ionization is mainly due to plant's inorganic ash content species (more especially potassium), that are emitted from thermally decomposing plant structure into the flame during combustion. The amount of ionization in flames with potassium impurities is influenced by both the temperature and the amount potassium impurities in the flame. A numerical experiment was conducted using a local thermal equilibrium‐based model to study the influence of inorganic wildfire contents on wildfire electrical conductivity. Simulated very high intensity wildfires (21–90 MWm−1) were used to quantify steady‐state electrical conductivity. Its variation with wildfire plume height is important for high voltage power flashover research. In the simulation, vegetation potassium content was varied from 0.50% to 3.0% on dry weight basis, a reflection of its content in natural vegetation. The model predicted a maximum conductivity of 0.053 mhom−1 in 90 MWm−1 crown fire in vegetation with 3.0% potassium content. A 90 MWm−1 crown fire in vegetation with potassium content of 0.5% was predicted to produce a maximum conductivity of 0.022 mhom−1. Electrical conductivities were lower for a shrub fire with an intensity of 21 MWm−1. The model predicted conductivities of 0.0021 and 0.0009 mhom−1 for potassium content of 3.0 and 0.5% in vegetation, respectively.

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Effects of agricultural fires on the performance of overhead transmission lines

Cited by 45 publications

References 1 publication

Two Dimensional Axisymmetric Simulation Analysis of Vegetation Combustion Particles Movement in Flame Gap under DC Voltage

Two Dimensional Axisymmetric Simulation Analysis of Vegetation Combustion Particles Movement in Flame Gap under DC Voltage

Study on the breakdown characteristics of the transmission line gap under forest fire conditions

Wildfire plume electrical conductivity

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