Dielectric properties of gas mixtures with per-fluorocarbon gas and gas with low liquefaction temperature

Wada, Junichi; Ueta, Genyo; Okabe, Shigemitsu; Hikita, Masayuki

doi:10.1109/tdei.2015.005373

Cited by 43 publications

(18 citation statements)

References 7 publications

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“…In the literature, there have been a considerable number of gases that were previously investigated and proposed as potential replacement to SF6 [4]- [8]. This paper adopts a simple selection method which is based on four key criteria: dielectric strength, global warming potential, toxicity and boiling point.…”

Section: A Sf6 Alternatives For Insulation Applicationsmentioning

confidence: 99%

“…Fig. 1 process to narrow down an appropriate gas candidate from a wide range of potential SF6 alternatives [4]- [8]. From this process, C3F7CN has emerged as a gas medium that can be considered technically viable for the retro-fill research investigation carried out in this paper.…”

Section: A Sf6 Alternatives For Insulation Applicationsmentioning

confidence: 99%

“…From this process, C3F7CN has emerged as a gas medium that can be considered technically viable for the retro-fill research investigation carried out in this paper. Group 1 illustrates a wide selection of potential SF6 alternatives studied to date [4]- [8]. Group 2 excludes the gases that have low dielectric strength relative to SF6.…”

Section: A Sf6 Alternatives For Insulation Applicationsmentioning

confidence: 99%

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Technical Viability of Retro-Filling C₃F₇CN/CO₂ Gas Mixtures in SF₆-Designed Gas Insulated Lines and Busbars at Transmission Voltages

Loizou

Chen

Liu

et al. 2020

IEEE Trans. Power Delivery

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Sulphur hexafluoride (SF6), the most popular dielectric medium adopted in compressed gas insulated equipment, has been identified as a highly potent greenhouse gas. This has led to increased interest in finding a more environmentally friendly replacement candidate. In this paper, the technical viability of C3F7CN/CO2 gas mixtures was assessed as a potential retro-fill solution for existing SF6-filled gas insulated lines (GIL) and busbars (GIB). A reduced-scale coaxial prototype was developed to establish the breakdown strength of 20% C3F7CN / 80% CO2 and 16% C3F7CN / 84% CO2 gas mixtures in direct comparison with pure SF6 under the standard lightning impulse (1.2/50 μs). Breakdown results demonstrate that a mixture of 20% C3F7CN / 80% CO2 exhibits comparable insulation capability to pure SF6 in coaxial geometries with similar field uniformity to GIL / GIB. This initial finding has led to the construction of a full-scale GIB demonstrator rated for 420/550 kV. Type tests according to IEC 62271-204 showed that the 20% C3F7CN / 80 % CO2 gas mixture has passed all the required voltage levels as SF6. The research findings in this paper are an encouraging step towards a technically viable SF6-free retro-fill solution for existing GIL / GIB installed for the 400 kV transmission network in the UK.

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Section: A Sf6 Alternatives For Insulation Applicationsmentioning

confidence: 99%

Section: A Sf6 Alternatives For Insulation Applicationsmentioning

confidence: 99%

Section: A Sf6 Alternatives For Insulation Applicationsmentioning

confidence: 99%

See 1 more Smart Citation

Technical Viability of Retro-Filling C₃F₇CN/CO₂ Gas Mixtures in SF₆-Designed Gas Insulated Lines and Busbars at Transmission Voltages

Loizou

Chen

Liu

et al. 2020

IEEE Trans. Power Delivery

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“…However, universally replacing SF 6 in power equipment has proven to be a challenging task as no alternative gas can yet be adopted as a onefor-one replacement. Different families of gases have been studied such as perfluorocarbons [5], fluoroketones [6] and natural origin gases [7]. All of these were found to have drawbacks which do not allow a simple retro-fill replacement in existing SF 6 -containing equipment.…”

Section: Introductionmentioning

confidence: 99%

Lightning impulse breakdown characteristics of SF₆ and 20% C₃F₇CN / 80% CO₂ mixture under weakly non-uniform electric fields

Loizou

Chen

Liu

et al. 2020

IEEE Trans. Dielect. Electr. Insul.

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This paper provides a comparative study on the impulse breakdown performance of SF 6 and 20% C 3 F 7 CN / 80% CO 2 gas mixture under weak non-uniform electric fields. Two geometrically distinct electrode configurations, with similar field utilization factor, were subjected to standard lightning impulse waveform (1.2/50 μs) and the effects of pressure, gap distance and impulse polarity on breakdown characteristics were studied. The results show that SF 6 has a higher breakdown voltage than the C 3 F 7 CN/CO 2 mixture and the positive 1.2/50 µs breakdown voltages were found to be higher than the negative counterparts. These results show that the effect of polarity on breakdown voltage does not exclusively depend on electrode geometry but also on pressure and gas type. The results of this paper identify the weaker polarity for 20% C 3 F 7 CN / 80% CO 2 tested with hemispherical rod-plane and coaxial electrode configurations and the results contribute to the design of SF 6-free gas insulated equipment. Index Terms-heptafluoro-iso-butyronitrile (C 3 F 7 CN), sulphur hexafluoride (SF 6), lightning impulse, non-uniform field, polarity effect, breakdown, gas insulation

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“…In addition to the traditional gases mentioned above, potential alternatives to SF 6 that have been considered in recent years include perfluorocarbons (PFCs), trifluoroiodomethane (CF 3 I), HFO-1234zeE, fluoronitrile (C 4 F 7 N), and fluoroketones (C5-PFK and C6-PFK). The GWP of PFCs is high (e.g., c-C 4 F 8 and C 2 F 6 have GWPs of 8700 and 12,200, respectively); thus, there is no significant reduction in GWP [13][14][15]. CF 3 I is classified as a type 3 mutagen and presents disadvantages such as iodine I 2 (acute toxicity) precipitation after repeated discharges.…”

Section: Introductionmentioning

confidence: 99%

Compatibility between C6F12O–N2 Gas Mixture and Metal Used in Medium-Voltage Switchgears

et al. 2019

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C6F12O has been introduced as the potential alternative gas to SF6 because of its excellent insulation properties and great eco-friendly performance. Considering that C6F12O may react with the internal materials of switchgears in practical applications, its compatibility with metal materials must be tested to evaluate its long-term application possibilities. In this work, the compatibility of C6F12O–N2 gas mixtures with aluminum and copper was tested at different temperatures by setting up a heat-aging reaction platform between the gas and each metal. The metal surface morphology and gas composition before and after the reaction were compared and analyzed. The results show that the surface color of the copper sheet changed considerably, and the corrosion degree of the surface deepened with the increase of temperature. The decomposition of C6F12O was also promoted. In contrast, aluminum did not react severely with the gas mixture. The compatibility of the gas mixture with aluminum was generally better than that of copper.

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Dielectric properties of gas mixtures with per-fluorocarbon gas and gas with low liquefaction temperature

Cited by 43 publications

References 7 publications

Technical Viability of Retro-Filling C₃F₇CN/CO₂ Gas Mixtures in SF₆-Designed Gas Insulated Lines and Busbars at Transmission Voltages

Technical Viability of Retro-Filling C₃F₇CN/CO₂ Gas Mixtures in SF₆-Designed Gas Insulated Lines and Busbars at Transmission Voltages

Lightning impulse breakdown characteristics of SF₆ and 20% C₃F₇CN / 80% CO₂ mixture under weakly non-uniform electric fields

Compatibility between C6F12O–N2 Gas Mixture and Metal Used in Medium-Voltage Switchgears

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Dielectric properties of gas mixtures with per-fluorocarbon gas and gas with low liquefaction temperature

Cited by 43 publications

References 7 publications

Technical Viability of Retro-Filling C3F7CN/CO2 Gas Mixtures in SF6-Designed Gas Insulated Lines and Busbars at Transmission Voltages

Technical Viability of Retro-Filling C3F7CN/CO2 Gas Mixtures in SF6-Designed Gas Insulated Lines and Busbars at Transmission Voltages

Lightning impulse breakdown characteristics of SF6 and 20% C3F7CN / 80% CO2 mixture under weakly non-uniform electric fields

Compatibility between C6F12O–N2 Gas Mixture and Metal Used in Medium-Voltage Switchgears

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Product

Resources

About

Technical Viability of Retro-Filling C₃F₇CN/CO₂ Gas Mixtures in SF₆-Designed Gas Insulated Lines and Busbars at Transmission Voltages

Technical Viability of Retro-Filling C₃F₇CN/CO₂ Gas Mixtures in SF₆-Designed Gas Insulated Lines and Busbars at Transmission Voltages

Lightning impulse breakdown characteristics of SF₆ and 20% C₃F₇CN / 80% CO₂ mixture under weakly non-uniform electric fields