Development of insulation structure and enhancement of insulation reliability of 500 kV DC GIS

Hasegawa, T.; Yamaji, K.; Hatano, Masayuki; Endo, Fumio; Rokunohe, Toshiaki; Yamagiwa, T.

doi:10.1109/61.568241

Cited by 66 publications

(16 citation statements)

References 9 publications

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“…Although the supporting insulators in GIS/GIL separate the high voltage and ground, the electric field distribution of coaxial cylindrical structure inside the apparatus was changed not to mention the presence of metal particles [1][2][3][4]. Therefore, operation experience of GIS/GIL demonstrates that the flashover of its supporting insulators is the most common failure [5][6][7].…”

Section: Introductionmentioning

confidence: 88%

Negative DC Flashover of PTFE and PE Insulators in Sf6

Jia¹,

Chen²,

Li³

et al. 2012

2012 Asia-Pacific Power and Energy Engineering Conference

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With the extensive application of high voltage power transformation and distribution apparatus such as GIS and GIL, the dielectric strength of interior supporting insulators become an important factor for equipments' safe and stable operation. In this paper, the cone-plane electrode assembly has been built to simulate the electric field distribution of the coaxial cylindrical configuration in GIS/GIL. Key factors that affect PTFE and PE insulators' flashover characteristics in SF 6 under DC voltage are investigated mainly from the view of the insulator's surface roughness and metal particles. Results show that the surface dielectric strength of umbrella insulators with smooth surface is fine whether the insulator is made of PTFE or PE. Moreover, whatever the metal particle adhered to insulator surface is near high voltage conductor or grounded enclosure, flashover voltages of the insulator are the lowest under relatively high pressures (≥0.3MPa) if the metal particle is positively charged.

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Section: Introductionmentioning

confidence: 88%

Negative DC Flashover of PTFE and PE Insulators in Sf6

Jia¹,

Chen²,

Li³

et al. 2012

2012 Asia-Pacific Power and Energy Engineering Conference

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“…Furthermore, besides the electric conductivity effect, the shape of the solid epoxy spacer influences significantly the distribution of the electric field resulting in local electric field intensification in the gas at the gas-spacer interface and particularly at the contacts: the HV conductor/grounded enclosure-gas-epoxy spacer, called triple junctions [1,2]. Consequently, the spacer shape must be optimized in a suitable manner for HVDC operation and verified by testing.…”

Section: Introductionmentioning

confidence: 99%

Development of Future Compact and Eco-Friendly HVDC Gas-Insulated Systems: Shape Optimization of a DC Spacer Model and Novel Materials Investigation

Zebouchi

Haddad

2020

Energies

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Testing and validating the electrical insulation performance of full-size compact high-voltage direct current (HVDC) gas-insulated systems, gas-insulated transmission lines (GIL) and gas-insulated switchgears (GIS) is very costly and take long time. Therefore, a reduced scale system was designed and constructed to study thoroughly the spacer’s performance when subjected to higher electric fields under HVDC with different shapes, made of new advanced materials, and housed in new SF6-free gas environment. Since the stationary DC electric field distribution along the spacer is controlled by spacer material conductivity and strongly depends upon its shape, this, the first part of two articles, proposes in a first step based on electric field calculations with COMSOL Multiphysics software, an optimized shape of a spacer model using a standard high-voltage alternating current (HVAC) alumina-filled epoxy material. Then, two novel types of materials were introduced and investigated: (i) modified filled epoxy material with a lower temperature-dependent conductivity than that of the standard HVAC material, which is interpreted by a lower thermal activation energy; and (ii) nonlinear resistive field grading material with a low nonlinearity coefficient, with and without the presence of a temperature gradient which occurs under operating service load. The numerical results show that, despite that the DC optimized profile of the spacer made of standard HVAC, alumina-filled epoxy is very effective in relaxing the electric field magnitudes along the spacer under uniform temperature—its distribution is significantly affected by the presence of a high temperature gradient causing the maximum electric field shifts along the spacer surface towards the earthed flange. Under this condition, the modified filled epoxy material with a weaker temperature-dependent conductivity results in a significant reduction of the electric field enhancement, representing thus a relevant key solution for HVDC GIL/GIS applications. Nonlinear resistive field grading material is also effective but seems unnecessary. The optimized DC spacer models are being fabricated for tests verification with C4-Perfluoronitrile (C4-PFN, 3MTM NovecTM 4710)/CO2 and Trifluoroiodomethane (CF3I)/CO2 gas mixtures in the reduced scale gas-insulated test prototype.

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“…Given the connection of new large-scale energy and the rapid development of HVDC transmission technology and flexible HVDC technology, DC gas-insulated equipment (DC-GIE) has attracted significant attention because of its technological advantages in improving system reliability and reducing space occupation [1][2][3][4][5][6]. Pure SF 6 gas has stable chemical properties and is not easily decomposed.…”

Section: Introductionmentioning

confidence: 99%

Decomposition Characteristics of SF6 and Partial Discharge Recognition under Negative DC Conditions

Tang

Yang

et al. 2017

Energies

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Four typical types of artificial defects are designed in conducting the decomposition experiments of SF 6 gas to obtain and understand the decomposition characteristics of SF 6 gas-insulated medium under different types of negative DC partial discharge (DC-PD), and use the obtained decomposition characteristics of SF 6 in diagnosing the type and severity of insulation fault in DC SF 6 gas-insulated equipment. Experimental results show that the negative DC partial discharges caused by the four defects decompose the SF 6 gas and generate five stable decomposed components, namely, CF 4 , CO 2 , SO 2 F 2 , SOF 2 , and SO 2 . The concentration, effective formation rate, and concentration ratio of SF 6 decomposed components can be associated with the PD types. Furthermore, back propagation neural network algorithm is used to recognize the PD types. The recognition results show that compared with the concentrations of SF 6 decomposed components, their concentration ratios are more suitable as the characteristic quantities for PD recognition, and using those concentration ratios in recognizing the PD types can obtain a good effect.

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Development of insulation structure and enhancement of insulation reliability of 500 kV DC GIS

Cited by 66 publications

References 9 publications

Negative DC Flashover of PTFE and PE Insulators in Sf6

Negative DC Flashover of PTFE and PE Insulators in Sf6

Development of Future Compact and Eco-Friendly HVDC Gas-Insulated Systems: Shape Optimization of a DC Spacer Model and Novel Materials Investigation

Decomposition Characteristics of SF6 and Partial Discharge Recognition under Negative DC Conditions

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