Theoretical investigation of HVDC disc spacer charging in SF<sub>6</sub> gas insulated systems

Straumann, U.; Schüller, Michael; Franck, Christian M.

doi:10.1109/tdei.2012.6396980

Cited by 141 publications

(71 citation statements)

References 15 publications

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“…As it was shown in [1] it is not possible to conclude from small scale models to full scale geometries taking the gas phase of the setup into account. That is because the larger the geometry, the higher the ion current in the gas gets due to natural ionization, as the possible way of an electrical field line also gets longer when the setup turns from small size models into real applications [1].…”

Section: Methodsmentioning

confidence: 99%

“…That is because the larger the geometry, the higher the ion current in the gas gets due to natural ionization, as the possible way of an electrical field line also gets longer when the setup turns from small size models into real applications [1]. Thus the constructed test setup should have dimensions like a real GIS application and should be operated at voltages close to real applications.…”

Section: Methodsmentioning

confidence: 99%

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Time dependence of spacer charging in SF<inf>6</inf> under DC stress

Schueller

Straumann

Franck

2012

2012 Annual Report Conference on Electrical Insulation and Dielectric Phenomena

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As gas insulated DC transmission systems unite the advantages of space saving installation and big transmission capacity, this technology will become essential soon. The main problem in operation with respect to insulation seems to be identified today, which is charge accumulation on the surface of the insulators, so called spacers. These trapped charges can cause a reduction of dielectric strength and can lead to a breakdown, especially at polarity reversals and overvoltages. For experiments, a full encapsulated test setup was constructed. Test voltages up to 700 kV DC and a pressure up to 8 bar SF6 are possible. The main component of this setup is a 3 axis fully automated robotic handle system for moving the probe over the test samples inside the encapsulation. So the surface charge can be measured at all positions at the sample surface. The time dependence of the charging mechanism till the saturated state is of big interest. Thus the experiments presented in this paper deal with the influence of the measurement itself on the charging process.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Time dependence of spacer charging in SF<inf>6</inf> under DC stress

Schueller

Straumann

Franck

2012

2012 Annual Report Conference on Electrical Insulation and Dielectric Phenomena

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“…Up to now, the formation mechanism of the critical radius has not been interpreted satisfactorily. When a switching impulse is applied to a large air gap, the gap discharge experiences four steps in turn: the corona, the leader stem, the leader continuous propagation, and the final jump [10]. However, the formation of the leader in air has little relevance to that in strongly electronegative gases.…”

Section: Mechanism For Critical Radius Phenomenonmentioning

confidence: 99%

“…A fixed metal conducting particle on the surface of the electrode or insulator distorts the electric field in GIS, which results in breakdown voltages of GIS under VFTO decreasing sharply [3][4][5][6]. The insulation failures of GIS caused by VFTO have exceeded those caused by lightning impulses (LIs) at high voltage levels, which has drawn researchers' attention and become a hot topic worldwide [7][8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Critical radius phenomenon and mechanism for SF₆ gaps under very fast transient and lightning impulse voltages

Zhang¹,

Wu²,

Wang³

et al. 2017

IEEJ Transactions Elec Engng

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Insulation-related accidents of gas-insulated switchgear, induced by very fast transient overvoltage, have become increasingly serious in high-voltage power systems. A steep-fronted impulse voltage test equipment is developed for studying the discharge characteristics and mechanisms in the SF 6 gap. The influence of the electrode radius on the breakdown characteristic of a fixed-distance SF 6 gap is studied. It is found that discharge behaviors of the SF 6 gap show the so-called critical radius effect. With decreasing electrode radius r, the 50% breakdown voltage of the gap decreases till a critical radius R cr is reached, and then remains practically constant for further reduction of r. R cr increases with decreasing gas pressure and wave front time. Calculation results show that R cr is physically close to the length of the filamentary streamer zone L for negative voltages, whereas for positive voltages, R cr is close to the length of the homogeneous streamer zone l . The critical radius phenomenon is related to the streamer-precursor-leader discharge process in SF 6 gas, which is discovered and explained for the first time in this paper by the proposed critical charge criterion of leader breakdown.

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“…As shown in the previous section, to describe the non-linear nature of the conduction mechanism in the gas, the best approach is to solve the drift-diffusion-reaction equations for the gaseous ions in parallel with the Poisson equation for the electric field [22,23,24]. This is done here with Finite Element Modeling (FEM) numerical simulation (COMSOL) on a rotational symmetric model of the experimental setup described in section 3.2.…”

Section: Surface Potential Modelingmentioning

confidence: 99%

Micro discharges in HVDC gas insulated systems

Schueller

Gremaud

Doiron

et al. 2015

IEEE Trans. Dielect. Electr. Insul.

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Theoretical investigation of HVDC disc spacer charging in SF₆ gas insulated systems

Cited by 141 publications

References 15 publications

Time dependence of spacer charging in SF<inf>6</inf> under DC stress

Time dependence of spacer charging in SF<inf>6</inf> under DC stress

Critical radius phenomenon and mechanism for SF₆ gaps under very fast transient and lightning impulse voltages

Micro discharges in HVDC gas insulated systems

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Theoretical investigation of HVDC disc spacer charging in SF6 gas insulated systems

Cited by 141 publications

References 15 publications

Time dependence of spacer charging in SF<inf>6</inf> under DC stress

Time dependence of spacer charging in SF<inf>6</inf> under DC stress

Critical radius phenomenon and mechanism for SF6 gaps under very fast transient and lightning impulse voltages

Micro discharges in HVDC gas insulated systems

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Product

Resources

About

Theoretical investigation of HVDC disc spacer charging in SF₆ gas insulated systems

Critical radius phenomenon and mechanism for SF₆ gaps under very fast transient and lightning impulse voltages