SF<sub>6</sub> high voltage circuit breaker contact systems under lightning impulse and very fast transient voltage stress

Simka, Philipp; Straumann, U.; Franck, Christian M.

doi:10.1109/tdei.2012.6215088

Cited by 12 publications

(6 citation statements)

References 11 publications

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“…One major consequence of pollutants in such areas is the reduction of insulation or losing the insulation in transmission lines and stations. In such areas, an identification of an effective insulation in pollution scenarios is not only important for designing and selecting the appropriate type of insulation but also for adopting a proper maintenance plan of insulation devices . According to the literature, field visits, laboratory tests on insulators, computer simulation, and experience, there is a need for reconsidering insulation coordination in Mazandaran and Golestan power network.…”

Section: Statement Of the Problemmentioning

confidence: 99%

Reconsidering insulation coordination and simulation under the effect of pollution due to climate change

Valinejad

Firouzifar

Marzband

et al. 2018

Int Trans Electr Energ Syst

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Summary Climate change and air pollution have a direct impact on the performance and lifetime of insulating materials. In recent years, Mazandaran and Golestan provinces in Iran have witnessed a climate change and an increase in air pollution. This problem increases outages and losses in transmission and overhead distribution network. Moreover, traditional and empirical methods have been used for insulation coordination in past decades. As a result, research is needed on the regional power line isolation, revision of insulated surface design, and the number of insulators used. In this paper, a specialized software was used for checking existing lines in Mazandaran and Golestan Regional Power. Insulation computations and isolation studies using MATLAB software were used to present solutions for transmission and overhead distribution networks. This specialized software has the ability to calculate the required minimum air gap and the minimum creepage distance and the number of insulators with due attention to regional pollution, overvoltage due to switching and lightning, and power frequency.

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Section: Statement Of the Problemmentioning

confidence: 99%

Reconsidering insulation coordination and simulation under the effect of pollution due to climate change

Valinejad

Firouzifar

Marzband

et al. 2018

Int Trans Electr Energ Syst

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“…A certain electrode arrangement, typically needle-plane, coaxial or parallel planes, is chosen, and the breakdown voltage level is measured for a particular wave shape. A large number of breakdown experiments has to be carried out to properly account for the statistical nature of the breakdown process and it has to be ensured that each measurement is independent of the previous ones [12,13,14]. The resulting information is only valid for this configuration and wave shape and cannot be generalized or otherwise transferred.…”

Section: Introductionmentioning

confidence: 99%

“…For the macroscopic methods, the input consists of a set of transport parameters [13]. For the scope of discharges in technical equipment, it is usually sufficient to know the parameters of electron transport, energy transport, momentum transport, and the transport parameters for ions and excited gas species.…”

Section: Introductionmentioning

confidence: 99%

An Efficient Procedure to Identify and Quantify New Molecules for Insulating Gas Mixtures

Franck

Dahl

Rabie

et al. 2013

Contrib. Plasma Phys.

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Author(s):Franck, Christian M.; Dahl, Dominik A.; Rabie, M.; Haefliger, P.; Koch, M. Publication Date: 2014 Permanent Link:https://doi.org/10.3929/ethz-a-010881816 Originally published in:Contributions to plasma physics 54(1), http://doi.org/10.1002/ctpp.201300030 Rights / License:In Copyright -Non-Commercial Use Permitted This page was generated automatically upon download from the ETH Zurich Research Collection. For more information please consult the Terms of use. ETH LibraryThis is the pre-peer reviewed version of the following article: In this contribution, a new procedure to systematically identify and quantify novel molecular gases with low global warming potential for application in high voltage insulation as gas mixtures is presented. The attention is focused on highly efficient procedures to be able to scan a large number of candidate gases. To identify new molecules, we derived an empirical correlation between the electric strength of a gas and certain molecular properties, like polarizability or dipole moment, which can be calculated by means of density functional theory. The swarm parameters of these pre-selected molecules in mixtures with buffer gases is then quantified, using a newly set-up Pulsed Townsend experiment. The setup operates with a high degree of automation to enable systematic evaluation of gas mixtures not to miss possible synergistic effects. Key element of this PT setup is a new photocathode that works with a high quantum efficiency and long lifetime even when exposed to reactive species during the measurements. Moreover, for an automated operation it is important to know precisely in which range the experiment can be operated, i.e. for example to know up to which electron density space charge effects can be neglected. Finally, the measured swarm parameters need to be translated into breakdown voltage strengths of different electrode arrangements and different applied voltage wave shapes. For this, a model of the the streamer to leader transition in SF6 will be applied to general strong electronegative gases in future studies.

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“…In [7] 350 s for 0.1 MPa and 440 s for 0.4 MPa are reported for the time needed to reach 90% of the equilibrium state. Experimental investigations at the authors' institute showed that these waiting times are not always sufficient to achieve statistical independent series [8,9].…”

Section: Introductionmentioning

confidence: 99%

“…Geometry of electrode arrangement[9] Fig. 4: Breakdown probability depending on waiting time and supplied voltage level The electric field of the electrode arrangement is calculated with the FEM program Comsol.…”

mentioning

confidence: 99%

Determination of waiting times between successive breakdown experiments

Koch

Straumann

Franck

2012

2012 Annual Report Conference on Electrical Insulation and Dielectric Phenomena

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A common duty in high voltage engineering is the experimental determination of the breakdown voltage probability distribution of gaseous insulated electrode configurations. Due to electron detachment from negative ions in the case of electron attaching gases, the breakdown probability does not only depend on the gas and its density, but also on the ion density in the gas. If a disruptive discharge occurs in a gas gap, the number of ions in the gap is significantly increased compared to the equilibrium state at zero voltage. If the time until the next voltage application is too short, the statistical time lag will be decreased and, as a consequence, the probability of breakdown will be increased. To perform statistical independent breakdown experiments it is necessary to ensure identical ion densities in the gas gap before every new voltage application. In the literature waiting times mostly around six minutes are proposed as sufficient for ion density equalization in sulfur hexafluoride (SF 6 ). However, simulations of the behavior of SF 6 performed for the present contribution reveal that six minutes are not always sufficient to achieve statistical independent results. Especially at higher pressures longer waiting times are necessary. To investigate this problem, measurements of the natural ion pair generation in SF 6 were performed at different laboratories. Based on this data the temporal development of the ion distribution in the gas is calculated. Two cases are of interest: the changes in ion density after a disruptive discharge and in case the gap withstood the applied voltage and therefore all ions are swept out. After transformation of the temporal ion density into breakdown probability curves it is possible to estimate the necessary waiting time.

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SF₆ high voltage circuit breaker contact systems under lightning impulse and very fast transient voltage stress

Cited by 12 publications

References 11 publications

Reconsidering insulation coordination and simulation under the effect of pollution due to climate change

Reconsidering insulation coordination and simulation under the effect of pollution due to climate change

An Efficient Procedure to Identify and Quantify New Molecules for Insulating Gas Mixtures

Determination of waiting times between successive breakdown experiments

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SF6 high voltage circuit breaker contact systems under lightning impulse and very fast transient voltage stress

Cited by 12 publications

References 11 publications

Reconsidering insulation coordination and simulation under the effect of pollution due to climate change

Reconsidering insulation coordination and simulation under the effect of pollution due to climate change

An Efficient Procedure to Identify and Quantify New Molecules for Insulating Gas Mixtures

Determination of waiting times between successive breakdown experiments

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Product

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SF₆ high voltage circuit breaker contact systems under lightning impulse and very fast transient voltage stress