Charge accumulation on insulating spacers for HVDC GIS

Surface charge accumulation on cone-type insulators is a remarkable phenomenon in Gas Insulated Line (GIL), especially under DC voltage. It may lead to a considerable reduction of the flashover voltage of insulators. For this respect, this paper focuses on the surface charge distribution on the real insulator after applying DC voltage. In order to study this phenomenon, a set of device for measuring surface voltages on the insulator is designed, base on the electrostatic probe method. After applying different DC voltage amplitudes to the cone-type insulator, the surface voltage distributions, which reflect charge distributions to some extent, are measured by an electrostatic probe in SF 6 gas. Despite of the axial symmetry of the insulator, the measurement results show that the charge distribution is nonaxisymmetrical. The negative charge accumulates mostly under positive DC voltage. On the other hand, no apparent positive charge accumulation is observed on the surface. In areas which are close to electrode, the measured voltage amplitudes are much higher than outer areas.

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“…The decay time constant is about several hours [7,8]. During the measurement the charge will change.…”

Section: A General Setupmentioning

confidence: 99%

“…After 30 minutes the electrode is grounded. This time is chosen because the charge will tend to saturate after 30 minutes according to some related researches [7]. While the electrode is grounded, the surface voltages of the insulator are all inducted by charge on the surface.…”

Section: B Experimental Proceduresmentioning

confidence: 99%

Surface charge accumulation on the cone-type insulator under DC voltage

Wang

Zhang

Wang

et al. 2010

2010 IEEE International Power Modulator and High Voltage Conference

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“…As far as measurements and investigations of such a surface charging on the solid insulators are concerned, various reports have so far appeared [3][4][5][6][7][8]. However, there has been few research work on how the surface charging reduces the insulation performance inside the apparatus [9][10].…”

Section: Membermentioning

confidence: 99%

Creepage Discharge Propagation on Charged Dielectric Surface in SF<sub>6</sub> Gas and Its Optical Observation

et al. 1995

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“…The triple junction interface of conductor-spacer-gas in high-voltage DC gas insulated switchgear (GIS) is known to be the most susceptible point for flashover to occur because it is the focal spot for charge injection [1]. Its importance has been highlighted in controlling and limiting charge accumulation on the surface of cast epoxy spacers under prolonged high-voltage DC stress.…”

Section: Introductionmentioning

confidence: 99%

Influence of fluorination time on surface flashover of epoxy in insulating gas

Mohamad

Chen

2015

2015 IEEE Electrical Insulation Conference (EIC)

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Abstract-The accumulation of charges on polymeric insulation under high voltage DC stress is a major concern in the transmission system as its formation distorts the local electric field and has an adverse impact on the electrical performance. By undergoing fluorination treatment on the insulation, improved surface properties similar to fluoropolymers can be attained without changing the bulk properties of the original material. The change in chemical components at the surface of polymeric insulation should lead to a corresponding change in electrical properties at the surface and thus can suppress charge build up. Previous research on surface flashover on fluorinated epoxy resin at atmospheric condition shows a significant improvement in flashover strength. In this paper, the authors investigated the effect of different degree of fluorination treatment on cast epoxy resin on suppressing surface charge accumulation and its contribution towards the improvement in surface breakdown strength. In comparison to previous research, it has been found that there is an optimum time duration of fluorination treatment which improves the surface breakdown strength of epoxy spacer. The mechanisms that govern the effect of fluorination treatment on surface flashover were discussed.

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Charge accumulation on insulating spacers for HVDC GIS

Cited by 98 publications

References 11 publications

Surface charge accumulation on the cone-type insulator under DC voltage

Surface charge accumulation on the cone-type insulator under DC voltage

Creepage Discharge Propagation on Charged Dielectric Surface in SF<sub>6</sub> Gas and Its Optical Observation

Influence of fluorination time on surface flashover of epoxy in insulating gas

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