Insulation characteristics of 1100 kV GIS under very fast transient overvoltage and lightning impulse

Very fast transient overvoltage (VFTO) in gas insulated switchgear (GIS) is of great concern at the higher rated voltages because the difference between the rated lightning impulse (LI) and the VFTO withstand voltage decreases. In order to clarify VFTO withstand level of 1100 kV GIS, a simulation system was designed for generation of VFTO. The breakdown characteristics of sphere-plane gap and rod-plane gap in SF6 under VFTO and LI were investigated for different gas pressures. Experimental results show that the breakdown voltages in slightly inhomogeneous field gaps under VFTO are higher than that under LI. However, for the rod-plane gaps, the breakdown voltages and voltage-time curves under VFTO fall below that of LI at higher pressure in the case of negative polarity. The polarity effect of rod-plane gaps under LI is reversed at a certain pressure. Based on the analyses, it is concluded that the different breakdown characteristics of SF6 gaps may be attribute to the difference between space charge behaviors during the discharge development under the impulse with different wave front and oscillation tail of VFTO and LI.

[1]  E. Kuffel,et al.  The pressure dependence of the leader stepping time for a positive point-plane gap in gas , 1998 .

[2]  Hisashi Goshima,et al.  Quantitative evaluation of lightning surge range voltage–time characteristics in high‐pressure SF6 gas , 2007 .

[3]  N. Wiegart,et al.  The mechanism of leader breakdown in electronegative gases , 1989 .

[4]  Takehisa Hara,et al.  The role of leader re-illumination in the development of surface discharges in SF6 exposed to a very fast transient overvoltage , 1998 .

[5]  Bok-Hee Lee,et al.  Impulse breakdown characteristics of the plane-to-plane electrode system with a needle-shaped protrusion in SF6 , 2007 .

[6]  J. Meppelink,et al.  Very fast transients in GIS , 1989 .

[7]  E. Kuffel,et al.  Breakdown Characteristics of Non-Uniform Gaps In SF6 under Fast Oscillating Impulse Voltages , 1991 .

[8]  F. D. A. BOYLETT,et al.  Variation of Breakdown Voltage of a Positive-point/Plane Gap with Applied Voltage Waveshape , 1965, Nature.

[9]  M. Hara,et al.  The effect of impulse rising steepness on streamer to leader transition in non-uniform field gap in SF6 , 2003 .

[10]  B. Loncar,et al.  The Validity of the Similarity Law for the Electrical Breakdown of $\hbox{SF}_{6}$ Gas , 2007, IEEE Transactions on Plasma Science.

[11]  H. Okubo,et al.  Impulse partial discharge characteristics and their mechanisms under non-uniform electric field in N/sub 2//SF/sub 6/ gas mixtures , 2005, IEEE Transactions on Dielectrics and Electrical Insulation.

[12]  Y. Qiu,et al.  Effect of initiatory electrons on breakdown characteristics of SF/sub 6/ and its mixtures , 2001 .

[13]  Tatsuo Kawamura,et al.  Transient Impulse Breakdowns of SF6 Gas in Inhomogeneous Electric Fields , 1999 .

[14]  S. Okabe,et al.  Insulation characteristics of GIS spacer for very fast transient overvoltage , 1996 .

[15]  L Niemeyer,et al.  Partial discharges and breakdown at protrusions in uniform background fields in SF6 , 2008 .

[16]  M. J. Thomas,et al.  Very fast transient overvoltages in GIS with compressed SF/sub 6/-N/sub 2/ gas mixtures , 2001 .

[17]  L. G. Christophorou,et al.  Gaseous Dielectrics III , 1982 .

[18]  Iu. P. Raizer.  Gas Discharge Physics , 1991 .

[19]  Predrag OsmokroviTamara,et al.  The Validity of the Similarity Law for the Electrical Breakdown of SF 6 Gas , 2007 .

[20]  A. Qureshi,et al.  A Review of Particle-Contaminated Gas Breakdown , 1981, IEEE Transactions on Electrical Insulation.

[21]  L. H. Andersen,et al.  Measured lifetime of SF6-. , 2008, Physical review letters.

[22]  S. Okabe,et al.  Evaluation of breakdown characteristics of gas insulated switchgears for non-standard lightning impulse waveforms under diverse conditions , 2008, IEEE Transactions on Dielectrics and Electrical Insulation.

[23]  I. Gallimberti,et al.  Streamer and leader formation in SF6 and SF6 mixtures under positive impulse conditions. II: Streamer to leader transition , 1986 .

[24]  I. Chalmers,et al.  A study of alternative insulating gases to SF6 , 1999 .

[25]  H. Kojima,et al.  Surface charge accumulation and partial discharge activity for small gaps of electrode/epoxy interface in sf6 gas , 2009, IEEE Transactions on Dielectrics and Electrical Insulation.

[26]  S. Boggs,et al.  Prediction of breakdown in SF/sub 6/ under impulse conditions , 1995, Proceedings of 1995 Conference on Electrical Insulation and Dielectric Phenomena.

[27]  H. Murase,et al.  Non-Uniform Field Flashover Characteristics in SF6 Gas under Negative Steep-Front and Oscillating Impulse Voltages , 1990 .

[28]  L. C. Campbell,et al.  SF6 breakdown in GIS , 1996 .

[29]  Qiaogen Zhang,et al.  Mechanism of discharge development in SF6 with and without spacers under fast oscillating impulse condition , 2005 .

[30]  S. Okabe,et al.  Evaluation of breakdown characteristics of gas insulated switchgears for non-standard lightning impulse waveforms - breakdown characteristics under non-uniform electric field , 2008, IEEE Transactions on Dielectrics and Electrical Insulation.

[31]  Masaru Ishii,et al.  Breakdown Characteristics of SF6 Gap Disturbed by a Metallic Protrusion under Oscillating Transient Overvoltages , 1994 .

[32]  Hitoshi Okubo,et al.  Impulse Partial Discharge Characteristics and Their Mechanisms under Non-uniform Electric Field in N rSF , 2005 .