SF6 breakdown in GIS

Tekletsadik, K.; Campbell, L.C.

doi:10.1049/ip-smt:19960546

Cited by 23 publications

(7 citation statements)

References 4 publications

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“…Previous reported work has shown that dielectric current plays an essential role in the breakdown process of insulation dielectrics. When localised arc forms in the dielectrics, high dielectric current would greatly contribute to the propagation of the localised arc, which is beneficial to the breakdown of the dielectrics [20][21][22]. As shown in Fig.…”

Section: Test Resultsmentioning

confidence: 99%

“…It has been reported that dielectric current greatly affects the breakdown characteristics of insulation dielectrics, especially when the localised arc forms in the dielectrics. The dielectric current can help the propagation of the localised arc, and thus contribute to the breakdown [20][21][22]. Considering the dielectric current is closely related to the time parameters of lightning impulse waveform, we established the simulation model of OIP, and calculated the dielectric current of insulation model under the lightning impulse voltage with different time parameters.…”

Section: Simulating Analysis Of the Influence Of Time Parameters On Tmentioning

confidence: 99%

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Impact of time parameters of lightning impulse on the breakdown characteristics of oil paper insulation

et al. 2016

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At present, the insulation performances of electrical apparatus under lightning impulse voltages are always evaluated by the withstand test of standard lightning impulse voltage (1.2/50 µs), which is recommended by IEC Standard. However, the actual time parameters of transformer invading lightning impulse voltage present an obvious dispersibility characteristics. The standard wave shape is only representative of one particular class of lightning waves, which is far from satisfactory to act as the guidance waveform in the design of power equipment insulation. On the basis of the above research background, the relationship between breakdown characteristics of oil paper insulation and time parameters of applied lightning impulse voltage was investigated in this study. The 50% breakdown voltage characteristics of oil paper insulation under lightning impulse voltage with different time parameters were determined. The test results indicate that a short wave front time could lead to relatively low 50% breakdown voltage, while when the wave tail time varied, the 50% breakdown voltage of oil paper insulation barely changed. At last the simulation model of oil paper insulation was developed, and the current flowing through the oil paper insulating system under lightning impulse voltage was calculated. On the basis of the simulating results, the relationship between current and time parameters was analysed.

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Section: Test Resultsmentioning

confidence: 99%

Section: Simulating Analysis Of the Influence Of Time Parameters On Tmentioning

confidence: 99%

Impact of time parameters of lightning impulse on the breakdown characteristics of oil paper insulation

et al. 2016

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“…It is observed that the V BDV are found to be 31.5kV, 29.5kV and 25.5 kV for a lightning impulse of 1.4/50 µs (within the accepted tolerance of ±30% in front of wave), steep fronted wave of 0.38/50 µs and VFTO of 0.064/50 µs respectively. As the steepness of the wave increases V BDV decreases due to high displacement current produced as a result of high dV/dt [9,10].…”

Section: A V-n Characteristics -Measurementmentioning

confidence: 99%

Life estimation of transformer insulation under repeated impulses

Balaji

Usa

2013

2013 IEEE 1st International Conference on Condition Assessment Techniques in Electrical Systems (CATCON)

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Oil Impregnated Paper (OIP) is commonly used dielectric material in transformer windings. The most of the transformer winding failures are due to breakdown of dielectric material. The breakdown mechanism of composite dielectric undergoes gradual degradation in nature. OIP is subjected to rapid degradation when it is subjected to overvoltages. The severity of the degradation depends on steepness of the waveshape. It is necessary to analyze the characteristics of OIP for varying wavefronts (t f ) ranging from lightning to Very Fast Transient Overvoltages (VFTO). V-N characteristic provides detailed information on degradation with respect to repeated overvoltages. The time interval (∆t) between the successive impulse overvoltages plays a vital role in determining the V-N characteristics. In this paper, an attempt has been made to predict the V-N characteristics for any (t f ) and (∆t) using exponential model and the results are validated with test waveshape of 0.78/50 μs with ∆t = 2s. Apart from the V-N characteristics of OIP, the remaining life of the transformer can be estimated from degree of polymerization (DP) using Ekenstam second order equation.

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“…In power systems with voltage levels higher than 330 kV, the insulation failures of GIS induced by VFTO have exceeded those induced by lightning impulse (LI), which has excited extensive research interest in the field of the power system. Some investigations [3][4][5][6] into the voltage-time (V-t) characteristics of SF 6 gas gaps under VFTO and LI have been conducted due to their great importance in insulation coordination of GIS [7]. It has been reported that the V-t curves of slightly inhomogeneous field gaps are quite flat and the polarity effect can be ignored under low gas pressures (around 0.1 MPa) [8].…”

Section: Introductionmentioning

confidence: 99%

Prediction model of voltage–time characteristics for SF ₆ long gap under VFTO and lightning impulse voltage

Zhang¹,

Wang²,

Sun

et al. 2018

IET Generation, Transmission & Distribution

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SF6 breakdown in GIS

Cited by 23 publications

References 4 publications

Impact of time parameters of lightning impulse on the breakdown characteristics of oil paper insulation

Impact of time parameters of lightning impulse on the breakdown characteristics of oil paper insulation

Life estimation of transformer insulation under repeated impulses

Prediction model of voltage–time characteristics for SF ₆ long gap under VFTO and lightning impulse voltage

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SF6 breakdown in GIS

Cited by 23 publications

References 4 publications

Impact of time parameters of lightning impulse on the breakdown characteristics of oil paper insulation

Impact of time parameters of lightning impulse on the breakdown characteristics of oil paper insulation

Life estimation of transformer insulation under repeated impulses

Prediction model of voltage–time characteristics for SF 6 long gap under VFTO and lightning impulse voltage

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Prediction model of voltage–time characteristics for SF ₆ long gap under VFTO and lightning impulse voltage