Long front time switching impulse tests of long air gap in UHV projects at altitude of 2100 m

Liao, Yongli; Gao, Chao; Li, Ruihai; Wang, Guoli; Lü, Gongxuan

doi:10.1109/tdei.2014.6832240

Cited by 16 publications

(6 citation statements)

References 9 publications

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“…The magnetic flux density (B) of magnetic field was set to 0, 100, 200 and 400 mT. Figure 2 shows a waveform obtained from the high voltage pulse source, the rise time and fall time are 100 and 120 s respectively, which is employed to simulate the switching surges [2]. Under each condition, 20 specimens were measured to consider the statistical variations.…”

Section: Experimental Apparatus and Proceduresmentioning

confidence: 99%

“…DEGRADATION of electrical insulation due to the occurrence of repetitive pulse generated by lightning, switching surges and commutation failure of HVDC system is a serious problem for XLPE cable and its accessories [1][2]. It is also noticed that cable accessories are not solely exposed to electric field, but they are also subjected to magnetic field which is excited by current flow within the inner conductor of the cable.…”

Section: Introductionmentioning

confidence: 99%

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Effects of magnetic field on electrical tree growth in silicone rubber under repetitive pulse voltage

Han

2015

IEEE Trans. Dielect. Electr. Insul.

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Electric field, accompanying with the magnetic field produced by high current, can generate electro-magnetic force in HVDC system, which enormously affects the treeing process. Electrical tree behavior of silicone rubber SiR was investigated by application of magnetic field with repetitive pulse voltage. The samples were made of silicone rubber with a pin-plane electrode system. The inserted needle had a tip radius of 3 m and the pin-plane distance was 2 mm. The rise time and fall time of the repetitive pulse voltage were 100 and 120 s respectively. The pulse frequency was 200 Hz, while the pulse amplitude ranging from 6 to 12 kV was applied. The magnetic flux density (B) of the magnetic field was 100, 200 and 400 mT respectively. The results were presented from experimental investigations in order to characterize electrical tree as a function of amplitude and polarities of the applied pulse voltage. The patterns of electrical tree, tree length, accumulated damage and tree breakdown characteristics were studied. It is revealed that both the pulse amplitude and polarity have a significant impact on electrical tree growth characteristics of silicone rubber. Results show that the pulse amplitude plays the leading role in electrical tree initiation, propagation and breakdown processes. Compared with the positive pulse, it is suggested that the larger tree accumulated damage is more easily to occur with the negative pulse. It also has been found that tree structure is greatly dependent on the B of magnetic field. Results show that magnetic field promotes tree growth and accelerates the treeing process.Index Terms -silicone rubber, magnetic field, repetitive pulse voltage, electrical tree, tree length, accumulated damage.

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Section: Experimental Apparatus and Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of magnetic field on electrical tree growth in silicone rubber under repetitive pulse voltage

Han

2015

IEEE Trans. Dielect. Electr. Insul.

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“…In recent years, the extra/ultra‐HV transmission technologies have become mature gradually, and various EHV and UHV transmission projects have been commissioned or under construction in several countries [1–3]. Numerous discharge tests have been carried out in the past few decades to evaluate the dielectric strength of air insulation with typical electrode arrangements or full‐scale engineering gap configurations [3–6]. The experimental results obtained by these costly and time‐consuming tests are useful to guide the external insulation design of UHV transmission projects.…”

Section: Introductionmentioning

confidence: 99%

Discharge voltage prediction of UHV AC transmission line–tower air gaps by a machine learning model

Qiu

Ruan

et al. 2019

J. eng.

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“…This provided strong support for developing UHVDC transmission technology from theoretical research to engineering application [9][10][11][12][13][14][15]. Currently, China has completely mastered ±800 kV transmission technology on overvoltage suppression and insulation coordination [16][17][18][19], external insulation [20][21][22][23][24][25], electromagnetic environment control [26][27][28], development of core equipment [29][30][31][32] and its integration into power systems, and successfully applied them to engineering [33][34][35][36][37][38][39]. By December 2017, China had constructed and put into service ten ±800 kV projects and three ones are being constructed.…”

Section: Introductionmentioning

confidence: 99%

Research on key technologies in ±1100 kV ultra‐high voltage DC transmission

et al. 2018

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Based on completely mastering ±800 kV transmission technologies, the first ±1100 kV direct current (DC) transmission demonstration project is being constructed in China. Combining theoretical analysis and a large number of experiments, the margin of switching overvoltage in converter stations, the configuration scheme and performance of lightning arresters, the shielding angles of ground lines under different geographical conditions, and the maximum air gap of lines have been determined. The switching impulse flashover characteristics of equipotential sphere and typical rod-plane air gaps are also provided. The external insulation is designed differently for light, medium, and heavy pollution areas. For the ±1100 kV project, if the 8 × 1250 mm 2 conductors are applied, the pole gap is 26 m and the height of the line is 25 m, all the electromagnetic parameters will meet the requirement of international electromagnetic standards. The key design points of ±1100 kV converter transformers, smoothing reactors, converter valves, and wall bushings are researched and the 75 mH smoothing reactors, ±1100 kV/5000 A converter valves, and ±1100 kV/5523 A wall bushings are successfully made. The optimised hierarchical connection modes and coordination control measure of the ±1100 kV project are studied and the results can provide sufficient technical support for the demonstration project.

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Long front time switching impulse tests of long air gap in UHV projects at altitude of 2100 m

Cited by 16 publications

References 9 publications

Effects of magnetic field on electrical tree growth in silicone rubber under repetitive pulse voltage

Effects of magnetic field on electrical tree growth in silicone rubber under repetitive pulse voltage

Discharge voltage prediction of UHV AC transmission line–tower air gaps by a machine learning model

Research on key technologies in ±1100 kV ultra‐high voltage DC transmission

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