Study on the accumulative effect of repeated lightning impulses on insulation characteristics of transformer oil impregnated paper

Sima, Wenxia; Sun, Potao; Yang, Qing; Yuan, Tao; Chen, Lü; Yang, Ming

doi:10.1109/tdei.2014.004298

Cited by 28 publications

(20 citation statements)

References 14 publications

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“…The number of valid data for each test was more than 50. The test procedure for the accumulative effect test is outlined in detail in our previous work [ 22 , 23 , 24 , 26 ].…”

Section: Methodsmentioning

confidence: 99%

“…The relation between amplitude of applied impulse voltage (V) and number of applied impulses before breakdown (N), the V–N characteristic, is an essential index reflecting the electrical performance of OIP [ 22 , 23 , 24 ]. We identified the V–N characteristics of OIP and NOIP with different nano-TiO 2 particle concentrations.…”

Section: Effect Of Nanoparticles On the Electrical Performance Of mentioning

confidence: 99%

“…We have been monitoring a 110 kV power transformer in China for a long time. Monitoring results revealed that more than 50 lightning impulses invaded this transformer each year [ 22 , 23 , 24 , 25 ]. The number of recorded switching impulses was even higher at four to five per day.…”

Section: Introductionmentioning

confidence: 99%

“…Such repeated impulses may cause irreversible damage to insulation dielectrics, or even premature failure. This phenomenon is known as accumulative dielectric failure, which was studied in our previous work [ 21 , 22 , 23 , 24 , 25 , 26 ]. Therefore, focusing on the above problems, the breakdown characteristics and accumulative failure characteristics of both OIP and NOIP were determined in this work.…”

Section: Introductionmentioning

confidence: 99%

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Failure Characteristics and Mechanism of Nano-Modified Oil-Impregnated Paper Subjected to Repeated Impulse Voltage

et al. 2018

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Nano-modification is a prospective method for improving the electrical properties of transformer oil. In most situations, transformer oil combined with cellulose paper is used to construct an insulation system for power equipment, such as power transformers. However, the influence of nanoparticles on the electrical performance of oil-impregnated paper is still unclear. Therefore, in this paper, we identify the failure characteristics of both fresh and nano-modified oil/paper. Specifically, the accumulative failure characteristics of nano-oil-impregnated paper (NOIP) are experimentally determined. The space charge distribution and trap characteristics of fresh paper and NOIP were measured, and the effect of nanoparticles on the space charge behavior are then analyzed. Finally, we measure the microstructure of fresh paper and NOIP subjected to repeated impulses. The test results indicate that nano-titanium oxide (TiO2) particles have a limited effect on the breakdown voltage of NOIP. However, the particles can dramatically improve the resistant ability of NOIP against repeated impulses. For the NOIP with a nano-concentration of 0.25 g/L, the improvement reaches 62.5% compared with fresh paper. Under repeated applications of impulse voltages, the space charge density of NOIP is much lower than that of fresh paper. The deep trap density of NOIP is much higher than that of fresh OIP, whereas shallow trap density is relatively lower. Micropores are generated in paper insulation subjected to repeated impulses. The amount of the generated micropores in NOIP is lower than that in fresh paper. Nano-TiO2 particles suppress the accumulation of space charge in the oil paper insulation, which weakens the electric field distortion in the dielectric. However, nanoparticles reduce the accumulative damage caused by repeated impulses. The above two points are considered the main reasons to improve the resistant ability against repeated impulses.

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“…The number of valid data for each test was more than 50. The test procedure for the accumulative effect test is outlined in detail in our previous work [ 22 , 23 , 24 , 26 ].…”

Section: Methodsmentioning

confidence: 99%

Section: Effect Of Nanoparticles On the Electrical Performance Of mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Failure Characteristics and Mechanism of Nano-Modified Oil-Impregnated Paper Subjected to Repeated Impulse Voltage

et al. 2018

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“…For instance, some authors [3][4][5][6][7][8] have analysed the effect of oil and pressboard ageing (electrical and/or thermal) on the characteristic of PD from inception to flashover, surface discharge inception voltage (SDIV) variation, creepage discharge inception voltage (CDIV) or creepage discharge flashover voltage (CDFV) of oil/solid insulation specimens with different ageing degrees. Other authors have studied the effect of polarity on the accumulation of charges at the oil-solid interface [9], the accumulative effect of repeated lightning impulses and its damage mechanism [10], the electrical deterioration caused by PD under long-term AC voltage [11] or the performance of alternative liquids in comparison with mineral oil [12].…”

Section: Introductionmentioning

confidence: 99%

Assessment of Dielectric Paper Degradation through Mechanical Characterisation

Fernández-Diego¹,

Fernández²,

Fernández³

et al. 2018

Simulation and Modelling of Electrical Insulation Weaknesses in Electrical Equipment

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Power transformers life is limited fundamentally by the insulation paper state, which can be analysed through different techniques such as furanic compound concentration, dissolved gases, methanol concentration, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, refractive index of cellulose fibres, degree of polymerisation or tensile strength. The two last techniques provide the best way to evaluate mechanical resistance of insulation paper. This chapter describes briefly the most remarkable studies about post-mortem assessment and thermal ageing tests in which mechanical properties are some of the characteristics evaluated to determine paper degradation. This work also gathers the main relationships developed until now to relate different by-products generated during transformer operation with loss of paper mechanical properties. Finally, this chapter defines the future approaches, which could be used to study paper degradation.

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