Influence of Electrical Aging on Space Charge Dynamics of Oil-Impregnated Paper Insulation under AC-DC Combined Voltages

Wang, Yan; Li, Jian; Wu, Sicheng; Sun, Peng

doi:10.5370/jeet.2013.8.6.1512

Cited by 4 publications

(3 citation statements)

References 26 publications

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“…Under the higher applied electric fields at the higher temperature, a large amount of hetero space charges was detected earlier after the voltage application [8]. In addition, more charges are found trapped in the bulk of an aging sample after a long time of electrical aging time [9].…”

Section: Introductionmentioning

confidence: 99%

Comparison on space charge and voltage distribution of high voltage insulator subjected to different contamination levels

Samuri¹,

Othman²,

Piah³

et al. 2019

Bulletin EEI

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This paper presents the study of space charge distribution on high voltage (HV) insulators under different levels of contamination. Two types of HV insulators were used in this work particularly glass and porcelain insulators. A string of 4-unit glass and porcelain insulators with 33 kV of lines voltage was designed and simulated using QuickfieldTM software. Four levels of contamination layer with different thickness have been applied on the surface of insulators to observe the effect of space charge distribution. Simulation results show that different types of insulators used at transmission lines give different effects on charge and voltage distribution. It is also found that the amplitude of charge for a single porcelain insulator is much higher compared to a single glass insulator. Similarly for a string of 4-unit insulators, the voltage distribution along the creepage distance of porcelain insulators is much higher compared to glass insulators under all contamination levels.

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Section: Introductionmentioning

confidence: 99%

Comparison on space charge and voltage distribution of high voltage insulator subjected to different contamination levels

Samuri¹,

Othman²,

Piah³

et al. 2019

Bulletin EEI

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show abstract

“…Reference [5] estimated the degree of polymerization (DP) and percentage of moisture content (PMCs) in oil-impregnated paper insulation using dielectric response sensing obtained from frequency-domain spectral tests. The insulating paper aging platform constructed in reference [6] studied the microstructure and electrical characteristic changes in insulating paper under different AC/DC composite voltages and found consistency in the degradation mechanism and microstructure of insulating paper under different composite voltages. In reference [7], accelerated thermal aging experiments were carried out on insulating paper at 120 • C and 130 • C, respectively, and the results showed that the crystallinity index and refractive index of cellulose fiber in insulating oil could be used as feasible indexes for the diagnosis of paper degradation.…”

Section: Introductionmentioning

confidence: 99%

Investigating Aging Characteristics of Oil-Immersed Power Transformers’ Insulation in Electrical–Thermal–Mechanical Combined Conditions

Yuan,

Wang,

Ren

et al. 2023

Polymers

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The condition and health of large oil-immersed power transformers’ insulation have a direct impact on the safety and stability of the power grid. Therefore, it is crucial to investigate the aging characteristics of oil–paper insulation in power transformers. In this study, we developed a computational model for reclosing current calculation and multiphysics coupling models for magnetic-circuit-force, electrostatic field, and temperature field simulations. The calculated aging resulted in a mechanical stress of 8.71 MPa, an electric field strength of 2.26 × 106 V/m, and a temperature of 113.7 °C. We conducted combined electrical–thermal–mechanical aging tests on the oil–paper insulation and measured various insulating paper performance parameters at different aging stages. Our study revealed that both the mechanical and electrical properties of the insulating paper deteriorated in both aging groups. However, the changes were more pronounced in the electrical–thermal–mechanical aging group compared to the electrical–thermal aging group, indicating that mechanical stress accelerated the aging process of the insulating paper. In the early stages of aging, the rate of performance changes in the electrical–thermal aging group was similar to that in the electrical–thermal–mechanical aging group. However, as the aging time increased, the degradation of performance induced by mechanical aging became more significant. This suggests that the insulating paper’s resistance to mechanical damage, specifically short-circuit resistance, noticeably decreased after prolonged aging.

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“…Oil-paper insulation is one of the major types of insulation in converter transformers. Valve-side windings of HVDC converter transformers were subjected to pulsating DC voltage stresses consisting of AC, DC and strong harmonic components [3][4][5]. With the increase of the transmission voltage rating, partial discharges (PDs) will happen in the weak insulation of converter transformer.…”

Section: Introductionmentioning

confidence: 99%

Partial Discharge Process and Characteristics of Oil-Paper Insulation under Pulsating DC Voltage

Bao¹,

Li²,

Zhang³

et al. 2016

Journal of Electrical Engineering and Technology

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-Oil-paper insulation of valve-side windings in converter transformers withstand electrical stresses combining with AC, DC and strong harmonic components. This paper presents the physical mechanisms and experimental researches on partial discharge (PD) of oil-paper insulation at pulsating DC voltage. Theoretical analysis showed that the phase-resolved distributions of PDs generated from different insulated models varied as the increase of the applied voltages following a certain rule. Four artificial insulation defect models were designed to generate PD signals at pulsating DC voltages. Theoretical statements and experimental results show that the PD pulses first appear at the maximum value of the applied pulsating DC voltage, and the resolved PD phase distribution became wider as the applied voltage increased. The PD phase-resolved distributions generated from the different discharge models are also different in the phase-resolved distributions and development progress. It implies that the theoretical analysis is suitable for interpretation of PD at pulsating DC voltage.

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Influence of Electrical Aging on Space Charge Dynamics of Oil-Impregnated Paper Insulation under AC-DC Combined Voltages

Cited by 4 publications

References 26 publications

Comparison on space charge and voltage distribution of high voltage insulator subjected to different contamination levels

Comparison on space charge and voltage distribution of high voltage insulator subjected to different contamination levels

Investigating Aging Characteristics of Oil-Immersed Power Transformers’ Insulation in Electrical–Thermal–Mechanical Combined Conditions

Partial Discharge Process and Characteristics of Oil-Paper Insulation under Pulsating DC Voltage

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