Structural design for dc bushing core based on the material life

Cao, Wen; Shen, Wei; He, Baosheng; Wu, Kai

doi:10.1109/tdei.2013.6451368

Cited by 19 publications

(11 citation statements)

References 7 publications

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“…In addition to the radial temperature gradient mentioned in previous studies [2,7,14], inhomogeneity of the axial temperature should not be ignored. The HST distribution hardly reflects the overall temperature distribution of the insulation layer.…”

Section: Axial Equalisation Methodsmentioning

confidence: 99%

“…As one of the core components of the high voltage direct current converter transformer, the converter valve-side bushing is vital for the safe operation of a hybrid power grid [1][2][3]. In recent years, China's Yimin, Baoji, and Jinhua converter stations have suffered failures due to breakdowns of valve-side bushings caused by the distortion of local electro-thermal coupled fields.…”

Section: Introductionmentioning

confidence: 99%

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Investigation on distribution of electro‐thermal coupled field and improved design of ±1100 kV converter valve‐side bushing

Liu

Chen

Liang

et al. 2020

IET Science, Measurement & Technology

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Section: Axial Equalisation Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigation on distribution of electro‐thermal coupled field and improved design of ±1100 kV converter valve‐side bushing

Liu

Chen

Liang

et al. 2020

IET Science, Measurement & Technology

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“…The difference is insignificant when the electric field is lower than 8 kV/mm, yet an apparent increase of the conductivity is observed when the field increases up to 16 kV/mm due to the Poole-Frenkel effect. It should be noted that the maximum field strength is often designed below 8 kV/mm under DC voltage for dry-type bushings [24], and the influence of electric field on conductivity is ignored in this paper. Figure.…”

Section: Electrical Experimentsmentioning

confidence: 99%

Improved Electric Field Distribution Within Bushing Insulation by EP/GO Nanocomposites With Reduced Temperature Coefficient of Conductivity

Sun

Kong

et al. 2020

IEEE Access

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Field grading within the dry-type bushing insulation presents a major challenge for DC applications due to the highly temperature-dependent conductivity of the epoxy resin insulation. An electric field regulation method based on the epoxy/graphene oxide (EP/GO) nanocomposites with the reduced temperature coefficient of conductivity is proposed and investigated in this paper. DC conductivity of EP/GO nanocomposites with different loadings of 0, 0.05, 0.1 and 0.5 wt% at various temperature are investigated. Trap level distributions are characterized by the isothermal discharge current (IDC) method to clarify the conduction mechanism. Obtained results show that more shallower traps are introduced and the thermal activation energies of the nanocomposites are reduced by the GO nanoparticles, indicating that the temperature coefficient of conductivity of the nanocomposites is reduced. The improvement of electric field distribution within the bushing insulation under operating voltage is verified when the EP/GO nanocomposite with an appropriate content is employed, based on an established ±800 kV valve-side bushing for a converter transformer. However, more defects will be introduced by the GO fillers with excessive content (0.5 wt%), resulting in an obvious reduction of the DC breakdown strength. INDEX TERMS Valve-side bushing, electric field regulation, temperature coefficient of conductivity, graphene oxide, epoxy-based nanocomposites.

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“…Cao et al . considered the effect of the temperature difference on the electric field of a DC bushing [5]. It showed that the electric field in the high temperature zone near the conductor was low, while the electric field in low temperature zone located in the external part of bushing core was high.…”

Section: Introductionmentioning

confidence: 99%

“…What is more, under DC voltages, the electric field of bushings is determined by resistance of the different insulation materials, and the resistivity of commonly used insulation materials varies greatly with temperature [3,4]. Therefore, the electrical and thermal properties of the bushing affect each other [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Electro‐Thermal Coupling Field Simulation of Converter Transformer Valve Side Bushings

Wang

Xie

Tian

et al. 2020

IEEJ Transactions Elec Engng

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In the actual operation, converter transformer valve side bushings are subjected to high voltages and large current loads with large number of harmonics simultaneously. In our previous papers, using the 3-D electromagnetic-fluid-thermal coupling analysis method, the 3-D temperature distribution of a converter transformer valve side bushing was researched, and the heating and dissipation characteristics of the bushing were analyzed. However, the electric field distribution of the bushing is affected by the temperature gradient inside the bushing. Related researches about the electro-thermal coupling field of the bushing are rare and most researches are concentrated on the single factor of voltage or temperature. In this paper, by using the electro-thermal coupling field simulation method proposed in our previous paper, the effect of the core outline size on the electric field distribution of the bushing under a certain temperature gradient was investigated. In addition, by using the transient electric field simulation method, the electric field distribution of the bushing in one cycle subjected to an actual voltage waveform and the current in temperature rise test simultaneously was analyzed considering the effect of the Joule heating power of the core. The proposed method will be able to provide a computation basis for the structure design and optimization of converter transformer valve side bushings.

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Structural design for dc bushing core based on the material life

Cited by 19 publications

References 7 publications

Investigation on distribution of electro‐thermal coupled field and improved design of ±1100 kV converter valve‐side bushing

Investigation on distribution of electro‐thermal coupled field and improved design of ±1100 kV converter valve‐side bushing

Improved Electric Field Distribution Within Bushing Insulation by EP/GO Nanocomposites With Reduced Temperature Coefficient of Conductivity

Electro‐Thermal Coupling Field Simulation of Converter Transformer Valve Side Bushings

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