Improvement of Corona Discharge Model and Its Application on Simulating Corona Discharge in the Presence of Wind

Guo, Xing; Zhang, Qilin; Zhang, Jinbo

doi:10.1155/2017/9853439

Cited by 10 publications

(9 citation statements)

References 27 publications

(56 reference statements)

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“…where ϕ is the node potential column vector, K ε is the finite element coefficient matrix of medium permittivity, and K γ is the finite element coefficient matrix of conductivity [23]. Based on these equations, a model of the stator bar end was constructed in COMSOL in order to calculate the electric field and loss distribution at each point.…”

Section: Finite Element Analysis Of the Electric Fieldmentioning

confidence: 99%

Optimization of the Electric Field Distribution at the End of the Stator in a Large Generator

Zhang

et al. 2018

Energies

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The electric field distribution at the end of a large hydro-generator is highly nonuniform and prone to corona discharge, which damages the main insulation and significantly reduces the service life of the hydro-generator. In order to reduce the thickness of the main insulation and the physical size of a large hydro-generator, it is necessary to understand the distribution of the electric field at the end of its stator bar. In this paper, the stator bar at the end of a large generator is simulated using the finite element method to determine the distribution of the potential, electric field, and loss at the rated voltage, as well as to elucidate the differences between the linear corona protection, two-segment nonlinear corona protection, and three-segment nonlinear corona protection structures. The influences of the arc angle, length of each corona protection layer, intrinsic resistivity of the corona protection material, and nonlinear coefficient are also analyzed. The results manifest that the angle of the stator bar should be 22.5 • , the difference in resistivity between the two adjacent corona protection coatings should not exceed two orders of magnitude, and the resistivity of the medium resistivity layer should be nearly 10 6 Ω·m or 10 7 Ω·m, for an optimal design of the corona protection structure.

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Section: Finite Element Analysis Of the Electric Fieldmentioning

confidence: 99%

Optimization of the Electric Field Distribution at the End of the Stator in a Large Generator

Zhang

et al. 2018

Energies

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“…For multiple tips, Bazelyan et al [22,24] found that the height of a single tip and the distance between the tips determined the environmental threshold of corona initiation. Using a two-dimensional (2D) time-dependent CD model, Guo et al [25,26] discussed the CD characteristics of a double-needle system with unequal height. Using a three-dimensional (3D) CD model, Guo et al [25] studied the effect of wind on the CD of a single building, but their model did not consider two or more buildings.…”

Section: Introductionmentioning

confidence: 99%

“…Herein, based on the 2D uniform-grid double-needle CD model of Guo et al [25,26] and the 3D independent-needle CD model of Guo et al [27], a 3D variable-grid doubleneedle CD model is established to: (i) study the characteristics of CD between two buildings of equal height and variable separation; and (ii) evaluate the shielding effect of an equal-height building system on the ground electric field by comparing the cases with and without CD.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Simulation of Corona Discharge in a Double-Needle System during a Thunderstorm

Guo

Zhang

et al. 2023

Atmosphere

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The effect of corona discharge from buildings or structures on the surrounding atmospheric electric field is very important in the measurement of urban atmospheric electric fields and the early warning of lightning. However, most previous studies were focused on independent buildings, with little research on three-dimensional building groups. Therefore, based on three-dimensional numerical simulation technology, this paper uses a double-needle system to simulate the characteristics of thunderstorm corona discharge from two equal-height buildings separated by a variable distance. The shielding effect of the double-needle system on the ground electric field is evaluated both with and without corona discharge, and the main conclusions are as follows: (1) The larger the distance between the two needles, the closer the peak corona current from each tip of the double-needle system is to that from an independent lightning rod at the same height. When the peak corona current from each tip of the double-needle system equals the peak corona current from an independent lightning rod at the same height to some level of approximation, the distance between the two needle systems is determined by the needle height at this time. (2) If the distance between the two needles is 0.1 m, the corona charge released by the double-needle system is almost equal to that released by an independent lightning rod. The corona charge released by the double-needle system is approximately twice as much as that released by an independent lightning rod when the distance between the two needles is increased to a certain value that increases with the needle height and the time of corona discharge. (3) The greater the value of the time of corona discharge, the stronger the shielding effect of the corona discharge on the ground electric field and the larger the shielding range, but the greater the value of the needle height, the smaller the shielding range. (4) Compared with the shielding effect with no corona discharge, that with corona discharge is greater, but the greater the value of the needle height, the less the enhancement. For example, for corona discharge with a time of 10 s, the needle height is 20 m, and the shielding range is ca. 70 m, which is 8.8 times that without corona discharge; however, for the needle height of 100 m, the shielding range is ca. 150 m, which is only 1.5 times that without corona discharge.

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“…e frequent collision between gas molecules and electrons or ions causes the change of discharge path and space charge, and the gas discharge model in the flowing gases environment was established. Guo et al [30] improved a two-dimensional numerical model by considering the effect of wind velocity and wind direction on the movement of the corona charges. However, the dielectric breakdown process in strong wind-sand environment is the comprehensive effects of airflow and sand particles.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Strong Wind-Sand Dielectric Streamer Discharge

Kang

Shi

2022

Mathematical Problems in Engineering

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Due to the complex and harsh climate environment in Northwest China, the external insulation of power lines and high-speed train are exposed to strong wind-sand environment all year round, which brings severe challenges to the external insulation design and protection of the electric systems. Based on the theories of streamer discharge, the plate-plate electrode was taken as the analysis object, and a theoretical physical model of the strong wind-sand dielectric discharge is established. In this model, the analytical expressions of electron ionization coefficient and positive ion generation coefficient in a wind-sand environment are deduced considering the combined effects of the airflow velocity, the distortion of the electric field caused by sand particles, and the electrons captured by sand particles in the discharge process; furthermore, the streamer breakdown criterion in wind-sand environment is proposed. Research results can provide an important theoretical basis for the quantitative calculation of the breakdown voltage and the external insulation protection in a strong wind-sand environment.

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Improvement of Corona Discharge Model and Its Application on Simulating Corona Discharge in the Presence of Wind

Cited by 10 publications

References 27 publications

Optimization of the Electric Field Distribution at the End of the Stator in a Large Generator

Optimization of the Electric Field Distribution at the End of the Stator in a Large Generator

Three-Dimensional Simulation of Corona Discharge in a Double-Needle System during a Thunderstorm

Modeling of Strong Wind-Sand Dielectric Streamer Discharge

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