DC electrical tree initiation in silicone rubber under temperature gradient

Zhang, Yunxiao; Zhang, Ling; Zhou, Yuanxiang; Chen, Ming; Zhou, Zhongliu; Liu, Jie; Chen, Zhengzheng

doi:10.1109/tdei.2018.007086

Cited by 40 publications

(10 citation statements)

References 30 publications

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“…It can be seen that the calculated value 5.14 × 10 8 V/m of the equation is quite close to the simulated electric field intensity value 5.50 × 10 8 V/m, indicating that the extremely high electric field may reduce the potential barrier on the tip surface and result in the Fowler–Nordheim tunneling effect, which can induce electron emission from the needle tip [ 23 , 24 ]. The electron emission current density ( j ) under high electric field can be obtained by Equation (2) [ 25 ]:

where A , T , φ, E , ɛ 0 ɛ r and k are the constant depending on metal parameters, metal temperature in Kelvin, metal work function, electric field of the needle tip, dielectric constant and Boltzmann’s constant. Obviously, the

is linearity to the

and thus the electron emission current density increases with increasing electric field intensity.…”

Section: Discussionmentioning

confidence: 99%

“…In Figure 9 a, the E 0 higher than 10 8 V/m could lead to a considerable Fowler–Nordheim tunnel effect (see Equation (1)) and induce the emission of electrons from the tip of the needle [ 24 , 25 , 26 , 27 ]. Ionization occurs when electrons with high energy collide with molecules in the polymer (process ①).…”

Section: Discussionmentioning

confidence: 99%

“…These photons may induce more ionization (process ③) or transition to an excited state on other molecules or atoms near the tip. The unstable excited state would return to the ground state with radiating photons after around 10 −8 s, or emit electrons by the Auger effect (process ④) and transfer energy to other electrons, leading to some of the electrons in the normal state changing to hot electrons [ 24 , 25 ].…”

Section: Discussionmentioning

confidence: 99%

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Influence of Repetitive Square Voltage Duty Cycle on the Electrical Tree Characteristics of Epoxy Resin

et al. 2020

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The application of wide band-gap power electronic devices brings more challenges to insulating packaging technology. Knowing the influence of applied voltage parameters on insulation performance is helpful to evaluate the insulation condition of electric power equipment. In this paper, the effect of repetitive square wave voltage duty cycle on the growth characteristics of electrical trees in epoxy resin was studied. The experimental results show that the square wave voltage duty cycle has a significant influence on treeing features. The electrical tree proportion initiation has shown a decreasing trend, and the shape of the electrical tree changes from pine-like to branch-like by increasing the duty cycles. The length and damaged area of electrical tree increased with the increase in the duty cycle up to 10% and then decrease by increasing the duty cycle higher than 30%. It indicates that a low duty cycle will enhance the electron injection and accumulate space charges and thus accelerate electrical tree development. Under short duty cycles, the electric field due to the shielding effect near the needle tip suppresses the electrical tree growth, which results in treeing growth stagnation. The obtained results are helpful to keep these parameters in mind during the design of epoxy-based insulation such high-voltage rotating machines and power electronic device packaging.

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is linearity to the

and thus the electron emission current density increases with increasing electric field intensity.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Influence of Repetitive Square Voltage Duty Cycle on the Electrical Tree Characteristics of Epoxy Resin

et al. 2020

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“…These electrons escape from the trap and become hot electrons. The high temperature will trigger more hot electrons, causing the SIR molecular chains to break [37]. The high number of hot electrons produced by thermal stimulation is the main reason for the decrease of the tree inception voltage as the GD temperature rises with each HV side temperature, as shown in Figure 2.…”

Section: Trap Distributionmentioning

confidence: 99%

“…The increasing number of injected charges is one of the reasons for the lower tree inception voltage as the HV temperature rises, as shown in Figure 6. The injection current occurring in the interface between the high-voltage electrode and the SIR sample can be obtained by the Schottky formula [37], [38]. The increase in the HV side temperature leads to a decrease in the Schottky barrier and increases the injected charge.…”

Section: Trap Distributionmentioning

confidence: 99%

Effects of Temperature Gradient on Electrical Tree Growth and Partial Discharge in Silicone Rubber Under AC Voltage

et al. 2020

IEEE Access

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The Joule heat produced by the current in conductor decreases in the radial direction, producing a temperature gradient in the insulation. This existing temperature gradient can affect the electrical tree phenomenon in insulation materials because of the temperature dependence of insulation material, charge migration and tree growth. Different temperature gradients were obtained by controlling the temperature of high voltage (HV) and ground electrode (GD) sides. The electrical tree was recorded by a microscope, while the partial discharge (PD) was observed simultaneously. For better understanding the effects of the temperature gradient on electrical tree inception, the trap distribution in silicone rubber (SIR) with different temperature was analyzed by isothermal discharge current (IDC) method. With the fixed temperature in HV or GD side, it was found that the electrical tree inception voltage decreased linearly with increasing temperature in either side. The IDC results indicate that the increasing temperature contributes to the de-trapping of charges and lowers the inception voltage. Besides, the electrical tree length and accumulated damage gradually increase with the temperature gradient. The observed PD amplitude and quantity also increase with the temperature gradient, which facilitates the growth of electrical trees. These results indicate that the tree growth is promoted with an increase in the temperature gradient of the cable insulation, posing a threat to the safety of the cable system. INDEX TERMS AC plastic cable, cable accessories, silicone rubber, electrical tree, temperature gradient, tree inception, growth characteristics, partial discharge.

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Effect of silicone grease on electrical tree degradation of silicon rubber under AC electric field

Liao

Yang

Yan

et al. 2020

J Mater Sci: Mater Electron

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DC electrical tree initiation in silicone rubber under temperature gradient

Cited by 40 publications

References 30 publications

Influence of Repetitive Square Voltage Duty Cycle on the Electrical Tree Characteristics of Epoxy Resin

Influence of Repetitive Square Voltage Duty Cycle on the Electrical Tree Characteristics of Epoxy Resin

Effects of Temperature Gradient on Electrical Tree Growth and Partial Discharge in Silicone Rubber Under AC Voltage

Effect of silicone grease on electrical tree degradation of silicon rubber under AC electric field

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