Field distribution in polymeric MV-HVDC model cable under temperature gradient. Simulation and space charge measurements

2014 ◽  
Vol 17 (5-6) ◽  
pp. 307-325 ◽  
Author(s):  
Thi Thu Nga Vu ◽  
Gilbert Teyssedre ◽  
Bertrand Vissouvandin ◽  
Séverine Le Roy ◽  
Christian Laurent ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Space Charge ◽  
Field Distribution

scholarly journals Three-Dimensional Electro-Thermal Analysis of a New Type Current Transformer Design for Power Distribution Networks

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1792
Author(s):  
Bingbing Dong ◽  
Yu Gu ◽  
Changsheng Gao ◽  
Zhu Zhang ◽  
Tao Wen ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Temperature Field ◽  
Temperature Gradient ◽  
Field Distribution ◽  
Distribution Network ◽  
Current Transformer ◽  
Internal Temperature ◽  
Temperature Field Distribution ◽  
Type Design ◽  
New Type

In recent years, the new type design of current transformer with bushing structure has been widely used in the distribution network system due to its advantages of miniaturization, high mechanical strength, maintenance-free, safety and environmental protection. The internal temperature field distribution is an important characteristic parameter to characterize the thermal insulation and aging performance of the transformer, and the internal temperature field distribution is mainly derived from the joule heat generated by the primary side guide rod after flowing through the current. Since the electric environment is a transient field and the thermal environment changes slowly with time as a steady field under the actual conditions, it is more complex and necessary to study the electrothermal coupling field of current transformer (CT). In this paper, a 3D simulation model of a new type design of current transformer for distribution network based on electric-thermal coupling is established by using finite element method (FEM) software. Considering that the actual thermal conduction process of CT is mainly by conduction, convection and radiation, three different kinds of boundary conditions such as solid heat transfer boundary condition, heat convection boundary condition and surface radiation boundary condition are applied to the CT. Through the model created above, the temperature rise process and the distribution characteristics of temperature gradient of the inner conductor under different current, different ambient temperatures and different core diameters conditions are studied. Meanwhile, the hottest temperature and the maximum temperature gradient difference are calculated. According to this, the position of weak insulation of the transformer is determined. The research results can provide a reference for the factory production of new type design of current transformer.

Space charge characteristics in 160 kV DC XLPE cable under temperature gradient

2018 ◽  
Vol 25 (6) ◽  
pp. 2366-2374 ◽  
Author(s):  
Wang Xia ◽  
Chen Chi ◽  
Cheng Chuanhui ◽  
Wu Yang ◽  
Wu Kai ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Space Charge ◽  
Xlpe Cable

scholarly journals Evaluation of Electric Field and Space Charge Dynamics in Dielectric under DC Voltage with Superimposed Switching Impulse

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1836 ◽  
Author(s):  
Ik-Soo Kwon ◽  
Sun-Jin Kim ◽  
Mansoor Asif ◽  
Bang-Wook Lee
Keyword(s):  
Electric Field ◽  
Space Charge ◽  
Field Distribution ◽  
Electric Field Distribution ◽  
Numerical Study ◽  
Numerical Approach ◽  
Dc Voltage ◽  
Charge Dynamics ◽  
Electrical Stress ◽  
Dc Stress

The influx of a switching impulse during DC steady-state operations causes severe electrical stress on the insulation of HVDC cables. Thus, the insulation should be designed to withstand a superimposed switching impulse. All major manufacturers of DC cables perform superimposed switching impulse breakdown tests for prequalification. However, an experimental approach to study space charge dynamics in dielectrics under a switching impulse superposed on DC voltage has not been reported yet. This is because, unlike the DC stress, it is not possible to study the charge dynamics experimentally under complex stresses, such as switching impulse superposition. Hence, in order to predict and investigate the breakdown characteristics, it is necessary to obtain accurate electric field distribution considering space charge dynamics using a numerical approach. Therefore, in this paper, a numerical study on the switching impulse superposition was carried out. The space charge dynamics and its distribution within the dielectric under DC stress were compared with those under a superimposed switching impulse using a bipolar charge transport (BCT) model. In addition, we estimated the effect of a superimposed switching impulse on a DC electric field distribution. It was concluded that the temperature conditions of dielectrics have a significant influence on electric field and space charge dynamics.

A comparison of injection laws for the space charge equations in gases and dielectrics

1993 ◽  
Vol 443 (1919) ◽  
pp. 517-546 ◽  
Keyword(s):  
Electric Field ◽  
Space Charge ◽  
Field Distribution ◽  
Steady Motion ◽  
Plane Geometry ◽  
Symmetric Problem ◽  
Injection Process ◽  
Underlying Geometry ◽  
Current Characteristics ◽  
The Stability

We consider the steady motion of space charge from an injecting electrode to an earthed electrode in both a gas and a dielectric. Three models governing the process of charge injection from the electrode into the medium are compared and the resulting voltage–current characteristics calculated. In particular we examine injection laws in which the electric field, charge or current are specified. It is shown that if the injecting electrode is small in comparison to the underlying geometry then the resulting field distribution is almost independent of the injection process. The stability of the three models is compared and it is shown that the field specified and charge specified models are always stable. The calculations are performed exactly for the case of a symmetric problem and make use of the Deutsch approximation for a needle-plane geometry.

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