Voltage Distribution Studies in Polluted ZnO Arrester Using the FEMLAB

2011 ◽  
Vol 268-270 ◽  
pp. 412-417 ◽  
Author(s):  
Ferhat Tighilt

The voltage and electric field distribution in an arrester are very important for its long operation 15 kV with and without pollution. In order to clarify the influence of pollution severity conditions on metal oxide surge arrester, the finite element method (FEM) compilation of the voltage distribution in the ZnO column varistors under different pollution layer conductivity (200 μS, 70μS, 20μS) and clean was employed using the FEMLAB package.

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2510 ◽  
Author(s):  
Haitao Hu ◽  
Xiaohong Zhang ◽  
Yanli Liu ◽  
Lijun Guo ◽  
Junguo Gao

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 106 Ω·m or 107 Ω·m, for an optimal design of the corona protection structure.


2011 ◽  
Vol 695 ◽  
pp. 513-516
Author(s):  
Jie Ren ◽  
Li Fu ◽  
Ling Bao Meng

The CdZnTe (CZT) devices with various screening depth in dimensions 3×3×6mm3 were fabricated. The influence of Ring length (screening depth) and length of crystal on the electric field distribution in CZT devices has been explored by finite element method. The results indicated that ring length (screening depth) plays an important role on the detecting performance of CZT Frisch-ring devices. Longer screening depth gives rise to an electric field which is compressed more greatly. Measured spectra indicated that extreme compressed electric field could reduce detecting resolution. A FWHM energy resolution of approximately 3.71% at 662 keV was obtained for a device with dimensions 3×3×6mm3 and 4.8mm screening depth.


2014 ◽  
Vol 521 ◽  
pp. 317-320
Author(s):  
Hui Hui Li ◽  
Zheng Zheng ◽  
Hong Bo Chen ◽  
Huan Bai ◽  
Hua Zhao Zhang ◽  
...  

Faulty insulators could appear in the HV transmission line insulator string under the comprehensive effect of electrical, mechanical and environmental factors and they can be detected according to the space potential and electric field distribution variation characteristics around the insulator string. Finite Element Method (FEM) was used to study the potential and electric field distributions of a 220kV suspension insulator string contained a zero-value insulator in windage condition, comparing with a fine insulator string. The results show that the variation of the space potential and electric field distributions of insulator string is the same as that under no windage condition. The curve of synthetic electric field along the central axis around the good insulator string is U-shape. The 10th and 11th insulators from the high-voltage end are the sensitive insulators where the distortion ratio of synthetic field strength is higher than 3%, when a faulty insulator is in the string. This result can provide preferences for the online detection of faulty insulators.


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