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Abstract

This article presents the results of an examination performed on a set of samples of glass-epoxy core rods used in composite insulators with silicone rubber housings. The goal of the examination was to test the aging resistance of the core material when exposed to Direct Current (DC) high voltage. Long term exposure of a glass-epoxy core rod to DC high voltage may lead to the gradual degradation of its mechanical properties due to the ion migrations. Electrolysis of the core material (glass fiber) may cause electrical breakdown of the insulators and consequently lead to a major failure. After being aged for 6000 hours under DC high voltage, the samples were subjected to microscopic analysis. Their chemical composition was also examined using Raman spectroscopy and their dielectric losses and conductance in the broad range of frequencies were tested using dielectric spectroscopy.

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Authors and Affiliations

K. Wieczorek
M. Jaroszewski
P. Ranachowski
Z. Ranachowski
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Abstract

Optimizing the aerodynamic structure of composite insulators can guarantee the safe operation of power systems. In this study, we construct a simulation model for composite insulator contaminant deposition using the COMSOL simulation software, and the rationality of the simulation model and method is verified through wind tunnel experiments. Taking the FXBW4-110/100 composite insulator as an example, we adopt a progressive optimization plan to explore the impacts of shed spacing s, and shed inclination angles α and β on its contaminant deposition characteristics under DC and AC voltages. Based on the numerical simulation results, we analyze the antifouling performance of insulators before and after structural optimization. The results indicate the following: 1) The contaminant deposition of the insulator under AC and DC voltages is negatively correlated with the shed spacing s, but positively correlated with the lower inclination angle β. 2) Under AC voltages, the contaminant deposition of the insulator increases with the upper inclination angle α, while under DC voltages, the contaminant deposition shows an uptrend first, then a downtrend and then an uptrend again with the increase of the upper inclination angle α. 3) Compared with the original model, the AC-optimized model ( α = 6°, β = 2° and s = 98 mm) with a larger shed spacing s, and smaller shed inclination angles α and β showed superior antifouling performance at wind speeds of no less than 2 m/s, and under the typical conditions ( v = 2.5 m/s, d = 20 μm, and ρ = 2 200 kg/m 3), its contaminant deposition is 15% less than that of the original model ( α = 10°, β = 2° and s = 80 mm).
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Authors and Affiliations

Yukun Lv
1
Zeze Chen
1
ORCID: ORCID
Qian Wang
1
Yao Lu
1
Xiaojing Li
1

  1. Department of Power Engineering, School of Energy, Power and Mechanics, North China Electric Power University, China
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Abstract

Suspension line insulators are during their operation subject to static forces and variable loads, usually of a cyclic character. These variable loads have a significant impact on the mechanical durability of composite insulators. A method of providing durability forecast for composite line insulators based on fatigue characteristics has been proposed. The method allows providing durability forecast of insulators in a wide range of variable loadings, i.e. from quasi-static to high amplitude loadings.
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Authors and Affiliations

Jerzy Bielecki
1
ORCID: ORCID
Jacek Wańkowicz
1
ORCID: ORCID

  1. Institute of Power Engineering – Research Institute, 8 Mory Str., 01-330 Warsaw, Poland
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Abstract

The aging of composite insulators in outdoor operation for a long time has a direct impact on the safe and stable operation of the power grid. To solve this problem, fuzzy comprehensive evaluation of composite insulators based on level difference maximum is proposed. To verify the feasibility of this method, insulators in Xinjiang are sampled and the index evaluation system for composite insulators is established based on electrical, mechanical, hydrophobic and other properties, combined with operational years, geographical environment and other factors; Firstly, different membership functions are established according to index types. It is more likely to determine the grade of insulator by comparing measured data with the boundary value. Then, to solve the problem that weights cannot be effectively integrated in the combination weighting, level difference maximization is proposed (during the operation of insulators, the index which has a greater influence on the performance of insulators takes a higher proportion of the weight). Finally, on the basis of fully considering the clarity and ambiguity of grade division, the grade state of insulators is obtained by using the linear weighting method. The results show that compared with the traditional method, the improved method of the membership function and level difference maximum can realize the dynamic adjustment of the index based on the degree of information change. The method can better evaluate the insulator grade. The case study shows that the model can accurately and quickly judge the state of composite insulators, which can be used as a reference for manufacturing and maintenance departments.
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Bibliography

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Authors and Affiliations

Sihua Wang
1
ORCID: ORCID
Long Chen
1
ORCID: ORCID
Lei Zhao
1
Junjun Wang
1

  1. Lanzhou Jiaotong University, Lanzhou, 730070, China

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