Materials Based Lifetime Assessment of Porcelain Insulators

Schulte-Fischedick, Jan; Singh, Prashant; Lehretz, Fabian; Hettich, P.; Bucharsky, C.; Schell, Karl G.; Hoffmann, Michael J.; Marthen, Wolfgang; Wekenborg, Heinrich; Pohlmann, Heinrich

doi:10.1007/978-3-030-31680-8_53

Cited by 4 publications

(7 citation statements)

References 3 publications

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“…where a is the defect size and Y is a geometry factor that varies from 1.13 for ball-shaped defects in volume to 1.99 for surface defects (long semiellipse). K Ic varies between 1.8 to 2.1 MPa•m 1/2 [3]. Using the data for K IC = 2 MPa•m 1/2 and Y = 2 (worst case), a defect size of ≥1600 µm (1.6 mm) can be estimated for a strength of 25 MPa, ≥400 µm for 50 MPa.…”

Section: Discussionmentioning

confidence: 99%

“…The samples with the lower quartz content are designated "lq" for low quartz, and those with the higher quartz content are designated "hq" for high quartz. Samples were cut out of the materials with a diamond saw in pieces of approximately 1 × 1 × 1 cm 3 .…”

Section: Methodsmentioning

confidence: 99%

“…High-voltage insulators are essential for the transmission of electrical energy. Such insulators must have a long service life and high reliability, as they are often in use for more than 30 years [1][2][3][4]. The microstructure of the insulators is a multi-phase one.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, some studies postulate a low quartz content as a prerequisite for high strength. However, besides large quartz grains, a number of other defects (pores/impurities or surface defects -cracks) can determine the strength as well [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

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Investigation of the Quartz Distribution in Electro-Porcelain Materials

Senze,

Höhn,

Matthey

et al. 2023

Ceramics

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Analysis of the microstructure of electro-porcelain is important to better understand its influence on mechanical, electrical and aging behavior. The microstructures of two electro-porcelain materials with low and high quartz contents were analyzed with respect to the distribution of quartz. Using an adequate evaluation of EDS (energy dispersive spectroscopy) mapping data, a reproducible analysis of the size distribution and quantity of quartz was achieved. The method allows the analysis of large areas (12.5 mm2). Therefore, the probability of occurrence for a few large quartz grains could be determined. Independent of the overall amount of quartz in the materials, a wide distribution of the grain size was observed. The size of the large detected quartz grains in both materials was very similar. Around the large quartz particles, microcrack systems with lengths of several 100 µm were observed. They are linearly correlated with the equivalent circle diameter of the quartz grains. The evaluation of the cracks allowed us to determine the critical size below which no cracks around the quartz particles are formed. This size is approximately 10 µm.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation of the Quartz Distribution in Electro-Porcelain Materials

Senze,

Höhn,

Matthey

et al. 2023

Ceramics

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“…This improves the mechanical and electrical strength of the insulator [9]. Furthermore, Piva reported that Fe 2 O 3 enhances the dielectric constant and loss tangent, which tends to result in an increase in heating through dielectric losses [1,12,13].…”

Section: Introductionmentioning

confidence: 99%

Failure Trends of High-Voltage Porcelain Insulators Depending on the Constituents of the Porcelain

Sanyal

Kim

et al. 2020

Applied Sciences

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The aging of porcelain insulators is responsible for the failure of power utilities. Porcelain insulators from different places in South Korea, possessing various aging times and years of installation, have been investigated to carry out lifetime statistics. These samples have a mass of 36,000 lbs and are operated at 154 kV. X-ray fluorescence (XRF) and scanning electron microscopy (SEM) were performed on the porcelain bodies of the samples collected. XRF and SEM revealed trends in the weight percentage of SiO2, Al2O3, and Fe2O3 in the porcelain bodies of the collected samples. The SiO2 and Fe2O3 weight percentage reduced to 8.93% and 73.17%, respectively, in sample C compared to A. However, the Al2O3 weight percentage increased to 16.23% in sample C compared to sample A. This change in weight percentage of SiO2, Fe2O3, and Al2O3 contributed toward enhancing the mechanical and electrical properties of the insulators. Mechanical load tests with electrical voltage (M&E), thermal and mechanical load tests (T&M), and hardness tests (HRB) were performed to evaluate these characteristics. Experiments revealed an increase of 90.9% in the inequality factor (K) in sample C compared to A. The impact of constituents of porcelain on the lifetime expectancy of a porcelain insulator was reported by implementing statistical strategies, such as the Weibull distribution.

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