Comparative evaluation of the leakage current and aging performance of htv sr insulators of different creepage lengths when energized by ac, dc+ or dc– in a severe marine environment

Elombo, A. I.; Holtzhausen, J.P.; Vermeulen, H.J.; P, Pieterse; Vosloo, W.L.

doi:10.1109/tdei.2013.6508743

Cited by 27 publications

(15 citation statements)

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“…Content may change prior to final publication. In addition, this case was in line with [10,12,15,17,18,26] because the rise in the local time occurred between 04:00 and 08:00. According to Pieterse et al [10], it occurred on the relatively low creepage distance of 615 mm, rather than the high creepage distance of 1175 mm.…”

Section: Figure 3sample Waveforms Of the Jpeg Picturesupporting

confidence: 78%

“…In a further study conducted by Chrzan et al [14], the ratio of variations in the leakage current between the silicone coating and the porcelain insulators was investigated. According to research conducted by Elombo et al [15], dc(-) yielded the maximum absolute peak daily leakage current at night compared to dc(+) and ac. Vosloo et al [16] reported a maximum peak of negative and positive leakage currents on SIR and EPDM, which were relatively high and low for approximately half at the beginning and at the end, respectively.…”

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The Evaluation of Daily Comparative Leakage Currents on Porcelain and Silicone Rubber Insulators Under Natural Environmental Conditions

2021

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In this research, the leakage current (LC) and applied voltage waveforms on samples of installed outdoor porcelain and silicone rubber (SIR) insulators were measured by using a storage digital oscilloscope concurrent with humidity, temperature, and illuminance measurements. Essentially, the measurements were conducted daily, every three hours, for thirty days, and the data were analyzed using exponential regressions, box plots, and correlation coefficients. The porcelain and SIR insulator leakage currents varied from 23.7 A to 28.8 A and 8.4 A to 10.35 A for median values, respectively, while for outlier excluded values, they varied from 20.3 A to 40.0 A and 5.1 A to 17.1 A, respectively. Both leakage currents slightly increased as the exposure duration of the insulator rose, while the ratio decreased very slightly. Additionally, the leakage currents decreased moderately and slightly as the temperature and illuminance increased, respectively. However, the parabolic leakage currents increased as the humidity rose, especially at high humidity. Therefore, the porcelain insulator was more susceptible than the daily SIR, while the SIR insulator was more highly influenced by aging of the exposure duration. The rainy condition contributed to the highest leakage currents on both insulators, whereas the drizzle condition contributed to the highest leakage current on the SIR insulator. The total harmonic distortion (THD) and phase angle of the porcelain insulator leakage currents experienced differences of 5.8% and 7.8 degrees in the minimum and maximum humidity, respectively, but both quantities were less for the SIR insulator. INDEX TERMS humidity, leakage current, porcelain, silicone rubber I. INTRODUCTION High voltage outdoor insulators have an important role in electrical power transmission and distribution systems, including operational reliability, safety, and efficiency [1]. However, their functions are mostly influenced by environmental conditions [2-3]. Common insulator materials include glass and porcelain, which are ceramic materials that have been used for hundreds of years. Moreover, composite and cast cycloaliphatic epoxy resin (epoxy resin, ER), as a polymeric category, has been used in the last few decades [3-4]. These insulators have sheds for reducing the electric field stress and tolerating the accumulation of pollution [5]. Currently, research conducted on insulator leakage currents based on daily time functions is limited. Vosloo et al. [6] illustrated the average peak leakage currents on some insulators, and Roman et al. [7] monitored the insitu dc leakage current magnitudes, namely, rain, humidity, and temperature, on composite and glass insulators. According to Castillo-Sierra et al. [8], the ceramic insulator leakage currents were measured using a clamp meter, as were the temperature and humidity, followed by a regression analysis. Further research by Vosloo and Holtzhausen [9] showed that the peak leakage current of porcelain insulators, including precipitation, relative humidity (RH), ul...

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Section: Figure 3sample Waveforms Of the Jpeg Picturesupporting

confidence: 78%

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The Evaluation of Daily Comparative Leakage Currents on Porcelain and Silicone Rubber Insulators Under Natural Environmental Conditions

2021

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“…A resistive shunt and an online leakage current analyser (OLCA) can detect AC and DC LC. With an OLCA, a glass stand-off insulator is normally installed in series at the ground-end of the insulator under test [26], [27].…”

Section: Lc Monitoring On Hvdc Insulatorsmentioning

confidence: 99%

In-Situ Monitoring of Leakage Current on Composite and Glass Insulators of the Cahora Bassa HVDC Transmission Line

Roman¹,

Zyl²,

Parus³

et al. 2019

SAIEE Afr. Res. J.

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High voltage transmission line design requires careful insulator selection to ensure good operational performance. This paper reports on the in-situ measurements of leakage current (LC) on composite and glass insulators of the Cahora Bassa high voltage direct current (HVDC) transmission line in South Africa over a 6month period. The influence of temperature, humidity, dew, rain and the HVDC line's voltage and current on LC are investigated. The results show that the composite and glass insulator LC behaviour is similar, except in cases of high humidity or rain. At the commencement of rainfall and humidity (>90%), elevated LC levels are observed on glass insulators, while composite insulators demonstrate lower LC levels under these conditions. Under nominal weather conditions of no rain and low humidity, the LC measurements exhibit an almost square-wave behaviour with LC switching between lower (≈20 µA) and higher values (≈60 µA) with relatively short transitions on a daily basis. This phenomenon can be ascribed to condensation on the insulators, which is a primary determinant of the LC levels on contaminated insulators. The line current and voltage fluctuations do not influence the LC level.

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“…The hydrophobicity change varied from the low voltage end to the high voltage end, where the lowest contact angles were found [10]. High leakage current levels were recorded in summer due to high pollution levels and high humidity [12]. Figure 1 shows the peak value of leakage current on an SR insulator on different days in October during field testing on the southern coast of Japan [14].…”

Section: Introductionmentioning

confidence: 99%

Influence of Moist Environment on Aging Performance of Energized Silicone Rubber Used for Outdoor Insulation

Zhu

Liu

2019

IEEE Access

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The influence of moist environments on the aging performance of silicone rubber (SR) used for outdoor insulation was investigated by a salt-fog test. High-temperature vulcanized (HTV) SRs with different alumina trihydrate (ATH) filler contents were adopted as the test specimens. For the test of a single water droplet, the vibration and elongation of the water droplet caused a flashover, and the flashover voltage decreased with increasing ATH content. In the first cycle of the salt-fog test, the leakage current increased with increasing ATH content. The relatively higher hydrophobicity of the specimen with a low ATH content than the specimen with a high ATH content had an inhibitory effect on the initial leakage current development. In the last cycle of the salt-fog test, the heat from dry band arc discharge became the dominant factor affecting the surface aging after the loss of hydrophobicity, and the specimen with a higher ATH content inversely had a better inhibitory effect on leakage current development. According to the X-ray photoelectron spectroscopy (XPS) analysis results, when the energized SR was exposed to a moist environment, the heat from dry band arc discharge and the hydrolysis reaction caused a change in the binding state between Si and O, which is considered the mechanism responsible for material degradation. During this process, the higher content of ATH had a remarkable effect on alleviating surface aging.INDEX TERMS Moist environment, silicone rubber, hydrophobicity, dry band arc discharge, aging performance.

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Comparative evaluation of the leakage current and aging performance of htv sr insulators of different creepage lengths when energized by ac, dc+ or dc– in a severe marine environment

Cited by 27 publications

References 3 publications

The Evaluation of Daily Comparative Leakage Currents on Porcelain and Silicone Rubber Insulators Under Natural Environmental Conditions

The Evaluation of Daily Comparative Leakage Currents on Porcelain and Silicone Rubber Insulators Under Natural Environmental Conditions

In-Situ Monitoring of Leakage Current on Composite and Glass Insulators of the Cahora Bassa HVDC Transmission Line

Influence of Moist Environment on Aging Performance of Energized Silicone Rubber Used for Outdoor Insulation

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