FTIR analysis of non-ceramic composite insulators

Chughtai, A. R.; Smith, D. Moody; Kumosa, L.; Kumosa, M.

doi:10.1109/tdei.2004.1324348

Cited by 59 publications

(39 citation statements)

References 17 publications

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“…The authors have noticed over the years that a vast majority of failures by brittle fracture of nonceramic suspension insulators have occurred above the hardware, near the energized end fittings [13], [14], [18]- [20], [30], [31], [51]. It has also been observed that the failures above the hardware always occurred above the grading rings, if present.…”

Section: Brittle Fracture Morphologymentioning

confidence: 99%

“…Despite their relative structural simplicity, very complex, difficult-to-prevent, and predict failure modes can occur in nonceramic insulators under in-service conditions [1]- [31], [51]. This makes the evaluation of the effects of the manufacturing process, design, selection of materials, and in-service conditions on the mechanical and electrical integrity of the insulators very difficult.…”

Section: Scc Of Grp Nonceramicsmentioning

confidence: 99%

“…This makes the evaluation of the effects of the manufacturing process, design, selection of materials, and in-service conditions on the mechanical and electrical integrity of the insulators very difficult. The authors' observations presented in this article are based on a large multidisciplinary study of the failure analysis of insulators performed between 1992 and 2004 [13]- [21], [23], [26], [29]- [31], [37]- [61]. The three primary goals of the study have been 1) to identify mostly mechanical failure modes of the insulators (including brittle fracture); 2) to evaluate the effect of various manufacturing techniques, material selections, insulator designs, loading conditions, etc.…”

Section: Scc Of Grp Nonceramicsmentioning

confidence: 99%

“…The fact that suspension nonceramic insulators are subjected, in service, to tensile mechanical stresses predominantly, which can be highly concentrated in the rods inside the fittings, is rather obvious. However, the origin of an acidic environment is not apparent, if one reads the available literature on this topic [1]- [31]. Also, it is not very clear how the design of the fittings and the way they are attached to the rods could influence the concentrations of mechanical stresses in the GRP rods, either increasing or decreasing the probability of SCC and brittle fracture.…”

Section: Scc Of Grp Nonceramicsmentioning

confidence: 99%

“…It quickly became clear that the project was more difficult than was initially assumed and that the identification of the chemistry of the process would require major long-term efforts. Despite this, several assumptions were made which, later on, turned out to be correct [21], [31]. It was assumed [13], [14], [16] that the failure process was truly caused by SCC and that there was an acid (or acids) involved.…”

Section: A Initial Assumptionsmentioning

confidence: 99%

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Failure analyses of nonceramic insulators. Part 1: Brittle fracture characteristics

Kumosa

Armentrout

2005

IEEE Electr. Insul. Mag.

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mechanically in service by rod fracture. One of the mechanical failure modes of the insulators is a failure process called brittle fracture [1]-[31], which is caused by the stress corrosion cracking (SCC) of the GRP rods [32]-[51]. The process is catastrophic and unpredictable, leading to the drop of energized transmission lines [13], [18]. Several attempts have been made over the years [1]-[31] to understand this process and provide potential remedies to avoid it in service. In Fig. 2(a-d), some examples are presented of brittle fracture failures of failed nonceramic insulators operated at 115 kV (Fig. 2a, b), 345 kV (Fig. 2c), and 500 kV (Fig. 2d). It should be noted that all insulators in Fig. 2 were made by the same manufacturer and were based on the epoxy

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Section: Brittle Fracture Morphologymentioning

confidence: 99%

Section: Scc Of Grp Nonceramicsmentioning

confidence: 99%

Section: Scc Of Grp Nonceramicsmentioning

confidence: 99%

Section: Scc Of Grp Nonceramicsmentioning

confidence: 99%

Section: A Initial Assumptionsmentioning

confidence: 99%

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Failure analyses of nonceramic insulators. Part 1: Brittle fracture characteristics

Kumosa

Armentrout

2005

IEEE Electr. Insul. Mag.

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Surface degradation of styrene acrylonitrile exposed to corona discharge

Handala

Lamrous

2007

Int Trans Elec Energy Syst

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SUMMARYAn experimental investigation of the degradation of styrene acrylonitrile (SAN) exposed to corona discharge under ambient conditions was presented. SAN specimens were subjected to a corona stress generated by two plane parallel electrodes. The surface physicochemical changes were studied using scanning electron microscope, energy-dispersive X-ray analysis, Fourier transformed infrared spectroscopy and surface resistance measurements.The results showed significant damage on the specimen' surface caused by the corona discharge. Surface erosion was seen in the micrographs and colour change was observed on the aged surface.The surface resistance dropped rapidly during the first hours of exposure to the corona discharge, then approached a saturation value asymptotically. It was established that hydrophilic hydroxyl (O-H) and carbonyl (C --O) groups have formed on the surface of the aged sample. Moisture adsorbed by the hydrophilic OH groups plays an important role in the decrease of the surface resistance, as, under dry conditions after removal from the corona discharge, the surface resistance increased and tended to recover its original value.

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Mechanism of fracture related heating for 500-kV composite insulators in highly humid areas

Cheng

Wang

Zhang

et al. 2015

Int. Trans. Electr. Energ. Syst.

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Summary With the adoption of composite insulators in the field of high voltage transmission, it is essential to focus on its safety performance. Our study paid attention to the extensive heating within HV ending of 500‐kV AC composite insulators in southern China with high level of humidity and proposed corresponding countermeasures. Via superficial examination, IR and UV test, interface quality inspection, chemical analysis and water absorption test and etc., we were able to study the defected insulators. According to our observation, insulators were slightly covered with pollutants and maintained superficial hydrophobic properties. The heating performance of HV ending of insulators was closely related to humidity as well as the type and site of loading voltage. We suggested that when exposed to high humidity, polarization of the molecules from water, polar groups of material and the interlayer resulted in the abnormal heating; on the other hand, when the environment humidity was low the heating was attributed to partial discharge. Consequently, we provided several solutions toward the issue according to our observations. Copyright © 2015 John Wiley & Sons, Ltd.

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FTIR analysis of non-ceramic composite insulators

Cited by 59 publications

References 17 publications

Failure analyses of nonceramic insulators. Part 1: Brittle fracture characteristics

Failure analyses of nonceramic insulators. Part 1: Brittle fracture characteristics

Surface degradation of styrene acrylonitrile exposed to corona discharge

Mechanism of fracture related heating for 500-kV composite insulators in highly humid areas

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