Study on decay‐like fracture of 500 kV composite insulators: Infrared, ultraviolet and electric field distribution detection

Zhang, Zhijin; Pang, Guohui; Lu, Ming; Gao, Chao; Jiang, Xingliang

doi:10.1049/gtd2.12584

Cited by 8 publications

(8 citation statements)

References 25 publications

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“…An experimental setup was prepared for the simulation of the surface discharge, which is minutely introduced in Ref. [ 24 ]. The GFRE sample was placed in a closed cavity with a pair of annular electrodes that were fixed at both ends of the rod.…”

Section: Materials and Methods Of Surface Discharge Testmentioning

confidence: 99%

“…In addition, the “decay” characteristics shown in Figure 1 b suggest the severe degradation of the resin matrix, which cannot be the result of liquid immersion only. Hence, considering the abnormal temperature increase detected in actual operation, overheating is most likely another cause [ 23 , 24 ]. Moreover, because the overheating area is highly concentrated, it should be attributed to the current concentration or partial discharge instead of the overall temperature increase in the insulator [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

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Influence of Surface Discharge on Resin Degradation in Decay-like Fracture of Composite Insulators

Wang

Bao²,

Gao³

et al. 2023

Polymers

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Composite insulators have gradually become the preferred approach for electrical insulation in power systems, especially in polluted areas. Composite insulators consist of three main components: the shed, rod, and end fitting. Insulators withstand mechanical stresses via rods that are composed of glass-fiber-reinforced epoxy (GFRE). However, regardless of the high tensile strength of GFRE rods, in real-life operation, abnormal fractures have frequently been reported all over the world, which substantially increase the risk of major accidents in power systems. Fractural accidents mainly consist of brittle and decay-like fractures, which exhibit rather different morphologies at the cross sections. Brittle fracture has been effectively eliminated, while the mechanism of decay-like fracture has still not been clearly revealed. In this study, surface discharge tests were applied to investigate the discharge influence on the degradation of GFRE. The test successfully simulated the composition variation of the rods in real-life composite insulators with decay-like fractures. Moreover, it confirmed that the distinction between the characteristics of brittle fracture and decay-like fracture stems from epoxy degradation due to hydrolysis and carbonization. In addition, the respective influences of the resin type, glass fiber type, and acid liquid immersion on the degradation process were probed, and the degradation mechanism proposed in this research was verified. Based on the results, measures for preventing the development of decay-like fractures in real-life operations were determined.

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Section: Materials and Methods Of Surface Discharge Testmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of Surface Discharge on Resin Degradation in Decay-like Fracture of Composite Insulators

Wang

Bao²,

Gao³

et al. 2023

Polymers

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“…(1) The sheath surface was black or had noticeable electrical erosion marks and even had electrical erosion holes; (2) The bonding strength of the core rod-sheath interface decreased and was even destroyed. (3) The surface color of the core rod gradually became black and even carbonized; (4) Filamentous fiber appears on the core rod surface, like decayed wood.…”

Section: Experimental Set-upmentioning

confidence: 99%

“…Composite insulators are increasingly used in the power grid and have become critical equipment in the transmission lines [1,2]. The reliability of the power grid is directly correlated with its performance.…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study of Abnormal Heating Composite Insulators

Gao

Liu

2023

Polymers

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The abnormal heating of composite insulators on transmission lines frequently occurs, seriously threatening the power grid’s safe and stable operation. For different types of abnormal heating composite insulators, undifferentiated replacement wastes a lot of labor and material resources. This study explores the abnormal heating composite insulators under different environmental humidity and wind speed conditions. The heating and discharge of composite insulators are observed, and the heating range, heating shape, and temperature rise (ΔT) are analyzed. The abnormal heating of the sheath-aging composite insulator is related to the aging of the silicone rubber and the environmental humidity. The partial discharge caused by the core rod’s defect is the primary source of the temperature rise in the decay-like insulator. The heating range of the contaminated insulator is connected to the environmental humidity, and the ΔT increases with the salt density. The ΔT and heating range of the three types of abnormal heating increase with the ambient humidity. The heating phenomenon under low humidity is an important characteristic that distinguishes decay-like and contaminated insulators from sheath-aging insulators. Therefore, the on-site infrared inspection should be carried out in sunny and windless weather to prevent the impact of high humidity and wind speed on infrared temperature measurement.

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“…There are various research methods for corona discharge characteristics of transmission lines, and generally the method of measurement is used. At present, the main measurement methods used include the following: direct observation of corona discharge with an ultraviolet imager [4][5][6], direct measurement of corona current on conductors [7][8][9], indirect measurement of various effects caused by corona discharge phenomenon, such as ionic electric field, radio interference etc. [10,11].…”

Section: Introductionmentioning

confidence: 99%

Corona current and audible noise characteristics of HVDC transmission lines and their relationship at high‐altitude

Zhao

Xie

Liu³

et al. 2023

IET Generation Trans & Dist

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The audible noise (AN) of HVDC transmission lines, as an external manifestation of the corona discharge, intensifies with the increase of altitude. In high‐altitude area, the AN has been a key factor in determining the type of conductors for transmission lines. In order to study the characteristics of corona current and AN of HVDC transmission lines at high‐altitude, we erected a HVDC test line at an altitude of 4300 m, and carried out AN and corona current tests under different voltages. Through the test, the basic data of AN and corona current of HVDC test line at high‐altitude were obtained. Based on the corona current curve, the corona inception electric field strength of the conductor was proposed. The relationship between the equivalent A‐weight sound level and the high‐frequency noise component was clarified. The relational expression of the AN and corona current for the HVDC test line were suggested. The research results show that, there is a relatively fixed difference of about 7–8.3 dB between the equivalent A‐weight sound level and the 8 kHz sound pressure level at altitude 4300 m, and a clear logarithmic relationship between the equivalent A‐weight sound level and the average value of the corona current.

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Study on decay‐like fracture of 500 kV composite insulators: Infrared, ultraviolet and electric field distribution detection

Cited by 8 publications

References 25 publications

Influence of Surface Discharge on Resin Degradation in Decay-like Fracture of Composite Insulators

Influence of Surface Discharge on Resin Degradation in Decay-like Fracture of Composite Insulators

A Comparative Study of Abnormal Heating Composite Insulators

Corona current and audible noise characteristics of HVDC transmission lines and their relationship at high‐altitude

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