Assessment of thermally aged XLPE insulation material under extreme operating temperatures

Lv, Hongkun; Lu, Tianhao; Xiong, Lingqi; Zheng, Xianggao; Huang, Yuyan; Ying, Mingliang; Cai, Jiecong; Li, Zhuo

doi:10.1016/j.polymertesting.2020.106569

Cited by 28 publications

(15 citation statements)

References 27 publications

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“…Remarkably, the elongation at break displayed in Figure 2a abruptly drops below 50%, before which it remains almost constant. Generally, a decrease in elongation at break to 50% of the initial value is taken as a threshold indicating the end of service life for XLPE insulation [22]. From this aspect, there exists a critical ageing time for the specimens, which is 5040 h at 105°C, 1176 h at 135°C, and 336 h at 155°C.…”

Section: Critical Ageing Time Behaviour Of Mechanical Dielectric and ...mentioning

confidence: 99%

Correlation between antioxidant depletion kinetic model and ageing behaviour of cross‐linked polyethylene cable insulation

Zheng

Long

et al. 2022

High Voltage

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A concise kinetic model catering for the antioxidant reaction of thermally aged crosslinked polyethylene (XLPE) cable insulation before its abrupt performance deterioration is proposed for life prediction and condition assessment. The alternating current breakdown strength, elongation at break, carbonyl index, and pyrolysis activation energy of XLPE insulation are found to consistently display an abrupt change at a certain point of ageing time. This is strongly correlated to the depletion of the antioxidant whose content gradually decreases with ageing time and drops to a critical value, after which the abrupt degradation of the above macroscopic performances happens. Based on the simplified chain reactions of XLPE during thermal-oxidative ageing, a concise kinetic model about antioxidant prediction is accordingly established by solving the chemical kinetics equations. It indicates that the antioxidant content decays with the reciprocal of time before the abrupt degradation occurs. Results of antioxidant content predicted by the kinetic model at different temperatures matches well with the experimental results, and its reliability can also be proved by the Arrhenius relationship of the obtained results. The kinetic model proposed herein demonstrates satisfying conciseness and thus can be highly feasible in ageing condition assessment and life predicting of XLPE insulation.

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Section: Critical Ageing Time Behaviour Of Mechanical Dielectric and ...mentioning

confidence: 99%

Correlation between antioxidant depletion kinetic model and ageing behaviour of cross‐linked polyethylene cable insulation

Zheng

Long

et al. 2022

High Voltage

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“…According to standards, that is the allowed maximum conductor temperature during the normal operation. In regards to the emergency situation, different standards describe different criteria of acceptance, for example, IEC 63026 allows for short-circuit 5 s maximum duration with maximum conductor temperature of 250 • C. US standards, for example, ICEA S-97-682, ICEA S-97-639, and ICEA S-97-649, accepting up to 1500 h of a total cable lifetime in elevated temperatures of 130 • C for XLPE and 140 • C for Ethylene Propylene Rubber (EPR) insulation [21]. The main factor leading to cable failure in long-term cable service is the phenomenon of electrical and electrochemical tree formation, often referred to as water tree.…”

Section: Working Conditions and Operational Factors Of Submarine Cablesmentioning

confidence: 99%

Radial Water Barrier in Submarine Cables, Current Solutions and Innovative Development Directions

Resner

Paszkiewicz

2021

Energies

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With wind turbines increasing in size, installed at greater distances from the mainland, and greater depths, submarine cables are facing new challenges. Materials and technologies used so far for the production of submarine cables with lead, aluminium, or copper sheaths make them unsuitable or even obsolete for modern solutions such as floating wind farms. The article discusses types of submarine cables, their construction, working conditions, and operational factors, with emphasis placed on the role of the radial water barrier. The focus has been placed on dry and semi-dry designs. The article is also devoted to a discussion regarding directions of further development, possible materials, and constructions that may appear in the future. Current research and results regarding the use of multi-layer coatings with the use of thermoplastic block copolymers for the layer with high moisture absorption are also presented.

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“…Recently, Zhang Y [10] constructed the relation between thermal deterioration and residual AO content. Generally, the Arrhenius model combined with the accelerated thermal ageing of XLPE slices is used to estimate the lifetime of the cable at operating temperature [11,12]. This is no doubt that it can provide vital reference for the electric power industry.…”

Section: Introductionmentioning

confidence: 99%

Dynamic ageing research of cross‐linked polyethylene cable insulation based on temporal‐spatial dimension under combined electro‐thermal effect

Zhao

Xie

Zhao³

et al. 2023

High Voltage

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Dynamic ageing process of cross‐linked polyethylene (XLPE) cable insulation under combined electro‐thermal effect is investigated by the construction of theoretical analysis model and the practice of operation‐simulated ageing test. Firstly, theoretical analysis model is constructed from time and spatial dimensions. From the time dimension, in the light of the impeding trend of internal stress to external stress, the XLPE ageing process of Steady state ‐Transition state ‐Steady state (STS) is proposed to illustrate the dynamic ageing process of XLPE. From the spatial dimension, the insulation is divided into three scales to quantify the ageing. Secondly, to practice the theoretical analysis model, an operation‐simulated ageing test was conducted on two high voltage alternating current cables with service years of 15 and 30 for 540 days. Subsequently, relevant diagnostic measurements were applied to analyse the influence of physicochemical characteristics on the dielectric and heat transfer performances of the cables. The results show that the degradation of the actual operating cable is an extremely slow process. On the one hand, the response in physical changes of morphology counterbalances the external stress, maintaining the stability. On the other hand, once the chemical changes occur, negative feedback mechanism tends to impede the occurrence of further degradation by regulating fields distribution.

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Assessment of thermally aged XLPE insulation material under extreme operating temperatures

Cited by 28 publications

References 27 publications

Correlation between antioxidant depletion kinetic model and ageing behaviour of cross‐linked polyethylene cable insulation

Correlation between antioxidant depletion kinetic model and ageing behaviour of cross‐linked polyethylene cable insulation

Radial Water Barrier in Submarine Cables, Current Solutions and Innovative Development Directions

Dynamic ageing research of cross‐linked polyethylene cable insulation based on temporal‐spatial dimension under combined electro‐thermal effect

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