Diagnosis of the aged XLPE cable using frequency and temperature characteristics of tan /spl delta/ II

Hirano, N.; Tsujimura, Tohru; Shimizu, Noriyuki; Horii, Kenji

doi:10.1109/iseim.1988.763468

Cited by 4 publications

(4 citation statements)

References 2 publications

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“…The results shown in Fig.3 can be explained as follows: The noted decrease of the dissipation factor at the beginning of exposure to UV can be attributed to the improvement of the XLPE insulation quality, indicating a drop in molecular mobility [21]. As it is known, tanδ is strongly influenced by the oxidation phenomenon in the case of polyethylene [22]- [23]. Therefore, the growth of tanδ can be interpreted as the formation due to oxidation of electrically assymetric carbonyl compounds.…”

Section: Results and Analysis A Dielectric Proporeties 1) Dissimentioning

confidence: 86%

Effect of Ultraviolet Radiations on Medium and High Voltage Cables Insulation Properties

Hedir¹,

Moudoud²

2016

IJET

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Under operating conditions effect, insulated power cables can undergo critical degradations. Ultraviolet (UV) radiations are one of the most destructive constraints which affect the properties of the material used for insulation. Because of its good properties, crosslinked polyethylene (XLPE) is widely used in medium voltage (MV) and high voltage (HV) cables insulation. Regardless of its excellent performances, XLPE can degrade when exposed to UV. The objective of this work is to report experimental results concerning the effect of accelerated UV ageing on the properties of XLPE insulation. For this purpose, dielectric characterization, visual observations and scanning electron microscopy (SEM) analysis are performed to assess the extent of ageing. Obtained results show that UV ageing affects greatly the XLPE insulation. So, an evolution in the dielectric properties (dielectric constant, dissipation factor, dielectric loss index and AC volume resistivity), color change and deterioration of surface morphology with ageing time are noticed.

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Section: Results and Analysis A Dielectric Proporeties 1) Dissimentioning

confidence: 86%

Effect of Ultraviolet Radiations on Medium and High Voltage Cables Insulation Properties

Hedir¹,

Moudoud²

2016

IJET

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“…It is known, tanδ is strongly influenced by the oxidation phenomenon in the case of Polyethylene [22]. Therefore, the tanδ depends on the losses polarization such as dipole polarization [23].The increase of tanδ can be attributed to the formation of electrically asymmetric carbonyl compounds due to the oxidation, these later are the mainly factor in increasing of dielectric losses [24].…”

Section: E Dielectric Behaviormentioning

confidence: 99%

Correlations between physico-chemical properties and dielectric behavior of thermally aged XLPE cables insulation

Sebbane

Boubakeur

Mekhaldi

2022

ENPESJ

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The carried out investigations aim at clarifying the correlations between physico-chemical properties and the variation of dielectric losses of Cross-Linked Polyethylene (XLPE) as Medium Voltage cable insulation during thermal aging. The used cables were manufactured by ELSEWEDY CABLES. They have been installed in Algeria where they must resist high temperatures that could exceed 50 degrees in the south of the country. For this aim, thermal aging measurements were performed on XLPE cables samples at 80, 100 and 140 °C for aging time of 5000 hours. The chemical properties were evaluated through Fourier Transform Infrared Spectrum (FTIR). In addition, the effect of aging on the crystallinity ratio, the lamellar thickness and the melting peak temperature was assessed using Differential Scanning Calorimetry (DSC). Frequency domain dielectric spectroscopy has been conducted on the aged XLPE cables in order to study the evolution of the dielectric losses. The obtained results showed that the principal aging mechanism is thermal oxidation which heads to deteriorate the morphology and increase both the polarization and losses, principally at low frequencies. It has been found that the color changes caused by the chains scission indicate the increase of interfaces between the cable insulating and semi-conductive layers, which could head to increase the dielectric losses due to the interfacial polarization.

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“…In this case, one problem raised for those cables that have reached the designed service year: continue operation or replaced by new cables? Although many detection technologies have been developed, such as the detection of partial discharge, damped oscillation waves, and time-frequency reflection, the accuracy of these measurements is still lacking because of the multiple interferences from other cables and the complex on-site environment [4]- [6]. Until now, a feasible method for the accurate assessment of insulation degradation that is conducive to the evaluation of cable retirement was not currently available.…”

Section: Introductionmentioning

confidence: 99%

Rejuvenation of Retired Power Cables by Heat Treatment: Experimental Simulation in Lab

et al. 2020

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In this work, heat treatment was performed on three retired 110 kV AC cables with service years of 0, 15 and 30, and the effects on the thermal and electrical performance of the cable insulation were investigated. First, each cable with a length approximately of 5 m was prepared and cut into five equal segments. Four segments of each cable were annealed at a temperature of 90, 95, 100, or 105 • C by building a small circuit to simulate cable operation. Then, a section at the middle of each segment was cut out, and the insulation layer was peeled away. The peeled-off layers from the inner, middle and outer positions were selected as the test samples. Subsequently, Fourier transform infrared spectrometry (FTIR), and differential scanning calorimetry (DSC) were performed, and the DC conduction current and dielectric breakdown strength were measured. The best thermal properties of the highest melting point, crystallinity, and smallest melting range were found when the cables were annealed at 100, 105, and 105 • C for the inner, middle, and outer positions, respectively. The highest dielectric breakdown strength and lowest electrical conductivity were found at temperatures of 95 or 100 • C for the inner and middle positions, respectively, and at 105 • C for the outer position. The FTIR results showed that thermal annealing for hundreds of hours did not adversely affect the molecular chains. It is found that this type of heat treatment could be a feasible method to rejuvenate retired cables, and a conservative temperature of 95 • C is regarded as the optimum annealing temperature. INDEX TERMS Cable, DSC, melting point, crystallinity, electrical conductivity, dielectric breakdown strength.

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Diagnosis of the aged XLPE cable using frequency and temperature characteristics of tan /spl delta/ II

Cited by 4 publications

References 2 publications

Effect of Ultraviolet Radiations on Medium and High Voltage Cables Insulation Properties

Effect of Ultraviolet Radiations on Medium and High Voltage Cables Insulation Properties

Correlations between physico-chemical properties and dielectric behavior of thermally aged XLPE cables insulation

Rejuvenation of Retired Power Cables by Heat Treatment: Experimental Simulation in Lab

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