Space charge in thermally aged polyethylene and its electrical performance

Li, Ziyun

doi:10.1088/2053-1591/aaf61b

Cited by 5 publications

(4 citation statements)

References 18 publications

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“…Space charge density values can be obtained by substituting relative permittivity values at 50 Hz of these tested samples into (1). Figure 1 Therefore, relative permittivity can be greatly affected by DCP content and thermal aging time.…”

Section: Space Charge Measurementmentioning

confidence: 99%

“…Cross-linked polyethylene (XLPE) has been widely used as power cable insulation materials [1,2]. Compared with traditional oil-paper-insulated cables, XLPE cables have many significant advantages such as high softening point, low thermal deformation, high mechanical strength at high temperature, light weight, acid resistance, alkali resistance, corrosion resistance, almost no cracking and so on [1][2][3][4]. Therefore, owing to these advantages, XLPE cables quickly conquered the power industry as soon as they came out.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Thermal Aging on Space Charge Accumulation and Dissipation of Cross-Linked Polyethylene With Different Cross-Linking Agent Contents

Wang

Quan

et al. 2020

IEEE Access

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This article presents the influence of thermal aging on space charge accumulation and dissipation of cross-linked polyethylene (XLPE) with different cross-linking agent contents. In this article, dicumyl peroxide (DCP) and low-density polyethylene (LDPE) respectively are used as cross-linking agent and basic experimental material. Additionally, an improved PEA method is used to measure space charge densities during voltage application and removal when thermal aging time respectively is 0, 5, 15, 30 and 80 days due to higher accuracy. And experimental results indicate thermal aging can introduce negative charge traps into pure LDPE and make space charges easier to inject and accumulate in pure LDPE and XLPE, but space charge densities in XLPE increase more rapidly as thermal aging time increases, moreover, thermal aging can simultaneously increase densities of deep and shallow charge traps in pure LDPE and XLPE, etc. And we have also explained the change of space charge accumulation and dissipation of pure LDPE and XLPE after thermal aging from the perspective of micro-structure change of pure LDPE and XLPE through the quantitative analysis of average charge densities. Besides, theoretical model of the average charge decay has also been summed up, and this model can perfectly reflect the dissipation of space charges in pure LDPE and XLPE of different thermal aging time. INDEX TERMS Cross-linked polyethylene (XLPE), DCP content, improved Pulsed Electro-Acoustic (PEA) method, low-density polyethylene (LDPE), thermal aging; space charge

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Section: Space Charge Measurementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of Thermal Aging on Space Charge Accumulation and Dissipation of Cross-Linked Polyethylene With Different Cross-Linking Agent Contents

Wang

Quan

et al. 2020

IEEE Access

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“…One of the more prominent problems is that the space charges can distort the distribution of electric field strength in the insulation materials that are used for power equipment and cables. Therefore, this can shorten the service life of the power insulation materials [1,2,3,4]. Therefore, the space charge characteristics of XLPE under the strong direct current (DC) electric field have always been the focus of scholars and engineers at home and abroad.…”

Section: Introductionmentioning

confidence: 99%

The Impact of Cross-Linking Effect on the Space Charge Characteristics of Cross-Linked Polyethylene with Different Degrees of Cross-Linking under Strong Direct Current Electric Field

et al. 2019

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Cross-linked polyethylene (XLPE) obtained by the crossing-linking reaction of polyethylene (PE) can greatly enhance the mechanical properties and other properties of PE, which makes XLPE widely applied in the field of electric power engineering. However, the space charges can distort the distribution of the electrical field strength in the XLPE applied in the insulation materials, which can shorten the service life of the insulation materials. Therefore, the space charge characteristics of XLPE under the strong direct current (DC) electric field have been the focus of scholars and engineers all over the world. This article has studied the impact of the cross-linking effect on the space charge characteristics of XLPE with different degrees of cross-linking. For this issue, we used dicumyl peroxide (DCP) as the cross-linking agent and low-density polyethylene (LDPE) as the base material for the preparation of samples. Besides, the space charge distribution was measured by the pulsed electro-acoustic method (PEA). In addition, the average charge density as a characteristic parameter was introduced into the experiment, which was used to quantitatively analyze the impact of the cross-linking effect on the space charge characteristics of XLPE with different degrees of cross-linking. Meanwhile, we also explained the impact of the cross-linking effect on XLPE with different degrees of cross-linking from a microscopic point of view. Ultimately, some important conclusions can be obtained. For instance, the cross-linking effect significantly increases the threshold electrical field strength of XLPE, and as the content of cross-linking agent increases, the threshold electrical field strength increases at first and then decreases, and the threshold electrical field strength reaches the maximum value when the content of the cross-linking agent is 1.0% or 2.1%. Besides, the cross-linking effect introduces negative charge traps into the LDPE and increases the densities of the deeper charge traps, and so on. In addition, we have also analyzed the average charge density, and we have summarized the theoretical model of the average charge decay, namely, Q ( t ) = Q 0 + α e − t β , which is very effective for explaining the dissipation characteristics (more conclusive contents can be seen in the conclusion section of this article).

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“…The stress–strain curves have shown that the molded PE-MA-Epo solid can be crushed back into powder and repeatedly hot-pressed into shape (Figure d). The mechanical tensile data in Table S3 show that the regenerated material exhibits comparable tensile strength with more loss in elongation at break, which is due to the slow degradation and free radical thermal cross-linking reaction of PE also at the cyclic regeneration temperature, resulting in a decrease in elongation at break . However, the tensile strength and elongation at break of the second-generation and third-generation recycled materials remained essentially unchanged, suggesting that the degree of degradation and thermal cross-linking of the material at this temperature is very limited and does not affect its recycling.…”

mentioning

confidence: 97%

Dynamic Cross-Linked Polyethylene Networks with High Energy Storage and Electrical Damage Self-Healability

Li,

Wen,

Song

et al. 2023

ACS Macro Lett.

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Dielectric polymers that exhibit high energy density U e , low dielectric loss, and thermal resistance are ideal materials for next-generation electrical equipment. The most widely utilized approach to improving U e involves augmenting the polarization through increasing the dielectric constant ε r or the breakdown strength E b . However, as a conflicting parameter, the dielectric loss also increases inevitably at the same time. In addition, due to the long-term work under a strong electric field or high potential, dielectric materials often produce electrical damage (electrical tree), which is one of the main factors affecting the reliability and service life of electrical equipment. To address these problems, we herein develop dynamic cross-linked polyethylene materials (PE-MA-Epo) by polyethylene-graft-maleic anhydride (PE-MA) and polar epoxy monomers, which showed high ε r (>7), low dielectric loss (<0.02), high U e (5.16 J/cm 3 at 425 MV/m), and outstanding discharge efficiency (97%). The performances of the materials are adequate to rival biaxially oriented polypropylene (BOPP) films. Moreover, the excellent self-healing capability of PE-MA-Epo enables the total recovery of ε r and tan δ after electrical tree healing. After two cycles of electrical breakdown healing, E b remained at 80%, which improves the durability and reliability of dielectric polymers. Therefore, PE-MA-Epo shows great potential for applications in advanced electronic power devices.

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Space charge in thermally aged polyethylene and its electrical performance

Cited by 5 publications

References 18 publications

Influence of Thermal Aging on Space Charge Accumulation and Dissipation of Cross-Linked Polyethylene With Different Cross-Linking Agent Contents

Influence of Thermal Aging on Space Charge Accumulation and Dissipation of Cross-Linked Polyethylene With Different Cross-Linking Agent Contents

The Impact of Cross-Linking Effect on the Space Charge Characteristics of Cross-Linked Polyethylene with Different Degrees of Cross-Linking under Strong Direct Current Electric Field

Dynamic Cross-Linked Polyethylene Networks with High Energy Storage and Electrical Damage Self-Healability

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