The characteristics of electrical trees in the inner and outer layers of different voltage rating XLPE cable insulation

Xie, Ansheng; Zheng, Xiaowei

doi:10.1088/0022-3727/42/12/125106

Cited by 23 publications

(14 citation statements)

References 24 publications

(27 reference statements)

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“…where Xc is the degree of crystallinity, H is a melting enthalpy, H 0 is a melting enthalpy with a crystallinity of 100%, H 0 = 287.3J/g [27]. FIGURE 10 and TABLE 1 show that the melting and crystallization peak of XLPE changes obviously before and after aging.…”

Section: Thermal Performance Analysismentioning

confidence: 98%

Morphological, Structural, and Dielectric Properties of Thermally Aged AC 500 kV XLPE Submarine Cable Insulation Material and Its Deterioration Condition Assessment

et al. 2019

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Cross-linked polyethylene (XLPE) has been widely used as insulation material for cables. In 2019, the highest voltage level AC 500 kV XLPE submarine cable has been operated in Zhoushan, China. The irreversible degradation poses a safety hazard to the operation of submarine cable. Therefore, it is necessary to investigate the physical, chemical and electrical properties of XLPE submarine cable insulation under aging condition and explore the method for its deterioration degree assessment. In this paper, the AC 500 kV XLPE submarine cable insulation material was thermally aged at 130 • C. The deterioration characteristics of materials were analyzed based on morphology, chemical structure, mechanical property, thermal property and dielectric properties. Multiple characteristic parameters were extracted and new deterioration condition assessment model was established. Results show that the physicochemical characteristic parameters including retention rate of elongation at break, carbonyl index (CI) based on FTIR, full-width at half-maximum (FWHM) of the diffraction peak based on XRD, melting enthalpy based on DSC analysis, and the dielectric characteristic parameters including modified Cole-Cole model parameter χ sα and AC breakdown strength are sensitive to deterioration condition of XLPE material. According to the change of elongation retention at break, the deterioration condition of XLPE sample was divided into enhanced stage, wear-out stage and disposal stage. The new multi-factor deterioration condition assessment model including six characteristic parameters (retention rate of elongation at break, CI, FWHM, melting enthalpy, modified Cole-Cole model parameter χ sα , AC breakdown strength) was successfully established by grey correlation analysis. The new model can reflect the property of mechanical, chemical, thermal and dielectric property and has prominent effect in differentiating deterioration degree of the AC 500 kV XLPE submarine cable insulation material. INDEX TERMS Cross-linked polyethylene (XLPE), thermal aging, physicochemical properties, dielectric properties, condition assessment.

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Section: Thermal Performance Analysismentioning

confidence: 98%

Morphological, Structural, and Dielectric Properties of Thermally Aged AC 500 kV XLPE Submarine Cable Insulation Material and Its Deterioration Condition Assessment

et al. 2019

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“…The main cable insulation materials of PE, XLPE and PP are semi‐crystalline polymers at room temperature, they are in the glassy state with a high elastic modulus [54]. The cable accessory insulation materials of ethylene propylene diene monomer (EPDM) and silicone rubber (SIR) are amorphous polymers at room temperature, they are in the elastic state with a low elastic modulus [55].…”

Section: Influencing Factors Of Electrical Treementioning

confidence: 99%

Electrical tree degradation in high‐voltage cable insulation: progress and challenges

Su¹,

2020

High Voltage

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High‐voltage direct current (HVDC) and high‐voltage alternating current (HVAC) cables are the most important equipment for high‐voltage, large‐capacity and long‐distance power transmission. Electrical tree is a pre‐breakdown phenomenon leading to failure of insulation materials, and it is the major issue that threatens the safe and stable operation of HVDC and HVAC cable systems. This study summarises and analyses the achievements in the research of electrical tree for HVDC and HVAC cables. The initiation mechanisms of the electrical tree, including Maxwell electro‐mechanical stress, charge injection–extraction, charge trapping and electroluminescence theories, are elaborated for fully understanding the electrical degradation process in insulation materials. Then, the influences of the high electric field, high temperature and mechanical stress on electrical tree behaviours are discussed, and the relationship between charge transport and the electrical tree is analysed and illustrated. The suppression methods of the electrical tree are put forward by introducing inorganic and organic additives into insulation materials, and the suppression mechanisms are presented from the viewpoints of the structure‐property and microscale–macroscale relationships. Recently, the electrical tree research studies are focused on the high‐precision of initiation models, high‐dependence of multi‐physical fields and high‐efficiency of suppression methods. The achievements provide theoretical support for improving the electrical performance of insulation materials, while it is a practical problem to explore their application feasibility in HVDC and HVAC cable.

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“…Raetzke et al , carried out work on epoxy nanocomposites and they have observed that failure of epoxy resin due to electrical tree can drastically be reduced by incorporating nano filler to the insulating material [19]. Xie et al , carried out electrical treeing studies in 110 kV XLPE cable insulation and have concluded that insulating material having narrow molecular weight distribution with lower impurity, the material will have higher treeing resistance [20]. Thus by mitigating the impurity level in the cable insulation, it is possible to reduce the cable insulation failure due to electrical treeing.…”

Section: Influence Of Electrical Stress On the Size And Shape Of Treementioning

confidence: 99%

Understanding Electrical Treeing Phenomena in XLPE Cable Insulation Adopting UHF Technique

Sarathi¹,

Nandini²,

Danikas³

2011

Journal of Electrical Engineering

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A major cause for failure of underground cables is due to formation of electrical trees in the cable insulation. A variety of tree structure can form from a defect site in cable insulation viz bush-type trees, tree-like trees, fibrillar type trees, intrinsic type, depending on the applied voltage. Weibull studies indicate that a higher applied voltage enhances the rate of tree propagation thereby reducing the life of cable insulation. Measurements of injected current during tree propagation indicates that the rise time and fall time of the signal is of few nano seconds. In the present study, an attempt has been made to identify the partial discharges caused due to inception and propagation of electrical trees adopting UHF technique. It is realized that UHF signal generated during tree growth have signal bandwidth in the range of 0.5-2.0 GHz. The formation of streamer type discharge and Townsend type discharges during tree inception and propagation alters the shape of the tree formed. The UHF signal generated due to partial discharges formed during tree growth were analyzed adopting Ternary plot, which can allow one to classify the shape of tree structure formed.

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The characteristics of electrical trees in the inner and outer layers of different voltage rating XLPE cable insulation

Cited by 23 publications

References 24 publications

Morphological, Structural, and Dielectric Properties of Thermally Aged AC 500 kV XLPE Submarine Cable Insulation Material and Its Deterioration Condition Assessment

Morphological, Structural, and Dielectric Properties of Thermally Aged AC 500 kV XLPE Submarine Cable Insulation Material and Its Deterioration Condition Assessment

Electrical tree degradation in high‐voltage cable insulation: progress and challenges

Understanding Electrical Treeing Phenomena in XLPE Cable Insulation Adopting UHF Technique

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