The end part of cryogenic H. V. bushing insulation design in a 230/20 kV HTS transformer

Moradnouri, Ahmad; Vakilian, Mehdi; Hekmati, Arsalan; Fardmanesh, Mehdi

doi:10.1016/j.cryogenics.2020.103090

Cited by 12 publications

(5 citation statements)

References 26 publications

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“…It is also difficult to accurately analyze the mechanical stress and electric field intensity distribution by merely depending on experimentation. This issue can be overcome using the finite element method (FEM) [19,20]. According to the geometric structure, stress environment, and boundary conditions of the physical object, a simulation model can be developed to promote accurate and real-time analysis of the electrical and mechanical properties of an insulation spacer.…”

Section: Introductionmentioning

confidence: 99%

Impact of Air Gap Defects on the Electrical and Mechanical Properties of a 320 kV Direct Current Gas Insulated Transmission Line Spacer

et al. 2023

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Air gap defects inside a spacer reduce its insulation performance, resulting in stress concentration, partial discharge, and even flashover. If such gap defects are located at the interface between the insulation and conductor, a decrease in mechanical stress may occur. In this work, a finite element method-based simulation model is developed to analyze the influence of gap defects on the electrical and mechanical properties of a ±320 kV direct current gas insulated line (DC GIL) spacer. Present findings reveal that a radially distributed air gap produces a more significant effect on the electric field distribution, and an electric field strength 1.7 times greater than that of the maximum surface value is observed at the air gap. The axial distribution dominates the distortion of the surface stress by generating a stress concentration region in which the maximum stress of the air gap is twice the pressure in the surrounding area.

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Section: Introductionmentioning

confidence: 99%

Impact of Air Gap Defects on the Electrical and Mechanical Properties of a 320 kV Direct Current Gas Insulated Transmission Line Spacer

et al. 2023

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“…Glass-fiber-reinforced plastic (GFRP) has high specific strength, chemical resistance, and distinguished electrical properties (e.g., the maximum AC breakdown strength of 25 kV/mm) [31]. It has been widely applied in shipbuilding, vehicle manufacture, wind power systems, and pipe production [32].…”

Section: Introductionmentioning

confidence: 99%

Mechanical and Thermal Insulation Properties of rGFRP Fiber-Reinforced Lightweight Fly-Ash-Slag-Based Geopolymer Mortar

Zhang

Qiu

et al. 2023

Sustainability

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As a lightweight cementitious material for thermal insulation, the mechanical performance of foamed geopolymer is always compromised by its density reduction. In this study, recycled-glass-fiber-reinforced plastic (rGFRP) fiber was used to reinforce the fly ash-slag based foamed geopolymer, and vitrified micro bubbles (VMB) were applied to further decrease the thermal conductivity and modify the resistance of the lightweight mortar against drying shrinkage. The results revealed that the density, compressive strength, and thermal conductivity of the foamed geopolymer with/without VMB decreased with the increase in foaming agent content. By adding 2~6% of rGFRP fiber, the compressive strength was increased by 25~165%, and the drying shrinkage was reduced the most, by 55%. After the addition of 10% of VMB, the density, thermal conductivity, and drying shrinkage of foamed geopolymer mortar were further decreased, with the highest reductions of 8%, 26%, and 64%, respectively, due to the reduced pore volume and increase proportion of closed pores. With 6% of rGFRP fiber and 25% of foaming agent, the lightweight geopolymer mortar had the optimum performance, with compressive strength of 1.343 MPa, thermal conductivity of 0.134 W/(m·K), and drying shrinkage of 0.095%. This study developed a sustainable lightweight mortar with multiple types of industrial by-products, which benefit both the development of thermal insulation materials and reuse of solid wastes.

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“…As pointed out in the literature [14][15][16], several types of faults that are often encountered in transformers mainly include short circuit faults, insulation damage faults and overheating faults. Among them, various short circuit faults in transformers, such as single phase to ground, two phases to ground or three phases to ground, are most serious.…”

Section: Introductionmentioning

confidence: 99%

Application of Improved PNN in Transformer Fault Diagnosis

Zhang

Zuo

2023

Processes

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A transformer is an important part of the power system. Existing transformer fault diagnosis methods are still limited by the accuracy and efficiency of the solution and excessively rely on manpower. In this paper, a novel neural network is designed to overcome this issue. Based on the traditional method of judging the ratio of dissolved gas in transformer internal insulation oil, a fast fault diagnosis model of a transformer was built with an improved probabilistic neural network (PNN). The particle swarm optimization (PSO) algorithm was used to find the global optimal smoothing factor and improve the fault diagnosis accuracy of PNN. The transformer fault diagnosis model based on improved PNN not only eliminates the influence of human subjective factors but also significantly improves the diagnosis speed and accuracy, meeting the requirements for real-time application in practical projects. The feasibility and effectiveness of the method proposed in this paper are illustrated by a case study of actual data. Through analysis and comparison, the diagnostic accuracy of the proposed method is 10% higher than that of the general BPNN and 5% higher than that of the traditional PNN on the premise of ensuring the efficiency of the solution.

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The end part of cryogenic H. V. bushing insulation design in a 230/20 kV HTS transformer

Cited by 12 publications

References 26 publications

Impact of Air Gap Defects on the Electrical and Mechanical Properties of a 320 kV Direct Current Gas Insulated Transmission Line Spacer

Impact of Air Gap Defects on the Electrical and Mechanical Properties of a 320 kV Direct Current Gas Insulated Transmission Line Spacer

Mechanical and Thermal Insulation Properties of rGFRP Fiber-Reinforced Lightweight Fly-Ash-Slag-Based Geopolymer Mortar

Application of Improved PNN in Transformer Fault Diagnosis

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