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X. Yu
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3 records found
1
The pulsed electro-acoustic (PEA) method is widely used to measure space charge distribution in dielectric materials, and its measurement accuracy strongly depends on the transfer function and gain coefficient obtained during system calibration. Conventional calibration structures based on multi-layer epoxy resin are sensitive to thermal and mechanical stresses, and their preparation process is relatively complex, which reduces experimental repeatability. To improve the stability and controllability of the calibration structure, this paper proposes the use of FR-4 laminates, commonly used as printed circuit board substrates, as an alternative solution. The FR-4 laminated structure provides precise thickness control, high mechanical stability, and convenient multilayer stacking. Preliminary PEA experiments were conducted to evaluate the influence of the FR-4 structure on acoustic signal propagation through waveform comparison and quantitative waveform metrics. The results provide an experimental basis for constructing a structurally stable and modular PEA calibration structure and support the development of improved calibration models.
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The pulsed electro-acoustic (PEA) method is widely used to measure space charge distribution in dielectric materials, and its measurement accuracy strongly depends on the transfer function and gain coefficient obtained during system calibration. Conventional calibration structures based on multi-layer epoxy resin are sensitive to thermal and mechanical stresses, and their preparation process is relatively complex, which reduces experimental repeatability. To improve the stability and controllability of the calibration structure, this paper proposes the use of FR-4 laminates, commonly used as printed circuit board substrates, as an alternative solution. The FR-4 laminated structure provides precise thickness control, high mechanical stability, and convenient multilayer stacking. Preliminary PEA experiments were conducted to evaluate the influence of the FR-4 structure on acoustic signal propagation through waveform comparison and quantitative waveform metrics. The results provide an experimental basis for constructing a structurally stable and modular PEA calibration structure and support the development of improved calibration models.
Partial discharge (PD) within cavities in oil-impregnated paper (OIP) is one of the key aging mechanisms that can alter space-charge behavior and eventually contribute to insulation failure in underground cables. This study investigates the evolution of charge-transport characteristics in a three-layer OIP sample containing an artificial cavity under PD aging. Time-resolved pulsed electroacoustic (PEA) measurements show that PD aging changes the measured space-charge profiles, leading to a lower injected charge density, faster charge redistribution during depolarization, and enhanced charge accumulation near the oil–paper interfaces. To interpret these experimentally observed trends, a modified charge transport model incorporating dual-trap energy levels and hopping conduction is developed. Model fitting to the measured PEA profiles suggests that PD aging is associated with a reduction in the effective deep-trap energy level and an increase in shallow-trap density, which facilitates carrier de-trapping and promotes the redistribution of space charge from the bulk region toward the interfaces. The results provide insight into the relationship between PD-induced charge-transport modification and OIP insulation degradation, and may support the condition assessment and maintenance of underground cable insulation systems.
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Partial discharge (PD) within cavities in oil-impregnated paper (OIP) is one of the key aging mechanisms that can alter space-charge behavior and eventually contribute to insulation failure in underground cables. This study investigates the evolution of charge-transport characteristics in a three-layer OIP sample containing an artificial cavity under PD aging. Time-resolved pulsed electroacoustic (PEA) measurements show that PD aging changes the measured space-charge profiles, leading to a lower injected charge density, faster charge redistribution during depolarization, and enhanced charge accumulation near the oil–paper interfaces. To interpret these experimentally observed trends, a modified charge transport model incorporating dual-trap energy levels and hopping conduction is developed. Model fitting to the measured PEA profiles suggests that PD aging is associated with a reduction in the effective deep-trap energy level and an increase in shallow-trap density, which facilitates carrier de-trapping and promotes the redistribution of space charge from the bulk region toward the interfaces. The results provide insight into the relationship between PD-induced charge-transport modification and OIP insulation degradation, and may support the condition assessment and maintenance of underground cable insulation systems.
The PEA(pulsed electro-acoustic) method is widely used for measuring space charge distribution in insulation materials. However, the measured quantity reflects a voltage curve over time rather than the actual space charge distribution. Therefore, establishing a calibration procedure is crucial to determine the relationship between these two quantities. This calibration procedure aims to convert the measured voltage into the spatial distribution of space charge while correcting for non-idealities such as distortion and attenuation. This paper outlines the main steps of the PEA system calibration and provides a detailed discussion on the selection of the reference signal. Furthermore, recommendations are provided to enhance the accuracy and reliability of the calibration process.
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The PEA(pulsed electro-acoustic) method is widely used for measuring space charge distribution in insulation materials. However, the measured quantity reflects a voltage curve over time rather than the actual space charge distribution. Therefore, establishing a calibration procedure is crucial to determine the relationship between these two quantities. This calibration procedure aims to convert the measured voltage into the spatial distribution of space charge while correcting for non-idealities such as distortion and attenuation. This paper outlines the main steps of the PEA system calibration and provides a detailed discussion on the selection of the reference signal. Furthermore, recommendations are provided to enhance the accuracy and reliability of the calibration process.