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Space charge has been a general concern related with the reliability and the life-time of HVDC components. In this present work, the space charge profiles in oil-impregnated pressboards are investigated by the means of the pulsed electroacoustic (PEA) technique under AC voltage with 50 Hz at the room temperature. It has been observed that the ageing status of the mineral oil and the presence of the...
In this paper, a set of accelerate thermal ageing experiments on oil immersed insulation paper were performed under 110□ and lasted for more than 100 days. The degree of polymerization (DP), the frequency domain spectroscopy (FDS) and water concentration in insulating oil and paper, as well as the AC breakdown voltage of insulation paper were tested and analyzed. The results indicate that the dielectric...
As we know, streaming electrification due to oil flow is an important phenomenon in power transformers particularly on those high rated voltage ones, and the study around it is still a challenge. In this paper, the streaming electrification characteristic of insulation mineral oil from Nynas was studied by using an improved mini-static tester to measure the electrostatic charging tendency (ECT) of...
In order to analysis the influence of copper ion on aging rate of oil-paper insulation, accelerate thermal aging experiments have been designed and performed on oil-paper insulation at two aging temperatures. A number of characteristic parameters such as dissolved gases, degree of polymerization, furfural content, water content and Acid number of oil have been tested periodically. The experiments...
In order to analyze the thermal aging mechanism of the insulation paper inside the power transformer, a series of accelerated thermal aging tests were performed on pressboard. Subsequently, the atomic force microscope (AFM) together with scanning electron microscope (SEM) and X-ray diffraction (X-RD) were utilized to observe the micro surface of the thermal-aged pressboard. The experiments and analysis...
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