The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
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...
The degradation of transformer oil-paper insulation is decided by the chemical and physical processes in oil-paper insulation. The thermal aging plays the main role in the electrical and thermal degradation. In order to study aging mechanism of oil-paper insulation, accelerated thermal aging experiments in laboratory were performed. Four types of oil paper compounds, which are composed by regular...
In this paper, in order to analysis the nanostructures varieties and ageing mechanism of power transformer insulation paper under electrical and thermal stresses, both Atomic Force Microscope and MS 4.0 software were used to analysis the microscopic figure variation of insulation paper during thermal and electrical ageing. The results indicate that in some parts, paper sample was punctured because...
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...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.