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.
Power transformer is one of the most important components in a power system. It experiences thermal and electrical stresses during its operation. The insulation system consisting of mineral oil and the insulation paper used in transformer undergoes chemical changes under these stresses and gases are generated. These gases dissolve in oil. The extracted dissolved gases are analysed in the laboratory...
The need for improved performance of power systems in terms of reliability and higher productivity has necessitated more and more application of condition monitoring techniques, which can provide early warning of potential failure with the opportunity of organizing avoidance strategies to minimize loss of time and unexpected costs. Periodic condition monitoring tests have limitations such as continuous...
Transformer life depends on the life of the oil impregnated paper insulation system. Degradation of the cellulose insulation is an irreversible process. Chemical reaction of cellulose cause opening of glucose rings providing free glucose molecules, water, CO2 and organic acids. These glucose monomers further decompose and produce furanic compounds as end products. DP and furan tests are used to identify...
Periodic testing and analysis supported by proper diagnostic techniques is must for better understanding and assessment of health and serviceability of the transformers. Further, effectiveness of the diagnosis is based on proper choice of diagnostic techniques. Design review is a powerful diagnostic tool. Now-a-days, with the advances in technology of sensors and software integration, on-line non-invasive...
Power transformers are important and expensive components in electric energy networks. Unplanned outages of power transformers has a higher economical impact, which motivates, preventive tests and diagnosis for tapping the benefit of predicting condition to optimize maintenance and increase reliability of power system. Application of advanced diagnostic techniques for power transformers, provide the...
FRA is used to determine the mechanical and electrical integrity of the core and the windings of power transformers. It can be used to detect core movement, winding movement, open circuits, short circuits and problems related to core ground. Various practical case studies demonstrate the effectiveness of this technique. This paper will demonstrate the effect of change in moisture content on the resonance...
Partial discharge (PD) is an important indicator of insulation condition in a power transformer. The PD phenomenon is exhibited in various observable forms such as electrical, mechanical, optical and electromagnetic energy. Many modern systems use a combination of these techniques, because electrical detection is a proven technology, combining it with modern techniques gives the conformity and the...
Sweep Frequency Response Analysis for condition monitoring of power transformer is today a general accepted technique to identify faults in a transformer. The aim of this paper is to assess the possibility of generating transfer functions which could be realized into networks using the circuit synthesis approach. In circuit synthesis the transfer function has to satisfy the conditions of positive...
Sweep Frequency Response analysis (SFRA) is a widely used technique for condition assessment of power transformers and reactors. With SFRA, it is possible to analyze the integrity of transformer without prior dismantling. Changes in geometric configuration change the impedance of network which in turn changes the transfer function. Changes in transfer function will reveal a wide range of failure modes...
Moisture and aging strongly influence the dielectric properties of composite oil/cellulose insulation system used in power transformer. So the knowledge about moisture content in oil impregnated paper is essential when estimating remaining life time of such system. A scaled down transformer insulation model was developed to gain wide experiences of on-site measurements of moisture content using dielectric...
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.