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eng A century of dissolved gas analysis - part I
Grisaru, Marius
Transformers Magazine Vol. 6, No. 3, 2019
Electricity powers the world and is an indispensable product for humanity, almost like water and food. This energy category needs two types of materials which make it feasible - electrical conductors and electrical insulators. In practice, no one can afford to use ideal conductors and insulations matrixes. Accordingly, the industry has to compromise with the best available materials at acceptable prices. Power transformers, like any other electrical device, have to contain these two types of materials. The most advantageous insula...
Hrčak ID: 222745


eng A century of dissolved gas analysis - Part II
Grisaru, Marius
Transformers Magazine Vol. 6, No. 4, 2019
Future brings some changes to DGA. It is expected that offline DGA in standard laboratories will gradually disappear as a routine test and transformers without online DGA will be tested by using simple portable devices. The online sensors will be monitored from a central control room with a sophisticated artificial intelligence in an effort to predict failures.
Hrčak ID: 226061


eng A century of dissolved gas analysis - part III
Grisaru, Marius
Transformers Magazine Vol. 7, No. 1, 2020
With time, the size of the transformer increased exponentially both in power andvoltage. Although huge improvements have been made regarding the magnetic core and the decrease of core losses, a transformer is now producing much more heat due to the design optimization and size reduction. Heat reduces the insulating properties of the insulating matrix, reducing the conducting properties and accelerating all chemical reactions including ageing and corrosion. The stresses from the insulation materials increase gradually. In the last century, th...
Hrčak ID: 232078


eng Standards relevant to transformers – Part VIII
Ramachandran, P.; Jhala, A.S.
Transformers Magazine Vol. 9, No. 3, 2022
There is a large number of national and international standards covering various aspects of transformer insulating fluids such as specifications, sampling techniques, testing procedures, maintenance, diagnostics, and so on. The present paper summarises available standards and technical brochures related to the above aspects of the insulating fluid for an immediate reference to the user.
Hrčak ID: 280329


eng THERMAL STABILITY CHANGE OF SYNTHETIC ESTER-BASED TRANSFORMER OIL
Haramija, Veronika; Vrsaljko, Dijana; Đurina, Vedran; Vrsaljko, Domagoj
Journal of Energy Vol. 63, No. 1-4, 2014
For good transformer condition assessment it is necessary to determine the condition of insulating materials, both liquid and solid. Transformer is reliable for as long as its insulation system resists deterioration. Therefore, thermal and oxidation stability are important characteristics of transformer oil. It is a measure of oil resistance for decomposition by the influence of oxygen and temperature. Oils with good thermal and oxidation stability retain their characteristics regardless the thermal stress. Because of environmental and saf...
Hrčak ID: 199223


eng Transformer oil fault gases under thermal stress at 160 °C – Part I
Christian, Bernd; Glaeser, Armin
Transformers Magazine Vol. 5, No. 2, 2018
Dissolved gas analysis is a common technique in the supervision and maintenance of transformers. It can give hints on defects and faults in oil-immersed transformers by determining and quantifying the gases arising due to the thermal or electrical stress. Different algorithms for the assessment of transformers, which utilize data obtained from dissolved gas analysis, have been published so far. However, only few investigations exist that deal with the influence of the oil´s composition on the oil´s tendency of releasing gases. This research stu...
Hrčak ID: 202539


eng Transformer oil fault gases under thermal stress at 160 °C – Part II
CHRISTIAN, Bernd; GLÄSER, Armin
Transformers Magazine Vol. 5, No. 3, 2018
Dissolved gas analysis is a common technique in the supervision and maintenance of transformers. It can give hints on defects and faults in oil-immersed transformers by determining and quantifying gases arising due to thermal or electrical stress. Different algorithms for the assessment of transformers, which deploy data obtained from dissolved gas analysis, have been published so far. However, only few investigations exist that deal with the influence of the oil’s chemical composition towards the oil’s tendency of releasing gases. This researc...
Hrčak ID: 207736


eng Not all mineral oils are equal
Lukenda, Nikola
Transformers Magazine Vol. 6, No. 4, 2019
The life of a transformer is inherently linked to the fundamental role of insulating oils to dissipate heat and protect the transformer’s solid insulation. Developments in refining technology means that not all mineral oils are equal, and isoparaffinic oils in particular can offer enhanced oxidative stability, lower viscosity in colder temperatures, and superior heat transfer which results in improved reliability and utility for transformer operators.
Hrčak ID: 226063


eng Economical and Reliable Transformer Maintenance by Holistic Interpretation of Insulating Oil Condition
Grisaru, Marius
Transformers Magazine Vol. 1, No. 1, 2014
The importance and cost of transformers is described and stressed in all the literature. Transformers are one of the most important and vital links in the electricity supply chain. Despite the very high cost related to transformer failures, the tests and diagnoses of the equipment itself, the transformer owner or a person responsible for its proper operation is faced with many diagnostic approaches and most of them are either inaccurate or unnecessary and irrelevant to individual case. Of course the lack of specialists in transformer diagnoses...
Hrčak ID: 186883


eng Fire testing for transformer pit fire protection
Lindström, Johan; Försth, Michael
Transformers Magazine Vol. 1, No. 3, 2014
Transformer pits are conventionally filled with rocks in order to achieve passive fire safety in the event of an oil leak from the transformer. Other solutions also exist but there is no well defined test method that allows an assessment of the fire performance. In this brief article, such a test is presented together with test results for an alternative system where profile planks are used instead of rocks.
Hrčak ID: 185466