Corrosive sulfur and the effect that it has in transformer systems can be significant. The extent of the corrosion damage caused by sulfur, if left unchecked, can be so severe as to cause failure of the apparatus. The problems with corrosive sulfur have been recognized for quite some time. As early as 1948, F.M. Clark and E.L. Raab [1] issued a report on the subject for method development withi...

The most important parameter in transformers life expectancy is the hot-spot temperature level which accelerates the rate of aging of the insulation. The aim of this paper is to present thermal models for transformers loaded at prefabricated MV/LV transformer substations and outdoor situations. The hot-spot temperature of transformers is studied using their top-oil temperature rise models. The ...

The paper focuses on corrosion phenomena involving copper, corrosive sulphur and solid insulation of oil-immersed transformers. A study of the available mitigation technique such as passivation to reduce the effects of corrosion phenomena is carried out with the commercially available passivator, Irgamet 39 (Toluiltriazole dialkylamine) (ciba), with concentration of 100 ppm. The paper insulated...

The resistivity of oil impregnated paper will decrease during its aging process. This paper takes paper resistivity as an assessment index to evaluate the insulation condition of oil impregnated paper in power transformer. The feasibility of this method are discussed in two aspects: reliability and sensitivity. Iterative inversion of paper resistivity was combined with finite element simulation...

Measurement errors of a capacitive voltage transformer (CVT) are relevant to its equivalent parameters for which its capacitive divider contributes the most. In daily operation, dielectric aging, moisture, dielectric breakdown, etc., it will exert mixing effects on a capacitive divider’s insulation characteristics, leading to fluctuation in equivalent parameters which result in the measurement ...

High voltage transmission has been chosen in electric power system due to its capability to transfer a large amount of electric power. Several key equipments such as generator, transformer, GIS, cable and insulator play important role in determining the reliability of the power system. The high voltage equipments in general contain gas, liquid or solid insulation. Defects and a particular condi...

Transformers are one of the most valuable assets of power systems. Maintenance and condition assessment of transformers has become one of the concerns of researchers due to huge number of transformers has been approached to the end of their lifetimes. Transformer’s lifetime depends on the life of its insulation and the insulation’s life is strongly influenced by its moisture attraction as well....

Transformer is a soul of both transmission and distribution systems. It performs low voltage to high voltage conversion in transmission lines and similarly high voltage to low voltage conversion in distribution lines. The operation of transformer is decided by the cooling provided to the system. The efficient cooling method is achieved by the use of forced (or) natural oil cooling medium. The o...