A MneZn ferrite magnetic fluid (TCF-56) having 5.6 mT fluid magnetization and high pyromagnetic coefficient, (vM/vT 1⁄4 177 A/m K) has been investigated as a coolant in a 3 kW prototype transformer for overloading condition (167%). The winding temperature of a transformer submerged in magnetic fluid reaches at 396.8 K after 3 h of overloading, which is 20 K lower, when the same experiment was c...

Power transformers are one of the most critical devices in power systems. It is responsible for voltage conversion, power distribution and transmission, and provides power services. Therefore, the normal operation of the transformer is an important guarantee for the safe, reliable, high quality and economical operation of the power system. It is necessary to minimize and reduce the occurrence o...

It is important to predict the incipient fault in transformer oil accurately so that the maintenance of transformer oil can be performed correctly, reducing the cost of maintenance and minimise the error. Dissolved gas analysis (DGA) has been widely used to predict the incipient fault in power transformers. However, sometimes the existing DGA methods yield inaccurate prediction of the incipient...

This paper develops a novel dynamic correction method for the reliability assessment of large oil-immersed power transformers. First, with the transformer oil-paper insulation system (TOPIS) as the target of evaluation and the winding hot spot temperature (HST) as the core point, an HST-based static ageing failure model is built according to the Weibull distribution and Arrhenius reaction law, ...

This contribution presents an approach to determine the overload capabilities of oil-cooled power transformers depending on the ambient temperature. For this purpose the investigated method introduces a simplified, empirical based thermal model that predicts changes in oil temperature with high accuracy. This model considers the entire transformer as a single, homogenous tempered body with a ce...

Electrical energy is the paramount need in a nation’s development. To cater for large demand for electricity there is a need for reliable and proficient power system. For a power system to work reliably, the role of Transformers is critical. Health of the transformer mainly depends on its insulation. Among the different insulating material used in transformers, mineral oil is the most widely us...

Abstract—Reducing the weight of transformers while providing good performance, cost reduction and increased efficiency is important. Weight is one of the most significant factors in all electrical machines, and as such, many transformer design parameters are related to weight calculations. This study presents a comparison of the weight of oil type transformers and dry type transformer weight. O...

The transformer plays so important equipment in power system that engineers take more measures on the insulating oil of transformer by diagnosis. The dissolved gas analysis (DGA) is an effective technique for detecting incipient faults in oil-immersed power transformers. So the paper investigates the DGA methods, while employ the ANSI/IEEE C57.104 standards and the Key Gas diagnosis rules as ba...

In this paper, the properties of the physical and chemical materials, such as low loss amorphous HB1 core, high temperature resistance winding and insulation vegetable oil have been developed for use in liquid-immersed power transformer. The measured results of magnetic properties with different ferromagnetic materials core were obtained. Considering winding property for operation above 95°C co...

Marina A. Tsili, Eleftherios I. Amoiralis, Antonios G. Kladas and Athanassios T. Souflaris 1 Faculty of Electrical & Computer Engineering, National Technical University of Athens, GR-15780, Athens, Greece (e-mail: [email protected], [email protected]) 2 Department of Production Engineering and Management, Technical University of Crete, 73100, Greece, (email: [email protected]) 3 Schneide...