Power transformers are one of the most important components in the electrical energy network. Extending transformer life is very economically valuable due to power outage. Therefore the development of instruments to monitor the transformer condition is of great interest. Detection of partial discharges (PDs) in power transformers is an effective diagnostic because it may reveal and quantify an ...

This paper presents the results of testing electrical and fire properties mineral oil low-viscosity natural ester mixtures. Properties such as breakdown voltage, relative permeability, dispersion coefficient, conductivity, flash burn point, lower heating values were investigated in different concentrations mixtures two liquids, well for base liquids. To ensure equal humidity levels, prepared sa...

Power transformers are among the most important and expensive equipments in the electric power systems. Consequently the transformer protection is an essential part of the system protection. This paper presents a new method for locating transformer winding faults such as turn-to-turn, turn-to-core, turn-totransformer body, turn-to-earth, and high voltage winding to low voltage winding. In this ...

The energizing of large power transformers has long been considered a critical event in the operation of an electric power system. When a transformer is energized by the utility, a typical inrush current could be as high as ten times its rated current. This could cause many problems from mechanical stress on transformer windings to harmonics injection, and system protection malfunction. There h...

Fault diagnosis of power transformers have always drawn the attention among the users, without removing the transformers from the service. Thus it is necessary to detect the incipient fault of a power transformer at an early stage and diagnose properly on optimum way. Dissolved gas analyses (DGA) is widely used to detect incipient faults in oil filled power transformers. Throughout the world, d...

Present development and production of power transformers with lower losses in addition to replacement of outdated transformers assume regular measurement of losses in both load and no-load regime. These measurements are very demanding especially in the case of on-situ measurements. The complexity of the measurements grows with the size of transformer. This paper presents one typical test of los...

Assuming that the reader is familiar with basic magnetic design theory, this topic provides design guidance to achieve high efficiency, low electromagnetic interference (EMI), and manufacturing ease for the magnetic components in typical offline power converters. Magnetic-component designs for a 90-W notebook adapter and a 300-W ATX power supply are used as examples. Magnetic applications to be...

In this paper, visualization and neural network techniques are applied together to a power transformer condition monitoring system. Through visualizing the data from the chromatogram of oil-dissolved gases by 2-D and/or 3-D graphs, the potential failures of the power transformers become easy to be identified. Through employing some specific neural network techniques, the data from the chromatog...