MEFISTO, together with the companion instrument WPT, are planning the first-ever in situ measurements of the electric field in the magnetosphere of planet Mercury. The instruments have been selected by JAXA for inclusion in the BepiColombo/MMO payload, as part of the Plasma Wave Investigation coordinated by Kyoto University. The magnetosphere of Mercury was discovered by Mariner 10 in 1974 and ...

power system overvoltages due to switching, lightning and other disturbances are the main problem for designers of the power transformers. once some frequencies of the incoming surges match with some of the natural frequencies of transformer winding, the resonance phenomenon is expected in transformer winding. the resonant overvoltages may destroy the insulation between turns and cause to insul...

A pair of ion cyclotron range of frequencies (ICRF) antennas in the large helical device (LHD), HAS antennas showed high efficiency in minority ion heating. However the low loading resistance must be increased to prevent breakdown in transmission line. Moreover, the voltage and the current around the feed-through must be reduced to protect it. For these purpose, we developed a design procedure ...

An electronic current transformer with a B-dot sensor is proposed in this study. The B-dot sensor can realize the current measurement of the transmission line in a non-contact way in accordance with the principle of magnetic field coupling. The multiple electrodes series-opposing structure is applied together with differential input structures and active integrating circuits, which can allow th...

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...

Current transformers are essential for substation protection. It converts large currents into smaller that used measurement and triggering protection systems. Errors in the conversion of electric current can lead to inaccuracies system failures. Improper maintenance use shorten life transformer also earlier failure. One tests applied is tan delta test determine loss coefficient insulating mater...

Abstract A used oil sample of KTPJO 10/27.5/023 power transformers which are on the railway was selected and cleaned by means electric field. This process carried out using a device assembled basis special scheme. Unrefined refined samples were tested for electrical strength, i.e. breakdown voltage, AID-70m HUAZHENG (HZJQ-X1 Transformer Oil BDV Tester) dielectric testers. The results compared a...

On-line monitoring of electric power transformers can provide a clear indication of their status and ageing behavior. This paper proposes neural modeling and the local statistical approach to fault diagnosis for the detection of incipient faults in power transformers. The method can detect transformer failures at their early stages and consequently can deter critical conditions for the power gr...

− Methods enabling a determination of errors εI and δI for a high transformation ratio difference between a standard and tested instrument current transformers (ICT) are described in this article. A widespread method uses an automatic transformer test set for the measurement of a difference between a standard and tested ICT. A method transforming secondary currents to voltages and an indirect m...