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Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ultra-high voltage transformers have compact structure and low insulation margin. The field strength concentration area was likely to cause "rapid development" discharge faults under the high voltage.In this paper, the high-frequency second impulse current signals under different discharge development stages were obtained by building a "rapid development" creeping discharge test platform for transformer oil-paper insulation based on the "pin-plate" defect.According to the difference of its phase-amplitude and phase-discharge maps, the discharge process was divided into three parts: "early stage"（sparse discharge), "middle stage" (large-value intense discharge) and "late stage"（small-amplitude dense discharge). On the basis of 18 characteristic parameters extracted from its PRPD map, an evaluation method of Stacked Denoising Autoencoder joint Support Vector Machine was constructed, and the development status of the "rapidly developing" creeping discharge of the transformer was evaluated, which shows a good effect. [ABSTRACT FROM AUTHOR]

Train on-board vacuum circuit breaker (VCB) performance is one of the important guarantees of safe and stable operation of the high-speed train. Recently, a foreign EMU ran into a VCB delayed disconnection fault when passing a neutral section, resulting in lowering the bow to prevent the safety hazard caused by charged passing. In view of the above problem, it is presumed that the cause is the VCB contact between the arc ablation or traction transformer closing moment excitation inrush current caused by VCB overload. This paper focuses on the traction transformer closing excitation inrush current research, through field testing and PSCAD simulation to explore the influence of the excitation inrush current factors and the actual maximum achievable. The results show that the measured maximum current reaches 756. 67 A after the train over-phase VCB closes, which will cause substantial damage to the VCB contact. The size of the traction transformer excitation inrush is mainly affected by the phase angle of the VCB closing voltage and the remanence of the transformer core. And the excitation inrush current is not the main factor leading to the VCB contact fusion welding, VCB closed between the contacts of the arc ablation is the main cause of VCB contact fusion welding. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Donghua University (Natural Science Edition) is the property of Journal of Donghua University (Natural Science) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)