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Morimoto H.,Power Supply Systems Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) (Japan) | Year: 2011

Correct analysis of feeding circuits requires correct line constants of overhead lines and rails. Consideration of the frequency response of self-impedances and mutual impedances on steady state analysis is necessary because they affect calculation results. However, there are only a few reports on transient analysis of feeding circuits which take frequency response into account. This paper suggests a transient analysis model of overhead lines and rails with approximated frequency response, and shows the results of transient analysis on a simplified DC feeding circuit. Source


Morimoto H.,Power Supply Systems Laboratory | Uzuka T.,Power Supply Systems Laboratory | Akita T.,Japan Railway Construction
Quarterly Report of RTRI (Railway Technical Research Institute) (Japan) | Year: 2010

Most Shinkansen substations in Japan receive their electric power supply for traction from extra-high voltage systems. "Modified-Woodbridge connection" transformers have been used for this since 1972; however, these have a rather complicated structure. As such, studies were carried out to develop a new type of transformer, which had the same functions, but was simpler. The transformer has been coined the "roof-delta connection" transformer since it has both roof and delta windings. Test results from a prototype of this transformer revealed that it could be used in AC traction feeding systems. This paper describes the fundamental characteristics of the roof-delta connection transformer and results from tests. Source


Tanaka H.,Power Supply Systems Laboratory | Akagi M.,Power Supply Systems Laboratory | Yoshii T.,Power Supply Systems Laboratory | Uzuka T.,Power Supply Systems Laboratory | Ajiki K.,Sankosha Corporation
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2013

Two methods currently exist to evaluate degradations in arresters in Shinkansen substations. One method uses a surge current counter device to count the number of strokes of lightning. However, surge current counter devices sometimes pick up small switching surge of changeover switches, which are not deterioration to the arrester. The other method is to measure normal leakage current of arrester. This method though is potentially unreliable because the leakage current is strongly affected by the feeding voltage harmonics. A deterioration diagnosis device was thus designed with functions to suppress unwanted small surge current counts and provide accurate measurements of the leakage current in the target arrester. This paper describes various field measurement results, the principle underlying the developed deterioration diagnosis device and a new method for extracting the resistive current in the arrester from the overall measured leakage current. Source

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