著者

持永 芳文 小山 義夫 竹内 竹次

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌D(産業応用部門誌) (ISSN:09136339)

巻号頁・発行日

vol.110, no.5, pp.570-579, 1990-05-20 (Released:2008-12-19)

参考文献数

10

被引用文献数

1 1

---

Auto-transformer feeding system is standard equipment for power supply to high-speed trains and prevention of inductive interference with the telecommunication lines on the AC electrified Shinkansen lines in Japan.In the present AT feeding system in which the feeder side of the feeding transformer is not grounded, the insulation level on the feeder side at the substation is set twice as high as the vehicle voltage.For the purpose of economizing on the substation power system, the authors have developed new methods adopting a three-winding Scott-connected transformer to make the insulation level on the feeder side a half of the present value and additionally employing a series capacitor with a simplified structure to compensate for the voltage drop.This paper describes the structure and characteristics of the three-winding transformer, and insulation level reduction method using it.Specifically various features of the system are discussed through simulation of feeding performance by multi-circuit networks analysis and study of various phenomena under use of the series capacitor.Furthermore by confirmation tests executed in the Osaka area of the Tokaido Shinkansen line, the practical applicability of the system is proved.

著者

川原 敬治 持永 芳文 前川 千明 佐藤 重勝

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌D(産業応用部門誌) (ISSN:09136339)

巻号頁・発行日

vol.120, no.1, pp.96-103, 2000-01-01 (Released:2008-12-19)

参考文献数

9

---

Railway structures and traction substations suffered much damage by the Large-Magnitude Hanshin-Awaji Earthquake in 1995. In electric railway substations, structures were cracked, also a number of pieces of equipment such as transformers and silicon rectifiers were damaged, insulation oil leaked, base anchorbolts were cut, and high-voltage equipment supports inclined, and insulators cracked because of crack in the ground and uneven subsidence. This report describes the survey results of damaged traction substations and explains an earthquake-proof design method for traction substation equipment.We surveyed natural frequencies of traction substations equipment below 170kV. This survey showed that natural frequencies of equipment below 170kV were in relatively high frequency area (about 10-20Hz) than those of equipment above 170kV. As the real dominant frequency of earthquake is several Hz, these equipments rarely cause resonance due to earthquake move, and moving responses are weak also.From the analysis of the gliding phenomena of heavy equipment, it is found that the horizontal acceleration is in the range of 0.4-0.6G. So anchorbolts should be protected from large bending moment. Definite plans are using longer anchor-sockets, stuffing gaps between equipment and base and removing anti-vibration rubber plates.

著者

持永 芳文

出版者

一般社団法人 電気学会

雑誌

電気学会誌 (ISSN:13405551)

巻号頁・発行日

vol.121, no.9, pp.629-632, 2001-09-01 (Released:2008-04-17)

参考文献数

1

著者

兎束 哲夫 池戸 昭治 上田 啓二 持永 芳文 船橋 眞男 井手 浩一

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌. B (ISSN:03854213)

巻号頁・発行日

vol.125, no.9, pp.885-892, 2005

被引用文献数

8 7

---

In AC electric Railway, three-phase voltage is changed into the single-phase circuit of two circuits with the Scott-connected transformer. If it becomes large unbalancing of the load between single-phase circuits, voltage fluctuation becomes large on three-phase side. Then, Railway Static Power Conditioner (RPC) was developed for the purpose of controlling voltage fluctuation on three-phase side. An RPC is comprised of a pair of self-commutated PWM inverters. These inverters connect the main phase and teaser feeding buses, coupled with a DC side capacitor such as a Back-To-Back (BTB) converter. In this way, the two self-commutated inverters can act as a static var compensator (SVC) to compensate for the reactive power and as an active power accommodator from one feeding bus to another.<br>20MVA/60kV RPCs started commercial operation in 2002 at each two substations on the newly extended Tohoku Shinkansen for compensating voltage fluctuation on three-phase side caused by traction loads, absorbing harmonic current. The results of operational testing indicate that an RPC can accommodate single-phase loads such as those of PWM-controlled Shinkansen and thyristor phase-controlled Shinkansen, and handle the exciting rush current of transformers, as well as compensate for harmonics successfully.

著者

持永 芳文 藤江 宏史 三戸 将照

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌D(産業応用部門誌) (ISSN:09136339)

巻号頁・発行日

vol.107, no.3, pp.336-343, 1987

著者

安喰 浩司 持永 芳文 兎束 哲夫 斎藤 勉 吉舗 幸信

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌D(産業応用部門誌) (ISSN:09136339)

巻号頁・発行日

vol.121, no.3, pp.340-346, 2001-03-01 (Released:2008-12-19)

参考文献数

4

被引用文献数

3 6

---

At substations of Shinkansen, three-phase power received from the utility power system is converted into a pair of single phase power sources with different phases. When a Shinkansen car passes the boundary of two power sources with different phases, the power source for Shinkansen instantly switches from one to the other. Vacuum switches have been used as changeover switches so far. It takes about 300 msec for switching. By this system, Shinkansen cars can pass the boundary of two power sources under powering.Generally speaking, when a vacuum switch is closed at a voltage-phase of 90°, the inrush current into transformer will become small. On the other hand, although the power from substation is not supplied to Shinkansen at no-voltage of power source switching at the changeover section, counter electromotive force by auxiliary motor appears on the main transformer on the car. Due to the counter electromotive force, it is difficult to suppress the inrush current into the main transformer by the conventional vacuum switch. In contrast, the use of static switch such as semiconductor device can decrease the exciting inrush current into the transformer of Shinkansen car, when the turn-on timing of changeover switch is controlled. We investigated the control method for suppressing the exciting inrush current into transformer when a static switch is used as a changeover switch instead of vacuum switch. To verify the control method, we built and tested a mini model to simulate a changeover switch.

著者

長谷 伸一 持永 芳文 八木 英行 江本 政春

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌D(産業応用部門誌) (ISSN:09136339)

巻号頁・発行日

vol.118, no.7-8, pp.930-936, 1998-07-01 (Released:2008-12-19)

参考文献数

8

---

Takasaki-Nagano section, a part of Hokuriku Shinkansen was opened in October, 1997, just before Nagano Winter Olympics. Hokuriku Shinkansen has been electrified by 30kV a. c. commercial frequency AT feeding system.As for the commercial frequency, Japan is divided into two zones: the western part of Japan is a 60Hz zone and its eastern part is a 50Hz zone. Two different power frequencies exist in Hokuriku Shinkansen which passes power frequency borders between different electric power companies. Therefore, in case of a contact fault between two different power frequencies, a beat-formed large fault current will flow, which should be immediately detected and cut off.At present, a distance relay and an AC ΔI type relay are used as protective relays for a feeding circuit of Shinkansen lines. However, it was experimentally made clear that those relays do not operate by a beat-formed fault current which appears in the case of a contact fault between two different power frequencies. For this reason, we have developed and put to practical use a protective relay for a contact fault between two different frequencies, which operates by detecting 55Hz component peculiar to the current caused by the contact fault and also detecting power frequency of an opponent traction substation.They have been installed at a frequency-bordered sectioning post and at traction substations which sandwich the sectioning post.

著者

持永 芳文 浜田 博徳 新井 浩一

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌D(産業応用部門誌) (ISSN:09136339)

巻号頁・発行日

vol.110, no.1, pp.41-50, 1990-01-20 (Released:2008-12-19)

参考文献数

6

被引用文献数

1

---

In the single-phase AC railroad electrification, the voltage unbalance of three-phase electric power system has to be reduced. For this purpose, three-phase power is converted to two-phase power by the Scott-connected transformer, and the electric power is received from a powerful or high-tension source.Recently, regenerative braking has come to be applied to electric rolling-stocks, but occasionally the regenerative brake increases the voltage unbalance in the three-phase electric power source with the ordinary two-phase feeding system. So, in some cases unbalance power compensation may be found more profitable than the Scott-connected transformer.This paper describes a theoretical study and results of a test on a mini-model which uses a scalene Scott-connected transformer, switched reactors and capacitors for the purpose of reducing the voltage unbalance in the three-phase electric power source. By this method, main phase (M) and teaser transformer (T) voltages of scalene Scott-connected transformer secondary side are decided by a single load power factor, and the sum of the capacities of the reactors and the capacitors is equal to the apparent power of single-phase load.For example in SCR switched control of the reactors/capacitors which has four steps in power running and two steps in regenerative braking, the voltage unbalance in the three-phase electric power source can be reduced satisfactorily.

著者

長谷 伸一 持永 芳文 八木 英行 江本 政春

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌. D, 産業応用部門誌 = The transactions of the Institute of Electrical Engineers of Japan. D, A publication of Industry Applications Society (ISSN:09136339)

巻号頁・発行日

vol.118, no.7, pp.930-936, 1998-07

参考文献数

8

被引用文献数

2

---

Takasaki-Nagano section, a part of Hokuriku Shinkansen was opened in October, 1997, just before Nagano Winter Olympics. Hokuriku Shinkansen has been electrified by 30kV a. c. commercial frequency AT feeding system.<br>As for the commercial frequency, Japan is divided into two zones: the western part of Japan is a 60Hz zone and its eastern part is a 50Hz zone. Two different power frequencies exist in Hokuriku Shinkansen which passes power frequency borders between different electric power companies. Therefore, in case of a contact fault between two different power frequencies, a beat-formed large fault current will flow, which should be immediately detected and cut off.<br>At present, a distance relay and an AC &Delta;I type relay are used as protective relays for a feeding circuit of Shinkansen lines. However, it was experimentally made clear that those relays do not operate by a beat-formed fault current which appears in the case of a contact fault between two different power frequencies. For this reason, we have developed and put to practical use a protective relay for a contact fault between two different frequencies, which operates by detecting 55Hz component peculiar to the current caused by the contact fault and also detecting power frequency of an opponent traction substation.<br>They have been installed at a frequency-bordered sectioning post and at traction substations which sandwich the sectioning post.