JPH05161203A - Arc detecting method for pantograph - Google Patents

Abstract

PURPOSE:To accurately detect existence of arc between a pantograph and a stringing. CONSTITUTION:Potential of a pantograph 2 is detected through a current doubler 8 and delivered to a comparator 12 which then produces a potential signal 13. An-acceleration sensor 3 fixed to the pantograph 2 detects vibrational acceleration of the pantograph 2 which is then fed through an amplifier 4 and a bandpass filter 5 to a comparator 6 in order to produce a contact loss signal 14. An AND gate 15 then produces a logical product of these two signals thus producing an arc signal 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an arc generated between a pantograph and an overhead line in an electric railway.

[0002]

2. Description of the Related Art In conventional electric railways, it is required to reduce the damage to the pantograph and overhead wire due to the arc, electromagnetic noise due to the arc, and noise due to the arc in order to determine whether or not an arc is generated between the overhead wire and the pantograph. Therefore, various detection methods have been tried. For example, monitoring by a television camera or visual inspection, and monitoring of arc generation by a photo detector.

[0003]

However, it is difficult to quantify by a method using a television camera or visual observation. Further, the method of detecting the arc generation by the photodetector is difficult to distinguish from other pantographs, train arcs, and disturbances such as neon signs, and it is difficult to accurately measure the arc generation.

Therefore, the present invention is to make it possible to accurately detect the arc generation state between the pantograph and the overhead line.

[0005]

According to the present invention, a pantograph is provided with an acceleration sensor. This sensor monitors the movement of the pantograph and detects mechanical contact. The potential sensor monitors the potential of the pantograph to detect electrical contact with the overhead line. The occurrence of an arc is known from the logical product of these two signals.

[0006]

According to the present invention constructed as described above, since the movement and the electric potential of the pantograph are detected, it is possible to know the accurate arc generation state.

The principle of the present invention will be described with reference to the timing chart shown in FIG. In the mechanical contact state between the pantograph and the overhead wire, the distance between the pantograph and the overhead wire ((1) in FIG. 2) is zero. When the pantograph vibrates and there is no mechanical contact with the catenary, the distance between the pantograph and the catenary is no longer zero. At this time, the pantograph has a separated line. The presence or absence of this mechanical contact is shown in (2) of FIG. Overhead wire is usually 1500 V DC or 2 AC
Since 0000 volt or 25,000 volt is applied, when the distance between the pantograph and the overhead wire is small, the electrical insulation of the air between the pantograph and the overhead wire is broken, and an arc is generated. At this time, the pantograph and the overhead wire have almost the same potential. As the distance increases, the arc becomes unsustainable, causing a potential difference between the catenary and the pantograph.
That is, it becomes 0 volt. Again, when the distance is reduced, an arc is generated and the pantograph has the same potential as the overhead wire ((3) in FIG. 2). Therefore, the state of arc generation is shown in FIG.
(4), the logical product of (2) and (3) should be taken in order to obtain (4) from (2) and (3).

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the arc detecting method of the present invention will be described with reference to FIG. The electricity used as the power of the electric vehicle is collected from the overhead wire 1 by the pantograph 2. The doubler 8 is a voltage dividing resistor for taking in the voltage applied to the pantograph to the electronic circuit. One end of the doubler 8 is connected to the pantograph 2, and the other end is grounded via the wheel 10 and the track 11. The voltage signal taken in by the doubler is compared with the ground potential by the comparator 12, and the potential signal 13 of the pantograph 2 (see FIG.
(Corresponds to (3)).

The output of the acceleration sensor 3 attached to the pantograph 2 enters the inside of the vehicle body 17 via the signal line 9, is converted into an appropriate electric signal by the amplifier 4, and is transmitted through the bandpass filter 5 by the comparator 6. It is compared with the output of the reference voltage generator 7 and becomes the disconnection signal 14 of the pantograph 2.

The disconnection signal 14 and the potential signal 13 form an arc signal 16 by an AND gate 15.

In the above embodiment, the case of direct current electrification is described, but in the case of alternating current electrification, the doubler 8 may be replaced with a PT and a rectifier.

If an optical fiber accelerometer FA2010 and an acceleration sensor FAP1 manufactured by Takatake Corporation are used as the acceleration sensor, insulation and noise countermeasures are not required, and acceleration measurement can be easily realized.

[0013]

As described above, the arc can be accurately detected by directly monitoring the movement and potential of the pantograph. This is useful for discriminating between a disconnection line and an arc, which was conventionally unclear.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an arc detector according to the present invention.

FIG. 2 is a diagram showing a timing chart of the present invention.

[Explanation of symbols]

 1 Overhead line 2 Pantograph 3 Acceleration sensor 4 Acceleration sensor amplifier 8 Doubler 10 Wheel 11 Track 12 Comparator 15 AND gate 16 Arc signal

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Takeji Inoue 5-7-21 Kitashinagawa, Shinagawa-ku, Tokyo Orix Rentec Co., Ltd. 1-chome Takadaka Manufacturing Co., Ltd. Technology Development Center (72) Inventor Akira Ito 3-chome, Yoshino-cho, Nishibiwajima-cho, Nishibashijima-cho, Nishikasugai-gun, Aichi Prefecture Takadake Manufacturing Co., Ltd. Technical Development Center

Claims (1)

[Claims] 1. An acceleration sensor is attached to a pantograph, and a potential sensor for measuring the potential of the pantograph is provided, and an arc generated between the pantograph and the overhead wire is detected from a logical product of the output of the acceleration sensor and the output of the potential sensor. Arc detection method for pantograph.