JPS5963233A - Direct current feeding system for electric car - Google Patents

Abstract

PURPOSE:To reduce a leakage current without providing many feeders, by connecting each end of one or more thyristor apparatuses to each of rails that have been divided by insulating sections and each of the other ends to a common feeder. CONSTITUTION:Rails 3a1-3d2 have been divided by the insulating sections 5a-5c, the intermediate points of the rails are connected respectively to the thyristor apparatuses 6a-6d, and the other ends of the thyristor apparatuses are connected via the common feeder 7 to substations 1a, 1b. If an electric car 4 is on the side of the section 5b away from the intermediate between the sections 5a 5b, the electric currents from the substations 1a, 1b are fed respectively via electric-car lines 2b, 2c, the electric current from the electric car 4 returns via the rail 3b2 and the thyristor apparatuses 6b to the substations 1a, 1b, and the electric current is prevented from flowing into rails other than the rails 3b1, 3b2 by the other thyristor apparatuses. Thus without providing many feeders, a leakage current can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a DC feeding system for supplying DC power to electric trains.

In conventional electric railways, the running rail is used as the return path for the main current for operation, and because the insulation of the sleepers and trackbed is extremely imperfect, the insulation resistance between the rail and the ground is low even though the conductor resistance of the rail □ is low. is greatly influenced by the weather; in rainy weather, especially during storms, the insulation resistance drops significantly and the leakage current from the rail to the ground increases significantly. Leakage current from the rails is determined by two factors: train load current, return resistance, and substation spacing.
Squared.

and inversely proportional to leakage resistance. Therefore, in principle, the leakage current can be reduced by reducing the former and increasing the latter. The size of the leakage current is from several tens of OA to 1
It may even reach 00OA.

FIGS. 1 and 2 show conventional feeding configurations. In the diagram, (1) is a substation, (2) is an overhead contact line, and (3) is a rail.

(4) shows a train. In FIG. 1(a), it is assumed that the electric train (4) has an operating current Ip at a position l away from the substation (1). In this case, the ground potential of the rail (3) near the train (4) is positive, and the ground potential of the rail (3) near the substation (1) is negative. In the vicinity of the train (4), current leaks from the rail (3) to the ground, and in the vicinity of the substation (1), the current that leaks to the ground returns to the rail (3). Figure 1(b)-(d)
) shows the relationship between each current IL, IN, In and the position at that time.

This leakage current is commonly known to occur in rails, their accessories, cables, and water pipes.

In addition to electrolytic corrosion of underground metal objects such as gas pipes, there are also problems with induction disturbances to nine communication lines and disturbances to geomagnetic observatories.

As stipulated in Article 257 of the Electrical Equipment Technical Standards regarding ground currents, it is necessary to ensure that they do not interfere with the observation of geomagnetic observatories or earth drowsiness observatories.

As shown in Figure 2, the DC m circuit of conventional DC electric railways carries out parallel feeding, and is electrically positive.

It is also connected in parallel with the negative electrode. Therefore, the leakage current leaking from the rail to the ground spreads over a wide range, and the magnetic force generated by the leakage current affects the earth's magnetism in the natural world. The magnetic field that spreads from electric railways is calculated by the Biot-Savart law, but since the current directions of the overhead contact line and the rail are opposite, most of the magnetic fields cancel each other out in the distance, and the difference current and leakage current affect the earth's magnetism. Affect. The differential current produces a vertical component of the magnetic field on the earth's surface, and the component of the leakage current that goes underground produces a horizontal component of the magnetic field.

Possible ways to suppress leakage current from railway substations include reducing return resistance, shortening the distance between substations, increasing the insulation resistance between the rails and the ground, or adopting a fourth rail system or AC electrification system.

For new line plans or telegraph sections, it is possible to adopt the fourth rail system, and for new line plans, it is possible to increase the insulation resistance between the rail and the ground.

For transportation networks with large train intervals and fixed speeds between stations, it is conceivable to adopt an AC electrification system. Conventional DC electrification will be used for electrification of transportation networks in urban areas, suburbs, etc., extensions of DC sections, or sections where DC trains are installed.

In order to suppress leakage current and reduce return resistance, it is theoretically possible to install a feeder line alongside the rail, but the size of the attached feeder line would be very large, making it uneconomical, and the spacing between substations would be too large. Leakage current can be suppressed to some extent by shortening the current, but in cases where the train load current is large or the train operation intervals are short, the ground current will be scattered over a wide area because the rails are connected over the entire line, and this will not be very effective. There was a problem that could not be solved.

This invention was made in order to eliminate the drawbacks of the conventional ones as described in t.In addition to providing an insulating section on the rail, one end of one or more sets of thyristor devices is connected to each rail divided by the insulating section. The object of the present invention is to provide a DC feeding system that can suppress leakage current by connecting the other end of each thyristor device to a common feeding line.

An embodiment of the present invention is shown in FIG. 8 below. In the figure (
1) is a substation, (2) is a contact line, (3) is a rail, (4
) is the train, (5) is the rail insulation section, (Iristor device since June, and (7) is the feeder line.

The effects of the present invention in such a configuration will be explained below. The figure shows an example in which the anode of the Cyrisk device is connected to the center of a rail divided by rail insulation sections. Connect the anode of the thyristor device (6) to the center of each rail (3), and connect each thyristor device (6a) (6b
Connect the cathodes to common feeder wires (7a) (7b) (#c
Connect to 7d ) (7e ) (7f > Crg ).

Connect the connection point of the feeder line (7b
is connected to the negative terminal of. In the figure, electric current for the electric train (4) is supplied from the substation (1a) through the overhead contact line (2b), and from the substation (2a) through the overhead contact line (2C). At this time, the thyristor device (6a X6c Therefore, the current passing through the train is the rail (ab tXsb z
) and passes through the thyristor device (6b) to the electric wire (7C
) to substation (1a), feeder line (7dX7eX7f)
From there, I headed back to the substation (2a). On the other hand, l! ! When there are no cars on the rails (8a) (8b) (8C), the electric wire (
7) connected to the Cyrisk device (6g) (6c) (
ad) is in a blocking state, so the current that has flowed into the single-carrier wire (7) cannot flow into the section where no train is present. In addition, the current leaking from the rail (8b1) (8bρ also flows through the rail (8b1) (8bρ).
ga) (8cX8d) cannot flow. Therefore, the train (4
)t, the leakage current from the rail is caused by the rail (8
bt) (8bz) only. As a result, the leakage current can be made smaller than in the conventional system, and the earth current does not spread over a wide area, but only flows within the rail (8b), which has the advantage of greatly reducing the influence of the magnetic field on the earth's magnetism.

As is clear from the following, according to the present invention.

Leakage current and ground current are more effectively suppressed than conventional methods. This is achieved by providing an insulating section on the rail, connecting one end of the thyristor device to each rail divided by the insulating section, and connecting the other end of each thyristor device to a common feeder line.

In addition, the present invention is not limited to the embodiment shown in the drawings.1 For example, the figure shows a case where the overhead contact line is positive and the rail is negative, but when the overhead contact line is negative and the rail is positive. It goes without saying that the same effect can be obtained and that the invention can be modified and implemented as appropriate without changing the gist.

To further increase the effect, the leakage current can be further suppressed by installing thyristor devices at both ends of the divided rail instead of in the center, as shown in Figure 4. Furthermore, increasing the number of thyristor devices installed It is a matter of course that the invention is within a scope that can be practiced without changing the gist of the invention.

As described above, according to the present invention, a DC feeding system is constructed in which a silisk device is provided for each rail divided by a rail insulation section, and the other end is connected to a common feeding line, thereby economically suppressing leakage current. There is an effect that can be done.

According to the conventional system, it was necessary to shorten the distance between substations or add a large number of feeder lines.9 However, according to the present invention, the distance between substations is the same as that of the conventional system, and leakage current can be reduced without adding a large number of wires. can be reduced.

[Brief explanation of drawings]

Figure 1 is a diagram showing the principle of leakage current generation, Figure 2 is a diagram showing a conventional DC feeding system, Figure @8 is a diagram showing a DC feeding system according to an embodiment of the present invention, and Figure 4 is a diagram showing the present invention. It is a figure showing other examples of. In the diagram, (1)...substation, (2)...telephone line, (3)...rail. (4)...[car, (5)...rail insulation section, (6)...thyristor device, (7)...feeder line. Note that the same line numbers in Figure 1 indicate the same or corresponding parts. Figure 4 Continued from page 1 ■Applicant Mitsubishi Electric Corporation 2-2-3-21 Marunouchi, Chiyoda-ku, Tokyo

Claims (1)

[Claims] In a DC feeding system that supplies DC power to trains, an insulated section is installed on the rail, and one end of one or more sets of thyrisk devices is connected to each rail divided by the insulated section, and the other end of each thyrisk device is connected to a common one. A DC feeding system for a Lumi car, which is characterized by being connected to a feeding power line.