JPS61278435A - Direct current feeding system for tramcar - Google Patents

Abstract

PURPOSE:To restrain leak economically and effectively by configurating a device in such a way that insulating sections are provided in both a tramcar feeder and a rail allowing them to be divided into the plural number of zones which are electrically independent, and the primary winding of a transformer at each of direct current feeding installations is made to be common. CONSTITUTION:Each of insulating sections 5a-5c, and 6a-6c are provided for each of tramcar feeders 2a-2d, and for each of rails 3a-3d respectively making both each of tramcar feeders 2a-2d and each of rails 3a-3d an electrically independent zone. Each of direct current feeding installations (substation) 1a-1c are provided for each of the said zone so as to feed direct current to each zone. These substations 1a-1c are provided with transducers 1a1, 1a2-1c1, and 1c2 including transformers, the primary winding of which is made to be common. In this configuration, tramcar load current for tramcars 4a and 4b leaks from the rail to ground. However, as there is no way for leak to return to the transducers (shown as 1a1 and 1b1, and 1b2 and 1c1 in the figure) located in the zone where the tramcar runs. This can prevents leak from spreading extensively.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a direct current feeding system for electric trains, particularly a contact line,
It concerns the system configuration of rails and substations.

[Conventional technology]

FIG. 2 and FIG.
This figure shows the configuration of a conventional DC feeding system for electric trains as shown in No. In both figures, (1) is a substation that is DC feeding equipment, (2) is an overhead contact line, (3) is a rail, (ri) in Figure 2 and (''a) + (''b) in Figure 3. each indicates a train. In Figure 2(a), the substation (
1) Train (Hiro) at a distance D km away
Suppose that a person is working as an electrician. In this case, the train (
The ground potential of the rail (3) near the substation (1) becomes a positive potential, and the ground potential of the rail (3) near the substation (1) becomes a negative potential. Therefore, a train (electrician) flows on the rail (3) towards the substation (1), and a train (l) flows on the rail (3).
Electricity leaks to the ground from the rail (3) near where I) exists [
, flows, and the leakage current that leaked into the ground near the substation (1) returns to the rail (3). Figure 1 (b) to (d)
) are the currents at that time, namely the leakage current 5 between the rail (3) and the ground, the redundant current 8 flowing through the rail (3), the current flowing through the ground, the substation (1) and the electric train (river). ) shows the relationship with the position.

In conventional electric railways, the overhead contact line (2) is used as the outgoing route for the operating current, and the running rail (3) is used as the return route for the main operating current. Due to the imperfection, the insulation resistance between the rail (3) and the ground is greatly affected by the weather, even though the conductor resistance of the rail (3) is low, and the insulation resistance decreases significantly in rainy weather, especially in stormy conditions. However, the leakage current from the rail (3) to the ground increases significantly.

The leakage current from this rail (3) is the train load current,
Return resistance is proportional to the square of the substation spacing and inversely proportional to leakage resistance. Therefore, in principle, to reduce the leakage current, the former should be reduced and the latter should be increased. The size of the leakage current can range from several 100K to 100A.

[Problem that the invention seeks to solve]

The effect of this leakage current is generally known as galvanic corrosion of underground metal objects such as rails, their accessories, cables, water pipes, gas pipes, etc. There are problems such as induction disturbances or disturbances to geomagnetic observatories. Also, regarding ground current, please refer to the Electrical Equipment Technical Standards No. 1! As stipulated in Article R7, it is necessary to ensure that there is no obstruction to observation of geomagnetic observatories or geoelectrical observatories.

The conventional DC feeding circuit of a DC electric railway uses parallel feeding as shown in Figure 3, and is electrically positive.

It is also connected in parallel with the negative electrode. Therefore, the leakage current leaking from the rail (3) to the ground has a wide range K, and the magnetic force generated by the leakage current has a large influence on the earth's magnetism in the natural world. The magnetic field that spreads from an electric railway is calculated by the Biot-Savart law, but since the current direction of the overhead contact line (C) and the current direction of the rail (3) are opposite, most of the magnetic fields cancel each other out in the distance. , the magnetic field due to the current difference between the current in the overhead contact line (C) and the current in the rail (3) and the leakage current between the rail (3) and the earth influences the earth's magnetism. This differential current produces a vertical component of the magnetic field on the earth's surface, and a component of the leakage current that goes underground produces a horizontal component of the magnetic field.

To suppress leakage current from the substation (1), reduce the return resistance, shorten the distance between substations, increase the insulation resistance between the rail (3) and the ground, or adopt the second rail system or AC electrification system. is possible.

If it is a new line plan or an electrified section, it is possible to adopt the first rail system, and if it is a new line plan, it is possible to increase the insulation resistance between the rail (3) and the main rail. If the transportation network has large distances between stations, fixed speeds, etc., then AC electrification can be considered. On the other hand, electrification of transportation networks in the suburbs of cities, suburbs, etc., extension of DC sections, or sections where DC trains are installed will be electrified with DC.

In principle, it would be possible to suppress leakage current and reduce return resistance by installing a feeder line alongside the rail, but the size of the attached feeder line would be very large, making it uneconomical, and it would be difficult to install a feeder line at a substation. Leakage current can be suppressed to some extent by shortening the spacing, but in cases where the train load current is large or the running intervals are short, the ground current will be spread over a wide area because the rails are connected across the entire line. There is a problem in that a mild effect cannot be obtained.

This invention was made to solve these problems, and it provides a direct current supply to trains that economically and effectively suppresses leakage current without causing secondary failures. The purpose is to provide electric power system.

[Means for solving problems]

In the direct current feeding system for trains according to the present invention, insulating sections are provided on the contact line and the rails so that both the contact line and the rails are made into a plurality of electrically independent sections, and the contact line and the rails are divided by these insulating sections. Power is installed for each section, and the primary winding of the transformer of the DC feeding equipment that supplies direct current to each section is shared.

[Effect]

In this invention, an insulating section is provided on the overhead contact line and the rail to divide it into a plurality of sections, and the primary winding of a transformer in a DC feeding facility supplies direct current to each section divided by these insulating sections. This makes it possible to make the DC side electrically independent in each section divided by the insulation section, and because the primary side of the DC feeding equipment is shared, it is possible to reduce the potential difference between each section. Can be made smaller.

〔Example〕

An embodiment of the present invention is shown in FIG. 1 below. In the same figure, (ia”)z('h), (/C) are DC feeding equipment substations, (/at), (tako), (/bl
), (/ba), (/ct).

(/CJ) is a conversion device including a transformer with a shared seventh side, (2a), (Jb), (c), (2d)
are electric train lines, (3a) and (3b).

(3c), (, yci) are rails, (axis), (da b) are trains, (yo a).

(tb) and (jc) are contact wire insulating sections that electrically insulate each contact wire (2a) to (2d). (
xa).

(6b), (I, c) Hallail insulation sections electrically insulate each rail (3a) to (3d).

A contact line insulation section (t
a), (jb), (sc) and rail insulating sections (Aa), (Ab), (Ac), so for example, the train load current of trains (4'a), (tIb) is Although it leaks into the ground from yb) and (3c), the conversion device (/al), (Ibc and (/ba) in the section where trains (4'a) and (4th) exist)
Since the leakage current returns only to , (/C/), it is possible to prevent the leakage current from spreading over a wide range, and the leakage current flowing through the ground is also reduced. For example, the train load of the train (Qa) [flow leaks from the rail (3b) to the ground, and the rail (3a) in the section where there is no train → conversion device (/al) →
There is no circuit formed that goes from the overhead contact line (1) in the section where the train is present to the conversion device (Ib) via the overhead contact line (core a), so there is less chance of the morning sun spreading the leakage current.
Since the section where the rail is electrically connected to the ground is shortened, the leakage resistance to the ground is also large (the leakage resistance to the ground is because multiple leakage resistances are connected in parallel), which reduces the leakage current. be able to. Earth currents are generated in sections separated by insulating sections and disappear within those sections, which has the advantage of minimizing the influence of magnetic fields on geomagnetism.

In addition, since the power supply within the substations (TA) to (/C) shared the transformer/secondary winding, the contact line insulation section (JA)
~ (5c), rail insulation section (6a) ~ (6c)
The overhead contact lines (core a) to (cod), rails (3a) divided by
) to (3d), the potential difference between adjacent sections can be minimized. Especially in this case, if the electric power is supplied so that the potential difference between the sections (4ta) and (1Ib) is minimized, the potential difference between adjacent sections can be minimized.
is the insulation section (Qa)~(!rc), (6a)~(
6c) The generation of arcs when passing through can be suppressed.

It goes without saying that the present invention is not limited to the embodiments described above and shown in the drawings, but can be practiced with appropriate modifications within the scope of the invention.

〔Effect of the invention〕

As described above, according to the present invention, an insulating section is provided on the overhead contact line and the rail to divide the overhead contact line and the rail into a plurality of electrically independent sections, and an insulating section is installed in each of these sections to provide direct current to each section. / of the transformer of the DC feeding equipment that supplies
Since the secondary winding can be shared to a minimum, the generation of arcs when the electric car passes through the insulating section can be suppressed, and damage to the pantograph can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the DC feeding system for trains according to the present invention, Fig. 2 is a diagram showing the principle of leakage current generation, and Fig. 3 is a diagram showing the conventional DC feeding system for trains. FIG. In the figure, (ta), (Ib), (/C) are DC feeding equipment substations, (/az), (ta2)
+ (/bz) + (Ib2), (/Ct') +
(/CJ) is a conversion device, (core a) + (2b)
, (c), (2d) are tram lines, (ja), (jb),
(jc), (Jd) are rails, (daa), (4'b
) is a train, (ja), (jb), (jc) are contact line insulation sections, and (xa), (Ab), (Ac) are rail insulation sections. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In a device that supplies direct current from DC feeding equipment to electric trains via overhead contact lines and rails, an insulating section is provided on the overhead contact lines and rails so that each of the overhead contact lines and rails has a plurality of electrically independent sections; A DC feeding system for a train, characterized in that the primary winding of the transformer of the DC feeding equipment that supplies DC to each of these sections is shared.