JPS5845372B2 - DC electric railway power supply method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply method for electric railways, and more particularly to a power supply method for DC type electric railways that converts AC power into DC power and supplies it as a driving source for electric cars.

Conventionally, DC substations installed at appropriate intervals along railway lines are generally equipped with one or several sets of converters, and the DC output side of each converter is equipped with a dedicated DC breaker (hereinafter referred to as this). (referred to as a DC breaker for converter equipment),
The AC input side is directly connected to a common conductor (hereinafter referred to as negative electrode bus).

In other words, the power supply system including the forward power converter and the DC high-speed circuit breaker is connected in parallel between substations to form the DC power source of the DC substation, while the overhead contact line is generally connected between adjacent substations. The overhead contact lines (also referred to as feeder lines) of the divided power supply lines are divided by line (hereinafter referred to as power supply lines), and each line is equipped with a dedicated DC high-speed breaker (hereinafter referred to as a DC high-speed breaker for power supply). The rails are connected to the respective positive busbars at each substation via rails (referred to as rails), and the rails are connected to the negative busbars at each substation.

That is, generally, the divided overhead contact line is configured with a feeder circuit that supplies power from adjacent substations in parallel, and the group of DC high-speed circuit breakers that make up the feeder circuit are:
It is a mechanical structure with electrodes that cut off current in the air, and most of the substation maintenance effort is spent on cleaning and repairing the electrodes that are consumed when the current is cut off, and each substation is generally connected in parallel through each feeder circuit. Because it is connected to the output bus for the raw power converter in any parallel substation (
The current at the time of a short circuit accident at the DC positive bus (hereinafter referred to as DC positive bus) is:
Since the fault current supplied from the faulty substation is added to the fault current supplied from adjacent substations through each power supply line, there is a risk that damage in the event of a fault may be expanded.

In order to solve the above-mentioned problems, especially the disadvantages of using a DC high-speed circuit breaker, a power supply method as shown in FIG. 1 can be considered.

That is, in FIG. 1, 1.2 and 3 are DC substations, 4 is a three-phase AC transmission line, 5a, 5b and 5c are three-phase AC circuit breakers, 6a+6b and 6c are converter transformers, and 7
Reference numerals a and 7b are raw power converters, and 8 is an inverse power converter.

9a t9b and 9c are converter disconnectors, 10a
~10d are each composed of a sirisk switch 11 and a diode 12 necessary to make the potential difference between sections approximately zero, and are replaced with a static type that has approximately the same function as a well-known DC high-speed breaker. It is something that

14a to 14d are DC disconnectors for power supply, 15 is a DC positive electrode bus for substations, 16 is a negative electrode bus for substations, 17a, 1γ
A2, 17b1, and 11b2 are feeder lines indicating divided train sections, and 180 and 182 are rails.

Figure 1 shows an example in which three substations supply power in parallel to a general power supply circuit where the substation DC positive electrode bus 15 and the original power converter are supplied separately, and substation 2 is equipped with an inverse power converter. This is an example of a case where an electric car is operated on a train track with a predetermined operation of power and regeneration.

In Fig. 1, the electric power for running the electric car is generated by converting the 3-phase AC voltage received from the general commercial frequency 3-phase AC transmission line 4 through AC breakers 5a and sb into transformers 6a and 6b at each substation. converter 7a
, 7b into DC power, and the DC positive electrode bus 15,
Each divided electric wire 17a1, 1γa2, 1γb1, 17
It is supplied to electric cars 19a and 19b by b2.

When the electric car 19b shown between the substations 2 and 3 is in regenerative operation, this regenerative power reaches the DC positive bus bar 15 via the feeder line 17b2 and the disconnector 14c and stopper diode 12c of the substation 2 with regenerative capability. , are converted into three-phase power by the inverse power converter 8, and are connected to the transformer 6c,
The energy is regenerated to the three-phase AC power transmission line 4 via the circuit breaker 5c.

According to the conventional DC electric railway power supply method shown in FIG. 1, instead of the DC high-speed breaker, a static DC switch is used, which is formed by connecting a SIRISK switch 11 and a regenerative stopper diode 12 in antiparallel. Since 10a to 10d are used, the maintenance of the feeding equipment is simplified, and if a short circuit occurs at any point on the feeding line for some reason, the fault point can be completely removed from a healthy system. The required time is much shorter than when using a DC high-speed breaker, which has the advantage of preventing the spread of an accident.

At the same time, the potential difference between the put sections intervening between each substation is due to the action of the static DC switch group, and for example, only the sum of the si risk during conduction and the forward voltage drop of the stopper diode appears. For the most part, the potential difference between sections can be considered to be a negligible value, and in this respect it can be said to be an ideal DC feeding system configuration.

However, on the other hand, for example, the higher the capacity of the thyrisk element that constitutes a static switch, the more expensive it becomes. There are very strict restrictions, and the structure of the static switch itself is inevitably complicated and large, making it extremely uneconomical.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to transmit regenerative power to an AC power transmission line when an electric vehicle is in a regenerative operation state in addition to a DC positive bus in at least one substation. By installing a separate regeneration bus on the side and using only a unidirectional electric valve, such as a diode, in place of the DC switch found in conventional power supply systems, equipment can be simplified and investments can be rationalized. That's true.

A power supply method for a DC electric railway according to an embodiment of the present invention will be described below.

FIG. 2 shows an example of the configuration of the power supply circuit according to this embodiment, and the same or equivalent parts as those in FIG. 1 are designated by the same reference numerals.

In FIG. 2, 1a, 2a, and 3a are substations, respectively, and each of these substations 1a, 2a
And in 3a, when the DC positive electrode bus 15, the electric wire 1γa1
, 1γa2 t 1 yblt 17b2, there are stopper diodes 12a to 12d for direct current connecting to the DC disconnector 14.
The feeder line 1γal is connected via lines a to 14d and located in each substation section.

17a2, 1γb1. A put section 21 is interposed between each tlb2.

In addition, in the substation 2a, a regenerative bus 20 is provided in addition to the DC positive bus 15, and as shown in the figure, the regenerative bus 20 has the same number of arms as the number of arms (feeding lines) connected under the DC positive bus 15. Stopper diodes 22a to 22d are inserted into each arm as shown in the figure, and the cathode sides of these diodes are connected to the common regeneration bus 20, and the anode sides of each of the diodes 22a to 22d are connected to the common regeneration bus 20. The feeder line 17at is passed through each disconnector 14a to 14d.
t 17a2, 17bt.

11b2.

In the power supply circuit configured as described above, electric power for driving the electric car is supplied through the same route as in the case of FIG. 1, but in this embodiment, for example, the electric car 19 The regenerative power is transferred from the feeder line 11a1 to the substation 2.
The power reaches the regeneration bus 20 via the disconnector 14a of a and the diode 22d connected to the regeneration bus 20 side, and is input from the regeneration bus 20 to the reverse power converter 7c through the reactor 23 and the DC disconnector 9c.

The AC output voltage of the inverter 7c is transformed by the transformer 6c, and the transformed power is regenerated to the AC power transmission line 4 through the breaker 5c.

Further, in the power supply circuit configured as described above, the voltage across the dead section 21 of the power station 2a can always be made approximately zero regardless of the operating state of the electric vehicle, such as power running, regeneration, or stoppage.

That is, as an example of an operating condition in which the largest potential difference occurs in the feeder line 11a1 section located in front of the dead section 21 of the substation 2a, as shown in FIG. A case where there is a vehicle 19a inside the substation 3a and a vehicle 19c powering in the direction of the substation 3a at the same time will be described with reference to FIG.

In FIG. 3, G, 19a indicates a vehicle in regenerative operation with a constant regenerative current Ig, M, 19c indicates a vehicle powering (progressing) from the substation 2a to the substation 3a with a constant powering current Im, and 1
1 is a regenerative vehicle G from substation 2a.

The distance to 19a, X is from substation 2a to power vehicle M, 1
9c, and 12 is the distance between substations 2a and 3a.

Here, the voltage and current distributions shown in FIG. 3 can be equivalently represented by FIG. 4.

In addition, the forward converters 7a and 7b of substations 1a and 3a always change the feeding voltage to 15% up to the rated or 120% load.
It is possible to control the voltage at a constant voltage of 00 (V).

Furthermore, in the substation 2a, the current id + 12 of the stopper diodes 22a to 22d connected to the regenerative bus 20
The magnitude of 2b, 122c ric always monitors the polarity.

Based on this point, in the equivalent circuit diagram of FIG. 4, the stopper diode 12 is
a is reverse biased and the current ia flowing through the diodes 12 and 1 is zero, and since the vehicle 19c is in the driving mode, the substation 2a
The inter-terminal voltage e'i of the inverse power converter 7c and the inter-terminal voltage e's 1 of the original power converter γa are respectively e'i =
1500 (V), e's] = 1500 (V), and the adjacent substation 3a is also always e's2.
= 1500 (V).

Therefore, the no-load voltage ei of the reverse power converter IC during regenerative operation increases due to the internal voltage drop due to the regenerative current Ig, but in order to maintain this at 1500 (V), 1
500 (V) by the increase due to internal voltage drop.

In addition, the no-load voltage es of the raw power converters 7a and 7b is set to 1500 (V) by subtracting the internal voltage drop due to the current shared by the substation, so it is higher than 1500 (V) by the internal voltage drop. be limited to.

Of course, the raw power converter 7a tlb of the substation 3a
Since the substations 2a and 3a are controlled in the same manner as the raw power converter of the substation 2a, the substations 2a and 3a operate in parallel with the same feeding voltage for the vehicle load, and the following equations hold true.

(However, rt indicates the resistance value per unit length of the feeder wire.) Now, regenerative current Ig = 2800 (A), current lm =
2100 (A), internal resistance of the raw power converter rSO, 0
03375 (Q), internal resistance ri of the inverse power converter device =
0.0675 (IQ), contact wire resistance rt=0.026
7 (Ω/km), the substation interval is 12-2.65 (km), and the raw power converter 7atγb of the substation 2a and the reverse power conversion when the vehicle M moves from the substation 2a to the substation 3a. Voltage of device γC, raw power converter 7a of substation 3a
Figure 5 shows the voltage of yγb and the shared current of substations 2a and 3a.

That is, INV voltage (ei) of substation 2a ~ 1311 (V) CNV voltage (esl) of substation 2a ~ 1571 ~ 1500
(V), CNV voltage of substation 3a (es2) = 15
If adjusted within the range of 71-1500 (V), the raw power converter and reverse power converter 1c of the adjacent substation 1 a y 3a, which is about to flow into the reverse power converter 1c during regenerative operation, will be installed. Raw power converter γa of substation 2a
The circulating current from the dead section 21 is suppressed, and not only can the potentials of both electric circuits sandwiching the dead section 21 be maintained at the same potential, but also the regenerative power from the regenerative vehicle can be effectively regenerated to the commercial frequency power supply bus side.

Next, a case where a short circuit accident occurs between the feeder line and the rail will be explained with reference to the embodiment shown in FIG.

If a short-circuit accident occurs between the feeder line 11a1 and the rail 187 as shown at 25 at the position of the electric car 19a within the section of the current electric wire 17a1, for example, each substation 1a will be affected by the operation of an overcurrent detector (not shown).

A gate shift command was given to the raw power converters γa and γb of 2a, and the gates were narrowed down to the minimum position to stop the power supply to each substation 1a and 2a, and the current in the power supply system became zero. Disconnector 1 is activated at substation 2a after detecting the problem.
4a, in the substation 1a, 14d is opened by the opening command, the substation 1a+23 is completely stopped, and the feeding system in the faulty section is disconnected from the healthy bus.

Since the feeding system in the faulty section is disconnected after the short-circuit current is sufficiently limited in this way, the expansion of the fault can be prevented and the specified short-circuit protection can be reliably performed.

Next, there is a regenerative vehicle, and the other feeder line 17aI of the vehicle
We will discuss the protective operation in the event of a short circuit accident at T.

For example, when the electric car 19b under the feeder wire 1γb2 in Figure 2 is in regenerative operation, the electric car 19a under the other feeder wire 11a1
If this is the case, an accident will occur at the point 25 due to a leak in the insulator supporting the feeder wire 17a1 that supplies power to the electric car 19a, and the accident section will be immediately removed. The fault point must be isolated from the healthy busbar, but in such a case, the following predetermined actions are performed in this application.

That is, each raw power converter γa of substations 1a and 2a
, γb are gate-shifted to reduce the si-risk phase to the minimum position, and the power supply to the substations 1a and 2a is stopped, as in the conventional example, but at the same time, the operation of the inverse power converter 1c is continue.

For example, as a loop in which the regenerative power of the electric car 19b, which is in a regenerative state with the substations 1a and 2a already in a stopped state, is regenerated, the loop is as follows: vehicle 19b → feeder line 17b2 → substation 2a
This is a loop of disconnector 14c → diode 22b → regeneration bus 20 → reactor 23 → disconnector 9c → reverse power converter 7c → transformer 6c → breaker 5c → 3-phase transmission line 4, but in this application it is a loop of 3-phase power transmission line 4. Place 2. The positive electrode bus 15 and the regenerative bus 20 of a are separated as shown in the figure,
Furthermore, since the gates of the raw power converters 7a and 7b of the substations 1a and 2a are sufficiently narrowed down to the minimum value as described above and the substations are in a stopped state, the regenerative power flowing through the loop is transferred to the fault point in Figure 2. It never flows into 25.

Therefore, according to the present application, the disconnectors 14d and 14c inserted into the main circuits of the substations 1a and 2a are placed in the substation 1a at approximately the same time when the gate phase of each raw power converter is reduced to the minimum. The disconnect switch 14d at the substation 2a can be opened, and the disconnect switch 14a at the substation 2a can be opened, and the section of the feeder line 17a1 at the fault point 25 can be quickly disconnected.

As described above, according to the DC electric railway power supply method according to the embodiment of the present invention, the following various advantages can be obtained.

That is, (a) the line bus 20 is provided separately in the substation 2a, and the stopper diodes 12a to 12d are provided in each substation 1a to 3a, and the regenerative power is transmitted to the stopper diodes 22a to 22d under the regenerative bus 20.
Since regeneration occurs through the power supply, there is no need for DC high-speed circuit breakers or expensive thyristor switches, which require significant maintenance effort and power supply, making it extremely economical.

(→Feeding equipment will be simplified.

()→In the event of a fault, there is no inflow current from the adjacent substation, so the fault current value itself is lower than in the past, and the capacity of the circuit breaker and diode group can be reduced.

(→If there is a vehicle in regenerative operation, a potential difference will occur between the dead sections of the substation 2a, but the raw power converter 7a,
By controlling 7b and the inverse power converter IC,
Potential difference between sections can be eliminated.

(In the event of a power line accident, both substations sandwiching the accident point will instantly
100 to 150 m5), but even when the power supply is stopped, regeneration is possible through the inverse power converter, so energy can be used effectively.

In addition, in the above-mentioned embodiment, the circuit breakers 5a, 5b and the transformer 5a
, 6b are used to construct the conversion equipment, however, in the present invention, these may be of any type.

As explained above, the present invention provides power supply for a DC electric railway in which a plurality of substations are installed in parallel along the rails on which electric cars run, converting AC power into DC power as a power source for the electric cars. In the equipment, at least one of the plurality of substations is provided with a regenerative bus in addition to the DC positive bus, and the positive bus and electric wire of each substation are connected so that the positive side is on the positive bus side. A stopper diode is connected to the supplied stopper diode via a disconnector to supply power to the electric vehicle, and a stopper diode is connected between the electric wires at the time of the regenerative bus so that the positive electrode side is on the feeder line side. Since the regenerated power from the electric car is regenerated to the AC power source side, the power feeding equipment can be simplified and a high-performance power feeding method can be obtained.

[Brief explanation of drawings]

Figure 1 is an electrical wiring diagram showing a conventional power supply method, Figure 2 is an electrical wiring diagram showing a power supply method according to an embodiment of the present invention, and Figure 3 is an electrical wiring diagram showing a power supply method according to an embodiment of the present invention.
4 are electric circuit diagrams for explaining the operation of the power feeding method of FIG. 2, and FIG. 5 is a characteristic diagram for explaining the operation of the power feeding method of the present invention. 1a-3a...DC substation, 4...3
Phase AC transmission line, 5a-5c...:...3-phase AC breaker, 6a-6c...3-phase transformer, 7a + γ
b... Raw power converter, γC... Reverse power converter, 9a to 9c... DC disconnector, 12
a to 12d...stopper diode for power running, 1
4a to 14d...DC disconnector, 15...
・DC positive electrode bus, 16... Negative electrode bus, 1γal
117a2r 17b1.17b2--Feeder wire, 18. , 18□・・・Rail, 19...
...Electric car, 20...Regeneration bus, 21...
...Disconnector, 22a to 22d...Regeneration stopper diode.

Claims (1)

[Claims] 1. One or more forward power conversion devices that forward convert AC power input from a commercial frequency power supply bus into DC power;
A DC positive busbar provided on the DC output side of this device, a disconnector and a line diode (or a thyristor switch without arc extinguishing ability) connected under this busbar and separated for each feeder line. An anode is connected to each bridge point between a power diode (or a silisk switch without arc extinguishing ability) and a disconnector in these DC circuits, and a cathode is connected to the regeneration bus side. A plurality of power return loops including a group of regeneration diodes to be connected, and a reverse power conversion device that converts the regeneration capability derived from these plurality of power return loops back into AC power and regenerates it to the commercial frequency power supply bus side. A first substation installed, one or more forward power conversion devices adjacent to the first substation that convert AC power input from a commercial frequency power supply bus into DC power, and a DC output of this device. A plurality of DC positive electrode busbars provided on the side, and disconnectors and power diodes (or si-risk switches without arc extinguishing capability) connected under this busbar and divided correspondingly to each feeder line. A second substation equipped with a DC power line, and a desired DC power is supplied to each feeder line through a group of diodes for the lines of these first and second substations. Electric railway power supply method.