JP2001354052A - Ac feeder equipment for electric railway - Google Patents

Abstract

PROBLEM TO BE SOLVED: To preclude an antiphase component from flowing into a three-phase AC power system, and reduce a voltage drop caused by a line impedance. SOLUTION: A three-phase AC electric power of the electric power system 1 is converted into DC electric power of a prescribed DC voltage by an ac-to-dc converter 4 to be transmitted to an dc-to-ac inverter 7 provided in a feeder substation 6 via a DC circuit 5. The DC electric power transmitted via the circuit 5 is converted into an AC electric power of a prescribed single phase AC voltage in the inverter 7 to be supplied to an alternating current feeder circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric railway AC feeding device for supplying electric power to an electric railway AC feeding circuit.

[0002]

2. Description of the Related Art Generally, an AC feeder circuit for supplying a driving power supply to an electric car of an electric railway is configured to convert a three-phase alternating current into a single-phase alternating current at a substation to supply electric power to the electric car. In this case, a Scott-connected Scott-connected transformer for obtaining a single-phase AC from a three-phase AC is used in the substation.

FIG. 4 is a configuration diagram of such a conventional AC feeder for an electric railway. The three-phase AC voltage of the power system 1 is converted to a two-phase single-phase AC voltage using a Scott-connected Scott-connected transformer 2 and supplied to an AC feeder circuit 3 for an AC electric railway. In the Scott connection transformer 2, two-phase single-phase AC voltages of a T-seat and an M-seat having a phase difference of 90 (degrees) are obtained. Supply.

When the vehicle loads are balanced at the T- and M-coordinates of a single-phase AC voltage having a phase difference of 90 (degrees), the three-phase AC voltage source is used because the negative phase component is zero. There is no electrical harm to certain power systems. On the other hand, when the vehicle load is unbalanced between the T seat and the M seat, a reverse-phase current flows. Then, a negative-phase component flows into the power system which is a three-phase AC voltage source, which adversely affects a voltage waveform and the like.

[0005] Therefore, at present, the vehicle load is operated in a vehicle operation plan for reducing the unbalance between the T-seat load and the M-seat load, or a static unbalanced power compensator is installed on the three-phase AC voltage source side. In this case, adverse effects due to the generated reverse phase components are removed. In addition, each substation is provided for each fixed section,
The influence of the voltage drop due to the impedance of the line is suppressed.

[0006]

However, since a static type unbalanced power compensator uses a reactor or a capacitor, there is a problem of generation of harmonics in a three-phase AC voltage side circuit and an increase in vehicle load. Problems such as an increase in land due to the expansion of facilities due to the above, and a great influence on other control devices due to the electrical frequency characteristics of the AC feeder circuit.

Further, as a countermeasure against a voltage drop (voltage drop of the AC feeding voltage) due to the impedance of the line, a static var compensator is provided. This also had the major drawback of increasing the vehicle load and securing land for it.

[0008] It is an object of the present invention to provide an AC power feeding device for an electric railway which does not cause a negative-phase component to flow into a three-phase AC power system and has a small voltage drop due to line impedance.

[0009]

According to the first aspect of the present invention, there is provided an AC feeder for an electric railway, comprising: an AC / DC converter for converting three-phase AC power of a power system into DC power of a predetermined DC voltage;
A DC circuit for transmitting the DC power converted by the AC / DC converter to a feeding substation; and And a quadrature conversion device for converting the AC power into AC power.

In the AC feeder for an electric railway according to the first aspect of the present invention, three-phase AC power of a power system is converted into DC power of a predetermined DC voltage by an AC / DC converter, and the DC power is supplied via a DC circuit. Power is transmitted to the orthogonal transformer provided in the substation. In the orthogonal transform device, DC power transmitted via a DC circuit is converted into AC power of a predetermined single-phase AC voltage.

According to a second aspect of the present invention, there is provided an AC feeder for an electric railway, wherein the DC circuit comprises:
DC power is transmitted in parallel to the orthogonal transformers of the plurality of feeder substations.

In the AC feeder for an electric railway according to the second aspect of the present invention, in addition to the operation of the first aspect of the present invention, a DC circuit is provided for the orthogonal transformers of the plurality of feeder substations. Transmit DC power in parallel.

According to a third aspect of the present invention, in the AC feeder for an electric railway according to the first or second aspect of the present invention, the single-phase AC voltage of the AC power converted by the orthogonal transformer is set to a predetermined target. A quadrature control circuit for controlling the quadrature transformation device so as to obtain a value.

According to a third aspect of the present invention, in addition to the operation of the first or second aspect, the quadrature control circuit further comprises a unit for converting the AC power converted by the quadrature converter. The quadrature converter is controlled so that the phase AC voltage becomes a predetermined target value. Thus, the single-phase AC voltage of the AC feeding circuit is maintained at the target value.

According to a fourth aspect of the present invention, in the AC feeder for an electric railway according to any one of the first to third aspects, the DC voltage of the DC power converted by the AC / DC converter is previously determined. An AC / DC control circuit for controlling the AC / DC converter so as to have a predetermined target value is provided.

According to a fourth aspect of the present invention, in the AC feeder for an electric railway, one of the first to third aspects is provided.
In addition to the functions of the invention, the AC / DC control circuit controls the AC / DC converter so that the DC voltage of the DC power converted by the AC / DC converter becomes a predetermined target value. Thereby, the DC voltage of the DC circuit is maintained at the target value.

[0017]

Embodiments of the present invention will be described below. FIG. 1 is a configuration diagram of a railway AC feeder according to a first embodiment of the present invention. The three-phase AC voltage of the power system 1 is input to the AC / DC converter 4 via the transformer 8 and is converted into a DC voltage. The DC voltage is input to the quadrature converter 7 through the DC circuit 5 and converted into a single-phase AC voltage, and power is supplied to the single-phase AC feeding circuit 3 via the transformer 9.

The AC / DC converter 4 converts the three-phase AC voltage of the power system 1 obtained through the transformer 8 into a DC voltage. The DC power converted by the AC / DC converter 4 into a DC voltage is converted into a DC voltage. The electric power is transmitted to the orthogonal transformer 7 provided in the feeder substation 6 via the circuit 5. In the orthogonal transformer 7, the DC voltage of the DC power is converted into a single-phase AC voltage and supplied to the AC feeding circuit 3 via the transformer 9.

That is, the three-phase AC voltage is converted into a DC voltage by the AC / DC converter 4, and the DC voltage is transmitted via the DC circuit 5 to the feeder substation 6 which converts DC into single-phase AC. The DC voltage is converted into a single-phase AC voltage by the quadrature converter 7. As described above, since the DC circuit 5 is interposed between the three-phase AC system and the single-phase AC system, there is an operation of converting the load of the single-phase AC system into a balanced load on the three-phase AC system, and If the load on the AC system goes to the three-phase AC system side,
This is equivalent to connecting a load having the same characteristics as a state in which a three-phase balanced load is connected.

Therefore, the load of the single-phase AC system can be operated as a three-phase balanced load of the three-phase AC system. Power system 1
Even if the feeder substation 6 is provided at a location distant from the power supply, the feeder substation 6 can appropriately convert the single-phase AC voltage of the AC feeder system.

Next, a second embodiment of the present invention will be described. FIG. 2 is a configuration diagram of an AC feeder for an electric railway according to a second embodiment of the present invention. This second embodiment is different from the first embodiment shown in FIG.
Are orthogonal transformers 7a-7 of a plurality of feeder substations 6a-6c.
In this case, DC power is transmitted in parallel to c.

The three-phase AC voltage of the power system 1 is converted into a DC voltage by an AC / DC converter 4 via a transformer 8 and is supplied to each of a plurality of AC feeding substations 6a to 6c via a DC circuit 3. Power is transmitted to the orthogonal transform devices 7a to 7c to be installed.
Each of the orthogonal transformers 7a to 7c converts the voltage into a single-phase AC voltage, which is an AC feeding voltage, and supplies power to the vehicle load via transformers 9a, 9b, and 9c. That is, the orthogonal transformers 7a to 7c of the AC feed substations 6a to 6c are operated corresponding to the respective responsible feed sections. Here, since the orthogonal transformers 6a to 6c are connected in parallel, the operation can be continued by other sound orthogonal transformers 6a to 6c even if one of them is stopped.

According to the second embodiment, of the plurality of orthogonal transformers 6a to 6c for converting a DC voltage into a single-phase AC voltage of an AC feeding system, one of the orthogonal transformers performs a periodic inspection or a failure. Even if the operation is stopped, the single-phase AC voltage is established by the operation of the other orthogonally connected orthogonal transformers, so that the operation with the AC feeding circuit 3 can be continued.

Further, one of a plurality of feeder substations 6a to 6c for converting a voltage from a three-phase AC system into a DC voltage is provided.
Even if one feeder substation fails and cannot be operated, continuous operation is possible because the DC voltage is established in the operation of the other feeder substations connected in parallel with the DC circuit 5 and the power is stabilized. Can be supplied.

Next, a third embodiment of the present invention will be described. FIG. 3 is a configuration diagram of an AC power feeding device for an electric railway according to a third embodiment of the present invention. This third embodiment is different from the first embodiment shown in FIG. 1 in that an orthogonal control circuit 10 for controlling an orthogonal transform device 6 and an AC / DC converter 4
Is provided with an AC / DC control circuit 11 for controlling the power supply. The orthogonal control circuit 10 controls the orthogonal transformer 6 so that the single-phase AC voltage of the AC power converted by the orthogonal transformer 6 becomes a predetermined target value. On the other hand, the AC / DC control circuit 11 controls the AC / DC converter 4 so that the DC voltage of the DC power converted by the AC / DC converter 4 becomes a predetermined target value.

The DC voltage Vdc of the DC circuit 5 is detected by the DC voltage detecting device 12 of the AC / DC control circuit 11 and is set by the DC voltage comparing circuit 13 in advance.
Compared to zero. The DC voltage error ΔVd is input to the DC voltage control circuit 14 and outputs a control command to the AC / DC converter 4 via the control command generation circuit 15 so that the DC voltage error ΔVd disappears.

Now, it is assumed that the DC current increases and decreases due to the increase and decrease of the vehicle load, and DC voltage fluctuation occurs due to the influence of the DC voltage drop due to the resistance of the AC / DC converter 4 and the like. This DC voltage fluctuation corresponds to the DC voltage V detected by the DC voltage detector 12.
It is obtained as an error ΔVd between dc and the DC voltage target value Vd0. Then, since the AC / DC control circuit 11 controls the AC / DC converter 4 so that the DC voltage error ΔVd becomes zero, the DC voltage fluctuation value is appropriately suppressed.

On the other hand, the single-phase DC voltage Va of the AC feeding circuit 3
c is detected by the AC voltage detection device 16 of the orthogonal control circuit 10 and is compared by the AC voltage comparison circuit 17 with a predetermined AC voltage target value Va0. The DC voltage error ΔV
a is input to the AC voltage control circuit 18 and outputs a control command to the orthogonal transformation device 6 via the control command generation circuit 19 so that the AC voltage error ΔVa is eliminated.

The single-phase AC voltage varies depending on the operation mode of the vehicle. When a large number of vehicles are operated and a small number of vehicles are operated, a voltage value is greatly affected by an impedance drop due to a load current applied to a single-phase AC voltage source.

Therefore, the single-phase AC voltage Vac is detected by the AC voltage detector 16 in order to suppress the voltage fluctuation value.
The comparison circuit 19 calculates an error ΔVa between the detected voltage signal Vac and the set voltage target value Va0. The AC voltage error ΔVa is input to the AC voltage control circuit 18 and outputs a control command to the orthogonal transformation device 6 via the control command generation circuit 19 so that the DC voltage error ΔVa is eliminated. Thereby, the fluctuation of the single-phase AC voltage of the AC feeding circuit 3 is suppressed.

Here, the DC voltage is controlled by the AC / DC converter 4.
, The voltage fluctuation of the AC feeding circuit 3 can be suppressed by controlling the DC voltage fluctuation. Further, since the voltage change of the AC feeding circuit 3 is directly controlled to be suppressed by the orthogonal transformation device 6, the voltage change due to the increase and decrease of the load of the AC feeding circuit 3 can be appropriately suppressed.

In the above description, the case where both the orthogonal control circuit 10 for controlling the orthogonal transformer 6 and the AC / DC control circuit 11 for controlling the AC / DC converter 4 are provided, but either one is provided. Is also good.

[0033]

As described above, according to the present invention, a three-phase AC voltage is converted into a DC voltage, and a DC voltage is further converted into a single-phase AC voltage. It becomes a three-phase balanced load characteristic, and a device for countermeasures against the unbalanced load characteristic becomes unnecessary. Further, since power is transmitted using a DC circuit, the voltage drop due to the reactance component is small, which can greatly contribute to high-quality power supply as an electric railway AC feeding device.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a railway AC feeding device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a railway AC feeder according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a railway AC feeder according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional AC feeder for an electric railway.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electric power system, 2 ... Scott connection transformer, 3 ... AC feeder circuit, 4 ... AC / DC converter, 5 ... DC circuit, 6 ... Feeder substation, 7 ... Quadrature converter, 8, 9 ... Transformer, 10: orthogonal control circuit, 11: orthogonal control circuit, 12: DC voltage detection device, 13: DC voltage comparison circuit, 14: DC voltage control circuit, 15: control command generation circuit, 16: AC voltage detection device, 17: AC Voltage comparison circuit, 18 ... AC voltage control circuit, 19 ... Control command generation circuit

Claims (4)

[Claims] 1. An AC / DC converter for converting three-phase AC power of a power system into DC power of a predetermined DC voltage, and a DC circuit for transmitting the DC power converted by the AC / DC converter to a feeder substation. An orthogonal transformer for converting direct-current power transmitted through the direct-current circuit into an alternating-current power of a predetermined single-phase alternating-current voltage provided at the feeder substation. Feeding equipment. 2. The AC feeder for an electric railway according to claim 1, wherein the DC circuit transmits DC power in parallel to the orthogonal transformers of the plurality of feeder substations. . 3. A quadrature control circuit for controlling the quadrature converter so that the single-phase AC voltage of the AC power converted by the quadrature converter becomes a predetermined target value. The AC feeder for an electric railway according to claim 1 or 2. 4. An AC / DC control circuit for controlling the AC / DC converter so that the DC voltage of the DC power converted by the AC / DC converter becomes a predetermined target value. The AC feeder for an electric railway according to claim 3.