JP2022148181A - Three-phase power conversion system for electric railway - Google Patents

Abstract

To provide a three-phase power conversion system for an electric railway capable of appropriately protecting the system while suppressing an influence on a sound feeding circuit when a temporary heavy current is generated even when operated in conjunction with a three-phase railway power source.SOLUTION: A three-phase power conversion system for an electric railway includes a control device for controlling a conversion operation from DC power to three-phase AC power by an inverter. At normal time when the current flowing through a plurality of feeding circuits is determined to be lower than a predetermined value, the control device controls the operation of the inverter so that predetermined effective current and reactive current are supplied to the plurality of feeding circuits by setting a predetermined current command value on the output of the inverter. At the time of large current generation when the current flowing through any one of the feeding circuits is determined to be a predetermined value or higher, the control device controls the operation of the inverter so that the current output from the inverter becomes low by lowering the current command value to a lower level than at normal time.SELECTED DRAWING: Figure 2

Description

Embodiments of the present invention relate to a three-phase power conversion system for electric railways.

BACKGROUND ART A three-phase power conversion system for electric railways, which is operated in conjunction with a three-phase railway power source such as a rotating machine, is known. An electric railway three-phase power conversion system supplies three-phase AC power to a feeding substation together with a three-phase railway power supply. The feeder substation converts the three-phase AC power supplied from the three-phase railway power source and the three-phase power conversion system for electric railways into a plurality of single-phase AC powers, and converts the plurality of single-phase AC powers into a plurality of feeders. supply the circuit (railway load). Thereby, electric power can be supplied to the train and the train can be run.

A three-phase power conversion system for electric railways has a plurality of semiconductor switching elements. A three-phase power conversion system for electric railways converts three-phase AC power supplied from power systems such as electric power companies into three-phase AC power compatible with feeding circuits by switching multiple semiconductor switching elements. of three-phase AC power is supplied to the feeding substation.

In such a three-phase power conversion system for electric railways, there is a possibility that a transient large current will flow through the system due to a short circuit or ground fault in the feeder circuit. A three-phase railway power supply such as a rotating machine can continue to operate because it has a certain supply capacity for a large transient current. On the other hand, it is difficult for a three-phase power conversion system for electric railways, which is composed of a plurality of semiconductor switching elements, to bear a transient large current. For this reason, in a three-phase power conversion system for electric railways, when a transient large current occurs, the operation is stopped, thereby suppressing damage to a plurality of semiconductor switching elements.

However, if the operation of the three-phase power conversion system for electric railways is stopped in response to the occurrence of a transient large current, one of the feeding circuits that supplies single-phase AC power from the feeding substation Also, the output of the three-phase power conversion system for electric railways stops even for healthy feeder circuits other than feeder circuits in which a short circuit or ground fault has occurred. As a result, power is supplied to a healthy feeding circuit only by the three-phase railway power supply, and there is a possibility that the stability of the feeding voltage required by the feeding system of the electric railway cannot be maintained.

In addition, when a transient large current occurs, by reducing the output voltage of the three-phase power conversion system for electric railways, the output current is relatively reduced, and the withstand capacity of the three-phase power conversion system for electric railways is reduced. It is also proposed to store it inside. However, this method is a control that can be applied when the three-phase power conversion system for electric railways operates alone, and when the three-phase power conversion system for electric railways is operated in conjunction with a three-phase railway power supply, Since the voltage of the three-phase AC power is maintained by the output of the three-phase railway power supply, it is difficult to reduce the output current of the three-phase power conversion system for electric railways.

For this reason, the three-phase power conversion system for electric railways suppresses the impact on the healthy feeder circuit when transient large currents occur, even when operated in conjunction with a three-phase railway power supply. It is desirable to be able to protect the system appropriately while

JP 2014-80132 A JP 2017-175797 A

In the embodiment of the present invention, even when operated in conjunction with a three-phase railway power supply, when a transient large current occurs, the system can be appropriately controlled while suppressing the influence on a sound feeder circuit. To provide a three-phase power conversion system for an electric railway that can protect against

According to an embodiment of the present invention, a feeding substation for converting three-phase AC power into a plurality of single-phase AC powers and supplying the plurality of single-phase AC powers to a plurality of feeding circuits; a three-phase railway power supply that converts electric power into another three-phase AC power and supplies the converted three-phase AC power to the feeding substation, the three-phase railway power supply A three-phase power conversion system for electric railways operated in conjunction with a converter that converts three-phase AC power to DC power, and a three-phase that supplies the DC power output from the converter to the converter An inverter that converts AC power into another three-phase AC power that is different from AC power and supplies the converted three-phase AC power to the feeding substation; a current detector for detecting a current value or a current value of each of the plurality of single-phase AC powers supplied to the plurality of feeding circuits; and based on the current value detected by the current detector, the a control device for controlling an operation of conversion from the DC power to the three-phase AC power by the inverter, wherein the control device detects the current values detected by the current detector, It is determined whether or not the current flowing through each of the feeder circuits is equal to or greater than a predetermined value, and in the normal state when it is determined that the current flowing through each of the plurality of feeder circuits is less than the predetermined value, the predetermined current relating to the output of the inverter is determined. By setting a command value, the operation of the inverter is controlled so as to supply a predetermined active current and reactive current to each of the plurality of feeding circuits, and one of the plurality of feeding circuits is controlled. When a large current is generated when it is determined that the flowing current is equal to or greater than the predetermined value, the current command value is set lower than that during normal operation, so that the inverter outputs to the feeding circuit determined to be equal to or greater than the predetermined value. A three-phase power conversion system for electric railways is provided that controls the operation of the inverter so that the current drawn is low.

Even when operated in conjunction with a three-phase railway power supply, the three-way electric railway system can appropriately protect the system while suppressing the impact on the sound feeder circuit when a transient large current occurs. A phase power conversion system is provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which represents typically the feeding system which concerns on embodiment. BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which represents typically the three-phase power conversion system for electric railways which concerns on embodiment. It is a block diagram which represents typically the control apparatus which concerns on embodiment.

Each embodiment will be described below with reference to the drawings.
Note that the drawings are schematic or conceptual, and the relationship between the thickness and width of each portion, the size ratio between portions, and the like are not necessarily the same as the actual ones. Also, even when the same parts are shown, the dimensions and ratios may be different depending on the drawing.
In addition, in the present specification and each figure, the same reference numerals are given to the same elements as those described above with respect to the already-appearing figures, and detailed description thereof will be omitted as appropriate.

FIG. 1 is a block diagram schematically showing a feeding system according to an embodiment.
As shown in FIG. 1, the feeding system 2 includes an electric railway three-phase power conversion system 10, a three-phase railway power supply 12, a feeding substation 14, a plurality of feeding circuits 21 and 22, Prepare.

The three-phase railroad power supply 12 is, for example, a rotary machine connecting a motor and a generator. The electric railway three-phase power conversion system 10 is operated in conjunction with a three-phase railway power source 12 . An electric railway three-phase power conversion system 10 and a three-phase railway power supply 12 are connected to a power system such as an electric power company, and transfer three-phase AC power supplied from the power system to feeder circuits 21 and 22 corresponding to separate three Convert to phase AC power. The power system to which the electric railway three-phase power conversion system 10 is connected may be the same as or different from the power system to which the three-phase railway power source 12 is connected.

The electric railway three-phase power conversion system 10 and the three-phase railway power supply 12 are used, for example, as frequency converters. The electric railway three-phase power conversion system 10 and the three-phase railway power supply 12 convert, for example, 50 Hz three-phase AC power in the eastern part of Japan to 60 Hz three-phase AC power in the western part of Japan. However, the electric railway three-phase power conversion system 10 and the three-phase railway power supply 12 are not limited to frequency converters. Power conversion by the three-phase power conversion system 10 for electric railway and the three-phase railway power supply 12 is not limited to frequency conversion, and may be voltage or current magnitude conversion. The operation of power conversion by the electric railway three-phase power conversion system 10 and the three-phase railway power supply 12 may be any operation that converts three-phase AC power to another three-phase AC power.

The electric railway three-phase power conversion system 10 and the three-phase railway power supply 12 supply converted three-phase AC power to the feeder substation 14 .

The feeding substation 14 converts the three-phase AC power supplied from the electric railway three-phase power conversion system 10 and the three-phase railway power supply 12 into a plurality of single-phase AC powers, and converts the plurality of single-phase AC powers into a plurality of single-phase AC powers. feeder circuits 21 and 22.

The feeding substation 14, for example, converts the three-phase AC power supplied from the electric railway three-phase power conversion system 10 and the three-phase railway power supply 12 into two sets of single-phase AC power, One of the AC powers is supplied to the feeder circuit 21 and the other of the two sets of single-phase AC powers is supplied to the feeder circuit 22 . Thus, the feeding substation 14 is connected to, for example, two feeding circuits 21 and 22 and supplies single-phase AC power to each of the two feeding circuits 21 and 22 .

For the feeding substation 14, for example, a Scott-connected transformer, a modified Woodbridge-connected transformer, a roof-delta-connected transformer, or the like is used. However, the number of feeding circuits connected to the feeding substation 14 is not limited to two, and may be three or more. The feeding substation 14 may be configured to convert three-phase AC power into three or more sets of single-phase AC power. In the following description, it is assumed that there are two feeder circuits and that the feeder substation 14 converts three-phase AC power into two sets of single-phase AC power. In the following description, the feeding circuit 21 is assumed to be the first feeding circuit 21 and the feeding circuit 22 is assumed to be the second feeding circuit 22 .

A first feeding circuit 21 and a second feeding circuit 22 supply power to trains 23 and 24 . As a result, the electric railway three-phase power conversion system 10 and the three-phase railway power supply 12 supply three-phase AC power to the electric trains 23 and 24 so that the electric trains 23 and 24 can run.

The first feeding circuit 21 and the second feeding circuit 22 are connected to the feeding substation 14 via circuit breakers (not shown). In other words, the feeding system 2 includes a plurality of feeding circuits provided between the feeding substation 14 and the first feeding circuit 21 and between the feeding substation 14 and the second feeding circuit 22. It further comprises a circuit breaker. When an accident such as a short circuit or a ground fault occurs in the first feeding circuit 21 and the second feeding circuit 22, the feeding system 2 opens the circuit breaker corresponding to the faulty feeding circuit.

By opening only the circuit breaker corresponding to the faulty feeding circuit, the feeding system 2 prevents the power from continuing to be supplied to the faulty feeding circuit. continue to supply power to the electrical circuit. As a result, even when an accident occurs in one of the first feeding circuit 21 and the second feeding circuit 22, it is only necessary to stop the operation of trains in one of the feeding circuits where the accident has occurred, and the operation of the train in the other feeding circuit is stopped. Trains can continue to operate on healthy feeder circuits.

FIG. 2 is a block diagram schematically showing the three-phase power conversion system for electric railways according to the embodiment.
As shown in FIG. 2, the electric railway three-phase power conversion system 10 includes a power receiving transformer 40, a converter transformer 42, a converter 44, a DC capacitor 46, an inverter 48, and an inverter transformer. 50 , a transmission transformer 52 , a current detector 54 and a controller 56 .

The primary side of power receiving transformer 40 is connected to power system 30 . The secondary side of power receiving transformer 40 is connected to the primary side of converter transformer 42 . The secondary side of converter transformer 42 is connected to converter 44 . The power receiving transformer 40 and the converter transformer 42 transform the three-phase AC power supplied from the power system 30 into three-phase AC power corresponding to the converter 44 .

The power system 30 is, for example, the power system of a power company. The power system 30 may be, for example, a power system that supplies three-phase AC power supplied from a private power generator or the like to the three-phase power conversion system 10 for electric railways. The feeding system 2 may further include, for example, a generator that outputs three-phase AC power, and a power system 30 that supplies the three-phase AC power of the generator to the three-phase power conversion system 10 for electric railways.

In this example, two transformers, a power receiving transformer 40 and a converter transformer 42 are provided between the power system 30 and the converter 44 . The number of transformers provided between power system 30 and converter 44 is not limited to two, and may be one or three or more.

Converter 44 converts the three-phase AC power supplied from converter transformer 42 into DC power. Converter 44 is, for example, a three-phase bridge rectifier circuit having a plurality of three-phase bridge-connected rectifying elements. However, the configuration of the converter 44 is not limited to this, and may be any configuration that can convert three-phase AC power to DC power.

DC capacitor 46 is provided between converter 44 and inverter 48 . DC capacitor 46 suppresses fluctuations in the voltage of the DC power output from converter 44 .

Inverter 48 converts the DC power output from converter 44 into three-phase AC power. Inverter 48 converts the three-phase AC power supplied to converter 44 into another three-phase AC power. For example, if the electric railway three-phase power conversion system 10 is a frequency converter, the inverter 48 converts the three-phase AC power supplied to the converter 44 into another three-phase AC power with a different frequency. For example, the converter 44 converts the supplied 50 Hz three-phase AC power into DC power, and the inverter 48 converts the DC power into 60 Hz three-phase AC power.

However, as described above, the electric railway three-phase power conversion system 10 is not limited to a frequency converter. The inverter 48 may convert, for example, the three-phase AC power supplied to the converter 44 into another three-phase AC power having a different voltage or current.

The inverter 48 has a plurality of semiconductor switching elements (not shown), and converts DC power into three-phase AC power by switching the plurality of semiconductor switching elements. The inverter 48 has, for example, a plurality of semiconductor switching elements connected in a three-phase bridge. However, the configuration of the inverter 48 is not limited to the above, and may be any configuration that can convert DC power into three-phase AC power by switching a plurality of semiconductor switching elements.

A primary side of the inverter transformer 50 is connected to the inverter 48 . The secondary side of the inverter transformer 50 is connected to the primary side of the power transmission transformer 52 . The secondary side of the transmission transformer 52 is connected to the feeding substation 14 via the power system 32 or the like. The inverter transformer 50 and the transmission transformer 52 transform the three-phase AC power output from the inverter 48 into three-phase AC power corresponding to the feeding substation 14 .

Thereby, the three-phase AC power output from the electric railway three-phase power conversion system 10 is supplied to the feeder substation 14 . In other words, the inverter 48 converts the DC power into three-phase AC power, and supplies the converted three-phase AC power to the feeding substation 14 via the inverter transformer 50 and the transmission transformer 52 . The three-phase railroad power supply 12 is connected to, for example, a power grid 32 . As a result, the three-phase AC power output from the electric railway three-phase power conversion system 10 and the three-phase railway power source 12 is supplied to the feeder substation 14 .

In this example, two transformers, an inverter transformer 50 and a transmission transformer 52 are provided between the power system 32 and the inverter 48 . The number of transformers provided between the power system 32 and the inverter 48 is not limited to two, and may be one or three or more.

The current detector 54 detects the current value of the three-phase AC power supplied to the feeder substation 14 . The current detector 54 detects, for example, the current value of each phase of the three-phase AC power supplied to the feeder substation 14 . The current detector 54 is provided, for example, between the inverter 48 and the primary side of the inverter transformer 50 . In other words, current detector 54 detects the current value of the three-phase AC power output from inverter 48 . The current detector 54 inputs the detected current value to the controller 56 .

The position where the current detector 54 is provided is not limited to between the inverter 48 and the primary side of the inverter transformer 50 . The current detector 54 may be provided, for example, between the secondary side of the inverter transformer 50 and the primary side of the power transmission transformer 52 , or between the secondary side of the power transmission transformer 52 and the power system 32 . , or may be provided on the path of the power system 32 . The current value detected by the current detector 54 may be the current value of the three-phase AC power at an arbitrary position between the inverter 48 and the power substation 14 .

The control device 56 controls the conversion operation of the inverter 48 from DC power to three-phase AC power. Control device 56 controls the operation of inverter 48 based on the current value detected by current detector 54 .

Note that the control device 56 may further control the operation of the converter 44 as necessary. For example, as described above, when converter 44 is a three-phase bridge rectifier circuit, controller 56 does not need to control the operation of converter 44 . For example, when the converter 44 is configured using a plurality of semiconductor switching elements, the power conversion operation of the converter 44 is controlled by the control device 56 . However, the control device that controls the operation of the converter 44 may be a device different from the control device 56 that controls the operation of the inverter 48 .

In normal operation when the first feeding circuit 21 and the second feeding circuit 22 are sound, the control device 56 controls each of the first feeding circuit 21 and the second feeding circuit 22 to have a predetermined effective current. and control the operation of inverter 48 to supply reactive current.

In the feeding system 2, as described above, there is a possibility that an accident such as a short circuit or a ground fault will occur in the first feeding circuit 21 and the second feeding circuit 22 due to the influence of a fallen tree or the like. be. When the feeding system 2 detects a fault in the first feeding circuit 21 and the second feeding circuit 22, it opens the circuit breaker corresponding to the faulty feeding circuit and feeds the faulty feeding circuit. By disconnecting from the power substation 14, the power supply to the feeder circuit in which the accident has occurred is stopped. On the other hand, it takes about 150 ms, for example, for the feeding system 2 to detect a fault in the first feeding circuit 21 and the second feeding circuit 22 and disconnect the faulty feeding circuit. do. Therefore, there is a possibility that a transient large current will flow in the electric railway three-phase power conversion system 10 and the three-phase railway power source 12 from the time when the accident occurs until the feeding circuit is cut off by the feeding system 2. be.

The three-phase railway power supply 12, which is made up of a rotating machine or the like, has a certain supply capacity for a large transient current, so it can continue to operate even in the event of an accident. On the other hand, it is difficult for the electric railway three-phase power conversion system 10 having the inverter 48 composed of a plurality of semiconductor switching elements to bear a transient large current.

Therefore, based on the current value detected by the current detector 54, the control device 56 determines whether or not the current flowing through the first feeding circuit 21 and the second feeding circuit 22 is equal to or greater than a predetermined value. In response to determining that the current in at least one of the first feeding circuit 21 and the second feeding circuit 22 is equal to or greater than the predetermined value, a protection operation to protect the inverter 48 is performed. More specifically, the control device 56 determines whether or not the current flowing through the first feeding circuit 21 and the second feeding circuit 22 is equal to or greater than a predetermined value based on the current instantaneous value detected by the current detector 54. . For example, the control device 56 may determine whether at least one of the active current and the reactive current flowing through the first feeding circuit 21 and the second feeding circuit 22 is equal to or greater than a predetermined value.

When the control device 56 determines that the current flowing through the first feeding circuit 21 and the second feeding circuit 22 is less than the predetermined value, the control device 56 sets a predetermined current command value for the inverter 48 to The operation of the inverter 48 is controlled so as to supply predetermined active currents and reactive currents to the feeding circuit 21 and the second feeding circuit 22, respectively.

When the controller 56 determines that the current flowing through one of the first feeding circuit 21 and the second feeding circuit 22 is equal to or greater than a predetermined value, the control device 56 controls the flow of the first feeding circuit 21 and the second feeding circuit 22 when a large current is generated. By making the current command value for one of the circuits 22 lower than normal, the current output from the inverter 48 to one of the first feeding circuit 21 and the second feeding circuit 22 is reduced. control behavior.

Also, at this time, the controller 56 sets the current command value for the other of the first feeding circuit 21 and the second feeding circuit 22 to the same value as in normal times. In other words, when the control device 56 determines that the current flowing through one of the first feeding circuit 21 and the second feeding circuit 22 is equal to or greater than the predetermined value, the control device 56 22 is made lower than normal.

As a result, while continuing to supply power to the other of the fault-free healthy first feeding circuit 21 and second feeding circuit 22, The inverter 48 can be controlled so that the current output to one side of the circuit 22 is low, protecting the inverter 48 from transient high currents.

When the control device 56 determines that the current flowing through both the first feeding circuit 21 and the second feeding circuit 22 is equal to or greater than a predetermined value, for example, the first feeding circuit 21 and the second feeding circuit 22 are made lower than normal, or the operation of the inverter 48 is stopped. However, in the feeding system 2, the possibility of an accident occurring substantially simultaneously in both the first feeding circuit 21 and the second feeding circuit 22 is considered to be low.

FIG. 3 is a block diagram schematically showing the control device according to the embodiment.
As shown in FIG. 3, the control device 56 includes a command value generation unit 60, a current value calculation unit 62, an operation state signal input unit 64, a first application determination unit 66a, a second application determination unit 66b. , a first reduction rate calculator 68 a , a second reduction rate calculator 68 b , multipliers 70 a to 70 d , and a control signal generator 72 .

Control information is input to the command value generator 60 . The command value generator 60 generates a first active current command value for the first feeding circuit 21, a first reactive current command value for the first feeding circuit 21, a second feeding circuit 21, and a second feeding circuit 21 based on the input control information. A second active current command value for the circuit 22 and a second reactive current command value for the second feeding circuit 22 are generated.

In other words, the command value generator 60 converts the first active current command value, the first reactive current command value, the second active current command value, and the second reactive current command value into a predetermined current command related to the output of the inverter 48. Set as a value. Thus, the control device 56 regards the output of the inverter 48 as two sets of single-phase AC power and controls the operation of the inverter 48 .

The command value generator 60 inputs the generated first active current command value to the multiplier 70a, inputs the first reactive current command value to the multiplier 70b, and inputs the second active current command value to the multiplier 70c. , the second reactive current command value to the multiplier 70d.

The control information is input to the command value generator 60 from, for example, a higher-level controller. The control information represents, for example, power supply from the electric railway three-phase power conversion system 10 to the first feeding circuit 21 and the second feeding circuit 22, and stoppage of the power supply. The command value generator 60 generates each current command value, for example, when instructed to supply electric power. For example, when instructed to stop the power supply, the command value generator 60 stops generating each current command value, or sets each current command value to an output stop state (for example, 0). .

The control information may include, for example, information representing the magnitude of the current. The command value generator 60 may generate each current command value having a magnitude set by the control information. The control information may be, for example, a current command value for the three-phase AC power of the electric railway three-phase power conversion system 10 (inverter 48). The command value generation unit 60 generates current command values of single-phase AC power for the first feeding circuit 21 and the second feeding circuit 22 by performing calculations for converting the current command values for the three-phase AC power. may

Note that each current command value may be configured to be input to the control device 56 from a host controller or the like without being generated within the control device 56 . In this case, each input command value may be directly input to each multiplier 70a-70d. Therefore, in this case, the command value generator 60 can be omitted.

The current value of the three-phase AC power detected by the current detector 54 is input to the current value calculator 62 . The current value calculation unit 62 performs a predetermined calculation on the input current value of the three-phase AC power to determine the current value of the first feeding circuit 21 and the second feeding circuit 22 from the current value of the three-phase AC power. Calculate the current values of the two sets of single-phase AC power. The current value calculation unit 62 calculates, for example, instantaneous current values of two sets of single-phase AC power. The current value calculator 62 may, for example, calculate active current values and reactive current values of two sets of single-phase AC power. The method of calculating the current values of the two sets of single-phase AC power by the current value calculator 62 is determined according to the wiring method of the feeder substation 14 .

After calculating the current values of the two sets of single-phase AC power, the current value calculator 62 determines whether the calculated current values of the two sets of single-phase AC power are equal to or greater than a predetermined value.

When the current value calculation unit 62 determines that the current value of the single-phase AC power of the first feeding circuit 21 is equal to or greater than a predetermined value, the current value calculating unit 62 determines that the current of the first feeding circuit 21 is excessive. An excess current detection signal is input to the first application determination section 66a. In other words, when the current value calculator 62 determines that the current value of the single-phase AC power of the first feeding circuit 21 is equal to or greater than the predetermined value, the current value calculator 62 changes the first excess current detection signal from the non-detection state to the detection state. switch to More specifically, the current value calculator 62 detects the first excess current when it determines that at least one of the active current value and the reactive current value of the single-phase AC power of the first feeding circuit 21 is equal to or greater than a predetermined value. The signal is input to the first application determination section 66a.

Similarly, when the current value calculator 62 determines that the current value of the single-phase AC power of the second feeding circuit 22 is equal to or greater than a predetermined value, the current of the second feeding circuit 22 is excessive. is input to the second application determining section 66b.

The operation state signal input unit 64 inputs an operation state signal indicating whether or not the control device 56 performs a protective operation of the inverter 48 to the first application determination unit 66a and the second application determination unit 66b. The operation state signal input unit 64 generates an operation state signal based on, for example, a control signal input from a higher-level controller or the internal control state of the control device 56, and applies the generated operation state signal to the first application. It is input to the determination unit 66a and the second application determination unit 66b.

The first application determination unit 66a receives the first excess current detection signal from the current value calculation unit 62 in a state in which the operating state signal indicates that the protection operation of the inverter 48 is to be performed. is input to the first reduction rate calculator 68a. On the other hand, when the first application determination unit 66a receives the first excess current detection signal from the current value calculation unit 62 in a state in which the operation state signal indicates that the protection operation of the inverter 48 is not performed, the first application determination unit 66a The excessive current detection signal is not input to the first reduction rate calculator 68a. Thereby, the protection operation of the inverter 48 by the control device 56 can be performed only when the operation status signal indicates that the protection operation of the inverter 48 is to be performed.

Similarly, the second application determination unit 66b detects that the second current excess detection signal is input from the current value calculation unit 62 in a state where the operation state signal indicates that the inverter 48 is to be protected. The excess detection signal is input to the second reduction rate calculator 68b. When the second application determination unit 66b receives the second excess current detection signal from the current value calculation unit 62 in a state in which the operation state signal indicates that the protection operation of the inverter 48 is not performed, the second application determination unit 66b detects the second excess current. The detection signal is not input to the second reduction rate calculator 68b.

The first reduction rate calculation unit 68a calculates the reduction rate of the first active current command value and the first reactive current command value based on the first excess current detection signal input from the first application determination unit 66a, and calculates The resulting reduction rate is input to multipliers 70a and 70b.

The first reduction rate calculator 68a sets the reduction rate to 1 when the first excess current detection signal is not input from the first application determination section 66a. In other words, the first reduction rate calculator 68a sets the reduction rate to 1 when the first excess current detection signal is in the non-detection state. Then, the first reduction rate calculator 68a sets the reduction rate to a predetermined value lower than 1 when the first excess current detection signal is input from the first application determination section 66a. In other words, the first reduction rate calculator 68a sets the reduction rate to a predetermined value lower than 1 when the first excess current detection signal is in the detection state. The reduction rate in this case is set to an arbitrary value lower than 1 necessary to protect the inverter 48 from a transient high current caused by a fault in the first feeding circuit 21 .

The first reduction rate calculation unit 68a may switch the reduction rate between two values, 1 and a predetermined value lower than 1. For example, the current value calculation unit 62 determines that the current value is equal to or greater than the predetermined value The reduction rate may be changed according to the magnitude of the current value of the single-phase AC power of the first feeding circuit 21 . The first reduction rate calculator 68a may be configured to decrease the reduction rate as the magnitude of the current value of the single-phase AC power of the first feeding circuit 21 increases. For example, by including information representing the magnitude of the current value of the single-phase AC power of the first feeding circuit 21 in the first excess current detection signal, the single-phase AC power of the first feeding circuit 21 can be obtained as described above. The reduction rate can be changed according to the magnitude of the current value of power.

Similar to the first reduction rate calculation unit 68a, the second reduction rate calculation unit 68b calculates the second effective current command value and the second invalid value based on the second current excess detection signal input from the second application determination unit 66b. A reduction rate of the current command value is calculated, and the calculated reduction rate is input to the multipliers 70c and 70d.

The multiplier 70 a multiplies the input first active current command value and the reduction rate, and inputs the multiplied first active current command value to the control signal generator 72 .

The multiplier 70 b multiplies the input first reactive current command value and the reduction rate, and inputs the multiplied first reactive current command value to the control signal generator 72 .

The multiplier 70 c multiplies the input second active current command value and the reduction rate, and inputs the multiplied second active current command value to the control signal generator 72 .

The multiplier 70 d multiplies the input second reactive current command value and the reduction rate, and inputs the multiplied second reactive current command value to the control signal generator 72 .

Based on the current command values input from the multipliers 70a to 70d, the control signal generator 72 generates an active current corresponding to the first active current command value and a reactive current corresponding to the first reactive current command value to the first The operation of the inverter 48 is controlled so as to supply to the feeding circuit 21 and to supply to the second feeding circuit 22 an active current corresponding to the second active current command value and a reactive current corresponding to the second reactive current command value. A control signal is generated for the operation, and the generated control signal is input to the inverter 48 .

The control signal generator 72 also receives, for example, phase information of the three-phase AC power supplied from the three-phase railway power supply 12 to the feeder substation 14 . For example, based on the input information, the control signal generation unit 72 determines the phase of the three-phase AC power supplied from the inverter 48 to the feeding substation 14 from the three-phase railway power supply 12 to the feeding substation 14. A control signal is generated to control the operation of the inverter 48 so as to synchronize with the phase of the three-phase AC power supplied.

The control signal is, for example, a PWM signal for switching between ON and OFF states of the plurality of semiconductor switching elements of the inverter 48 . The control signal generation unit 72 generates a three-phase alternating current of the inverter 48 based on the active current command value and the reactive current command value of two sets of single-phase alternating current power of the first feeding circuit 21 and the second feeding circuit 22, for example. An active current command value and a reactive current command value or an active voltage command value and a reactive voltage command value of electric power are generated. Then, the control signal generation unit 72, for example, based on the active current command value and reactive current command value of the three-phase AC power of the inverter 48, or the active voltage command value and reactive voltage command value, the plurality of semiconductor switching of the inverter 48 A control signal is generated for switching the device between on and off states.

For example, the active current command value and reactive current command value of the three-phase AC power of the inverter 48, or the active voltage command value and reactive voltage command value of the three-phase AC power of the inverter 48 are input to the inverter 48 as control signals, and the inverter 48 may be converted to a PWM signal or the like. The control signal is not limited to the PWM signal, and may be any signal capable of controlling the operation of the inverter 48 so as to supply appropriate single-phase AC power to the first feeding circuit 21 and the second feeding circuit 22. good.

When the first feeding circuit 21 and the second feeding circuit 22 are in a healthy state, the reduction rate input from the first reduction rate calculation section 68a and the second reduction rate calculation section 68b to the multipliers 70a to 70d is 1. , and each command value generated by the command value generator 60 is input to the control signal generator 72 as it is.

Therefore, in normal times when the first feeding circuit 21 and the second feeding circuit 22 are in a sound state, the first feeding circuit 21 and the second feeding circuit 22 are controlled in accordance with the command values generated by the command value generation unit 60. The operation of inverter 48 is controlled to provide predetermined active and reactive currents to each of electrical circuits 22 .

When an accident occurs in the first feeding circuit 21, a transient large current flows through the first feeding circuit 21, and the current value of the single-phase AC power in the first feeding circuit 21 exceeds a predetermined value, the first The current value calculator 62 determines that the current value of the single-phase AC power of the feeder circuit 21 is equal to or greater than a predetermined value, and the current value calculator 62 sends a first excess current detection signal to the first application determination unit 66a. is entered.

When the first excess current detection signal is input from the current value calculation unit 62 to the first application determination unit 66a in a state in which the operation state signal indicates that the inverter 48 is to be protected, the first excess current detection signal It is input from the first application determination section 66a to the first reduction rate calculation section 68a.

When the first excess current detection signal is input from the first application determination section 66a, the first reduction rate calculation section 68a sets the reduction rate to a predetermined value lower than 1, and inputs the reduction rate to the multipliers 70a and 70b. do.

As a result, when a large current occurs in which the current value of the single-phase AC power of the first feeding circuit 21 is equal to or higher than a predetermined value, the current command value for the first feeding circuit 21 becomes lower than in normal times, and the inverter 48 The operation of the inverter 48 is controlled so that the current output from 1 to the first feeding circuit 21 is low. Thereby, the inverter 48 can be protected from a transient large current.

Also, at this time, if no accident has occurred in the second feeding circuit 22 and the current value of the single-phase AC power in the second feeding circuit 22 is less than the predetermined value, the second reduction rate calculation unit The reduction rate input from 68b to multipliers 70c and 70d remains 1. That is, the second active current command value and the second reactive current command value for the second feeding circuit 22 are the same as in normal times. As a result, it is possible to continue supplying power to the healthy second feeding circuit 22 in which no accident has occurred. The inverter 48 is controlled so that the current output to the faulty first feeding circuit 21 is reduced while continuing to supply power to the fault-free sound second feeding circuit 22. It is possible to protect the inverter 48 from a transient large current.

The feeding system 2 detects a fault in the first feeding circuit 21, opens the circuit breaker corresponding to the faulty first feeding circuit 21, and feeds the faulty first feeding circuit 21. When disconnected from the feeder substation 14, the current value of the single-phase AC power of the first feeding circuit 21 returns to less than the predetermined value. Therefore, after the feeding system 2 disconnects the first feeding circuit 21 from the feeding substation 14, the reduction rate input to the multipliers 70a and 70b from the first reduction rate calculator 68a becomes 1. Then, the current command value for the first feeding circuit 21 also returns to the normal state.

As in the case of the first feeding circuit 21, when the current value of the single-phase AC power of the second feeding circuit 22 is equal to or greater than a predetermined value, the second application determination unit 66b outputs the second excessive current detection signal. By inputting to the second reduction rate calculation section 68b, a predetermined reduction rate lower than 1 is input to the multipliers 70c and 70d from the second reduction rate calculation section 68b. As a result, when the current value of the single-phase AC power of the second feeding circuit 22 is equal to or higher than the predetermined value, the current command value for the second feeding circuit 22 becomes lower than normal, and the inverter 48 outputs the second feeding circuit. The operation of the inverter 48 is controlled so that the current output to the electrical circuit 22 is low.

When no accident has occurred in the first feeding circuit 21, while continuing to supply power to the sound first feeding circuit 21 in which the accident has not occurred, the second feeding circuit 22 in which the accident has occurred is continued. Inverter 48 can be controlled so that the current output to is low, and inverter 48 can be protected from a transient large current.

As described above, in the electric railway three-phase power conversion system 10 according to the present embodiment, the controller 56 controls the current flowing through one of the first feeding circuit 21 and the second feeding circuit 22 to be equal to or greater than a predetermined value. At the time of occurrence of a large current determined as and the operation of the inverter 48 is controlled such that the current output to one of the second feeding circuit 22 is low.

As a result, while continuing to supply power to the other of the fault-free healthy first feeding circuit 21 and second feeding circuit 22, The inverter 48 can be controlled so that the current output to one side of the circuit 22 is low, protecting the inverter 48 from transient high currents. Even when the electric railway three-phase power conversion system 10 is operated in conjunction with the three-phase railway power supply 12, when a transient large current occurs, the influence on the healthy feeder circuit is suppressed. , the system can be adequately protected.

Further, in the electric railway three-phase power conversion system 10 according to the present embodiment, the control device 56 regards the output of the inverter 48 as two sets of single-phase AC power and controls the operation of the inverter 48 . As a result, it is possible to directly adjust the current command value only for the feeding circuit in which the accident has occurred. It is possible to realize control that more appropriately suppresses the influence on a healthy feeding circuit.

However, the current command values set in the control device 56 do not necessarily have to be the current command values for the two sets of single-phase AC power. For example, current command values for the active current and reactive current of the three-phase AC power output from the inverter 48 are set, and the effective current of the three-phase AC power is set so that the current output to the feeder circuit where the fault has occurred is reduced. The current command values for current and reactive current may be lowered. The current command value set in controller 56 may be any current command value for the output of inverter 48 .

In the above embodiment, the current detector 54 detects the current value of the three-phase AC power supplied to the feeder substation 14 . Without being limited to this, the current detector 54 may be configured to detect the respective current values of the two sets of single-phase AC power after conversion at the feeder substation 14, for example. Thereby, in the control device 56, it is possible to omit the trouble of calculating the current values of the two sets of single-phase AC power.

On the other hand, when the current detector 54 detects the current value of each of the two sets of single-phase AC power, the distance between the current detector 54 and the control device 56 increases, and the current detector 54 may become complicated. As in the above embodiment, when the current detector 54 is configured to detect the current value of the three-phase AC power supplied to the feeding substation 14, for example, the configuration of the arrangement of the current detector 54 etc. can be simplified.

In the above embodiment, the number of feeding circuits connected to the feeding substation 14 is two. The number of feeding circuits connected to the feeding substation 14 is not limited to two, and may be three or more. When the number of feeding circuits is three or more, the controller 56 determines whether the current flowing through each of the plurality of feeding circuits is equal to or greater than a predetermined value based on the current value detected by the current detector 54. is determined, and the current flowing through each of the plurality of feeding circuits is determined to be less than the predetermined value, by setting a predetermined current command value for the output of the inverter 48, The operation of the inverter 48 is controlled so as to supply a predetermined active current and reactive current to the feeder circuit. The operation of the inverter 48 may be controlled so that the current output from the inverter 48 to the feeder circuit determined to be equal to or greater than the predetermined value is reduced by lowering the current command value.

In the above embodiment, a rotating machine is given as an example of the three-phase railway power supply 12 . The three-phase railway power supply 12 has a certain supply capacity against a transient large current in the event of an accident in the feeder circuit, not limited to rotating machines, and continues operation even in the event of an accident. Any power source capable of

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

2 Feeding system 10 Three-phase power conversion system for electric railway 12 Three-phase railway power supply 14 Feeding substation 21, 22 Feeding circuit 23, 24 Electric train 30, 32 Power system 40 Power receiving transformer 42 Converter transformer 44 Converter 46 DC capacitor 48 Inverter 50 Inverter transformer 52 Power transmission transformer 54 Current detector 56... Control device 60... Command value generation unit 62... Current value calculation unit 64... Operation state signal input unit 66a... First application determination unit 66b... Second application determination unit 68a... First reduction rate calculation Part 68b... Second reduction rate calculator 70a to 70d... Multiplier 72... Control signal generator

Claims (4)

a feeding substation that converts three-phase AC power into a plurality of single-phase AC powers and supplies the plurality of single-phase AC powers to a plurality of feeding circuits;
a three-phase railway power supply that converts three-phase AC power into another three-phase AC power and supplies the converted three-phase AC power to the feeder substation;
A three-phase power conversion system for an electric railway that is used in a feeder system comprising and operated in conjunction with the three-phase railway power supply,
a converter that converts three-phase AC power to DC power;
an inverter that converts the DC power output from the converter into three-phase AC power different from the three-phase AC power supplied to the converter, and supplies the converted three-phase AC power to the feeding substation; ,
a current detector for detecting a current value of the three-phase AC power supplied to the feeding substation or a current value of each of the plurality of single-phase AC powers supplied to the plurality of feeding circuits;
a control device that controls an operation of the inverter to convert the DC power into the three-phase AC power based on the current value detected by the current detector;
with
The control device is
determining whether or not the current flowing through each of the plurality of feeding circuits is equal to or greater than a predetermined value based on the current value detected by the current detector;
In a normal state when it is determined that the current flowing through each of the plurality of feeding circuits is less than the predetermined value, by setting a predetermined current command value for the output of the inverter, each of the plurality of feeding circuits controlling the operation of the inverter so as to supply a predetermined active current and reactive current through
When a large current is generated when it is determined that the current flowing through any one of the plurality of feeder circuits is equal to or greater than the predetermined value, the current command value is set lower than that during normal operation so that the inverter outputs the predetermined value. A three-phase power conversion system for electric railways, wherein the operation of the inverter is controlled such that the current output to the feeding circuit determined as above is low. The number of the plurality of feeding systems is two,
The feeder substation converts the three-phase AC power supplied from the three-phase railway power supply and the inverter into two sets of single-phase AC power, and converts the two sets of single-phase AC power to the two feeders. supply to the electrical circuit,
2. The three-phase power conversion system for an electric railway according to claim 1, wherein said controller regards the output of said inverter as said two sets of single-phase AC power and controls the operation of said inverter. The control device sets an active current command value and a reactive current command value for each of the two feeding circuits, and determines that the current flowing through one of the two feeding circuits is equal to or greater than the predetermined value. At the time of current generation, the active current command value and the reactive current command value for the one of the two feeding circuits are made lower than the normal time, so that the one of the two feeding circuits is supplied from the inverter. 3. The three-phase power conversion system for an electric railway according to claim 2, wherein the operation of said inverter is controlled so that the current output to the three-phase power conversion system is reduced. The current detector detects a current value of the three-phase AC power supplied to the feeding substation,
The control device performs a predetermined operation on the current values of the three-phase AC power detected by the current detector, thereby determining the two feeder circuits from the current values of the three-phase AC power. 4. The three-phase power converter for electric railways according to claim 2 or 3, wherein current values of a pair of single-phase AC power are calculated, and it is determined whether or not the current flowing in each of the two feeder circuits is equal to or greater than the predetermined value. system.

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