JP2008154355A - Power storage equipment - Google Patents

Abstract

【Task】
We propose a storage facility that prevents a significant drop in feeder voltage and regenerative vehicle expiration, detects when a substation stops, and supplies sufficient power.
[Solution]
In a power storage facility connected to a feeder system composed of a storage device and a controller, the operation mode is changed based on the feeder voltage and the charging rate of the storage device, and charging starts according to the feeder voltage, the charging rate of the storage device and the operation mode. By changing the target value of the voltage, the discharge start voltage, and the charge rate, the charge / discharge power is controlled to effectively use the power storage equipment.
[Selection] Figure 2

Description

  The present invention relates to a power storage facility for charging or discharging electric power for railways.

  A vehicle in an electric railway travels by receiving electric power transmitted from a substation. Since a voltage drop occurs in proportion to the distance between the substation that transmits power and the vehicle and the amount of current that is transmitted, the punter voltage of the vehicle varies greatly. If the punter voltage drops, the vehicle will not be able to accelerate. In addition, the electric vehicle regenerates kinetic energy to the feeder when braking by the regenerative brake. This power is used by other power trains to save energy as a whole.

  However, if the punter voltage rises above a certain level when the vehicle performs regenerative braking, regenerative braking is canceled and switched to air braking to prevent equipment damage due to overvoltage. This is called regeneration expiration. If regenerative invalidation occurs and it is changed to air braking, the running energy of the vehicle is changed to heat and released, so the energy cannot be used effectively.

  For this reason, usually, the substations are installed at appropriate intervals so that the punter point voltage is within about -25% to + 10% of the reference voltage. However, if the train exceeds the initially expected due to major changes in the schedule, etc., the initial consideration should be taken if the vehicle cannot travel on the schedule due to an unexpected situation such as an accident, vehicle failure, or signal abnormality. The voltage of the electric wire fluctuates more than what has been done, which may hinder the operation of the vehicle. For example, if more vehicles than initially envisaged within the range where power is supplied by the same substation simultaneously perform powering, the feeder voltage drops significantly and the vehicle cannot be accelerated. Further, when regenerating at the same time, it is conceivable that the power running vehicle cannot consume the regenerative power, and the feeder voltage rises to cause regenerative invalidation.

  There is Patent Document 1 as a conventional technique for coping with this. In this technology, power storage equipment connected to feeders is installed between substations. When the feeder voltage falls below a predetermined value, power is supplied from the power storage facility to prevent voltage drop. Moreover, when it becomes more than a predetermined value, an electrical storage equipment is charged and the rise of a voltage is prevented. Thereby, the extreme fluctuation | variation of feeder voltage can be prevented.

  In addition, the facility of Patent Document 1 charges and discharges electric power that does not change the feeder voltage when voltage fluctuation does not occur, and maintains the charging rate at an intermediate level between full charge and complete discharge. As a result, even when unexpected electric wire voltage fluctuations occur, both charging and discharging operations are possible.

JP 2006-34041 A

  The power storage facility can also be used as an emergency power source when some substations are shut down. As an emergency power source, it is desirable that the power storage equipment is fully charged during normal times so that the maximum power can be supplied. However, in the prior art, it is necessary to set the charging rate to a lower value in consideration of power absorption by regeneration. For this reason, sufficient power cannot be supplied in an emergency such as a substation stop. Although it is conceivable to install an emergency power supply separately from the power storage facility, there is a problem of an increase in cost.

  The purpose of the present invention is to prevent a drastic drop in the voltage of the feeder line and regenerative invalidation during normal times without incurring a significant increase in cost. It is to propose a power storage facility to be supplied.

  In order to achieve the above object, a power storage facility according to the present invention is a power storage facility connected to a feeder, a power storage device that stores power, a charge rate measuring unit that measures a charge rate of the power storage device, and a feeder A feeder voltage measuring unit that measures voltage, a power converter that converts power between the feeder and the power storage device, and a controller that controls charge / discharge power of the power converter, and the controller has a charging rate A mode determination unit that determines the operation mode based on the charging rate of the power storage device measured by the measurement unit and the feeder voltage measured by the wire voltage measurement unit, and charging / discharging that switches charging / discharging from the feeder voltage, the charging rate, and the operation mode. And a discharge control unit.

  In addition, a power storage facility connected to the feeder, a power storage device that stores electric power, a charge rate measurement unit that measures the charge rate of the power storage device, a feeder voltage measurement unit that measures the feeder voltage, A power conversion unit that converts power between the electric wire and the power storage device, and a controller that controls charge / discharge power of the power conversion unit, and the controller determines an operation mode based on an external input signal Assume that the determination unit and the charging / discharging control unit that switches charging / discharging from the feeder voltage, the charging rate, and the operation mode have an alternating current.

  Proposal of a power storage facility that prevents a significant drop in power line voltage and regenerative expiration during normal times without incurring a significant cost increase, detects this when a substation stops, and supplies sufficient power it can.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an overall configuration diagram of a power storage facility and a railway power supply system using the power storage facility according to a first embodiment of the present invention.

  In a direct current railway, current is supplied to the train from the substation through the feeder, and returns to the substation through the rail. Substations 41 and 42 feed a constant voltage direct current between feeder line 1 and rail 2. The electric vehicle 3 is connected as a load between the feeder 1 and the rail 2 and travels. The storage facility 13 is connected to the feeder 1 and is configured as follows.

  The feeder 1 is connected to a power storage device 9 that stores power through a rectifying reactor 6 and a DC / DC converter 7 that is a power converter. That is, the power conversion unit converts power between the feeder 1 and the power storage device 9, and the power conversion unit of this embodiment uses the DC / DC converter 7.

The power storage device 9 may be a secondary battery such as a lithium ion battery, a large capacity capacitor such as an electric double layer capacitor, or a flywheel. One end of the capacitor 5 is connected between the reactor 6 and the DC / DC converter 7, and the other end of the capacitor 5 is grounded. The controller 8 controls the DC / DC converter 7 to control power transfer between the feeder and the power storage device. That is, the controller 8 controls the charge / discharge power of the DC / DC converter 7 that is a power converter.

  The feeder voltage measuring unit 11 measures the feeder voltage, which is the voltage of the capacitor 5, and transmits the measured feeder voltage to the controller 8. The charging rate measuring unit 12 measures the charging rate of the power storage device 9 and transmits it to the controller 8. By replacing the DC / DC converter 7 with an AC / DC converter, it is possible to install a power storage facility on an AC powered railway as well.

  FIG. 2 is a functional block diagram of the controller 8 of FIG.

  The controller 8 includes a feeding voltage reading unit 81, a charging rate reading unit 82, a mode determination unit 83, and a charge / discharge control unit 84. The feeder voltage reading unit 81 reads the feeder voltage that is the voltage of the capacitor 5 measured by the feeder voltage measuring unit 11. The charging rate reading unit 82 reads the charging rate of the power storage device 9 measured by the charging rate measuring unit 12.

  The mode determining unit 83 is measured by the feeding voltage measuring unit 11 and input via the feeding voltage reading unit 81 and the charging voltage measuring unit 12 and is input via the charging rate reading unit 82. The operation mode is determined based on the charged rate, and if there is a change, the operation mode is changed and the changed operation mode is output.

  In this embodiment, as an operation mode, a normal operation mode, which is a first operation mode for the purpose of preventing absorption of a regenerative electric power from a vehicle and a voltage drop during normal operation, and an emergency power source when a substation is stopped. A voltage compensation mode, which is a second operation mode for supplying the maximum power, is provided. The condition for changing the operation mode will be described later.

  The charge / discharge control unit 84 performs control to switch charge / discharge based on the input feeder voltage, the charging rate, and the operation mode output from the mode determination unit 83. Specifically, the charge / discharge control unit 84 presets and sets the charge start voltage for starting the charging of the power storage device determined for each operation mode, the discharge start voltage for starting the discharge, and the target value of the charge rate. Based on the charging start voltage, the discharge starting voltage, and the target value of the charging rate, an operation command for the DC / DC converter 7 that is a voltage conversion unit is generated and output, and charging / discharging of the power storage device is controlled. Details of the control will be described later.

FIG. 3 is a diagram for explaining the mode determination unit 83 and the charge / discharge control unit 84 of FIG. 2 and illustrates threshold values in the normal operation mode. The vertical axis represents the feeder voltage [V], and the horizontal axis represents the charging rate [%] of the power storage device.

  First, the normal operation mode which is the first operation mode will be described. When the feeder voltage rises and becomes equal to or higher than the charging start voltage (1800 [V] in FIG. 3), which is a voltage at which the power storage device 9 starts charging, the power storage device 9 is charged to suppress the voltage increase. Further, when the voltage of the feeder line drops and becomes equal to or lower than a discharge start voltage (1400 [V] in FIG. 3), which is a voltage at which the power storage device starts discharging, discharge is performed to prevent voltage drop. If the charging start voltage is below the charging start voltage and the discharge starting voltage is above the intermediate range, when the feeder voltage is in the intermediate range, if the charging rate is lower than the charging rate target value, charge slowly, If it is large, it will slowly discharge. This is to enable both charging and discharging in preparation for the next voltage fluctuation. If the increase in feeder voltage is expected due to the number of trains traveling between the substations on both sides of the storage facility and the distance between the substations, lower the target value for the charge rate. If the power line voltage drop due to power running is expected to be large, the target value of the charging rate should be set higher. In this embodiment, the target value of the charging rate is 40%.

  Moreover, it is good to provide the dead zone which does not perform charging / discharging before and behind the target value of a charging rate.

  Further, two threshold values are determined in advance from the feeder voltage and the charging rate, and when both the feeder voltage and the charging rate fall within the range of region 1 (first threshold), the mode determination unit 83 sets the operation mode to the voltage compensation mode. change. The fact that both the feeder voltage and the charging rate are reduced means that the feeder voltage has not increased despite the fact that the power storage device has been discharged. This indicates that the power supply from the substation is insufficient for the power required by the train due to troubles such as substation stoppage. Therefore, the operation mode is changed to the voltage compensation mode.

  In addition, even if the charging rate does not decrease so much, if the feeder voltage is significantly reduced, it is considered that more power than the power that can be discharged by the power storage device is required. For this reason, the operation mode is changed to the voltage compensation mode.

  FIG. 4 is a diagram for explaining the mode determination unit 83 and the charge / discharge control unit 84 of FIG. 2, and illustrates threshold values in the voltage compensation mode. The vertical axis represents the feeder voltage, and the horizontal axis represents the charging rate of the power storage device.

In the voltage compensation mode, the discharge start voltage is set lower than that in the normal operation mode (1200 in FIG. 4).
[V]). This is to allow a slight voltage drop due to insufficient power supply and to give priority to avoiding a train stop by compensating for the minimum voltage instead.

  Further, the charging start voltage is also set lower than that in the normal operation mode (1500 [V] in FIG. 4). This is because the amount of discharge is expected to increase more than in the normal operation mode, and it is necessary to absorb as much regenerative power as possible within a range that does not affect the power running of other trains and keep the charging rate high. Even when the feeder voltage is in the intermediate range, the target value of the charging rate is set high in order to prepare for the discharge of high power.

  Further, when two threshold values are determined in advance from the feeder voltage and the charging rate, and both the feeder voltage and the charging rate fall within the range of region 2 (second threshold value greater than the first threshold value), the power storage device 9 It shows that the power that can not be absorbed by is supplied. Therefore, it is determined that an abnormality such as a substation stop has been recovered, and the mode determination unit 83 changes the operation mode to the normal operation mode. Thus, in the present invention, it is possible to detect the stoppage and re-operation of the substation from the feeder voltage and the charging rate of the power storage device.

  That is, the mode determination unit 83 sets the normal operation mode as the first operation mode when the feeder voltage measured from the feeder voltage measurement unit falls below the first threshold, and the feeder voltage is the first threshold. When a larger second threshold value is exceeded, control is performed to set the voltage compensation mode, which is the second operation mode.

  FIG. 5 shows a control flow for mode change determination of the mode determination unit 83.

  In step 101, the charging rate sent from the charging rate reading unit 82 and the wire voltage sent from the wire voltage reading unit 81 are read. In step 102, it is determined whether the electric wire voltage and the charging rate are within the region 1 in FIG. If the feeder voltage and the charging rate are within region 1, the process proceeds to step 103. If the feeder voltage and the charging rate are out of region 1, the process proceeds to step 104. In step 103, the operation mode is changed to the voltage compensation mode. When step 103 ends, the process ends. In step 104, it is determined whether the electric wire voltage and the charging rate are within the region 2 in FIG. If the feeder voltage and the charging rate are within the region 2, the routine proceeds to step 105. If the feeder voltage and the charging rate are outside the region 2, the process is terminated. In step 105, the operation mode is changed to the normal operation mode. When step 105 ends, the process ends.

  FIG. 6 shows a control flow of the charge / discharge control unit 84.

  In step 201, the charging rate sent from the charging rate reading unit 82 and the feeding wire voltage sent from the wire voltage reading unit 81 are read. In step 202, the operation mode is determined. If it is the voltage compensation mode, the process proceeds to step 203, and if it is the normal operation mode, the process proceeds to step 204. The target value of the charge start voltage, the discharge start voltage, and the charge rate for the normal operation mode set in advance in step 203 is read. In step 204, the target values of the charge start voltage, discharge start voltage, and charge rate for the voltage compensation mode set in advance are read. If it can be step 205 and the electric wire voltage is equal to or higher than the charging start voltage, the process proceeds to step 206, and if it is lower than the charging start voltage, the process proceeds to step 207. In step 206, the power storage device is charged. When step 206 ends, the process ends. If it can be step 207 and the electric wire voltage is equal to or lower than the discharge start voltage, the process proceeds to step 208, and if it is higher than the discharge start voltage, the process proceeds to step 209. In step 208, the power storage device is discharged. When step 208 ends, the process ends. If the charging rate is smaller than the charging rate target value at step 209, the routine proceeds to step 210. In step 210, charging is performed by reducing power so that the voltage of the feeder line does not drop to the discharge start voltage due to voltage fluctuation. When step 210 ends, the process ends. If the charging rate is larger than the charging rate target value in step 211, the process proceeds to step 212. In step 212, the electric power is reduced so as not to rise to the charging start voltage due to voltage fluctuation, and discharging is performed. When step 212 ends, the process ends.

FIG. 7 is an operation waveform diagram when a conventional power storage device and the power storage device of the present invention are installed in a certain section. The horizontal axis represents time, the vertical axis represents (a) the position of the station and substation and the position of the vehicle, (b) the feeder voltage at the position where the power storage equipment is connected, and (c) the conventional power storage equipment. Charging rate when connected,
(D) is the charging rate of the power storage device when the power storage facility according to the present invention is connected.

  The power storage equipment will be installed in the vicinity of the station where regeneration and power running occur frequently, and operation will start in the normal operation mode. At time T1, the vehicle 1 starts regeneration, and the feeder voltage rises. When the feeder voltage exceeds the charging start voltage, the power storage device starts charging. At time T2, the vehicle 1 stops at the station. Since the regeneration of the vehicle has ended, the feeder voltage drops. The feeder voltage is in an intermediate range lower than the charge start voltage and higher than the discharge start voltage, and the charge rate enters a dead zone centered on the charge rate target value, so the power storage device does not charge or discharge. At time T3, the substation B adjacent to the power storage facility stops, and the feeder voltage decreases. However, since the vehicle is not powered, the feeder voltage does not drop to the discharge start voltage. For this reason, the power storage device does not discharge. When the train starts powering at time T4, the feeder voltage decreases to the discharge start voltage, so the power storage device starts discharging and the charging rate gradually decreases. Since the electric wire voltage and the charging rate have entered region 1 in FIG. 5 at time T5, the operation mode is changed to the voltage compensation mode. Moreover, since the train has finished power running, the feeder voltage increases. Although the feeder voltage is in the middle range, the charging rate is decreasing, so the power storage device charges little by little. The vehicle starts regeneration at time T6, and the feeder voltage rises. Since the feeder voltage exceeds the charging start voltage, the power storage device starts charging. Since the vehicle has finished regeneration at time T7, the feeder voltage returns to the intermediate region.

  In the case of conventional control, since the charging rate of the power storage device has reached the target value range, no further charging is performed. As a result, when the vehicle starts powering from time T8, the charging rate becomes 0 before time T9, and the vehicle cannot be accelerated any further. On the other hand, since the target value of the charging rate is increased by changing the operation mode, the power storage device of the present invention charges little by little after time T7. As a result, the power storage device of the present invention has a discharge capacity before time T9, and the acceleration of the train can be continued. Thereafter, when the substation B restarts at time T10, the feeder voltage increases. Since the wire voltage has entered the region 2 in FIG. 5 at the charging rate at time T11, the operation mode is changed to the normal operation mode. By changing the operation mode to the normal operation mode, the target value of the charging rate is lowered and the charging capacity is increased. Thereby, it is possible to prevent regenerative invalidity from occurring because regenerative power cannot be absorbed at full charge.

  Next, a second embodiment will be described. The same number is attached | subjected to the structure same as 1st embodiment, and description is abbreviate | omitted.

  FIG. 8 is an overall configuration diagram of a power storage facility and a railway power supply system using the power storage facility according to the second embodiment of the present invention.

  The controller 15 has a method of receiving an external input, and controls the DC / DC converter 7 to control power transfer between the feeder and the power storage device. The external input 14 is connected to the substation 42 and transmits a stop signal to the controller 15 when the substation 42 stops.

  FIG. 9 is a functional block diagram of the controller 15. The mode determination unit 86 determines the operation mode based on the external input 14, that is, an input signal from the outside of the power storage facility. The charge / discharge control unit 84 switches charging / discharging based on the wire voltage and the charging rate in the operation mode determined here.

  FIG. 10 shows a control flow for mode change determination of the mode determination unit 86. First, in step 106, an external input is read. If the input from the external input notifies the substation stop in step 107, the process proceeds to step 103. Otherwise, the process proceeds to step. If the input from the external input notifies the substation restart in step 108, the process proceeds to step 105. If not, the process ends. With this configuration, the operation mode can be changed immediately after the substation is stopped.

1 is an overall configuration diagram of an embodiment of a power storage facility according to the present invention and a railway power supply system using the same. It is an example of the functional block diagram of the controller in 1st embodiment of this invention. It is the figure which showed the threshold value of control in the normal operation mode of this invention. It is the figure which showed the threshold value of control in the voltage compensation mode of this invention. It is a flowchart which shows control of the mode determination part in 1st embodiment of this invention. It is a flowchart which shows control of the charging / discharging control part of this invention. It is an operation | movement waveform diagram at the time of implementing 1st embodiment of this invention. It is a whole lineblock diagram of other embodiments of the electrical storage equipment concerning the present invention, and a railroad electric power feeding system using the same. It is a functional block diagram of the controller in other embodiments of the present invention. It is a flowchart which shows control of the mode determination part in other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Feed line 2 Rail 3 Electric vehicle 5 Capacitor 6 Reactor 7 DC / DC converter 8, 15 Controller 9 Power storage device 11 Feed voltage measurement part 12 Charge rate measurement part 13 Power storage equipment 14 External input 41, 42 Substation 81 Feed voltage Reading unit 82 Charging rate reading unit 83, 86 Mode determination unit 84 Charging / discharging control unit

Claims (7)

A storage facility connected to a feeder,
A power storage device for storing electric power;
A charge rate measuring unit for measuring the charge rate of the power storage device;
A feeder voltage measuring unit for measuring feeder voltage,
A power converter that converts power between the feeder and the power storage device;
A controller for controlling charge / discharge power of the power conversion unit,
The controller includes a mode determination unit that determines an operation mode based on a charging rate of the power storage device measured by the charging rate measurement unit and a feeder voltage measured by the feeder voltage measurement unit, and the feeder voltage. The electrical storage equipment which has the charging / discharging control part which switches charging / discharging from the said charging rate and the said operation mode. The power storage facility according to claim 1,
The mode determination unit has a first threshold value and a second threshold value determined from a wire voltage at a predetermined charging rate, and the feeder voltage measured from the feeder voltage measurement unit is the first threshold value. The power storage equipment is set to the first operation mode when the threshold value is below the first threshold value, and is set to the second operation mode when the feeder voltage exceeds the second threshold value that is greater than the first threshold value. The power storage facility according to claim 1,
The charge / discharge control unit is a feeder that is measured with respect to a predetermined charge start voltage at which the power storage device starts charging, a discharge start voltage at which the power storage device starts to discharge, and a target value of the charge rate. A power storage facility that controls charging and discharging of the power storage device based on a voltage. The power storage facility according to claim 3,
The charge / discharge control unit is a power storage facility that charges the power storage device when a measured feeder voltage is higher than the charge start voltage, and discharges the power storage device when lower than the discharge start voltage. The power storage facility according to claim 3,
The charging start voltage and the discharge start voltage are power storage facilities that have different preset values according to the operation mode. The power storage facility according to claim 3,
The charge / discharge control unit charges the power storage device when the measured charging rate is smaller than the target value of the charging rate, and the power storage device when the measured charging rate is higher than the target value of the charging rate. Electric storage equipment that discharges. A storage facility connected to a feeder,
A power storage device for storing electric power;
A charge rate measuring unit for measuring the charge rate of the power storage device;
A feeder voltage measuring unit for measuring feeder voltage,
A power converter that converts power between the feeder and the power storage device;
A controller for controlling charge / discharge power of the power conversion unit,
The controller includes a mode determination unit that determines an operation mode based on an input signal from the outside, and a charge / discharge control unit that switches charge / discharge from the feeder voltage, the charging rate, and the operation mode.

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