JP4711917B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device that reduces the burden on power supply equipment by charging when surplus power is generated and discharging when power shortage occurs in a DC power system, and in particular, demand peak reduction The present invention relates to a power storage device having a function.

In a DC feeding system, a storage element that accumulates power supplied via a DC overhead line, a charge / discharge circuit that performs a charge / discharge operation of the storage element, and a control circuit that controls the charge / discharge circuit are provided. There has been proposed a DC power supply device that effectively recycles the regenerative power of an electric vehicle by charging the power storage device with a voltage rise and discharging the power storage device with an output current to the electric vehicle (for example, Patent Document 1).
On the other hand, demand contracts are adopted for large-scale customers, and reducing peak power leads to savings in electricity charges, so demand control (suppressing power demand accumulated in 30-minute units below a certain level) is implemented. Even in a DC feeder system, a power storage device is provided, and when the surplus power is generated, the power storage device is charged, and when the power shortage occurs, the power supply facility is charged. It can be considered that the peak of power demand can be reduced.
JP 2005-206111 A

As described above, when a power storage device is provided in a DC feeder system and power shortage occurs, it is considered that the peak of power demand can be reduced by forcibly discharging, but conventional power storage devices There was no control to actively reduce the peak of power demand, and the effect was limited.
In the device described in Patent Document 1, the storage element is charged by the voltage rise of the DC overhead line, and the storage element is discharged by the output current to the electric vehicle, and the regenerative power of the electric vehicle is effectively reused. Although it was possible, it did not actively detect power demand and actively reduce power demand peaks.
In addition, since it is assumed that the power storage device is installed in a place away from a power supply source such as a substation, it is difficult to detect a power demand by installing a power detector, and the increase in power demand is not always appropriate. There was also a problem that it could not be detected.

Furthermore, in the case of a device that controls charging / discharging of a power storage device in accordance with the overhead line voltage, when a demand peak occurs, a supplementary charging operation of the power storage device may be performed without discharging the power storage device. There was also a problem that there was a possibility of increasing the peak of.
The present invention has been made in view of the above-described circumstances, and can predict demand peaks, autonomously charge and discharge, and reduce demand peak power without requiring a power detector. An object of the present invention is to provide a power storage device for direct current railway.

In the present invention, the above problem is solved as follows.
(1) In a power storage device for DC railways for suppressing a peak of power demand, which is an integrated value of power demand per unit time, between a power storage device, an overhead line supplying DC power, and the power storage device A DC-DC converter connected to the power supply, a first voltage detector for detecting the overhead line voltage, a second voltage detector for detecting the voltage of the power storage device, and a charge / discharge current of the power storage device. Based on the overhead voltage detected by the current detector and the first and second voltage detectors, the power storage device voltage, and the charge / discharge current detected by the current detector, the DC-DC converter is controlled. And a controller for controlling charging and discharging of the power storage device.
The control unit includes a demand detection means for detecting an increase in power demand, a peak in the power demand, and a charge / discharge current command value generation based on a rate of time when the power loss and / or the overhead line voltage in the overhead line falls below a predetermined value. And a control means for controlling the DC-DC converter to control the charge / discharge current of the power storage device according to the current command value generated by the charge / discharge current command value generating means, and the charge / discharge current command value When the power demand increase and the demand peak are not detected, the generating means outputs a normal power storage device current command value corresponding to the overhead line voltage and the power storage device voltage, and when the demand detection means detects an increase in demand, Outputs a power storage device current command value at the time of an increase in demand for charging the power storage device to increase the amount of power stored in the power storage device. When the peak demand has been detected by, to discharge the power storage device, and outputs a demand peak shaving power storage device current command value for suppressing the peak power demand.
(2) In the above (1), the unit time for integrating the power demand and obtaining the power demand is divided into a first time zone and a second time zone, and the demand detecting means In the band, an increase in power demand or a peak in power demand is detected.
The charge / discharge current command value generating means is configured to increase the power storage amount of the power storage device at least after the second time period when an increase in power demand is detected in the first time period. Demand peak cut power storage for outputting the power storage device current command value at the time of increase and suppressing the peak of the power demand at least in the second time zone when the peak of the power demand is detected in the first time zone. Outputs the device current command value.
(3) In the above (2), in order to suppress the discharge of the power storage device, a discharge memory control means for suppressing a demand peak cut operation is provided, and the discharge memory control means receives a demand peak from the charge / discharge current command value generation means. After the cut power storage device current command value is output, discharging of the power storage device is suspended at least in the first time zone in the next unit time.
(4) In the power storage device according to (1), (2), and (3), the demand detection means outputs a first demand increase detection signal c1 when the power loss in the DC overhead line exceeds the first threshold a1. The first demand calculation means for outputting the first demand peak detection signal c2 when the power loss exceeds the second threshold value a2 (a1 <a2), and the time when the overhead line voltage falls below a predetermined value. When the ratio exceeds the first threshold value b1, the second demand increase detection signal d1 is output, and the ratio of the time when the overhead wire voltage falls below the predetermined value exceeds the second threshold value b2 (b1 <b2). When the second demand calculation means for outputting the second demand peak detection signal d2 and the first and second demand increase detection signals c1 and d1 are output, the demand increase is detected, Second deman When peak detection signal c2, d2 is output, constituting a means for detecting a demand peak.
(5) In the power storage device of the above (1), (2), (3), and (4), the charge / discharge current command value generation means outputs a normal overhead wire voltage compensation current command value corresponding to the overhead wire voltage. Means, second means for outputting a normal-time storage capacity adjustment current command value according to the power storage device voltage, third means for outputting a demand-increasing overhead wire voltage compensation current command value according to the overhead wire voltage, The fourth means for outputting the storage capacity adjustment current command value at the time of demand increase according to the device voltage, the fifth means for outputting the peak cut current command value according to the battery voltage, and neither demand increase nor demand peak is detected. In normal times, the current command values output from the first and second means are combined to generate a charge / discharge current command value for the power storage device in normal times, and when an increase in demand is detected, the third and fourth Current finger output from the means of The value is synthesized to generate a charge / discharge current command value for the power storage device when the demand increases, and when the demand peak is detected, the current command values output from the third and fifth means are synthesized, It comprises charge / discharge current command value calculation means for generating a charge / discharge current command value for suppressing the peak.

In the present invention, the following effects can be obtained.
(1) When an increase in power demand is detected, and when an increase in demand is detected, the amount of power stored in the power storage device is increased by predicting that the demand will peak, so when a peak in demand is detected The peak of demand can be reliably suppressed by the power charged in the power storage device.
That is, according to the present invention, demand peak power can be reduced by predicting demand peaks and autonomously charging and discharging.
Moreover, since the increase in the power demand and the peak of the demand are detected based on the ratio of the time when the power loss in the overhead line and / or the overhead line voltage is lower than the predetermined value, the demand can be predicted without providing the power detector. Demand peak detection can be performed.
(2) The unit time for accumulating power demand and determining the power demand is divided into a first time zone and a second time zone, and an increase in power demand or a peak of power demand is detected in the first time zone. Since the control corresponding to the increase in the power demand or the peak detection of the power demand is performed at least after the second time zone, the control according to the change in the demand can be performed within the unit time. The peak can be reliably suppressed.
(3) Since the discharge of the power storage device is stopped at least in the first time zone in the next unit time after the demand peak cut power storage device current command value is output, excessive discharge of the power storage device is prevented. Can be suppressed.

FIG. 1 is a diagram showing a main circuit and a control unit of the power storage device of the present invention.
In the figure, 1 is a filter reactor, 2 is a filter capacitor, one end of the filter reactor 1 is connected to the + side of the DC feeding system, and the ground side of the filter capacitor 2 is the − of the DC feeding system. The side is connected. A voltage detector 22 for detecting the overhead wire voltage VL is provided on the one end side of the filter reactor 1.
A series circuit of a first switching element 3 and a second switching element 4 is connected in parallel to both ends of the filter capacitor 2, and a connection point between the first switching element 3 and the second switching element 4 is A smoothing filter composed of the smoothing reactor 5 and the smoothing capacitor 6 is connected.

Furthermore, a power storage device 7 composed of a battery or the like is connected to both ends of the smoothing capacitor 6, and the power storage device 7 is provided with a voltage detector 24 for detecting the voltage VB of the power storage device 7. Further, a current detector 23 that detects the charge / discharge current IB of the power storage device 7 is provided between the connection points of the smoothing reactor 5 and the first switching element 3 and the second switching element 4.
The first and second switching elements 3 and 4, the filter reactor 1, the filter capacitor 2, the smoothing reactor 5 and the smoothing capacitor 6 constitute a DC-DC converter, and the first switching element 3 and the second switching element 3 The power storage device 7 can be charged and discharged by switching the switching element 4.

The overhead line voltage VL detected by the voltage detector 22, the charging / discharging current (battery current) IB detected by the current detector 23, and the voltage VB of the power storage device detected by the voltage detector 24 are sent to the control unit 21. It is done.
As will be described later, the control unit 21 detects a demand increase and a demand peak in synchronization with a cycle (for example, 30 minutes) for calculating the average power of the demand. Then, the result at the time when 2/3 of the period has elapsed is determined and output, and the integrated data is cleared after the determination.
That is, a unit time (for example, 30 minutes, which will be described as 30 minutes hereinafter) that is a cycle for calculating the average power of demand is defined as a first time zone (for example, the first 20 minutes) and a second time zone (for example, In the remaining 10 minutes, the integrated value of the power loss amount in the overhead line is calculated in the first time zone, and the ratio of the time when the overhead line voltage VL is lower than the preset value is obtained.
Then, the integrated value of the power loss amount and the proportion of time when the overhead line voltage is lower than a preset set value are respectively compared with threshold values, and based on the result, an increase in demand and a peak of demand are detected.
When an increase in demand is detected, the DC-DC converter is controlled, a charging current is passed through the power storage device 7, and the power storage amount of the power storage device 7 is increased. When a demand peak is detected, the DC-DC converter is controlled to discharge the power storage device 7 and suppress the power demand peak.

FIG. 2 is a diagram showing the configuration of the control unit 21. In the following description, the configuration of each unit of the control unit is shown by a block diagram or the like, but the control unit can be realized by software executed by a computer, for example.
In FIG. 2, 11 is a first demand calculator, and 12 is a second demand calculator.
The first demand calculation unit 11 calculates the power loss generated in the transmission line (overhead line) from the substation to the power storage device of the present invention from the overhead line voltage VL, the transmission voltage Vo of the substation, and the overhead line resistance RL. Time integration is performed, and an integrated power loss value is obtained by the following equation (1) and compared with a preset threshold value WLL.

For example, when the unit time for obtaining the power demand is 30 minutes, the integration times t1 to t2 are 00 to 20 minutes and 30 to 50 minutes per hour. In Equation (1), no integration is performed when Vo−VL <0.
Then, when 2/3 of the period for calculating the average power of demand (for example, every 30 minutes) has elapsed, the integrated value of power loss is compared with the threshold WLL, and the integrated value of power loss is set in advance. When the first threshold value (for example, 90% of the threshold value WLL) is exceeded, the demand increase detection signal a2 is output, and when the second threshold value (for example, the threshold value WLL) is exceeded, the demand peak detection signal a1 is output.

In addition, the second demand calculation unit 12 obtains a voltage drop time td by integrating the time when the overhead line voltage VL is lower than a preset value for a predetermined time, and divides this by the predetermined time TL to obtain a unit time per unit time. The ratio of the voltage drop time is calculated, and this voltage drop ratio is compared with the threshold value VLLRATIO.
Similar to the first demand calculation unit 11, the calculation cycle is 00 to 20 minutes per hour and 30 to 50 minutes when the unit time for obtaining the power demand is 30 minutes, for example. Then, when 2/3 of the period for calculating the average power of demand (for example, every 30 minutes) has elapsed, the voltage drop rate is compared with the threshold value VLLRATIO, and the voltage drop rate is set to the first preset value. When the threshold value (for example, 90% of the threshold value VLL RATIO) is exceeded, the demand increase detection signal b2 is output, and when the second threshold value (for example, the threshold value VLL RATIO) is exceeded, the demand peak detection signal b1 is output.

When the demand increase detection signal a2 obtained by the demand calculation unit 11 and the demand increase detection signal b2 obtained by the demand calculation unit 12 are input to the AND gate G2, the AND gate G2 outputs both a2 and b2. (When both a2 and b2 become high level), a demand increase switching command signal PC90 is output.
The demand peak detection signal a1 obtained by the demand computation unit 11 and the demand peak detection signal b1 obtained by the demand computation unit 12 are input to the AND gate G1, and both a1 and b1 are output from the AND gate G1. (When both a1 and b1 are at a high level), the peak cut request signal PC100 is output.
When the power demand in the feeder system increases, the power loss of the transmission line increases due to the load such as a train connected to the overhead line, and the overhead line voltage detected by the voltage detector 22 decreases. Therefore, an increase in power demand and a peak can be detected by detecting the integrated value of power loss and the voltage drop rate of the overhead wire as described above and comparing the detected value with a preset threshold value.

  In this embodiment, when the demand peak detection signals a1 and b1 are output together using the AND gates G1 and G2, the peak cut request signal PC100 is output and both the demand increase detection signals a2 and b2 are output. At this time, the demand increase switching command signal PC90 is output. However, the logic for outputting the peak cut request signal PC100 and the demand increase switching command signal PC90 can be appropriately selected according to the installation status of the power storage device of the present invention, for example, any of the demand peak detection signals a1 and b1. When either is detected or when either of the demand increase detection signals a2 and b2 is detected, the peak cut request signal PC100 and the demand increase switching command signal PC90 may be output.

Reference numerals 13 and 14 shown in FIG. 2 are a normal overhead line voltage compensation current calculation unit and a demand increase overhead line voltage compensation current calculation unit, respectively, which are normal charge / discharge current command values of the power storage device 7 according to the DC overhead line voltage VL. The overhead wire voltage compensation current command value Itp and the demand increase overhead wire voltage compensation current command value Idp are output.
Reference numerals 15 and 16 denote a normal storage capacity adjustment current calculation unit and a demand increase storage capacity adjustment current calculation unit, respectively, which are normal-time storages that are charge / discharge current command values of the storage device 7 according to the storage device voltage VB. The capacity adjustment current command value Itpb and the storage capacity adjustment current command value Idpb at the time of demand increase are output.
Reference numeral 17 denotes a peak cut discharge current calculation unit that outputs a peak cut discharge current command value Ippc, which is a charge / discharge current command value of the power storage device 7 at the time of peak cut, according to the overhead line voltage VL.
The outputs of the normal overhead wire voltage compensation current calculator 13 and the demand increase overhead wire voltage compensation current calculator 14 are connected to the terminals a and b of the changeover switch SW1.
Also, the outputs of the normal storage capacity adjustment current calculation section 15 and the demand increase storage capacity adjustment current calculation section 16 are connected to the terminals a and b of the changeover switch SW2, and the output of the peak cut discharge current calculation section 17 is the changeover switch. It is connected to terminal b of SW3.

The change-over switches SW1 to SW3 are connected to the switching means 20a. It is switched by 20b. Normally, the switching means 20a conducts between the terminals a and c of the selector switches SW1 and SW2, and when the demand increase switching command PC90 is output, switches the selector switches SW1 and SW2 and conducts between b and c. State.
Further, the switching means 20b normally switches between the a and c terminals of the changeover switch SW3, and when the peak cut discharge command PCDSG is output from the discharge command storage unit 18, the changeover switch SW3 is changed to b− The connection between c is set in a conductive state (the operation of the discharge command storage unit 18 will be described later).
Accordingly, the normal time overhead line voltage compensation current command value Itp and the normal storage capacity adjustment current command value Itpb are output from the terminals c of the changeover switches SW1 and SW3, respectively. The overhead line voltage compensation current command value Idp and the demand increasing storage capacity adjustment current command value Idpb are output.
Further, when the peak cut discharge command PCDSG is output (in this case, the demand increase switching command PC90 is output), the overhead line voltage compensation current command value Idp at the time of demand increase from the terminal c of the changeover switches SW1 and SW3, the peak Cut discharge current command value Ippc is output.

Reference numeral 19 denotes a power storage device current command value calculation unit which synthesizes the current command values Itp and Itpb, or the current command values Idp and Idpb, or the current command values Idp and Ippc, which are output from the terminals c of the changeover switches SW1 and SW3. Thus, a power storage device current command value IP that is a charge / discharge current command value of the power storage device 7 is generated.
The power storage device current command value IP output from the power storage device current command value calculation unit 19 is given to the gate control unit 30 via the changeover switch SW4. The gate control unit 30 controls the DC-DC converter so that the charge / discharge current of the power storage device 7 becomes the power storage device current command value IP.
When the charge / discharge pause command PAUSE is not output from the discharge command storage unit 18, the changeover switch SW4 is switched by the switching means 20c so as to be in a conductive state between a and c, and the power storage device current command value is The IP is sent to the gate control unit 30. Further, when the charge / discharge pause command PAUSE is output, the changeover switch SW4 is switched by the switching means 20c so as to be in a conductive state between bc and 0A is given to the gate control unit 30 as a current command value. The charging / discharging operation of the power storage device 7 is stopped.

FIG. 3 shows the normal overhead line voltage compensation current command value Itp, the normal storage capacity adjustment current command value Itpb, the demand increase overhead line voltage compensation current command value Idp, the demand increase storage capacity adjustment current command value Idpb, and the peak cut discharge. It is a figure which shows an example of the pattern of electric current command value Ippc.
The normal overhead wire voltage compensation current command value Itp is set so that the discharge current of the power storage device 7 gradually increases when the overhead wire voltage VL falls below the first voltage d0 (for example, 1440 V), as shown in FIG. When the voltage drops below the second voltage d1 (eg, 1340V), the discharge current is set to -300A, and when the overhead line voltage VL falls below the third voltage d2 (eg, 1100V), the current command value of the power storage device is set to a predetermined value. (For example, 0).
Further, when the overhead line voltage VL becomes larger than the first voltage d0, the current command value of the power storage device is set to a predetermined value (for example, 0), and the overhead line voltage VL is higher than the first voltage by the fourth voltage c0. When the voltage rises above (for example, 1630 V), the charging current of the power storage device 7 is set to gradually increase. When the voltage becomes larger than the fifth voltage c1 (for example, 1730 V), the charging current is set to 570 A, and the overhead line voltage VL is When the voltage c2 becomes larger than the voltage c2 (for example, 1850 V), the charging current command value is set to a predetermined value (for example, 0).

The demand increase overhead wire voltage compensation current command value Idp has the same pattern as above, but as shown in FIG. 5B, the first voltage d01 is 1400V, the second voltage d11 is 1300V, for example. For example, the third voltage d21 is 1100V, the fourth voltage c01 is 1600V, the fifth voltage c11 is 1700V, and the sixth voltage c21 is 1850V, for example.
That is, when the demand increases, the overhead line voltage for starting charging (discharging) of the power storage device is reduced from the normal time. Thereby, when the demand increases, the power storage device 7 is charged even if the overhead line voltage is lower than the normal voltage, and the power storage device is not discharged unless the overhead voltage becomes a voltage lower than the normal voltage.

As shown in FIG. 5C, the normal-time storage capacity adjustment current command value Itpb is such that when the power storage device voltage VB falls below the first voltage db0 (for example, 650 V), the charging current of the power storage device 7 gradually increases. When the voltage is lower than the second voltage db1 (for example, 645V), the charging current is set to 180A.
Further, when the power storage device voltage VB becomes larger than the first voltage db0, the power storage device current command value is set to a predetermined value (for example, 0), and from a third voltage cb0 (for example, 670 V) that is larger than the first voltage. When the voltage rises, the discharge current of the power storage device 7 is set to gradually increase, and when the voltage becomes higher than the fourth voltage cb1 (for example, 675 V), the discharge current is set to -180A.
The demand increasing storage capacity adjustment current command value Idpb has the same pattern as above, but as shown in FIG. 4D, the first voltage db01 is 725V, the second voltage db11 is 720V, for example, and the like. The third voltage cb01 is, for example, 730V, and the fourth voltage cb11 is, for example, 735V.
That is, when demand increases, the power storage device voltage VB that starts charging / discharging of the power storage device is increased from the normal time. As a result, when the demand increases, the power storage device 7 is charged even if the power storage device voltage VB is higher than the normal time, and is not discharged unless the power storage device voltage VB is higher than the normal time.

  As shown in FIG. 5E, the peak cut discharge current command value Ippc is set so that the discharge current of the power storage device 7 gradually increases when the overhead line voltage VL is lower than the first voltage dp0 (for example, 1600 V). When the voltage drops below the second voltage dp1 (for example, 1500 V), the discharge current is set to -300A.

FIG. 4 is a diagram for explaining the synthesis of the current command value in the power storage device current command value calculation unit 19. FIG. 5A shows a case where the normal overhead wire voltage compensation current command value Itp and the normal storage capacity adjustment current command value Itpb are combined.
As shown in the figure, the power storage device current command value calculation unit 19 calculates the current command value of the normal overhead wire voltage compensation current command value Itp in the region where the overhead wire voltage is smaller than d1 or larger than c1. Output as value IP. When the overhead line voltage is larger than d0 and smaller than c0, the normal storage capacity adjustment current command value Itpb corresponding to voltage VB of power storage device 7 is set as the power storage device current command value. Further, when the overhead line voltage is smaller than d0 and larger than d1, or larger than c0 and smaller than c1, the larger absolute value of the normal overhead line voltage compensation current command value Itp and the normal storage capacity adjustment current command value Itpb is determined. Select the power storage device current command value.
That is, as shown in the figure, the area d1-c1 basically gives priority to the value of the normal-time storage capacity adjustment current command value.

  Note that the composition of the demand increase overhead wire voltage compensation current command value Idp and the demand increase storage capacity adjustment current command value Idpb is the same as described above. In the region where the overhead wire voltage is smaller than d11 or larger than c11, the demand is increased. The current command value of the increase overhead wire voltage compensation current command value Idp is output as the power storage device current command value IP. Further, when the overhead line voltage is larger than d01 and smaller than c01, the value of storage capacity adjustment current command value Idpb at the time of demand increase according to voltage VB of power storage device 7 is set as the power storage device current command value. Further, when the overhead line voltage is smaller than d01 and larger than d11, or larger than c01 and smaller than c11, the absolute values of the demand line overhead line voltage compensation current command value Idp and the demand increase storage capacity adjustment current command value Idpb are large. Is selected as the power storage device current command value.

FIG. 4B shows a case where the overhead line voltage compensation current command value Idp and the peak cut discharge current command value Ippc are combined when the demand increases.
As shown in the figure, the power storage device current command value calculation unit 19 calculates the current command value of the demand line overhead wire voltage compensation current command value Idp in the region where the overhead wire voltage is smaller than d11 or larger than c11. Output as command value IP. When the overhead wire voltage is larger than d01 and smaller than c01, the value of the peak cut discharge current command value Ippc corresponding to the overhead wire voltage VL is set as the power storage device current command value. Furthermore, when the overhead line voltage is smaller than d01 and larger than d11, or larger than c01 and smaller than c11, the larger one of the absolute values of the overhead line voltage compensation current command value Idp and the peak cut discharge current command value Ippc at the time of increasing demand is selected. And the power storage device current command value.

FIG. 5 is a diagram illustrating a configuration example of the gate control unit 30.
The power storage device current command value IP output from the changeover switch SW4 shown in FIG. 2 is given to the comparator 32 via the low-pass filter 31. Comparator 32 compares power storage device current command value IP with battery current IB and provides the deviation to current controller 33.
The current controller 33 generates a control output Vr corresponding to the deviation, and the control output Vr has its upper and lower limits limited by a limiter 34 and is given to the IGBT gate controller 35 as a voltage command VREF. The IGBT gate control unit 35 controls the switching elements 3 and 4 of the DC-DC converter shown in FIG. 1 to charge / discharge current of the power storage device 7 so that the power storage device current command value IP and the battery current IB become equal. To control.
The limiter 34 is provided for overcharge protection and overdischarge protection of the power storage device. The upper limit voltage and the lower limit voltage are set by an upper limit setting unit 36 and a lower limit setting unit 37. The upper limit setting unit 36 sets the voltage upper limit to a VFC larger than the VCM until the power storage device voltage VB reaches the upper limit VCM, and sets the voltage upper limit to the VCM that is the upper limit value when the upper limit value VCM is reached.
Lower limit setting unit 37 sets the voltage lower limit to 0 until power storage device voltage VB reaches VDM, which is the lower limit value, and sets the voltage lower limit to VDM, which is the lower limit value, when the lower limit value is reached.

FIG. 6 is a diagram showing a configuration example of the discharge command storage unit 18 shown in FIG.
In FIG. 6, the peak cut request signal PC100 and the demand increase switching command signal PC90, which are the outputs of the AND gates G1 and G2, are input to the AND gate G3, and when both the PC 100 and PC 90 become high level, the peak catch mode signal PCMODE goes high.
Here, when the peak cut discharge command signal is not issued before the previous cycle and the peak cut discharge is not stored, the flip-flop FF2 is not set, and the peak cut discharge storage signal DSGMEM which is the output thereof is It is at a low level, and the output of the inverter INV1 is at a high level.
Therefore, when the peak catch mode signal PCMODE becomes high level, the output of the AND gate G5 becomes high level, the flip-flop FF1 is set, and the peak cut discharge command signal PCDSG becomes high level. When the signal PCDSG becomes high level, the control unit 21 discharges the power storage device 7 as described above, and performs an operation of suppressing the peak of the power demand.

Further, when the peak cut discharge command signal PCDSG becomes high level, the timer TM1 starts measuring time. For example, after 10 minutes, the timer TM1 outputs a time-up signal and resets the flip-flop FF1. For this reason, the peak cut discharge command signal PCDSG becomes a low level, and the discharging of the power storage device 7 is stopped.
On the other hand, when the peak cut discharge command signal PCDSG becomes high level, the flip-flop FF2 is set, the fact that the peak cut discharge command signal PCDSG is output is stored, and the peak cut discharge storage signal DSGMEM becomes high level.
While the flip-flop FF2 is set, the output of the inverter INV1 is low level, and even if the peak catch mode signal PCMODE is output, the output of the AND gate G5 does not become high level, and the peak cut discharge command signal PCDSG is not output.
The peak catch mode signal PCMODE is input to the reset terminal side of the flip-flop FF2 via the inverter INV2. When the peak catch mode signal PCMODE becomes low level after the period for obtaining the next demand, the flip-flop FF2 is reset and discharge memory is stored. Is released.

Further, when the flip-flop FF2 is set and its output becomes high level, the peak catch mode signal PCMODE is high level, and further, when the flip-flop FF1 is reset by the timer TM1 and the peak cut discharge command signal PCDSG becomes low level, The PAUSE signal that is the output of the AND gate G4 becomes high level. When the PAUSE signal becomes high level, discharging of the power storage device 7 is stopped.
That is, the peak cut discharge command signal PCDSG is output for a set time (for example, 10 minutes) of the timer TM1, and during this time, the peak cut suppression operation due to the discharge of the power storage device 7 is performed, and the PAUSE signal is output after the set time has elapsed. Therefore, the peak cut suppression operation due to the discharge of the power storage device 7 is stopped.

FIG. 7 is a time chart showing the operation of the present embodiment, showing the relationship between the cycle for obtaining the average demand power and the operation mode, and the pattern of combinations of current command values in each operation mode. Hereinafter, the operation of the power storage device of this embodiment will be described with reference to FIG. 1 and FIG. 1, FIG. 2, FIG. 5, FIG.
As shown in FIG. 7, the demand peak detection operation is performed in the first 20 minutes in synchronization with the period for calculating the average power of the demand (for example, 30 minutes), and after 2/3 of this period has elapsed. Based on the determination result, charge / discharge of the power storage device 7 is controlled.
That is, a peak monitoring operation is performed at 00 to 20 minutes every hour, and it is determined whether the peak cut request signal PC100 and the demand increase switching command signal PC90 have been output when 20 minutes have passed. Further, it is determined whether the peak cut discharge memory signal DSGMEM described in FIG. 6 is output. Then, based on the determination result, a peak cut operation, a pause, a power storage device capacity increase operation, and the like are performed after the remaining 10 minutes.

When the power demand in the feeder system is at a normal level, the change-over switches SW1 to SW4 shown in FIG. 2 are in the state shown in the figure, and the power storage device current command calculation unit 19 has the normal overhead wire voltage compensation current calculation unit 13 The normal overhead line voltage compensation current command value Itp to be output and the normal storage capacity adjustment current command value Itpb output from the normal storage capacity adjustment current calculation unit 15 are combined to generate the storage device current command value Ip (FIG. 7 a + c operation pattern).
The gate control unit 30 operates the first switching element 3 and the second switching element 4 to store the current so that the current of the power storage device 7 becomes the power storage device current command value Ip generated by the power storage device current command calculation unit 19. The current of the device 7 is controlled (A in FIG. 7).

Here, when the power demand in the feeder system increases, the power loss generated in the transmission line from the substation to the power storage device increases due to a load such as a train connected to the overhead line, and is detected by the voltage detector 22. The overhead line voltage decreases.
As a result, for example, when the demand increase switching command signal PC90 and the peak cut request signal PC100 are simultaneously output, the peak cut discharge command PCDSG is output. At this time, it is assumed that the peak cut discharge memory signal DSGMEM is not output.
As a result, the contacts of the switches SW1, SW2 and SW3 shown in FIG. 2 are switched to the b side, and the normal overhead wire voltage compensation current command value Itp is changed to the overhead wire voltage compensation current command value Idp during demand increase. The command value Itpb is switched to the peak cut current command value Ippc. Note that the peak cut discharge memory signal DSGMEM is output by outputting the peak cut discharge command PCDSG.
The power storage device current command calculation unit 19 generates the power storage device current command value Ip by combining the demand increase overhead wire voltage compensation current command value Idp and the peak cut current command value Ippc (operation pattern b + e in FIG. 7). .
The gate control unit 30 operates the first switching element 3 and the second switching element 4 to control the current of the power storage device 7 to be the power storage device current command value Ip generated by the power storage device current command calculation unit 19. To do. Since the current command value obtained by combining the overhead line voltage compensation current command value Idp and the peak cut current command value Ippc is a command value that always discharges the power storage device regardless of the power storage amount of the power storage device 7, The device 7 discharges and suppresses the demand peak (B in FIG. 7).

The timer TM1 of the discharge command storage unit 18 shown in FIG. 6 is timed up at the end of the cycle for calculating the average power of demand, and stops the peak cut discharge command PCDSG. Further, as described above, the charge / discharge pause command PAUSE is output from the discharge command storage unit 18. As a result, the switch SW4 in FIG. 2 is switched to the b side, the power storage device current command value Ip becomes 0, and all charging / discharging is suspended. The discharge command storage unit 18 continues to output the charge / discharge pause command PAUSE while the peak cut discharge storage signal DSGMEM is output and the peak cut catch mode signal PCMODE is output, and the peak cut discharge command is output. No (C in FIG. 7).
On the other hand, during the period C in FIG. 7, the peak monitoring operation is performed. As a result, even if the demand increase switching command signal PC90 and the peak cut request signal PC100 are output at the same time, the peak cut discharge memory signal DSGMEM is Since it is output, the output of the AND gate G4 shown in FIG. 6 becomes high level, and the charge / discharge pause command PAUSE continues to be output (D and E in FIG. 7).

Here, when the power demand changes and the peak cut request signal PC100 is not output and the demand increase switching command signal PC90 is output by the determination of the period E in FIG. 7 (peak cut discharge storage signal DSGMEM). 2 is switched to the b side, and the switch SW3 is switched to the a side. Further, since the peak catch mode is canceled and the peak catch mode signal PCMODE in FIG. 6 becomes low level, the peak cut discharge pause signal PAUSE becomes low level, and the switch SW4 in FIG. 2 is switched to the a side.
As a result, the power line device current command calculation unit 19 is input with the demand increase time overhead voltage compensation current command value Idp and the demand increase time storage capacity adjustment current command value Itpb. The overhead line voltage compensation current command value Idp and the demand increase storage capacity adjustment current command value Itpb are combined to generate the storage device current command value Ip (operation pattern b + d in FIG. 7).
The gate control unit 30 operates the first switching element 3 and the second switching element 4 to store the current so that the current of the power storage device 7 becomes the power storage device current command value Ip generated by the power storage device current command calculation unit 19. The device 7 is charged to increase the amount of power stored in the power storage device 7 (F and G in FIG. 7).

  As shown in FIG. 3, the demand increase overhead wire voltage compensation current command value Idp is a command value that does not perform the discharge operation until the overhead wire voltage becomes lower than the normal overhead wire voltage compensation current command value Itp. In addition, since the storage capacity adjustment current command value Idpb at the time of demand increase is a command value for performing storage capacity adjustment charging until a voltage higher than the normal storage capacity adjustment current command value Itpb, By controlling the current of the power storage device 7 using the synthesized power storage device current command value Ip, energy can be stored up to the full capacity of the power storage device.

When the demand increases during the period G in FIG. 7, for example, when the demand increase switching command signal PC90 and the peak cut request signal PC100 are output simultaneously, the peak cut discharge command PCDSG is output. In addition, since the peak catch mode is once canceled in the period E, the peak cut discharge memory signal DSGMEM is not output at this time.
As a result, the contacts of the switches SW1, SW2 and SW3 shown in FIG. 2 are switched to the b side, and the normal overhead wire voltage compensation current command value Itp is changed to the overhead wire voltage compensation current command value Idp during demand increase. The command value Itpb is switched to the peak cut current command value Ippc. As described above, the power storage device current command calculation unit 19 generates the power storage device current command value Ip by synthesizing the demand increase overhead wire voltage compensation current command value Idp and the peak cut current command value Ippc (operation b + e). pattern).
The gate control unit 30 operates the first switching element 3 and the second switching element 4 to store the current so that the current of the power storage device 7 becomes the power storage device current command value Ip generated by the power storage device current command calculation unit 19. The device 7 is discharged to suppress the demand peak (H in FIG. 7).

Next, as described above, the charge / discharge pause command PAUSE is output from the discharge command storage unit 18 simultaneously with the end of the cycle for calculating the average power of the demand. As a result, the switch SW4 in FIG. 2 is switched to the b side, the power storage device current command value Ip becomes 0, and all charging / discharging is suspended. (I in FIG. 7).
If the peak cut request is not output in the next demand calculation cycle, the discharge command storage unit 18 resets the flip-flop FF2, cancels the storage of the peak cut discharge command, and clears the charge / discharge pause command. The peak of demand is reduced by repeating the above sequence.

It is a figure which shows the main circuit of the electric power storage apparatus of this invention. It is a figure which shows the structure of the control part of the electric power storage apparatus of this invention. It is a figure which shows an example of the pattern of current command values, such as a normal time overhead wire voltage compensation current command value. It is a figure explaining the synthesis | combination of the electric current command value by an electrical storage apparatus electric current command value calculating part. It is a figure which shows the structural example of a gate control part. It is a figure which shows the structural example of a discharge command memory | storage part. It is a time chart which shows operation | movement of the Example of this invention.

Explanation of symbols

1 Filter Reactor 2 Filter Capacitor 3 First Switching Element 4 Second Switching Element 5 Smoothing Reactor 6 Smoothing Capacitor 7 Power Storage Device 11 Demand Calculation Unit (Voltage Reduction Time Ratio)
12 Demand calculator (transmission line power loss)
DESCRIPTION OF SYMBOLS 13 Normal time overhead wire voltage compensation current calculation part 14 Demand increase time overhead voltage compensation current calculation part 15 Normal time storage capacity adjustment current calculation part 16 Demand increase storage capacity adjustment current calculation part 17 Peak cut discharge current calculation part 18 Discharge command storage part 19 power storage device current command calculation unit 21 control unit 22 voltage detector 23 current detector 24 voltage detector 30 gate control unit

Claims (5)

A power storage device for DC railways for suppressing a peak of power demand, which is an integrated value of power demand per unit time,
The power storage device includes a power storage device, an overhead wire supplying direct current power, a DC-DC converter connected between the power storage device, a first voltage detector that detects the overhead wire voltage, and the power storage device. A second voltage detector for detecting a voltage of the current, a current detector for detecting a charge / discharge current of the power storage device,
Based on the overhead line voltage detected by the first and second voltage detectors, the power storage device voltage, and the charge / discharge current detected by the current detector, the DC-DC converter is controlled to A control unit for controlling charging and discharging,
The control unit
A demand detecting means for detecting an increase in power demand and a peak of the power demand based on a rate of time when the power loss in the overhead line and / or the overhead line voltage falls below a predetermined value;
When neither the power demand increase nor the demand peak is detected, the normal power storage device current command value corresponding to the overhead line voltage and the power storage device voltage is output,
When an increase in demand is detected by the demand detecting means, the power storage device current command value at the time of demand increase for charging the power storage device and increasing the amount of power stored in the power storage device is output.
When a demand peak is detected by the demand detection means, the charge / discharge current command value generating means for discharging the power storage device and outputting a demand peak cut power storage device current command value for suppressing the power demand peak;
And a control unit that controls the DC-DC converter to control the charge / discharge current of the power storage device according to the current command value generated by the charge / discharge current command value generation unit. . The unit time for calculating the power demand by integrating the power demand is divided into a first time zone and a second time zone,
The demand detecting means detects an increase in power demand or a peak of power demand in the first time period,
The charge / discharge current command value generating means includes:
When an increase in power demand is detected in the first time zone, at least after the second time zone, a demand increase power storage device current command value for increasing the power storage amount of the power storage device is output, and When a power demand peak is detected in the first time zone, a demand peak cut power storage device current command value for suppressing the power demand peak is output at least in the second time zone. The power storage device according to claim 1. In order to suppress the discharge of the power storage device, comprising a discharge memory control means for suppressing the demand peak cut operation,
The discharge memory control means pauses the discharge of the power storage device at least in a first time zone in the next unit time after the demand peak cut power storage device current command value is output from the charge / discharge current command value generation means. The power storage device according to claim 2, wherein: The demand detecting means is
When the power loss in the DC overhead line exceeds the first threshold a1, the first demand increase detection signal c1 is output, and when the power loss exceeds the second threshold a2 (a1 <a2), the first demand is output. First demand calculation means for outputting a peak detection signal c2,
The second demand increase detection signal d1 is output when the proportion of the time when the overhead line voltage falls below the predetermined value exceeds the first threshold value b1, and the proportion of the time when the overhead line voltage falls below the prescribed value is the second percentage. Second demand calculation means for outputting a second demand peak detection signal d2 when a threshold value b2 (b1 <b2) is exceeded;
Demand increase is detected when the first and second demand increase detection signals c1 and d1 are output, and demand peaks are detected when the first and second demand peak detection signals c2 and d2 are output. The power storage device according to claim 1, wherein the power storage device is configured to include: The charge / discharge current command value generating means is:
A first means for outputting a normal overhead wire voltage compensation current command value according to the overhead line voltage; a second means for outputting a normal storage capacity adjustment current command value according to the power storage device voltage;
A third means for outputting a demand increase overhead wire voltage compensation current command value according to the overhead line voltage; a fourth means for outputting a demand increase storage capacity adjustment current command value according to the power storage device voltage;
A fifth means for outputting a peak cut current command value corresponding to the battery voltage;
During normal times when no demand increase or demand peak is detected, the current command values output from the first and second means are combined to generate a charge / discharge current command value for the power storage device during normal times, and an increase in demand is detected. When the demand peak is detected, the current command values output from the third and fourth means are combined to generate a charge / discharge current command value for the power storage device when demand increases. 5. Charge / discharge current command value calculation means for generating a charge / discharge current command value for suppressing a demand peak by synthesizing the current command values output from the means of claim 5; , 3 or claim 4.

Images