JP2015056983A - Reverse power detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable detection of inverse load flow irrespective of whether a sensor for monitoring passing current for each voltage line is properly mounted.SOLUTION: A reverse power detecting device 10 has acquiring units 111, 112, a calculator 12 and an output unit 13. The acquiring units 111, 112 acquire outputs from plural sensors 421, 422 for monitoring current for respective voltage lines L1, L2. The calculator 12 calculates the direction and size of power at the interconnection point between an electric power system 40 and a dispersed power source with respect to all the combinations of the outputs of the sensors 421, 422 acquired by the acquiring units 111, 112 and the inter-line voltages. When the reverse power directing from the dispersed power source to the electric power system 40 is contained in the power calculated by the calculator 12, the output unit 13 supplies the value of the largest reverse power to a controller 223 for managing the output of the dispersed power supply.

Description

  The present invention relates to a reverse power detection device that detects reverse power from a distributed power source connected to a power system to the power system.

  In recent years, distributed power sources that can be connected to an electric power system such as photovoltaic power generation devices, power storage devices, fuel cells, cogeneration devices, and electric vehicles equipped with storage batteries and that can output electric power have become widespread. Have been doing. Although domestic power companies currently allow the power generated by solar power generators to flow back into the power grid, ordinary consumers use the power output from other distributed power sources. Reverse tide is prohibited. Therefore, when the distributed power source is connected to the power system, it is necessary to monitor the power flow so that reverse power (that is, reverse power flow) from the distributed power source to the power system does not occur.

  Patent Document 1 describes that when a reverse power flow occurs, if it is determined that the reverse power flow includes power discharged from the storage battery, it is necessary to stop the discharge from the storage battery. The reverse power flow sensor provided for detecting the reverse power flow includes two ammeters (current sensors) for detecting AC currents of two voltage lines for a single-phase three-wire power system, And two voltmeters for detecting an alternating voltage between the voltage line and the neutral line. The reverse power flow sensor includes a calculation unit, which calculates active power based on the phase difference between the AC voltage detected by the voltmeter and the AC current detected by the ammeter, and reverse power flow based on the value of the active power. Whether or not has occurred.

JP 2013-74637 A

  By the way, patent document 1 judges whether the reverse power flow has arisen on the assumption that the two ammeters which comprise a reverse power flow sensor are correctly attached to the voltage line. However, it is necessary to provide an ammeter for each of the two voltage lines, and since the phase of the alternating current is used to detect the reverse power flow, if the ammeter is incorrectly attached to the voltage line, a reverse power flow will occur. There is a possibility of mistakenly judging that it is normal.

  The present invention provides a reverse power detection device capable of detecting the possibility of occurrence of reverse power regardless of whether or not a sensor for monitoring a passing current for each voltage line is correctly attached. With the goal.

  The reverse power detection apparatus according to the present invention includes a plurality of voltage lines whose line voltage to the non-voltage line is alternating current, and the voltage line is electrically connected to the power system and the distributed power source. An acquisition unit that acquires output from a plurality of sensors that monitor current for each, and an output of the sensor that acquires the direction and magnitude of power at a connection point between the power system and the distributed power source And the calculation unit for all combinations of the line voltages, and the power determined by the calculation unit includes reverse power directed from the distributed power source to the power system, the largest reverse power value is obtained. And an output unit that supplies a control unit that manages the output of the distributed power source.

  In this reverse power detection device, the electric circuit is a single-phase three-wire system, the sensor is two current transformers attached to two voltage lines, and the output unit is one current transformer. The current value measured in step I1 is I1, the current value measured in the other current transformer is I2, the line voltage of one voltage line to the non-voltage line is V1, and the other voltage line to the non-voltage line When the inter-voltage is V2, it is preferable to give the control unit a value that is in the direction of reverse power and has a larger absolute value among I1 × V1 + I2 × V2 and I1 × V2 + I2 × V1.

  In the reverse power detection device, it is preferable that the control unit stops the output of the distributed power supply when the value of the reverse power notified from the output unit is equal to or greater than a predetermined threshold.

  In the reverse power detection device, it is preferable that the control unit adjusts the output of the distributed power source so that reverse power does not occur in the power required by the calculation unit.

  Another reverse power detection device according to the present invention includes a plurality of voltage lines whose line voltage to a non-voltage line is an alternating current, and is electrically connected to a power system and a distributed power source. The acquisition unit that acquires output from a plurality of sensors that monitor the current for each voltage line, and the sensor that the acquisition unit acquires the direction and magnitude of power at the connection point between the power system and the distributed power source When the output obtained from the power source and the line voltage includes the reverse power in the direction from the distributed power source to the power system, the reverse power is generated. And an output unit that notifies a control unit that manages the output of the distributed power supply.

  In this reverse power detection device, it is preferable that the control unit stops the output of the distributed power supply when the output unit is notified of the occurrence of reverse power.

  In this reverse power detection apparatus, it is preferable that the acquisition unit acquires an output from the sensor only during a period in which the distributed power source outputs power.

  In this reverse power detection device, the distributed power source is preferably a power storage device.

  According to the configuration of the present invention, the current passing through the plurality of voltage lines is monitored for each voltage line by the plurality of sensors, and the arithmetic unit is configured to determine the direction of power at the connection point between the distributed power source and the power system and The magnitude is determined for all combinations of sensor output and line voltage. Further, when the power obtained by the calculation unit includes reverse power directed from the distributed power source to the power system, the output unit gives the largest reverse power value to the control unit that manages the output of the distributed power source. . By adopting this configuration, the possibility that reverse power is generated is detected regardless of whether or not the sensor for monitoring the passing current for each voltage line is correctly attached. That is, it becomes possible to make a judgment on the safe side with respect to the reverse power.

It is a block diagram which shows embodiment. It is a block diagram which shows the usage example same as the above. It is operation | movement explanatory drawing same as the above.

  The reverse power detection device 10 described below includes a plurality of voltage lines L1 and L2 whose line voltage to the non-voltage line L0 is alternating current, and is electrically connected to the power system 40 and the distributed power source (power storage device 22). Used for the electrically connected electric circuit 41. The reverse power detection device 10 includes acquisition units 111 and 112, a calculation unit 12, and an output unit 13. The acquisition units 111 and 112 acquire outputs from a plurality of sensors 421 and 422 that monitor currents for the voltage lines L1 and L2. The calculation unit 12 obtains the direction and magnitude of power at the connection point between the power system 40 and the distributed power supply for all combinations of the outputs of the sensors 421 and 422 acquired by the acquisition units 111 and 112 and the line voltage. . When the power obtained by the calculation unit 12 includes reverse power directed from the distributed power source to the power system 40, the output unit 13 controls the output of the distributed power source with the largest reverse power value. To give.

  The electric circuit 41 is preferably a single-phase three-wire system. In this case, the sensors 421 and 422 are desirably two current transformers attached to the two voltage lines L1 and L2, respectively. Here, the current value measured by one current transformer (sensor 421) is I1, the current value measured by the other current transformer is I2, and the line voltage of one voltage line with respect to the non-voltage line is V1, The line voltage of the other voltage line with respect to the non-voltage line is V2. It is desirable that the output unit 13 provides the control unit 223 with a power having a larger absolute value that is the power in the reverse power direction of I1 × V1 + I2 × V2 and I1 × V2 + I2 × V1.

  It is desirable that the control unit 223 stops the output of the distributed power supply when the value of the reverse power notified from the output unit 13 is equal to or greater than a predetermined threshold value. Alternatively, the control unit 223 desirably adjusts the output of the distributed power supply so that no reverse power is generated in the power required by the calculation unit 12.

  In another reverse power detection device, the arithmetic unit 12 outputs the direction and magnitude of power at the connection point between the power system 40 and the distributed power source, and outputs of the sensors 421 and 422 acquired by the acquisition units 111 and 112 and Obtained using the line voltage. The output unit 13 controls the output of the distributed power source that the reverse power is generated when the power obtained by the arithmetic unit 12 includes the reverse power directed from the distributed power source toward the power system 40. Notification to the unit 223.

  Note that the reverse power detection device 10 may be provided on the primary side of the interconnection breaker 33 depending on the purpose of the storage battery system.

  The control unit 223 desirably stops the output of the distributed power supply when the output unit 13 is notified of the occurrence of reverse power.

  It is desirable that the acquisition units 111 and 112 acquire outputs from the sensors 421 and 422 only during a period in which the distributed power supply outputs power. The distributed power source is preferably the power storage device 22.

  Hereinafter, the embodiment will be described in more detail. The configuration example shown in FIG. 2 is an example. In the illustrated example, the distribution board 30 includes a main breaker 31 and a plurality of branch breakers 32 connected to the secondary circuit of the main breaker 31. Further, the distribution board 30 includes an interconnection breaker 33 connected to the primary circuit of the main breaker 31 and an interconnection breaker 34 connected in parallel to the branch breaker 32. The branch breaker 32 branches the secondary circuit of the trunk breaker 31 into a plurality of systems. Each electric circuit branched by the branch breaker 32 supplies electric power to the electric load 35.

  The interconnection breaker 33 is inserted between the power system 40 and the main breaker 31, and the photovoltaic power generation device 21 is connected to the interconnection breaker 33. Therefore, the main breaker 31 can receive power not only from the power system 40 but also from the solar power generation device 21. Further, the power generated by the solar power generation device 21 can be reversely flowed to the power system 40. The solar power generation device 21 includes a solar cell 211 and a power conditioner (PCS: Power Conditioning System) 212 that converts DC power generated by the solar cell 211 into AC power.

  The interconnection breaker 34 is inserted between the secondary circuit of the main breaker 31 and the power storage device 22. In the configuration shown in the drawing, the electric power output from the power storage device 22 can be supplied to the electric load 35 through the secondary circuit of the main breaker 31. For example, it is possible to supply electric power from the power storage device 22 to the electric load 35 at night when the power generation of the solar power generation device 21 stops.

  The power storage device 22 includes a storage battery 221 and a power converter (charge / discharge device) 222 that charges and discharges the storage battery 221. In the illustrated example, the solar power generation device 21 and the power storage device 22 are described as independent configurations, but the power conditioner 212 and the power converter 222 may be housed in a common housing. In this case, a power conversion device combining the power conditioner 212 and the power converter 222 is configured, and the solar battery 211 and the storage battery 221 are connected to the power conversion device, whereby the solar power generation device 21 and the power storage device. The same operation as that of the configuration provided with 22 is performed.

  By the way, when power is output from the power storage device 22 when the power system 40 is normal, the power output from the power storage device 22 is prohibited from flowing backward to the power system 40. Therefore, it is necessary to monitor whether or not reverse power from the power storage device 22 to the power system 40 is generated. The reverse power means active power that goes back to the power system 40. In the illustrated configuration, the connection point between the power system 40 and the power storage device 22 is between the main breaker 31 and the connection breaker 33. That is, the electric circuit 41 between the main breaker 31 and the interconnection breaker 33 becomes an interconnection point that is electrically connected to the power system 40 and the power storage device 22. The interconnection point may be the secondary side (branch breaker 32 side) instead of the primary side (linkage breaker 33 side) of the main breaker 31. That is, it suffices if it is downstream from the interconnection breaker 33 and upstream from the branch breaker 32.

  In the present embodiment, a single-phase three-wire system is assumed as a wiring method for drawing power from the power system 40. Therefore, as shown in FIG. 3, the electric circuit 41 is composed of three lines of two voltage lines L1 and L2 and one non-voltage line (neutral line) L0. The names of the lines are various, but as an example, the voltage lines L1 and L2 may be referred to as U phase and W phase, and the neutral line L0 may be referred to as V phase. Note that the technical idea of this embodiment can be applied to other wiring systems such as a three-phase four-wire system.

  In order to monitor the reverse power at the interconnection point (electric circuit 41), a sensor 421 for monitoring the current passing through the voltage line L1 and a sensor 422 for monitoring the current passing through the voltage line L2 are provided in the electric circuit 41. ing. Each of the sensors 421 and 422 is a clamp-type current sensor (current transformer) so that the sensor 421 and 422 can be attached to the electric circuit 41 laid in advance. That is, the sensors 421 and 422 have a configuration in which a detection winding is wound around an annular core that can be opened and closed. The sensors 421 and 422 are independent members, and are individually attached to the voltage lines L1 and L2.

  Incidentally, the power storage device 22 includes a control unit 223 that manages output. Control unit 223 has a function of stopping output of power storage device 22 when reverse power is generated, and a function of adjusting output of power storage device 22 so that reverse power is not generated. Here, the function of stopping the output of the power storage device 22 when reverse power is generated is necessary to guarantee prohibition of reverse power. Further, the function of adjusting the output of the power storage device 22 so as not to generate reverse power is necessary when the output of the power storage device 22 is used as much as possible by the electric load 35.

  Control unit 223 manages the output of power storage device 22 based on the power for each of voltage lines L <b> 1 and L <b> 2 obtained by reverse power detection device 10. The reverse power detection device 10 is desirably provided in the power storage device 22 together with the control unit 223, but the reverse power detection device 10 may be provided separately from the power storage device 22. Further, the reverse power detection device 10 can be configured with individual components, but is preferably realized by a microcomputer with a built-in A / D converter, and the operations described below are preferably processed by calculation of digital values. . In this case, a program for causing the microcomputer to function as the reverse power detection device 10 described below is required. This type of program is pre-installed in a microcomputer before shipment from the factory, but it is desirable to be able to provide an update program (updater) through a telecommunication line such as the Internet. The update program may be provided using a computer-readable recording medium such as a removable memory card.

  The reverse power detection device 10 includes acquisition units 111 and 112 that acquire the outputs of the two sensors 421 and 422, respectively. The acquisition units 111 and 112 have a function of sampling the outputs of the sensors 421 and 422 and converting them into digital values (that is, an A / D conversion function). The sensors 421 and 422 detect the current in the electric circuit 41. In order to detect the reverse power in the electric circuit 41, the line voltage between the voltage lines L1 and L2 and the non-voltage line L0 in the electric circuit 41 is also necessary. is there. Therefore, the acquisition units 111 and 112 acquire the line voltage of the electric circuit 41 from the terminal connecting the electric circuit 41 to the main breaker 31 or the interconnection breaker 33. This line voltage may be obtained from the terminal of the power converter 222. Moreover, you may acquire from the terminal which the reverse power detection apparatus 10 receives the electric power supply from the branch breaker 32. FIG.

  The current value and voltage value for each of the voltage lines L1 and L2 acquired by the acquisition units 111 and 112 are input to the calculation unit 12. The calculation unit 12 obtains the direction and magnitude of power at the interconnection point for each of the voltage lines L1 and L2 using the current and voltage information received from the acquisition units 111 and 112.

  Now, as shown in FIG. 3, the value of the line voltage between the voltage line L1 and the non-voltage line L0 is V1, the value of the current monitored by the sensor 421 is I1, and the line between the voltage line L2 and the non-voltage line L0. The value of the inter-voltage is V2, and the value of the current monitored by the sensor 422 is I2. These values are instantaneous values (sampling values). When the sensors 421 and 422 are attached without error, the instantaneous value of power required by the calculation unit 12 is I1 × V1 for the voltage line L1 and I2 × V2 for the voltage line L2.

  In FIG. 3, dots (·) attached to the sensors 421 and 422 represent the polarities of the sensors 421 and 422. By the way, when the sensors 421 and 422 are attached to the voltage lines L1 and L2, the voltage lines L1 and L2 of the sensors 421 and 422 are excluded except when the attachment is defective and when the sensors 421 and 422 are attached to the non-voltage line L0. There are 8 combinations of attachment methods. That is, there are two polarities of the sensors 421 and 422 with respect to the respective voltage lines L1 and L2, and there are two combinations of the sensors 421 and 422 and the voltage lines L1 and L2. Become a combination.

  Including the case of poor attachment to the sensors 421 and 422 and the case of attaching one of the sensors 421 and 422 to the non-voltage line L0, there are a total of 37 combinations, and only one of them is correct. Become a combination.

  Here, it is assumed that the following work is performed to confirm whether or not the sensors 421 and 422 are correctly attached at the time of construction. First, all the electric loads 35 connected to the distribution board 30 (or all the branch breakers 32 to which the electric loads 35 are connected) are turned off, and the solar power generation device 21 is disconnected. That is, only the power storage device 22 is connected to the power system 40.

  In this state, when charging of the power storage device 22 with the power of the power system 40 is started, the current flowing only between the power system 40 and the power storage device 22 can be monitored in the electric circuit 41. Therefore, in this state, if the sensors 421 and 422 are correctly attached, the direction of power calculated by the calculation unit 12 is the direction from the power system 40 toward the power storage device 22 (power purchase direction). Here, the power purchase direction is determined in the positive direction of the electric power passing through the electric circuit 41.

  The calculation unit 12 in the reverse power detection device 10 passes through the electric circuit 41 based on the outputs of the sensors 421 and 422 after a period (for example, 5 seconds) in which the current is stabilized after the electric storage device 22 starts to store electricity. The power to be calculated is calculated. Since the arithmetic unit 12 needs to obtain not only the magnitude of the electric power but also the direction of the electric power, the electric power average value is obtained in a period of several cycles (for example, five cycles) of the AC voltage. Next, after a period in which the current is stabilized after the power storage of the power storage device 22 is stopped, the calculation unit 12 calculates the average power in several cycles of AC voltage (a period having the same length as the period during power storage). Find the value.

  When calculating the average value of the power obtained during the period when the power storage device 22 is charged and the average value of the power obtained during the period when the power storage device 22 is not charged, the arithmetic unit 12 then calculates both average values. Find the difference between In an ideal state, positive electric power is obtained in the electric circuit 41 only during the period in which the electric storage device 22 is charged, and no electric power passes through the electric circuit 41 in the period in which the electric storage device 22 is not charged. It is considered that the difference between the average values substantially matches the power for charging the power storage device 22.

  The calculation unit 12 only obtains the magnitude of the power passing through the electric circuit 41 and the direction in which the power passes, and the output of the calculation unit 12 is given to the control unit 223 through the output unit 13. Control unit 223 compares the difference between the value of power input to power converter 222 of power storage device 22 or the value of power output from power converter 222.

  And if the said difference with respect to the electric power input into the power converter 222 is in a predetermined range (for example, 20%), the control part 223 will judge that the sensors 421 and 422 are attached normally. That is, when the power (average value) input to the power converter 222 is X and the difference is Y, the control unit 223 indicates that the sensors 421 and 422 are normal if 0.8X ≦ Y ≦ 1.2X. It is judged that it is attached to.

  Assuming that the mounting state shown in FIG. 3A is a correct mounting state of the sensors 421 and 422 and the voltage lines L1 and L2, among the 37 combinations described above, 36 combinations excluding the correct mounting state are: It will be an incorrect installation state. Except for one of the incorrect mounting states, which will be described later, it is possible to detect an error in the mounting state according to the procedure described above.

  When the power storage device 22 is installed, the operation of confirming the attachment state of the sensors 421 and 422 may be performed using the remote control device 23 attached to the power storage device 22 (or the power conversion device). The remote control device 23 includes a display that displays information related to the operation of the power storage device 22 and an operating device that instructs the operation of the power storage device 22. The remote control device 23 has an operation mode for use by a contractor who performs construction or maintenance of the power storage device 22, and confirms the mounting state of the sensors 421 and 422 in this operation mode.

  When the electric load 35 or the branch breaker 32 is turned off in order to confirm the mounting state of the sensors 421 and 422, a message is displayed on the remote controller 23. When this message is displayed on the remote control device 23 and the remote control device 23 is instructed to start processing, the control unit 223 performs the above-described processing using the output of the reverse power detection device 10, and the sensors 421 and 422 It is automatically determined whether or not it is normally attached.

  The result of the determination is displayed on the remote control device 23. When it is determined that the attachment state of the sensors 421 and 422 is normal, the operation of the power storage device 22 is permitted. On the other hand, when it is determined that the mounting state of the sensors 421 and 422 is not normal, the remote control device 23 displays that the mounting state is not normal. If the mounting state of the sensors 421 and 422 is corrected at this time and the processing for checking the mounting state is performed again, the above-described operation is repeated. If it is determined that the mounting state of the sensors 421 and 422 is not normal and the mounting state of the sensors 421 and 422 is not corrected and the mounting state is not confirmed, the mounting is performed when the operation start of the power storage device 22 is instructed. It is displayed on the remote control device 23 that the state is unconfirmed. In this case, the operation of the power storage device 22 is stopped although the start of the operation of the power storage device 22 is instructed.

  Note that the determination result in the control unit 223 is stored in a non-volatile memory (not shown). When the determination result stored in the non-volatile memory is normal, the power storage device 22 can be operated, and the determination result is not normal. The operation of the power storage device 22 stops. At the time of shipment of the power storage device 22, information indicating that the storage device 22 is not normal is stored in the nonvolatile memory, and it is confirmed that the storage device 22 is normal by performing a process of checking the mounting state of the sensors 421 and 422. The power storage device 22 cannot be operated unless it is later.

  By the way, when the sensors 421 and 422 are attached to the wrong power lines L1 and L2 and the polarities of the sensors 421 and 422 with respect to the voltage lines L1 and L2 are also wrong as shown in FIG. The output produced will be the same as the correct combination. That is, when the sensor 422 is attached to the voltage line L1 and the sensor 421 is attached to the voltage line L2, and the polarities of the sensors 421 and 422 are opposite to the voltage lines L1 and L2, the sensor 421 , 422 are mistakenly attached. Therefore, even if the attachment state of the sensors 421 and 422 is confirmed by the above-described processing, the erroneous connection shown in FIG. 3B is not detected.

  Thus, in the present embodiment, the reverse power detection device 10 delivers the following information to the control unit 223 during operation of the power storage device 22 so that the control unit 223 can detect the occurrence of reverse power. That is, even if the sensors 421 and 422 are erroneously attached, the following information is used as information delivered from the reverse power detection device 10 to the power storage device 22 so that the power storage device 22 can be operated.

  Hereinafter, the value of the line voltage between the voltage line L1 and the non-voltage line L0 is V1, the value of the line voltage between the voltage line L2 and the non-voltage line L0 is V2, and the value of the current measured by the sensor 421 is I1. The current value measured by the sensor 422 is I2.

  As shown in FIG. 3A, when the sensors 421 and 422 are correctly attached, the power passing through the voltage line L1 is V1 × I1, and the power passing through the voltage line L2 is V2 × I2. On the other hand, as shown in FIG. 3B, when the polarities of the voltage lines L1 and L2 to which the sensors 421 and 422 are attached are opposite to each other, the value of the power passing through the voltage line L1 is V1 × I2. The value of power passing through L2 is V2 × I1. Therefore, in the state of FIG. 3A, the total value of power passing through the electric circuit 41 is V1 × I1 + V2 × I2, and in the state of FIG. 3B, the total value of power passing through the electric circuit 41 is V1 × I2 + V2 × I1.

  In order to guarantee that the electric power output from the power storage device 22 does not flow backward to the electric power system 40, no matter which value is obtained, no electric power is generated from the main breaker 31 to the interconnection breaker 33. It can be guaranteed. Here, regarding the attachment state of the sensors 421 and 422, it can be considered that errors other than the state shown in FIG. Although it is not possible to detect whether or not the error shown in FIG. 3B has occurred, the values of V1 × I1 + V2 × I2 and V1 × I2 + V2 × I1 are the line voltage values V1 and V2 and the sensor 421. It can be calculated by using current values I1 and I2 based on the output of 422.

  In other words, the calculation unit 12 calculates power for all combinations of the line voltage values V1 and V2 and the current values I1 and I2, and assumes the total value of the power calculated for each of the power lines L1 and L2. It calculates | requires for every attachment state of sensor 421,422. In the present embodiment, when the two sensors 421 and 422 are attached to the two power lines L1 and L2, since there is only a correct attachment state (one type) and an incorrect attachment state (one type), the calculation unit 12 The total value of power is obtained for each of the two types of mounting states. That is, the arithmetic unit 12 uses the line voltage values V1 and V2 and the current values I1 and I2 measured by the sensors 421 and 422 to obtain values of V1 × I1 + V2 × I2 and V1 × I2 + V2 × I1. Ask for.

  Here, in this embodiment, the power purchase direction is set to a positive direction. Further, the direction of the arrow attached to the current in FIG. 3 represents the direction of the reverse power. That is, since the current is an alternating current, the arrow is not the direction of the current but the direction of the power required by the calculation unit 12. The total of the two types of power obtained by the calculation unit 12 is delivered to the output unit 13.

  The output unit 13 determines whether or not the power is in the direction of the reverse power based on the sign of both the total values obtained by the arithmetic unit 12, and the control unit determines the larger value of the total values in the direction of the reverse power. Hand over to 223. That is, assuming that the maximum value among the values x1, x2,..., Xn is represented by max (x1, x2,..., Xn), the output unit 13 determines whether the direction of the reverse power is based on the sign of the total value. When the sign is negative, max (| V1 × I1 + V2 × I2 |, | V1 × I2 + V2 × I1 |) is delivered to the control unit 223.

  With the above-described configuration, the control unit 223 may generate reverse power regardless of whether the sensors 421 and 422 are attached normally or abnormally based on the power value delivered from the reverse power detection device 10. It becomes possible to judge. That is, since the calculation unit 12 and the output unit 13 of the reverse power detection device 10 operate as described above, the control unit 223 can reverse the power supply device 22 to the power system 40 without changing the specification of the control unit 223. Prevent power generation. Specifically, control unit 223 operates to stop operation of power storage device 22 when the value of power delivered from reverse power detection device 10 exceeds a predetermined threshold, and power delivered from reverse power detection device 10. At least one of the operations of adjusting the output in accordance with the size of.

  In the above-described operation example, the output unit 13 compares the magnitudes of the plurality of types of power obtained by the calculation unit 12. However, when reverse power is generated at the interconnection point, the power storage device 22 is operated. If it is only stopped, there is no need to obtain the magnitude of the reverse power. When the reverse power detection device 10 is used only for stopping the operation of the power storage device 22 so that no reverse power is generated, the calculation unit 12 is a combination of the current monitored by the sensors 421 and 422 and the line voltage. Just ask for.

  If it demonstrates using the code | symbol shown in FIG. 3, the calculating part 12 will each obtain | require the electric power calculated | required from V1 * I1, V2 * I2, V1 * I2, V2 * I1. The output unit 13 notifies the control unit 223 that reverse power is generated when the sign of any power indicates the direction of reverse power. Control unit 223 stops the operation of power storage device 22 when the output unit 13 is notified of the occurrence of reverse power. With this operation, regardless of whether the sensors 421 and 422 are erroneously attached, it is possible to operate on the safe side so that reverse power from the power storage device 22 to the power system 40 does not occur.

  By the way, since the purpose of this embodiment is to prevent a reverse power flow from the power storage device 22 to the power system 40, the power storage device 22 is operating to operate the reverse power detection device 10. Only period is enough. That is, it is desirable to operate the reverse power detection device 10 in conjunction with the operation of the power storage device 22.

  In the above-described operation example, regardless of the mounting state of the sensors 421 and 422, the case where they are correctly connected as shown in FIG. 3A and the case where they are incorrectly attached as shown in FIG. Assuming two types of total power are calculated. In other words, in the configuration example described above, it is possible to operate on the safe side so that reverse power due to the output of the power storage device 22 does not occur. However, when the sensors 421 and 422 are correctly attached as shown in FIG. 3A, the output of the power storage device 22 may stop even though no reverse power is generated. Therefore, it is desirable to provide an operation mode in which the calculation unit 12 calculates only V1 × I1 + V2 × I2 assuming that the mounting state in FIG. The operation mode is preferably selected using the remote control device 23.

  In the present embodiment, the solar power generation device 21 and the power storage device 22 are used as distributed power sources. However, instead of the power storage device 22, a cogeneration device including a fuel cell, a gas engine, or a complex thereof, etc. Other distributed power sources can be used. However, when these distributed power sources are used, the attachment state of the sensors 421 and 422 at the time of construction cannot be confirmed by the above-described procedure, so it is necessary to confirm by another procedure.

DESCRIPTION OF SYMBOLS 10 Reverse power detection apparatus 22 Power storage apparatus 12 Calculation part 13 Output part 40 Electric power system 41 Electric path 111,112 Acquisition part 223 Control part 421,422 Sensor L0 Non-voltage line L1, L2 Voltage line

Claims (8)

A plurality of sensors that monitor a current for each voltage line in an electric circuit that includes a plurality of voltage lines whose line voltage to the non-voltage line is an alternating current and is electrically connected to the power system and the distributed power source. An acquisition unit for acquiring output from
A calculation unit that obtains the direction and magnitude of power at an interconnection point between the power system and the distributed power source for all combinations of the sensor output and the line voltage acquired by the acquisition unit;
When the power obtained by the arithmetic unit includes reverse power directed from the distributed power source toward the power system, the output unit that gives the largest reverse power value to the control unit that manages the output of the distributed power source A reverse power detection device comprising: The electric circuit is a single-phase three-wire system,
The sensor is two current transformers attached to each of two voltage lines,
The output unit is
The current value measured by one current transformer is I1, the current value measured by the other current transformer is I2, the line voltage of one voltage line with respect to the non-voltage line is V1, and the other value with respect to the non-voltage line is the other. When the line voltage of the voltage line is V2,
The reverse power detection device according to claim 1, wherein the control unit is provided with a value that is in the direction of reverse power and has a larger absolute value among I1 × V1 + I2 × V2 and I1 × V2 + I2 × V1. The reverse power detection apparatus according to claim 1, wherein the control unit stops the output of the distributed power supply when the value of the reverse power notified from the output unit is equal to or greater than a predetermined threshold value. The reverse power detection device according to any one of claims 1 to 3, wherein the control unit adjusts an output of the distributed power supply so that no reverse power is generated in the power required by the calculation unit. A plurality of sensors that monitor a current for each voltage line in an electric circuit that includes a plurality of voltage lines whose line voltage to the non-voltage line is an alternating current and is electrically connected to the power system and the distributed power source. An acquisition unit for acquiring output from
A calculation unit that obtains the direction and magnitude of power at an interconnection point between the power system and the distributed power source using the sensor output and the line voltage acquired by the acquisition unit;
When the power obtained by the arithmetic unit includes reverse power in the direction from the distributed power source to the power system, the control unit that manages the output of the distributed power source notifies that the reverse power is generated. The reverse power detection apparatus comprising: The reverse power detection apparatus according to claim 5, wherein the control unit stops the output of the distributed power supply when the output unit is notified of the occurrence of reverse power. The reverse power detection apparatus according to any one of claims 1 to 6, wherein the acquisition unit acquires an output from the sensor only during a period in which the distributed power supply outputs power. The reverse power detection device according to claim 1, wherein the distributed power source is a power storage device.

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