Grid-connected power storage system and method for detecting mounting abnormality in current sensor

Abstract

To check whether a current sensor is properly mounted during operation of a power storage device.SOLUTION: A grid-connected power storage system includes, in a consumer's house, a current sensor that detects a current flowing through an AC electric path connected to a grid, and a power storage device that is connected to the AC electric path. The power storage device includes a storage battery, a power conversion unit that is disposed between the storage battery and the AC electric path and performs bi-directional power conversion between an AC current and a DC current, and a control unit that controls the power conversion unit and detects power based on the current detected by the current sensor and a voltage of the AC electric path. The control unit performs a charging instruction process for outputting DC power at a first charging power value from the power conversion unit in order to charge the storage battery, and a forced charging abnormality determination process for determining the presence / absence of a mounting abnormality in the current sensor on the basis of a detected value of power in the AC electric path during charging of the storage battery.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a grid-connected energy storage system and a method for detecting an installation anomaly of a current sensor. [Background technology]

[0002] In recent years, grid-connected energy storage systems that combine a photovoltaic power generation device with an energy storage device that has a built-in storage battery have been attracting attention. In such systems, the energy storage device is also connected to an AC circuit via an AC power conversion unit, and power can be supplied from the energy storage device to a load in the consumer's facility. Here, according to grid-connection regulations, the power generated by the photovoltaic power generation can be reversed (sold) beyond the consumer's power receiving point, but reversed power generation that has been discharged from the storage battery is prohibited.

[0003] Therefore, a current sensor is provided for monitoring purposes to prevent reverse flow of power based on the discharge of the storage battery (for example, see Patent Document 1). When the current sensor detects that reverse flow of power based on the discharge of the storage battery is occurring, it is necessary to immediately reduce the discharge power of the storage battery or stop the discharge.

[0004] The current sensor is, for example, a clamp-type current transformer (CT). In general, the CT is attached in or near a distribution board of a consumer when the power storage device is installed.

[0005] There are, for example, two CTs as mentioned above as current sensors, which must be installed in the correct position (wire) and in the correct direction to detect reverse current. However, in reality, they can be installed incorrectly due to carelessness. Even if they are installed correctly at first, they can fall off later. Furthermore, the detection signal wires drawn from the CTs can deteriorate over the years or be gnawed by mice, causing them to break.

[0006] Patent Document 2 discloses that during construction to install an energy storage device, all electrical loads connected to the distribution board are turned off, leaving only the energy storage device connected to the power grid, and then it is checked whether the current sensor is installed correctly. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2014-73043 A [Patent Document 2] JP 2015-56983 A Summary of the Invention [Problem to be solved by the invention]

[0008] As described above, after the energy storage device is installed, the current sensor may fall off or the detection signal line may be broken. For this reason, it is necessary to check whether the current sensor is correctly attached not only during construction to install the energy storage device but also during operation of the installed energy storage device. [Means for solving the problem]

[0009] A grid-connected energy storage system according to one embodiment of the present disclosure is a grid-connected energy storage system including a current sensor that detects a current flowing in an AC circuit of a consumer connected to a grid, and an energy storage device connected to the AC circuit, wherein the energy storage device includes a storage battery, a power conversion unit that is located between the storage battery and the AC circuit and performs bidirectional power conversion between DC and AC, and a control unit that controls the power conversion unit and detects power based on the current detected by the current sensor and the voltage of the AC circuit, and the control unit executes a charging command process that causes the power conversion unit to output DC power of a first charging power value to charge the storage battery, and a forced charging anomaly determination process that determines whether or not there is an installation anomaly with the current sensor based on the detection value of the power of the AC circuit while the storage battery is being charged. Effect of the Invention

[0010] According to the present disclosure, it is possible to check whether or not a current sensor is correctly attached when operating a power storage device. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a configuration diagram showing an example of a grid-connected electricity storage system using a single-function electricity storage device. [Diagram 2] FIG. 2 is a configuration diagram showing another example of a grid-connected electricity storage system using a single-function electricity storage device. [Diagram 3] FIG. 3 is a diagram showing an example of a grid-connected electricity storage system using a hybrid (multi-function) electricity storage device. [Figure 4] FIG. 4 is a circuit diagram showing an example of an internal circuit of the power storage device shown in FIG. [Diagram 5] FIG. 5 is a diagram showing an example of circuit connections within a consumer facility in the case where a solar power generation device is not provided and only a power storage device is provided. [Figure 6] FIG. 6 is a diagram showing an example of circuit connections within a consumer facility in the case where a power conditioner for photovoltaic power generation and a power storage device are provided and so-called single power generation is performed. [Figure 7] FIG. 7 is a diagram showing an example of circuit connections within a consumer facility in the case where a power conditioner for photovoltaic power generation and a power storage device are provided and so-called double power generation is performed. [Figure 8] FIG. 8 is a diagram showing an example of circuit connections within a consumer facility in a hybrid type, that is, in a case where the function of a power conditioner for photovoltaic power generation is mounted on a power storage device. [Figure 9] FIG. 9 is a diagram showing a correct mounting state of the current sensor as well as a full range of possible incorrect mounting states. [Figure 10] FIG. 10 is a flowchart showing a procedure for a sensor check in the first example. [Figure 11] FIG. 11 is a flowchart showing the procedure of the sensor check in the second example. [Figure 12] FIG. 12 is a flowchart showing the procedure of the sensor check in the third example. [Figure 13] FIG. 13 is a flowchart showing a procedure for a sensor check in the fourth example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] <Overview of the embodiment of the present disclosure> Below, an overview of the embodiments of the present disclosure will be listed and described.

[0013] (1) A grid-connected energy storage system according to the present embodiment is a grid-connected energy storage system including a current sensor for detecting a current flowing in an AC circuit connected to a grid of a consumer, and an energy storage device connected to the AC circuit, the energy storage device including a storage battery, a power conversion unit between the storage battery and the AC circuit for performing bidirectional power conversion between DC and AC, and a control unit for controlling the power conversion unit and detecting power based on a current detected by the current sensor and a voltage of the AC circuit, the control unit executing a charging command process for causing the power conversion unit to output DC power of a first charging power value in order to charge the storage battery, and a forced charging anomaly determination process for determining the presence or absence of an attachment anomaly for the current sensor based on a detection value of the power of the AC circuit while the storage battery is being charged. As a result, when the charging command process is being executed, a current required for charging the storage battery flows in the AC circuit, and the current sensor should detect the current flowing in the AC circuit. In other words, if the power in the AC circuit is correctly detected, it can be determined that the current sensor is correctly attached, and if the power in the AC circuit is not correctly detected, it can be determined that the attachment of the current sensor is abnormal. Therefore, when the power storage device is in operation, it can be checked whether the current sensor is correctly attached or not.

[0014] (2) In the above (1), the control unit may execute a non-charging anomaly determination process for determining whether or not there is an installation anomaly with respect to the current sensor based on a detection value of the power of the AC circuit while the storage battery is not being charged, and may execute the charging command process and the forced charging anomaly determination process when it is determined in the non-charging anomaly determination process that there is an installation anomaly with respect to the current sensor. In a consumer's house or facility, power is generally consumed day and night. Therefore, a current flows continuously in the AC circuit, and the current sensor should detect the current flowing in the AC circuit. That is, if the power in the AC circuit is correctly detected, it can be determined that the current sensor is correctly attached, and if the power in the AC circuit is not correctly detected, it can be determined that the attachment of the current sensor is abnormal. Therefore, even when the storage battery is not being charged, it is possible to check whether or not the current sensor is correctly attached. Furthermore, when it is determined that there is an installation anomaly with respect to the current sensor while the storage battery is not being charged, it is possible to more accurately determine whether or not there is an installation anomaly with respect to the current sensor by executing the charging command process and the forced charging anomaly determination process.

[0015] (3) In the above item (2), the control unit may execute the non-charging abnormality determination process again when it is determined in the forced charging abnormality determination process that there is an attachment abnormality in the current sensor. In this way, when it is determined in the forced charging abnormality determination process that there is an attachment abnormality in the current sensor due to the influence of noise, erroneous detection, etc., the control unit can repeat a cycle of the non-charging abnormality determination process, the charging command process, and the forced charging abnormality determination process again.

[0016] (4) In the above (3), the control unit may execute the non-charging abnormality determination process when it is determined that there is an attachment abnormality for the current sensor in the forced charging abnormality determination process from the 1st time to the N-1th time, where N is a specified number of times that is 2 or more, and may finalize the determination of the attachment abnormality for the current sensor when it is determined that there is an attachment abnormality for the current sensor in the Nth forced charging abnormality determination process. In this way, when it is determined that there is an attachment abnormality for the current sensor multiple times consecutively in the non-charging abnormality determination process and the forced charging abnormality determination process, a cycle of the non-charging abnormality determination process, the charging command process, and the forced charging abnormality determination process is repeated N-1 times. When it is determined that there is an attachment abnormality for the current sensor in the Nth non-charging abnormality determination process, the determination of the attachment abnormality is finalized. Therefore, it is possible to accurately determine the attachment abnormality for the current sensor.

[0017] (5) In any one of (1) to (4) above, the charging command process may be a process for continuing the output of the DC power from the power conversion unit to the storage battery for a specified time, and the specified time may be longer than a notification time from when charging of the storage battery in a fully charged state is started to when the storage battery outputs a notification of a charging error to the power storage device. In this way, when the storage battery is fully charged, a charging error is notified while the storage battery is being forcibly charged by the power receiving command process (during the specified time), and it can be determined that forcible charging is not possible.

[0018] (6) In the above (5), the control unit may cancel the charging command process when a notification of the charging error is received from the storage battery during execution of the charging command process. This makes it possible to cancel forced charging when a notification of the charging error is received.

[0019] (7) In any one of the above (1) to (6), the forced charging anomaly determination process may be a process for determining the presence or absence of an attachment anomaly of the current sensor based on whether or not power equal to or greater than a reference value that is greater than a lower limit value at which power in the AC circuit can be detected is detected. In this way, for example, by setting the reference value to a value close to the lower limit value, it is possible to determine whether or not a current is detected by the current sensor based on whether or not power equal to or greater than the reference value is detected. In other words, it is possible to determine whether the current sensor is attached (not detached) from the AC circuit or has detached from the AC circuit.

[0020] (8) In the above (7), when a power generation device connected to a grid is installed, the storage device selectively sets a first mode in which discharging from the storage battery is stopped when the power generation device is generating electricity, and a second mode in which discharging from the storage battery can be executed regardless of whether the power generation device is generating electricity or not, and when the first mode is set, the forced charging abnormality determination process may be a process of determining whether an absolute value of the detected power is equal to or greater than the reference value, and when the second mode is set, the forced charging abnormality determination process may be a process of determining whether a real value of the detected power is equal to or greater than the reference value. A consumer selects one of two power generation methods, single power generation and double power generation, and enters into a contract with an electric utility. Single power generation is a method in which discharging from the storage battery is stopped while the power generation device is generating electricity, and double power generation is a method in which discharging from the storage battery can be executed regardless of whether the power generation device is generating electricity or not. When the first mode corresponding to single power generation is set in the storage device, the detected power may be in the reverse flow direction. Therefore, by comparing the absolute value of the detected power with the reference value, it can be compared with the reference value without considering whether the detected power is positive or negative. When the second mode corresponding to dual power generation is set in the power storage device, the detected power does not flow in the reverse direction, so the actual value of the detected power is compared with the reference value. As a result, even in this case, it can be compared with the reference value without considering whether the detected power is positive or negative. Therefore, with the above configuration, it is possible to easily check whether the current sensor is correctly installed, regardless of whether the set mode is the first mode or the second mode.

[0021] (9) In any one of the above (1) to (8), the forced charging abnormality determination process may include a process for determining whether or not there is an abnormality in the installation direction of the current sensor based on the sign of the real value of the detected power. This makes it possible to determine whether or not there is an abnormality in the installation direction of a current sensor such as a CT (current transformer).

[0022] (10) In the above (1), the AC is a multiphase AC including a first phase and a second phase, the current sensor includes a first current sensor that detects a current flowing in an AC circuit of the first phase and a second current sensor that detects a current flowing in an AC circuit of the second phase, and the forced charging anomaly determination process may be a process of determining whether or not there is an attachment anomaly for the first current sensor based on a detection value of a first phase power of the AC circuit of the first phase while the storage battery is being charged, and determining whether or not there is an attachment anomaly for the second current sensor based on a detection value of a second phase power of the AC circuit of the second phase while the storage battery is being charged. This makes it possible to individually determine whether or not there is an attachment anomaly for the first current sensor and the second current sensor during operation of the power storage device.

[0023] (11) In the above (10), the control unit may determine the presence or absence of an attachment abnormality for the first current sensor based on a detection value of the first phase power while the storage battery is not being charged, execute a non-charging abnormality determination process to determine the presence or absence of an attachment abnormality for the second current sensor based on a detection value of the second phase power while the storage battery is not being charged, and execute the charging command process and the forced charging abnormality determination process when it is determined in the non-charging abnormality determination process that there is an attachment abnormality for at least one of the first current sensor and the second current sensor. Thereby, by executing the charging command process and the forced charging abnormality determination process when it is determined that there is an attachment abnormality for at least one of the first current sensor and the second current sensor while the storage battery is not being charged, it is possible to more accurately determine the presence or absence of an attachment abnormality for the current sensors.

[0024] (12) In the above (11), the control unit may execute the first determination process when it is determined in the non-charging abnormality determination process that there is an installation abnormality in the first current sensor. In this way, when it is determined that there is an installation abnormality in the first current sensor while the storage battery is not being charged, it is possible to more accurately determine the presence or absence of an installation abnormality in the first current sensor by executing a charging command process and a forced charging abnormality determination process.

[0025] (13) In the above (11) or (12), when it is determined in the non-charging anomaly determination process that there is an attachment anomaly in the first current sensor and that there is no attachment anomaly in the second current sensor, the control unit may execute the first determination process and not execute the second determination process. In this way, when it is determined that there is an attachment anomaly in the first current sensor and that there is no attachment anomaly in the second current sensor while the storage battery is not being charged, the control unit executes a charging command process and a forced charging anomaly determination process, thereby making it possible to more accurately determine whether or not there is an attachment anomaly in the first current sensor. Furthermore, for the second current sensor that is normally attached, repeated determination of an attachment anomaly can be avoided, and the processing load on the control unit can be reduced.

[0026] (14) In any one of (11) to (13) above, the control unit may execute the first determination process and execute the second determination process when it is determined in the non-charging abnormality determination process that there is an attachment abnormality for the first current sensor and that there is an attachment abnormality for the second current sensor. Thereby, when it is determined that there is an attachment abnormality for the first current sensor and that there is an attachment abnormality for the second current sensor while the storage battery is not being charged, a charging command process and a forced charging abnormality determination process are executed, thereby making it possible to more accurately determine the presence or absence of an attachment abnormality for each of the first current sensor and the second current sensor.

[0027] (15) The current sensor installation abnormality detection method according to the present embodiment is a current sensor installation abnormality detection method executed by a power storage device having a storage battery when the storage battery is connected to an AC circuit connected to a grid of a consumer and a current flowing through the AC circuit is detected by the current sensor, and the method outputs DC power of a first charging power value from the power conversion unit to charge the storage battery, detects power based on the current detected by the current sensor and the voltage of the AC circuit during charging of the storage battery, and executes a forced charging abnormality determination process to determine whether or not there is an installation abnormality for the current sensor based on the detected value of the power. As a result, when a charging command process is being executed, a current required to charge the storage battery flows through the AC circuit, and the current sensor should detect the current flowing through the AC circuit. That is, if the power in the AC circuit is correctly detected, it can be determined that the current sensor is correctly installed, and if the power in the AC circuit is not correctly detected, it can be determined that the installation of the current sensor is abnormal. Therefore, it is possible to check whether or not the current sensor is correctly installed during operation of the power storage device.

[0028] The present disclosure can be realized not only as a grid-connected energy storage system having the above-described characteristic configuration, or as a method for detecting an installation abnormality in a current sensor that includes steps of characteristic processing, but also as a storage device included in the grid-connected energy storage system, as a computer program for causing the storage device to execute characteristic processing, or as a semiconductor integrated circuit as part or all of the storage device.

[0029] <Details of the embodiment of the present disclosure> Hereinafter, the details of the embodiments of the present invention will be described with reference to the drawings. Note that at least some of the embodiments described below may be combined in any desired manner.

[0030] Example of system configuration 1 is a configuration diagram showing an example of a grid-connected electricity storage system using a single-function electricity storage device. In the figure, an electricity storage device 1 is installed in a consumer 100. In addition, a solar power generation panel 2 is installed in the consumer 100.

[0031] A power conditioner 3 is connected to the solar power generation panel 2. The power conditioner 3 performs MPPT (Maximum Power Point Tracking) control and converts DC power output from the solar power generation panel 2 into AC power. The output of the power conditioner 3 has, for example, a single-phase three-wire (AC200 / 100V) grid-connected output terminal T1 and a single-phase two-wire (AC100V) independent output terminal T2. The grid-connected output terminal T1 is connected to a general load distribution board 4, and the independent output terminal T2 is connected to the power storage device 1.

[0032] A general load (not shown) in the consumer 100 is connected to the general load distribution board 4 via indoor wiring, and the general load can be supplied with power from the commercial power system 200 or the power conditioner 3. Of the output of the power conditioner 3, the portion of the power that is not consumed in the consumer 100 can be reverse-powered (sold) to the commercial power system 200 via the general load distribution board 4. A current sensor (normally a CT) 7 for detecting reverse power, a power selling watt-hour meter 201, and a power buying watt-hour meter 202 are provided in the system-connected AC circuit 6 from the general load distribution board 4 to the commercial power system 200.

[0033] In addition, the general load distribution board 4 is connected to the power storage device 1, and in addition to being able to charge the power storage device 1 from the commercial power system 200 or the power conditioner 3, the power storage device 1 can also be discharged to supply power to a general load connected to the general load distribution board 4. In other words, this power storage device 1 is a grid-connected power storage device 1 that can also be connected to an AC circuit 6.

[0034] Furthermore, the general load distribution board 4 is connected to the important load distribution board 5. AC 100V is supplied directly from the general load distribution board 4 to the important load distribution board 5. During a power outage, AC 100V is supplied from the power storage device 1 to the important load distribution board 5. Important loads that are to be used even during a power outage are connected to the important load distribution board 5. During a power outage, if the power storage device 1 is generating solar power, AC 100V is supplied to it from the independent output terminal T2 of the power conditioner 3.

[0035] The power storage device 1 is connected to a remote control device 8, and the power storage device 1 can be operated from the remote control device 8. The remote control device 8 also functions as a monitor that displays the state of the power storage device 1, and can display the charge / discharge state, faults, etc. The remote control device 8 can also communicate with a router (gateway) 9 and a mobile information terminal 10 installed in the consumer 100. The router 9 is connected to the Internet 300.

[0036] Fig. 2 is a configuration diagram showing another example of a grid-connected energy storage system using a single-function energy storage device. The difference from Fig. 1 is that two energy storage devices are provided, one of which is a master energy storage device 1m and the other is a slave energy storage device 1s. The other configuration is the same as that of Fig. 1. In the case of Fig. 2, the detection output of the current sensor 7 is provided only to the master energy storage device 1m, and the slave energy storage device 1s is under the control of the master energy storage device 1m.

[0037] 1 and 2 show an example of a consumer 100 having a solar power generation system and a power storage device 1, but for example, there may be a consumer in FIG. 1 that does not have the solar power generation panel 2 and the power conditioner 3 and has only the power storage device 1. In this case, for example, nighttime electricity, when the electricity rate is low, can be stored in the power storage device 1 and discharged during the day to cover the consumer's power needs. Also, in the event of a power outage, the power storage device 1 can supply power to the consumer as an emergency power source. The same is true for Figure 2.

[0038] Fig. 3 is a diagram showing an example of a grid-connected energy storage system using a hybrid (multi-function) energy storage device 1. The difference from Fig. 1 is that there is no stand-alone power conditioner; instead, the energy storage device 1 also has the function of a power conditioner. Therefore, the output of the solar power generation panel 2 is directly provided to the energy storage device 1. The other configurations are the same as those in Fig. 1.

[0039] 《Example of an internal circuit of a power storage device》 FIG. 4 is a circuit diagram showing an example of an internal circuit of the power storage device 1 appearing in FIG. The energy storage device 1 has an input / output port and an input port. A grid-connected port P1 on the upper left side of the figure is an input / output port, and is connected to a commercial power system 200 (FIG. 1) via a general load distribution board 4 (FIG. 1). For example, varistors C1, C2, and C3 are provided within the energy storage device 1, and the varistor C1 is connected between U and O, the varistor C2 is connected between W and O, and the varistor C3 is connected between U and W.

[0040] The auxiliary input port P2 on the lower left side of the figure is connected to the independent output terminal T2 (AC 100V) of the power conditioner 3 (Figure 1). On the other hand, the power storage device 1 has one output port P3, and this output port P3 is connected to an important load distribution board 5 (FIG. 1).

[0041] The power storage device 1 includes a storage battery 1b, which is, for example, a lithium-ion battery, a power conversion unit (for example, a bidirectional inverter) 1a connected to the storage battery 1b, three switches SW1, SW2, and SW3, three voltage sensors V1, V2, and V3, a current sensor A1 provided on one side of an electric path leading to an output port P3, and a control unit 1c that controls the power conversion unit 1a and the switches SW1, SW2, and SW3. The power conversion unit 1a can convert DC power output from the storage battery 1b into AC power that can be connected to a grid, and conversely, can convert power provided from an AC electric path 6 into DC voltage to charge the storage battery 1b.

[0042] The switches SW1, SW2, and SW3 are relay contacts that are controlled to be opened and closed by the control unit 1c. The voltage sensors V1 and V2 detect the voltage (AC 200V) of the grid-connected port P1 and the input voltage (AC 100V) of the auxiliary input port P2, respectively. The voltage sensor V3 detects the voltage output to the switch SW3. The detection outputs of the voltage sensors V1, V2, and V3 are sent to the control unit 1c. In addition, the current sensor A1 detects the current flowing through the output port P3, and the detection output is sent to the control unit 1c.

[0043] In addition, the control unit 1c is also connected to the external current sensors (CT) 7u, 7w and the remote control device 8, as described above.

[0044] The control unit 1c controls the switching operation of the power conversion unit 1a and also has a function of detecting installation errors of the current sensors 7u and 7w (described in detail later). The control unit 1c includes, for example, a processor, and the processor executes software (computer programs) to realize the necessary control functions. The software is stored in a storage device (not shown) of the control unit 1c.

[0045] In the above-mentioned energy storage device 1, there are a grid-connected electric circuit L1 that connects the grid-connected port P1 to the power conversion unit 1a via the switch SW1, an independent power supply circuit L2 that leads from the auxiliary input port P2 to the output port P3 via the switch SW2, and a storage battery-side power supply circuit L3 that leads from the storage battery 1b to the output port P3 via the power conversion unit 1a. Note that the power conversion unit 1a operates so that the AC voltage is 200V when connected to the grid, and operates so that the AC voltage is 100V when power is supplied from the storage battery 1b to the output port P3.

[0046] If the consumer does not have a photovoltaic power generation device, there is no input to the auxiliary input port P2. In addition, in the case of a hybrid type such as the storage device 1 in Fig. 3, a power conditioner circuit is further installed in addition to the circuit configuration in Fig. 4.

[0047] <Circuit connection as a grid-connected energy storage system> Next, various circuit connection patterns will be described, mainly focusing on the power storage device and the current sensor (CT).

[0048] (Pattern 1) 5 is a diagram showing an example of circuit connections within a consumer facility when no photovoltaic power generation device is provided and only a power storage device 1 is provided. In the diagram, power is supplied to general loads 11 from an AC circuit 6 connected to a single-phase three-wire commercial power system 200 via a general load distribution board 4. Note that the general load distribution board 4 is actually provided with a large number of circuit breakers, and power is supplied to the general loads 11 through the circuit breakers and further via indoor wiring, but the circuit breakers are not shown and the indoor wiring is also shown in a simplified manner (same below).

[0049] The current sensors 7u and 7w are typically clamp-type CTs, and are attached to the U and W lines of a single-phase three-wire (voltage lines: U line, W line, neutral line: O line (N line)). The storage device 1 is connected to the single-phase three-wire AC circuit 6, and can be interconnected with the grid. However, reverse current is not permitted. The switch 13 is connected between the U line and the O line of the AC circuit 6, and can also receive the independent output of the storage device 1. When the voltage of the commercial power system 200 is normal, the switch 13 is internally connected to provide the important load 12 with a voltage of AC 100V between the U line and the O line. During a power outage, the connection can be switched to the storage device 1, and power can be received from the storage device 1 as an independent output, and can be provided to the important load 12.

[0050] In Fig. 5, if the commercial power grid 200 side is defined as "upstream" and the side where the general loads 11 and important loads 12 are located is defined as "downstream", the current sensors 7u and 7w are located upstream of the grid interconnection point Ps1 of the energy storage device 1. The energy storage device 1 can detect reverse power based on a voltage element detected internally and a current element sent from the current sensors 7u and 7w. In the case of the circuit configuration of Fig. 5, if reverse power is detected, the energy storage device 1 limits the output to prevent the reverse power.

[0051] (Pattern 2) Fig. 6 is a diagram showing an example of a circuit connection in a consumer facility when the consumer facility is provided with a power conditioner 3 for photovoltaic power generation and a power storage device 1 and performs so-called single power generation. The difference from Fig. 5 is that the power conditioner 3 is provided, and the consumer facility is connected to the grid and can provide an independent output to the auxiliary input port of the power storage device 1. The other configurations are the same as those in Fig. 5.

[0052] 6, the grid interconnection point Ps2 of the power conditioner 3 is located upstream of the grid interconnection point Ps1 of the power storage device 1, and the current sensors 7u and 7w are further located upstream of the grid interconnection point Ps2 of the power conditioner 3. The power storage device 1 can detect reverse power based on a voltage element detected internally and a current element transmitted from the current sensors 7u and 7w.

[0053] 6, in single power generation, discharging from the storage device 1 is stopped. Power generated by photovoltaic power generation is connected to the grid via a power conditioner 3 and used for power consumption within the consumer's facility. If there is still surplus power after being used for power consumption within the consumer's facility, it is reverse-powered (sold) to the commercial power grid 200. In this case, there is no problem because the reverse power is based only on photovoltaic power generation.

[0054] (Pattern 3) Fig. 7 is a diagram showing an example of a circuit connection in a consumer facility when the consumer facility is provided with a power conditioner 3 for photovoltaic power generation and a power storage device 1 and performs so-called double power generation. The difference from Fig. 6 is the positions of the current sensors 7u and 7w. The other configurations are the same as those in Fig. 6.

[0055] 7, the current sensors 7u and 7w are located upstream of the grid-connection point Ps1 of the energy storage device 1 and downstream of the grid-connection point Ps2 of the power conditioner 3. That is, the current sensors 7u and 7w are located midway between the two grid-connection points Ps1 and Ps2. The energy storage device 1 can detect reverse power based on a voltage element detected internally and a current element transmitted from the current sensors 7u and 7w.

[0056] 7, in double power generation, all the power generated by the photovoltaic power generation is sold. The power required for all the loads in the consumer's home is basically covered by discharging from the energy storage device 1. In this case, the reverse flow of power output from the power conditioner 3 does not pose a problem, but if the reverse flow of power exceeds the power limit, it is the reverse flow from the energy storage device 1, and if such a reverse flow is detected, the energy storage device 1 must limit its output.

[0057] (Pattern 4) 8 is a diagram showing an example of a circuit connection in a consumer facility when a hybrid type, that is, when the function of a power conditioner for photovoltaic power generation is installed in the power storage device 1. Although not shown in the figure, the power conversion unit 1a in this case is equipped with a DC / DC converter for the storage battery 1b and a DC / DC converter for the photovoltaic power generation panel 2, and is also equipped with a bidirectional inverter.

[0058] 8, the current sensors 7u and 7w are located upstream of a grid interconnection point Ps1 of the energy storage device 1. The energy storage device 1 can detect reverse power based on a voltage element detected internally and a current element transmitted from the current sensors 7u and 7w.

[0059] <Sensor check> In each of the above patterns, if the current sensors 7u, 7w are installed in the correct position and in the correct direction (polarity) as shown in the figure, reverse power can be detected reliably. If reverse power is detected when reverse power should not occur, the power storage device 1 limits the output to prevent reverse power. However, in reality, there may be cases where the current sensors 7u, 7w are not installed in the correct position and in the correct direction.

[0060] Fig. 9 shows the correct installation state of the current sensors 7u and 7w, as well as all the possible incorrect installation states. No. 1 (upper left) shows the correct installation state. That is, the current sensors 7u and 7w are installed in the correct direction relative to the voltage lines U and W of the single-phase three-wire system.

[0061] Incorrect installation conditions that differ from the correct installation condition in No. 1 are "installing the wrong wire," "installing in the wrong direction," or "disconnected." "Disconnected" also includes installation that is correct but the detection output signal wire is broken.

[0062] In No. 2 of Figure 9, the wires for attaching both current sensors 7u and 7w are correct, but the current sensor 7w on the W wire is facing in the opposite direction (the hatching in the figure indicates that it is facing in the opposite direction). In No. 3, both current sensors 7u and 7w are attached to the correct wires, but the current sensor 7u on the U wire is facing in the opposite direction. In No. 4, the wires for both current sensors 7u and 7w are correct, but they are both facing in the opposite direction.

[0063] In No. 5, the current sensors 7u and 7w are attached to opposite wires in the correct direction. In No. 6, the current sensors 7u and 7w are attached to opposite wires, and the current sensor 7u faces in the opposite direction. In No. 7, the current sensors 7u and 7w are attached to opposite wires, and the current sensor 7w faces in the opposite direction. In No. 8, the current sensors 7u and 7w are attached to wires opposite to each other, and the current sensors 7u and 7w face in opposite directions.

[0064] In No. 9, current sensor 7u is attached to the correct wire in the correct orientation, and current sensor 7w is attached to the incorrect wire (wire O) in the correct orientation. In No. 10, current sensor 7u is attached to the correct wire in the correct orientation, and current sensor 7w is attached to the wrong wire (wire O) in the wrong orientation. In No. 11, current sensor 7u is attached to the correct wire in the wrong orientation, and current sensor 7w is attached to the wrong wire (wire O) in the right orientation. In No. 12, current sensor 7u is attached to the correct wire in the wrong direction, and current sensor 7w is attached to the wrong wire (wire O) in the wrong direction.

[0065] In No. 13, current sensor 7u is attached in the correct orientation to the incorrect wire (wire O), and current sensor 7w is attached in the correct orientation to the correct wire. In No. 14, current sensor 7u is attached in the correct orientation to the wrong wire (wire O), and current sensor 7w is attached in the wrong orientation to the correct wire. In No. 15, current sensor 7u is attached to the wrong wire (wire O) in the wrong orientation, and current sensor 7w is attached to the right wire in the right orientation. In No. 16, current sensor 7u is attached to the wrong wire (wire O) in the wrong orientation, and current sensor 7w is attached to the correct wire in the wrong orientation.

[0066] In No. 17, current sensor 7u is attached to the correct wire in the correct orientation, and current sensor 7w has fallen off. In No. 18, current sensor 7u is attached to the correct wire in the wrong direction, and current sensor 7w has fallen off. In No. 19, the current sensor 7u is attached in the correct direction to the wrong wire (wire O), and the current sensor 7w has fallen off. In No. 20, the current sensor 7u is attached to the wrong wire (wire O) in the wrong direction, and the current sensor 7w has fallen off.

[0067] In No. 21, the current sensor 7u is attached in the correct direction to the wrong wire (wire W), and the current sensor 7w has fallen off. In No. 22, the current sensor 7u is attached to the wrong wire (wire W) in the wrong direction, and the current sensor 7w has fallen off.

[0068] In No. 23, current sensor 7w is attached to the correct wire in the correct orientation, and current sensor 7u has fallen off. In No. 24, current sensor 7w is attached to the correct wire in the wrong direction, and current sensor 7u has fallen off.

[0069] In No. 25, the current sensor 7w is attached in the correct direction to the wrong wire (wire O), and the current sensor 7u has fallen off. In No. 26, the current sensor 7w is attached to the wrong wire (wire O) in the wrong direction, and the current sensor 7u has fallen off.

[0070] In No. 27, the current sensor 7w is attached in the correct direction to the wrong wire (wire U), and the current sensor 7u has fallen off. In No. 26, the current sensor 7w is attached to the wrong wire (U wire) in the wrong direction, and the current sensor 7u has fallen off. In No. 28, both current sensors 7u and 7w have fallen off.

[0071] The energy storage device 1 can selectively be set to a first mode corresponding to single power generation and a second mode corresponding to double power generation. When the first mode is set, the energy storage device 1 stops discharging from the storage battery 1b while the solar power generation panel 2 is generating power. When the second mode is set, the energy storage device 1 can execute discharging from the storage battery 1b regardless of whether the solar power generation panel 2 is generating power or not. The first and second modes are set by the control unit 1c. The control unit 1c is provided with a storage unit (not shown), and when the first mode is set, setting information for the first mode is stored in the storage unit, and when the second mode is set, setting information for the second mode is stored in the storage unit.

[0072] Hereinafter, a procedure for the energy storage device 1 according to the embodiment to perform a sensor check (detection of an installation error of the current sensor) will be described.

[0073] The sensor check is performed at night when the solar power generation panel 2 is not generating power. For example, the sensor check is started at a fixed time every day (for example, 2:00 a.m.).

[0074] (Example 1) The first example is a sensor check in a so-called single power generation. That is, setting information for the first mode is stored in the storage unit of the control unit 1c.

[0075] 10 is a flowchart showing the procedure of a sensor check in a first example. The flowchart is executed by the control unit 1c of the power storage device 1. The sensor check is executed for each of the U phase and the W phase. The sensor check for the U phase will be described below as a representative example, but the same applies to the W phase.

[0076] When the sensor check starts, the control unit 1c measures (detects) the power P_dtc in the U-phase of the AC circuit 6 based on the current value detected by the current sensor 7u and the voltage of the AC circuit 6. The control unit 1c executes a non-charging abnormality determination process to determine whether the absolute value |P_dtc| of the power P_dtc is equal to or greater than a reference value CV (step S101).

[0077] Here, the reference value CV is a value greater than the lower limit at which power in the AC circuit 6 can be detected. That is, the lower limit at which power can be detected is determined by the lower limit at which the current sensor 7u can detect a current and the lower limit at which the voltage sensor inside the power storage device 1 can detect a voltage. The reference value CV is, for example, 50 W. That is, the condition that |P_dtc| is greater than or equal to the reference value CV is satisfied if the current sensor 7u detects a current flowing in the AC circuit 6.

[0078] For example, in the consumer 100, it is common that some general loads are in operation even at night. Therefore, even if the storage battery 1b is not being charged, a current flows through the AC circuit 6. If the current sensor 7u is correctly installed, |P_dtc| becomes equal to or greater than the reference value CV in the non-charging abnormality determination process (YES in step S101). In this case, it is determined that there is no installation abnormality in the current sensor 7u, and the sensor check ends.

[0079] If the current sensor 7u is not installed correctly, for example, if the current sensor 7u has fallen off the AC circuit 6, |P_dtc| will be less than the reference value CV in the non-charging abnormality determination process. There may also be a case where the consumer 100 does not have a general load that operates at night. In this case, |P_dtc| will also be less than the reference value CV in the non-charging abnormality determination process. Furthermore, |P_dtc| may also be less than the reference value CV due to the influence of noise, detection error, etc. In this way, when |P_dtc| is less than the reference value CV (NO in step S101), the control unit 1c executes a charging command process to command forced charging at 1 kW. This starts forced charging at 1 kW (step S102).

[0080] When the storage battery 1b is fully charged, if the storage battery 1b detects that charging is being performed, the storage battery 1b outputs an error notification. The error notification is output a predetermined time (hereinafter also referred to as the "notification time"; for example, 300 ms) after charging is detected. The control unit 1c determines whether or not an error notification has been received from the storage battery 1b (step S103).

[0081] When an error notification is received from the storage battery 1b (YES in step S103), the control unit 1c stops the sensor check.

[0082] If no error notification has been received from the storage battery 1b (NO in step S103), the control unit 1c judges whether or not a specified time (e.g., 400 ms) for performing forced charging has elapsed (step S104). The specified time is the time for which the power conversion unit 1a continues to output DC power to the storage battery 1b. The specified time is longer than the notification time. As a result, if the storage battery 1b is fully charged, an error notification is output during the forced charging, and the sensor check can be stopped.

[0083] The control unit 1c measures (detects) the power P_dtc in the U-phase of the AC circuit 6 based on the current value detected by the current sensor 7u during forced charging and the voltage of the AC circuit 6. The control unit 1c executes a forced charging anomaly determination process to determine whether the absolute value |P_dtc| of the power P_dtc is equal to or greater than a reference value CV (step S105).

[0084] During forced charging, a current for charging flows through the AC circuit 6. If the current sensor 7u is correctly attached, |P_dtc| becomes equal to or greater than the reference value CV in the forced charging abnormality determination process (YES in step S105). In this case, it is determined that there is no abnormality in the attachment of the current sensor 7u, and the sensor check ends.

[0085] If the current sensor 7u is not attached correctly, for example, if the current sensor 7u has fallen off the AC circuit 6, |P_dtc| will be less than the reference value CV in the forced charging abnormality determination process. Furthermore, |P_dtc| may also be less than the reference value CV due to the influence of noise, detection error, etc. When |P_dtc| is less than the reference value CV in this way (NO in step S105), the control unit 1c determines whether the number of retries has reached six (step S106) to retry, for example, six times. That is, the control unit 1c executes the above-mentioned processes from steps S101 to S105 a maximum of a specified number of times. When the number of retries is six, the specified number is seven.

[0086] If the number of retries is less than 6 (NO in step S106), the control unit 1c returns to step S101.

[0087] From step S101, S102 → S103 → S104 → S105 → S106 → S101 are repeated, and when the number of retries reaches six (YES in step S106), the control unit 1c determines that the current sensor 7u is abnormally attached (step S107). This ends the sensor check.

[0088] (Example 2) The second example is a sensor check in so-called double power generation. That is, setting information for the second mode is stored in the storage unit of the control unit 1c.

[0089] 11 is a flowchart showing the procedure of the sensor check in the second example. The flowchart is executed by the control unit 1c of the power storage device 1. The sensor check is executed for each of the U phase and the W phase. The sensor check for the U phase will be described below as a representative example.

[0090] When the sensor check starts, the control unit 1c measures (detects) the power P_dtc in the U-phase of the AC circuit 6 based on the current value detected by the current sensor 7u and the voltage of the AC circuit 6. The control unit 1c executes a non-charging abnormality determination process to determine whether the real value P_dtc of the detected power is equal to or greater than the reference value CV (step S111). The difference between steps S101 and S111 described above is whether the absolute value |P_dtc| or the real value P_dtc is compared with the reference value CV.

[0091] Steps S112 to S114 are the same as steps S102 to S104 in the first example described above, and therefore a description thereof will be omitted.

[0092] The control unit 1c executes a forced charging anomaly determination process to determine whether the real value P_dtc of the detected power during forced charging is equal to or greater than the reference value CV (step S115). The difference between steps S105 and S115 described above is that the comparison target with the reference value CV is the absolute value |P_dtc| or the real value P_dtc.

[0093] For example, the control unit 1c may selectively execute the above-mentioned sensor check for single power generation (first example) and the sensor check for double power generation (second example). For example, the control unit 1c selectively executes the sensor check for single power generation (first example) and the sensor check for double power generation (second example) depending on whether the setting information for the first mode or the setting information for the second mode is stored. That is, when the setting information for the first mode is stored, the control unit 1c executes the sensor check for single power generation (first example), and when the setting information for the second mode is stored, the control unit 1c executes the sensor check for double power generation (second example).

[0094] (Example 3) The third example is a sensor check in so-called double power generation. In the third example, an abnormality in the attachment direction of the current sensor 7u is judged.

[0095] 12 is a flowchart showing the procedure of a sensor check in the third example. The flowchart is executed by the control unit 1c of the power storage device 1. The sensor check is executed for each of the U phase and the W phase. The sensor check for the U phase will be described below as a representative example.

[0096] Steps S111 to S114 are the same as in the second example, and therefore the explanation will be omitted.

[0097] The control unit 1c determines whether the real value P_dtc of the detected power during forced charging is equal to or greater than the reference value CV (step S201). If P_dtc is equal to or greater than CV (YES in step S201), it is determined that the current sensor 7u is normally attached, and the sensor check is completed.

[0098] If P_dtc is less than CV (NO in step S201), the control unit 1c judges whether -P_dtc is equal to or greater than CV (step S202).

[0099] If the current sensor 7u is installed in the opposite direction, the polarity of the detected power P_dtc is reversed. Therefore, although the current is detected by the current sensor 7u, P_dtc is less than CV. Here, if P_dtc is multiplied by -1 to obtain -P_dtc, -P_dtc becomes equal to or greater than CV, and an abnormality in the installation direction of the current sensor 7u can be detected.

[0100] Two counters CNT1 and CNT2 are stored in the memory of the control unit 1c. CNT1 is a variable indicating the number of times that the current sensor 7u has been detected as being detached. CNT1 is a variable indicating the number of times that an abnormality in the installation direction of the current sensor 7u has been detected. The initial values ​​of CNT1 and CNT2 are zero.

[0101] If -P_dtc is less than CV, P_dtc is zero, and it is considered that no power is detected in the AC power circuit 6. Therefore, if -P_dtc is less than CV in step S202, it can be determined that the current sensor 7u has fallen off. If -P_dtc is less than CV (NO in step S202), the control unit 1c increments the counter CNT1 (step S203).

[0102] If -P_dtc is equal to or greater than CV, it is considered that the current sensor 7u is attached in the wrong direction. If -P_dtc is equal to or greater than CV (YES in step S202), the control unit 1c increments the counter CNT2 (step S204).

[0103] In the third example, the processes from steps S201 to S204 described above are the forced charging abnormality determination process.

[0104] After step S203, the control unit 1c judges whether or not CNT1 is equal to or greater than 7 (step S205). If CNT1 is less than 7 (NO in step S205), the control unit 1c returns to step S111 and retries the sensor check.

[0105] If CNT1 is equal to or greater than 7 (YES in step S205), the control unit 1c determines that the current sensor 7u has fallen off (step S206), and ends the sensor check.

[0106] After step S204, the control unit 1c judges whether or not CNT2 is equal to or greater than 7 (step S207). If CNT2 is less than 7 (NO in step S207), the control unit 1c returns to step S111 and retries the sensor check.

[0107] If CNT2 is 7 or more (YES in step S207), the control unit 1c determines that the mounting direction of the current sensor 7u is abnormal (step S208), and ends the sensor check.

[0108] (Example 4) The fourth example is a sensor check in a so-called single power generation. That is, the setting information of the first mode is stored in the memory of the control unit 1c. In the fourth example, a check is performed for an installation abnormality of each of the U-phase current sensor 7u and the W-phase current sensor 7w.

[0109] 13 is a flowchart showing a procedure for a sensor check in the fourth example. The control unit 1c of the power storage device 1 executes the flowchart.

[0110] When the sensor check starts, the control unit 1c measures (detects) the power P_dtc_u in the U-phase of the AC power circuit 6 based on the current value detected by the current sensor 7u and the voltage of the AC power circuit 6. The control unit 1c determines whether the absolute value |P_dtc_u| of the power P_dtc_u is equal to or greater than a reference value CV (step S401).

[0111] If the current sensor 7u is correctly attached, |P_dtc_u| is equal to or greater than the reference value CV in step S401 (YES in step S401). In this case, it is determined that there is no attachment abnormality with respect to the current sensor 7u.

[0112] When the sensor check starts, the control unit 1c measures (detects) the power P_dtc_u in the U-phase of the AC power circuit 6 based on the current value detected by the current sensor 7u and the U-phase voltage of the AC power circuit 6. The control unit 1c determines whether the absolute value |P_dtc_u| of the power P_dtc_u is equal to or greater than a reference value CV (step S401).

[0113] In step S401, if |P_dtc_u| is equal to or greater than the reference value CV (YES in step S401), the control unit 1c measures (detects) the power P_dtc_w in the W-phase of the AC power circuit 6 based on the current value detected by the current sensor 7w and the W-phase voltage of the AC power circuit 6. The control unit 1c determines whether the absolute value |P_dtc_w| of the power P_dtc_w is equal to or greater than the reference value CV (step S402).

[0114] In step S402, if |P_dtc_w| is equal to or greater than the reference value CV (YES in step S402), it is determined that there is no attachment abnormality in each of the current sensors 7u and 7w, and the sensor check ends. If YES in step S401, steps S401 and S402 are non-charging abnormality determination processing.

[0115] In step S402, if |P_dtc_w| is less than the reference value CV (NO in step S402), the control unit 1c executes a charging command process to command forced charging at 1 kW, which starts forced charging at 1 kW (step S403).

[0116] When the storage battery 1b is fully charged and detects that charging is being performed, the storage battery 1b outputs an error notification. The control unit 1c determines whether or not an error notification has been received from the storage battery 1b (step S404).

[0117] If an error notification is received from the storage battery 1b (YES in step S404), the control unit 1c stops the sensor check.

[0118] If the controller 1c has not received an error notification from the storage battery 1b (NO in step S404), the controller 1c determines whether or not a specified time has elapsed (step S405). If the specified time has not elapsed (NO in step S405), the controller 1c returns to step S404.

[0119] When the specified time has elapsed (YES in step S405), the control unit 1c checks whether the W-phase current sensor 7w determined to have an attachment abnormality in the non-charging abnormality determination process detects a current normally while the storage battery 1b is being forcibly charged. That is, the control unit 1c measures (detects) the power P_dtc_w in the W-phase of the AC circuit 6 based on the current value detected by the current sensor 7w during the forcible charging and the W-phase voltage of the AC circuit 6. The control unit 1c executes a forced charging abnormality determination process to determine whether the absolute value |P_dtc_w| of the power P_dtc_w is equal to or greater than a reference value CV (step S406).

[0120] In the forced charging abnormality determination process in step S406, if |P_dtc_w| is equal to or greater than the reference value CV (YES in step S406), it is determined that there is no attachment abnormality in the current sensor 7w, and the sensor check ends.

[0121] In the forced charging abnormality determination process in step S406, if |P_dtc_w| is less than the reference value CV (NO in step S406), the control unit 1c determines whether the number of retries has reached six (a specified number) (step S407).

[0122] If the number of retries is less than 6 (NO in step S407), the control unit 1c returns to step S401.

[0123] In step S401, if |P_dtc_u| is less than the reference value CV (NO in step S401), the control unit 1c determines whether the absolute value |P_dtc_w| of the power P_dtc_w is equal to or greater than the reference value CV (step S408), similarly to step S402. If NO in step S401, steps S401 and S408 are non-charging abnormality determination processing.

[0124] In step S408, if |P_dtc_w| is equal to or greater than the reference value CV (YES in step S408), the control unit 1c starts forced charging at 1 kW (step S409). Steps S409, S410, and S411 are the same as steps S403, S404, and S405 described above, respectively, and therefore will not be described here.

[0125] When the specified time has elapsed (YES in step S411), the control unit 1c checks whether the U-phase current sensor 7u determined to have an attachment abnormality in the non-charging abnormality determination process detects a current normally while the storage battery 1b is being forcibly charged. That is, the control unit 1c measures (detects) the power P_dtc_u in the U-phase of the AC circuit 6 based on the current value detected by the current sensor 7u during the forcible charging and the U-phase voltage of the AC circuit 6. The control unit 1c executes a forced charging abnormality determination process to determine whether the absolute value |P_dtc_u| of the power P_dtc_u is equal to or greater than a reference value CV (step S412).

[0126] In the forced charging abnormality determination process in step S412, if |P_dtc_u| is equal to or greater than the reference value CV (YES in step S412), it is determined that there is no attachment abnormality in the current sensor 7u, and the sensor check ends.

[0127] In the forced charging abnormality determination process in step S412, if |P_dtc_u| is less than the reference value CV (NO in step S412), the control unit 1c proceeds to step S407 and determines whether the number of retries has reached six (a specified number) (step S407).

[0128] In step S408, if |P_dtc_w| is less than the reference value CV (NO in step S408), the control unit 1c starts forced charging at 1 kW (step S413). Steps S413, S414, and S415 are the same as steps S403, S404, and S405 described above, respectively, and therefore will not be described.

[0129] When the specified time has elapsed (YES in step S415), the control unit 1c checks whether or not the U-phase current sensor 7u and the W-phase current sensor 7w, which are determined to have an attachment abnormality in the non-charging abnormality determination process, detect a current normally while the storage battery 1b is being forcibly charged. That is, the control unit 1c measures (detects) the power P_dtc_u in the U-phase of the AC circuit 6 based on the current value detected by the current sensor 7u and the U-phase voltage of the AC circuit 6 during the forced charging, and measures (detects) the power P_dtc_w in the W-phase of the AC circuit 6 based on the current value detected by the current sensor 7w and the W-phase voltage of the AC circuit 6 during the forced charging. The control unit 1c executes a forced charging abnormality determination process to determine whether or not the absolute value |P_dtc_u| of the power P_dtc_u is equal to or greater than a reference value CV, and whether or not the absolute value |P_dtc_w| of the power P_dtc_w is equal to or greater than a reference value CV (step S416).

[0130] In the forced charging abnormality determination process of step S416, if |P_dtc_u| is greater than or equal to the reference value CV and |P_dtc_w| is greater than or equal to the reference value CV (YES in step S416), it is determined that there is no installation abnormality for each of the current sensors 7u and 7w, and the sensor check is terminated.

[0131] In the forced charging abnormality determination process of step S416, if at least one of |P_dtc_u| and |P_dtc_w| is less than the reference value CV (NO in step S416), the control unit 1c proceeds to step S407 and determines whether the number of retries has reached 6 (a specified number) (step S407).

[0132] If the number of retries is less than 6 (NO in step S407), the control unit 1c returns to step S401.

[0133] When the number of retries reaches 6 (YES in step S407), the control unit 1c determines that at least one of the current sensors 7u and 7w is abnormally attached (step S417). For example, the control unit 1c can count the number of times that an attachment abnormality is determined for each of the current sensors 7u and 7w (i.e., the number of times that |P_dtc_u| or |P_dtc_w| is less than the reference value CV), and determine that a current sensor whose count value is equal to or greater than a predetermined value is abnormally attached.

[0134] In the sensor check during double power generation, the comparison target with the reference value CV in steps S401, S402, S406, S408, S412, and S416 may be changed from the absolute value |P_dtc_u| or |P_dtc_w| to the real value P_dtc_u or P_dtc_w.

[0135] 《Addendum》 The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims rather than the above-described embodiments, and includes the meaning equivalent to the claims and all modifications within the scope thereof. [Explanation of symbols]

[0136] 1,1m,1s power storage device 1a Power conversion section 1b storage battery 1c Control section 2. Solar panels 3 Power conditioner 4 General load distribution board 5. Important load distribution board 6 AC line 7,7u,7w current sensor 8 Remote Control Device 9. Router 10. Mobile Information Terminals 11 General load 12 Important loads 13 Switch 100 Consumers 200 Commercial power system 201 Electricity meter for sale 202 Electricity meter for electricity purchase 300 Internet A1 Current Sensor C1, C2, C3 Varistor L1 Grid connection circuit L2 independent feed line L3 Storage battery side power supply line P1 Grid connection port P2 Auxiliary Input Port P3 output port Ps1, Ps2 System connection points R load SW1, SW2, SW3 opening and closing parts T1 Grid connection output terminal T2 independent output terminal V1, V2, V3 voltage sensors

Claims

1. A grid-connected energy storage system including a current sensor for detecting a current flowing in an AC circuit connected to a grid of a consumer, and an energy storage device connected to the AC circuit, the energy storage device comprising: A storage battery, a power conversion unit that is disposed between the storage battery and the AC circuit and performs bidirectional power conversion between DC and AC; a control unit that controls the power conversion unit and detects power based on the current detected by the current sensor and the voltage of the AC current line, The control unit executes a charging command process for causing the power conversion unit to output DC power of a first charging power value in order to charge the storage battery, and a forced charging anomaly determination process for determining whether or not there is an installation anomaly with respect to the current sensor based on a detection value of the power of the AC current circuit while the storage battery is being charged. Grid-connected energy storage system.

2. the control unit executes a non-charging abnormality determination process for determining whether or not there is an installation abnormality with respect to the current sensor based on a detection value of the power of the AC circuit while the storage battery is not being charged, and executes the charging command process and the forced charging abnormality determination process when it is determined in the non-charging abnormality determination process that there is an installation abnormality with respect to the current sensor. The grid-connected electricity storage system according to claim 1 .

3. When it is determined that there is an attachment abnormality in the current sensor in the forced charging abnormality determination process, the control unit executes the non-charging abnormality determination process again. The grid-connected electricity storage system according to claim 2 .

4. The control unit executes the non-charging abnormality determination process when it is determined that there is an installation abnormality for the current sensor in the forced charging abnormality determination process from the 1st to the N-1th times, where N is a specified number of times that is 2 or more, and when it is determined that there is an installation abnormality for the current sensor in the Nth forced charging abnormality determination process, it finalizes the determination of the installation abnormality for the current sensor. The grid-connected electricity storage system according to claim 3 .

5. the charging command process is a process of continuing the output of the DC power from the power conversion unit to the storage battery for a specified time, the specified time is longer than a notification time from when charging of the storage battery in a fully charged state is started to when the storage battery outputs a notification of a charging error to the power storage device; The grid-connected electricity storage system according to claim 1 .

6. When the control unit receives a notification of the charging error from the storage battery during execution of the charging command process, the control unit stops the charging command process.

6. A grid-connected electricity storage system according to claim 5.

7. The forced charging anomaly determination process is a process for determining whether or not there is an attachment anomaly in the current sensor based on whether or not power equal to or greater than a reference value that is greater than a lower limit value at which power in the AC circuit can be detected is detected. The grid-connected electricity storage system according to claim 1 .

8. In cases where a power generating device that is connected to the grid is installed, The power storage device is a first mode in which discharging from the storage battery is stopped when the power generation device is generating power; a second mode in which discharging from the storage battery can be performed regardless of whether the power generation device is generating power or not; Selectively set When the first mode is set, the forced charging abnormality determination process is a process of determining whether or not an absolute value of the detected power is equal to or greater than the reference value, When the second mode is set, the forced charging abnormality determination process is a process of determining whether or not a real value of the detected power is equal to or greater than the reference value. The grid-connected electricity storage system according to claim 7.

9. The forced charging abnormality determination process includes a process of determining whether or not there is an abnormality in the attachment direction of the current sensor based on a sign of a real value of the detected power. The grid-connected electricity storage system according to any one of claims 1 to 8.

10. The alternating current is a multi-phase alternating current including a first phase and a second phase, the current sensor includes a first current sensor that detects a current flowing in the AC current circuit of the first phase, and a second current sensor that detects a current flowing in the AC current circuit of the second phase; The forced charging anomaly determination process includes at least one of a first determination process for determining whether or not there is an installation anomaly with respect to the first current sensor based on a detection value of a first phase power of the AC circuit of the first phase while the storage battery is being charged, and a second determination process for determining whether or not there is an installation anomaly with respect to the second current sensor based on a detection value of a second phase power of the AC circuit of the second phase while the storage battery is being charged. The grid-connected electricity storage system according to claim 1 .

11. the control unit determines whether or not there is an installation abnormality for the first current sensor based on a detection value of the first phase power while the storage battery is not being charged, executes a non-charging abnormality determination process to determine whether or not there is an installation abnormality for the second current sensor based on a detection value of the second phase power while the storage battery is not being charged, and executes the charging command process and the forced charging abnormality determination process when it is determined in the non-charging abnormality determination process that there is an installation abnormality for at least one of the first current sensor and the second current sensor. The grid-connected electricity storage system according to claim 10.

12. The control unit executes the first determination process when it is determined in the non-charging abnormality determination process that there is an attachment abnormality of the first current sensor. The grid-connected electricity storage system according to claim 11.

13. the control unit, when it is determined in the non-charging abnormality determination process that there is an installation abnormality of the first current sensor and that there is no installation abnormality of the second current sensor, executes the first determination process and does not execute the second determination process. The grid-connected electricity storage system according to claim 11.

14. When it is determined in the non-charging abnormality determination process that there is an installation abnormality of the first current sensor and when it is determined that there is an installation abnormality of the second current sensor, the control unit executes the first determination process and executes the second determination process. The grid-connected electricity storage system according to any one of claims 11 to 13.

15. A method for detecting an installation abnormality of a current sensor, which is executed by a power storage device having a storage battery, when a power storage device is connected to an AC circuit connected to a grid of a consumer and a current flowing through the AC circuit is detected by the current sensor, comprising: outputting DC power having a first charging power value from the power conversion unit to charge the storage battery; Detecting power based on a current detected by the current sensor and a voltage of the AC circuit while the storage battery is being charged; executing a forced charging abnormality determination process for determining whether or not there is an attachment abnormality in the current sensor based on the detected value of the power; A method for detecting an installation error in a current sensor.

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