JP7185597B2 - Power storage device and power storage system including the power storage device - Google Patents

Description

The present invention relates to a power storage device and a power storage system including the power storage device.

Conventionally, it is possible to store electricity by using electricity that is cheaper late at night, and use the stored electricity during the daytime when electricity demand peaks, or use the stored electricity to back up power in the event of a sudden power outage. There is an energy storage system that

100 [V] home electric appliances used in ordinary homes use single-phase three-wire 200 [V] single-phase U-phase or W-phase. A 100 [V] outlet is normally wired for U phase and W phase in a well-balanced manner. However, depending on the house, there may be cases where the wiring is biased toward the U phase or the W phase, or that even though the wiring of the outlets is uniform, the connected electrical appliances are biased toward one of the phases. can occur, and in extreme cases, appliances may be connected to only one of the phases.

Suppose that a power storage system is connected to a single-phase three-wire 200 [V] single-phase 100 [V] system in a situation where a home appliance, which is a load, is connected only to one of the phases. At this time, when one phase that is connected to the grid is unloaded and a load is connected to the phase that is not connected to the grid, the no-load that is connected to the grid is used to prevent reverse power flow. It is necessary to output power for the load of the phase that is not connected to the grid.

For this reason, when the load of the phase not connected to the grid is the same as the rated output power, a current twice the rated output current flows through the neutral wire, so wiring materials with an allowable current that is at least twice the rated output current , it is necessary to use a breaker, which increases the cost, and also affects the wiring because the wire becomes thicker. Therefore, techniques have been proposed to control the power storage system so that the value of the current flowing through the neutral wire does not exceed a predetermined allowable value.

Conventional technologies of this type include the technology described in Patent Document 1, in which DC power received from a DC power supply such as a solar battery is converted into AC power by a single-phase two-wire inverter. , in a grid-connected inverter that supplies AC power to a load by connecting with a single-phase three-wire commercial power system, the current value flowing in the neutral line is detected, and the current value is a predetermined allowable value A technique has been proposed for controlling the AC output so as not to exceed .

Japanese Patent No. 3107687

By the way, when connecting a single-phase 3-wire single phase 100 [V] to the grid, it is necessary to monitor the current and voltage of the single phase that is not connected to the grid. Here, according to the technique described in Patent Document 1, the neutral wire is provided with a neutral wire current detector (current sensor), and the wiring extending from the neutral wire current detector is connected to the grid-connected inverter. As long as the serviceman does not make a mistake in the wiring work, the grid-connected inverter can accurately grasp the value of the current flowing through the neutral line. Further, in the device described in Patent Document 1, since a single-phase two-wire 200 [V] is drawn into the inverter, it is sufficient to monitor the voltage between the drawn two wires.

On the other hand, the device described in Patent Document 1 requires a control line for connecting the current sensor and the inverter in order to monitor the current in the system. Furthermore, as described above, unlike the device described in Patent Document 1, when the system is connected to the single-phase 3-wire single-phase 100 [V], the voltage of the single phase that is not connected to the system is monitored. , a single-phase line that is not connected to the grid must also be drawn into the device (that is, all three lines, including two lines that are connected to the grid, must be drawn into the device), When connecting to [V], a suitable wiring work was required.

Therefore, in order to facilitate system interconnection, a plug with a grounding electrode is provided in the power storage device, and the plug with a grounding electrode is inserted into a single-phase, three-wire, single-phase 100 [V] outlet to connect power to the commercial power system. Giving and receiving can be considered. However, in such a power storage device that can be used simply by being connected to an outlet, it is extremely difficult to determine which of the two wires connected to the outlet is the neutral wire (O phase). . Also, a line that is not O-phase is either U-phase or W-phase, and it is extremely difficult to determine which one.

Although it is such a difficult situation, when the power storage device plug is inserted into the outlet, which of the two connection terminals of the outlet corresponds to the O phase, and the connection terminal that does not correspond to the O phase is the U phase or W phase. If it is not possible to accurately determine which phase corresponds to which, there is a possibility that the charge/discharge control of the power storage device cannot be performed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a power storage device and a power storage system that can be connected to a single-phase, three-wire single-phase system simply by connecting to an outlet.

In order to achieve the above object, the present invention has the configuration described below.

A power storage system equipped with a power storage device, which is a sensor that detects currents of U phase and W phase, voltage between U phase and O phase, and voltage between W phase and O phase in a single-phase three-wire distribution line of a commercial electric power system. and transmission means for transmitting the sensor value detected by the sensor, and the power storage device is connected to the single-phase three-wire distribution line via a grounded outlet, between the U phase and the O phase and the W phase. A power conditioner connected to one of the O phases and having a power conversion unit that performs charging and discharging operations on a storage battery, a control circuit that controls the power conversion unit, and a sensor value transmitted from the transmission means The control circuit compares the voltage with respect to the ground potential of one connection terminal of the grounded outlet with the voltage with respect to the ground potential of the other connection terminal, and determines which connection terminal is It is determined whether it corresponds to the O phase, and the voltage or current information of the connection terminal that has not been determined to correspond to the O phase is compared with the voltage or current information based on the sensor value received by the receiving means . and determining means for determining whether the connection terminal corresponds to the U phase or the W phase, and controlling the charging/discharging operation by the power conversion unit based on the determination result of the determining means. Characterized by

According to this configuration, it is possible to determine which of the two connection terminals of the grounded outlet is the O phase by comparing the potential difference between the two connection terminals of the grounded outlet. and the known voltage or current information received by the receiving means, it is possible to determine whether the connecting terminal that is not the O-phase is the U-phase or the W-phase. Therefore, it is possible to monitor the current flowing through the O phase and control the charge/discharge operation so that the current flowing through the O phase does not exceed a predetermined value. This eliminates the need to draw a control line into the power storage device to monitor the current in the system, and allows the power storage device to be connected to the power system in one phase of the single-phase three-wire system simply by connecting it to an outlet.

Here, it is preferable to monitor the receiving state of the receiving means, and to stop and/or disconnect the power converting section from the commercial power system when it is determined that the transmission from the transmitting means has stopped.

The power storage device is connected to either the U phase or the W phase, and the sensors are a first current sensor that measures the current of the phase connected to the grid and the current of the phase that is not connected to the grid. a second current sensor, a first voltage sensor that measures the voltage of the grid-connected phase, and a second voltage sensor that measures the voltage of the non-system-connected phase, wherein the control circuit Based on the measured value of the current sensor and the measured value of the second current sensor, the current value flowing through the O line may be calculated, and the current value may be controlled so as not to exceed a preset value. .

The power storage device included in the power storage system is connected to either the U-phase O-phase or the W-phase O-phase of the single-phase three-wire distribution line of the commercial power system via a grounded outlet, and charges and discharges the storage battery. and a control circuit for controlling the power conversion unit, U-phase and W-phase currents in the single -phase three-wire distribution line, the voltage between the U-phase and the O-phase, and W receiving means for receiving a sensor value from a sensor for detecting voltage between phases O, wherein the control circuit controls the voltage of one connection terminal of the grounded outlet with respect to the ground potential and the ground of the other connection terminal; By comparing the voltage with respect to the potential, it is determined which connection terminal corresponds to the O phase, and the voltage or current information of the connection terminal that has not been determined to correspond to the O phase and the sensor received by the receiving means It has a determination means for determining whether the connection terminal corresponds to the U phase or the W phase by comparing the voltage or current information based on the value, and based on the determination result of the determination means, the power It is characterized by controlling the charge/discharge operation by the conversion unit.

According to this configuration, it is possible to determine which of the two connection terminals of the grounded outlet is the O phase by comparing the potential difference between the two connection terminals of the grounded outlet. and the known voltage or current information received by the receiving means, it is possible to determine whether the connecting terminal that is not the O-phase is the U-phase or the W-phase. Therefore, it is possible to monitor the current flowing through the O phase and control the charge/discharge operation so that the current flowing through the O phase does not exceed a predetermined value. This eliminates the need to draw a control line into the power storage device to monitor the current in the system, and allows the power storage device to be connected to the power system in one phase of the single-phase three-wire system simply by connecting it to an outlet.

Here, it is preferable to monitor the reception state of the receiving means, and to stop and/or disconnect the power conversion unit from the commercial power system when it is determined that the sensor value is no longer received.

Further, the system is connected to either the U phase or the W phase, and the control circuit calculates the current value flowing through the O line based on the sensor value received by the receiving means, and the current value is set in advance. It may be controlled so that it does not exceed the preset value.

ADVANTAGE OF THE INVENTION According to this invention, the electrical storage apparatus and electrical storage system which can be connected to a single phase of a single phase three-line can be provided only by connecting to an outlet.

1 is a block diagram showing the configuration of a power storage system 1 according to one embodiment of the present invention; FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows the external appearance of the electrical storage system 1 in one Embodiment of this invention. 2 is a block diagram showing a main part of a relay circuit 27; FIG. 2 is a block diagram showing a main part of a control circuit 21; FIG. FIG. 2 is an explanatory diagram showing connection of a power conditioner 20 to system wiring in the power storage system 1 of the present embodiment; FIG. 3 is an explanatory diagram showing a case where there is no load on the U phase with which the power storage system 1 is connected to the grid, and there is a load of power consumption 2 [kW] on the W phase with which the power storage system is not connected to the grid. FIG. 7 is an explanatory diagram for a case where the neutral wire upper limit current IcMAX is set to 30 [A] in FIG. 6 ; FIG. 4 is an explanatory diagram for explaining charge/discharge control when a load is present in a phase (U phase) that is interconnected with the grid; FIG. 4 is an explanatory diagram for explaining charge/discharge control when there is no load on a grid-connected phase (U phase) and there is a load on a grid-disconnected phase (W phase);

An embodiment of the present invention will be described in detail below with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of a power storage system according to one embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the appearance of the power storage system according to one embodiment of the present invention.

[Configuration of power storage system 1]
As shown in FIG. 1 , the power storage system 1 includes a power storage device 2 and a current/voltage detector 50 . The power storage device 2 includes a storage battery 10, a power conditioner 20, a plug 40 (see FIG. 2) that can be plugged into a 100 [V] grounded outlet 200 installed inside and outside the house, and a home electric appliance plug. and an independent output outlet 42 (see FIG. 2).

The current/voltage detection unit 50 functions as the "detection unit" of the present invention, and as shown in FIG. there is The current/voltage detector 50 is installed in the distribution board 100 (see FIG. 2).

As shown in FIG. 2, the distribution board 100 is equipped with a system wiring 101, a main breaker 102, a plurality of branch breakers 103, an earth (ground) terminal 104, and a current/voltage detector 50. there is

The system wiring 101 is wiring for supplying commercial power from a commercial power system 150 drawn into the house from a power transmission line by a transformer, service line, or the like, to home electric appliances. Since the wiring system of the commercial power in this embodiment is a single-phase three-wire system, the system wiring 101 is composed of three wires of a U-phase wiring, an O-phase wiring, and a W-phase wiring. In the following description, the U-phase and W-phase wirings may be simply referred to as the U-phase and W-phase. Also, the O-phase wiring may be referred to as an O-phase or a neutral wire.

In the distribution board 100, the system wiring 101 is branched into a plurality of paths. The primary side of the branch breaker 103 is connected to two-phase wiring of either the O phase, the U phase, or the W phase from the branches of the U phase, the O phase, and the W phase, and extends from the secondary side of the branch breaker 103. A grounded outlet 200 of 100 [V] is arranged at the end of the system wiring 101 . The ground terminal 104 is a so-called frame ground (FG) terminal that grounds the housing of the distribution board 100 .

The current sensors 51 and 52 and the voltage sensors 53 and 54 of the current/voltage detection unit 50 are arranged in the system wiring 101 on the primary side with respect to the branch breaker 103. are arranged on the system wiring 101 on the primary side.

The current sensors 51 and 52 of the current/voltage detection unit 50 are generally called CT (current transformer) sensors for detecting current. The current sensor 51 is attached to the U phase, and the current sensor 52 is attached to the W phase. It is attached. The voltage sensor 53 detects the voltage between the U phase and the O phase, and the voltage sensor 54 detects the voltage between the W phase and the O phase. Sensor values detected by current sensors 51 and 52 and voltage sensors 53 and 54 are transmitted by sensor value transmitter 55 .

The sensor value transmitter 55 modulates the sensor values transmitted from the current sensors 51 and 52 and the voltage sensors 53 and 54 and transmits them to the sensor value receiver 24 wirelessly or by wire.

[Configuration of power conditioner 20]
Next, the power conditioner 20 will be explained.
The power conditioner 20 includes a control circuit 21 , a converter 22 , an inverter 23 , a sensor value receiver 24 and a relay circuit 27 . Note that the sensor value receiver 24 may be provided outside the power conditioner.

The control circuit 21 controls the power conditioner 20 as a whole.
The converter 22 boosts the DC voltage resulting from the discharge of the storage battery 10 and supplies it to the inverter 23 . Further, converter 22 steps down the DC voltage from inverter 23 and supplies it to storage battery 10 . Storage battery 10 is charged by supplying the stepped-down DC power to storage battery 10 .

The inverter 23 converts the DC power (discharge power) from the storage battery 10 boosted by the converter 22 into AC power, and supplies it to the general load 5 and/or the independent load (important load) 6 via the relay circuit 27. , performs DC/AC operation. Inverter 23 performs an AC/DC operation in which AC power input from system wiring 101 is converted into DC power (charged power) and supplied to storage battery 10 via converter 22 . Thus, in this embodiment, the converter 22 and the inverter 23 function as the "power converter" of the invention.

The sensor value receiver 24 receives sensor value information of the current sensors 51 , 52 and the voltage sensors 53 , 54 transmitted from the sensor value transmitter 55 , demodulates it, and transmits it to the control circuit 21 . Based on the received sensor value, the control circuit 21 can determine to which phase of the single-phase three-wire power storage device 2 is connected (to which phase the power storage device 2 is connected to the grid).

The relay circuit 27 includes, as shown in FIG. It is provided with an isolated output relay 27 b and an isolated output relay 27 c for connection and disconnection between the inverter 23 and the isolated load 6 . The self-sustained load 6 refers to a home appliance connected to the self-sustaining output outlet 42 (see FIG. 2).

By performing switching control of this relay circuit 27, for example, power is supplied from the commercial power system 150 to the self-sustaining load 6, power is supplied from the commercial power system 150 to the self-sustaining load 6, and the storage battery 10 is charged. It is possible to switch the supply source of power supplied to the self-sustaining load 6 , such as supplying power discharged by the storage battery 10 to the self-sustaining load 6 without supplying power from the commercial power system 150 .

[Phase discrimination/Polarity discrimination]
FIG. 4 is a block diagram showing the essential parts of the control circuit 21. The control circuit 21 comprises a CPU 25 and a comparator 26. As shown in FIG. The CPU 25 controls the power conditioner 20 as a whole. When plug 40 of power storage device 2 is inserted into grounded outlet 200, comparator 26 connects two connection terminals of either one of the U-phase and W-phase of system wiring 101 and the neutral wire (O-phase). Each is connected to one ground terminal. Comparator 26 is also connected to sensor value receiver 24 and CPU 25 .

First, the neutral wire is determined. Comparator 26 compares the potential difference between the two connection terminals with respect to the ground terminal in grounded outlet 200 . As a result of the comparison by the comparator 26, the CPU 25 determines that the terminal with the smaller potential difference is the connection terminal corresponding to the neutral line.

Next, the CPU 25 determines whether the connecting terminal that is not the neutral line is the U-phase or the W-phase. Specifically, the CPU 25 receives the voltage information (voltage value and phase) of the connection terminal other than the neutral line, and the known voltage information (voltage value and phase) of the distribution board 100 received by the sensor value receiver 24. compare. Thereby, it is determined whether the phase corresponding to the connection terminal that is not the neutral wire is the U phase or the W phase. Note that current information (current value and phase) may be compared instead of voltage information in order to determine whether the connection terminal other than the neutral wire is U-phase or W-phase.

The control circuit 21 makes various settings based on the result of the phase discrimination, and puts the power storage device 2 into an operable state. As a result, the power storage device 2 can be used with any grounded outlet 200 . On the other hand, when the communication between the sensor value transmitter 55 and the sensor value receiver 24 is interrupted and the above determination cannot be made, the control circuit 21 prevents the charge/discharge control of the power conditioner 20 from becoming impossible. , control to turn off (open) the interconnection relay 27a, and gate block the inverter 23 to stop the inverter 23 (turn off the semiconductor switch in the inverter). As a result, power storage device 2 is disconnected from commercial power system 150, and system interconnection is canceled. In order to cancel the system interconnection, either one of stopping the inverter 23 (power converter) and turning off (opening) the interconnection relay 27a may be executed.

As described above, according to the present embodiment, when the plug 40 is connected to the grounded outlet 200, the potential difference between the two connection terminals with respect to the ground terminal is compared to determine which of the connection terminals is the neutral wire (O phase). After determining whether or not the neutral wire, the voltage or current information of the connection terminal that is not the neutral wire is compared with the known voltage or current information on the distribution board 100 side received by the sensor value receiver 24, and the neutral wire is not Since it is possible to determine whether the connection terminal is in the U phase or the W phase, it is possible to control charging and discharging of the power storage device 2 without any trouble. In addition, it is not necessary to lead the control line into the power storage device 2, and the system can be connected to the single-phase three-wire single-phase system simply by connecting to an outlet.

[Control of power storage device]
5 to 9 are explanatory diagrams for explaining how current flows depending on the load status of the power conditioner 20 according to the power storage device of the present embodiment. FIG. A general load 5 (hereinafter, simply referred to as “load”) is a load with a power consumption of 2 [kW].

The control circuit 21 of the power storage system 1 of the present embodiment calculates the power in the U phase based on the sensor values of the current sensor 51 and the voltage sensor 53, including determination of the consumption direction and the supply direction, and the power value E is calculated. calculate. Similarly, based on the sensor values of the current sensor 52 and the voltage sensor 54, the power in the W phase is calculated including the consumption direction and the supply direction, and the power value F is calculated. The control circuit 21 controls the sum of the power value E and the power value F to be 0 (zero) or less in order to prevent reverse power flow.
E+F≦0 (W)

Here, the reason why the sum of the value E and the value F is controlled to 0 or less instead of 0 is to prevent the self-sustaining load 6 from exceeding 0 even if it suddenly decreases. is.

For example, if the rated power of the power conditioner 20 is 2 [kW], the storage battery 10 can cover up to 2 [kW] if the load 5 is connected to the U-phase interconnected as shown in FIG. At this time, the power value E is controlled to be 0 or less.
E≦0
On the other hand, since there is no load on the W phase side,
F = 0
become. Therefore,
E+F≦0
becomes. Here, instead of E+F≦0, if E+F=0 for simplicity, the U-phase current Ia and the W-phase current Ib are:
Ia = Ib = 0
As a result, the O-phase current also becomes zero.

Here, when the power consumption by the load 5 exceeds 2 [kW], for example, in the case of 2.5 [kW], the storage battery 10 can cover up to 2 [kW]. The portion exceeding 2 [kW] is supplied from the commercial power grid 150 . At this time E = -2.5 [kW] + 2.0 [kW] = -0.5 [kW]
, resulting in forward power flow.

In this case, the current of each phase is Ia=-0.5 [A], Ib=0, and the O-phase current is 0.5 [A].

In FIG. 6 , no load is connected to the U-phase that is connected to the power storage device 2 (no load), and a load of power consumption 2 [kW] is connected to the W-phase that is not connected to the grid. indicates if there is
Since the power F on the W-phase side is consumed by the load 5,
F = -2.0 [kW]
becomes. Also, since it is controlled so that E+F≦0, E+F=E-2.0 [kW]≦0
becomes. That is, E≦2.0 [kW].
Thus, although no load is connected to the U phase, it is necessary to output power of 2.0 [kW] or less from the power conditioner 20 .

Similarly in this case, if E+F=0 for simplification, the current of each phase is Ia=20 [A], Ib=20 [A], and O-phase current Ic=40 [A].

Therefore, assuming a 100 [V] grid connection with a rated power of 2.0 [kW], the current will be 20 [A]. If there is a load above the rating on the neutral wire, the current will flow in the neutral wire at least twice the rating.

Therefore, the upper limit current Ic (=Ia+Ib) of the neutral wire calculated from the value Ia of the current sensor 51 and the value Ib of the current sensor 52 is set in advance and controlled so as not to exceed this. It can reduce the current that flows through the sex line.

As described above, in the normal control described with reference to FIG. 6, the U-phase current Ia=20 [A] and the O-phase current Ic=40 [A]. 6 with the rated power of the power conditioner 20 and the load 5, and the upper limit current IcMAX of the neutral line is set to 30 [A], the current Ib of the W phase is 20 [ A] flows. Here, in the control of E+F=0 as described above, Ia=20 [A], but since IcMAX is set to 30 A,
Ia = Ic MAX - Ib = 30 [A] - 20 [A] = 10 [A]
, Ia=10 [A] and Ic=30 [A].

[Neutral wire current limit during charge/discharge]
The power storage system 1 of the present embodiment monitors the current of the neutral line and performs charge/discharge control.
FIG. 8 is an explanatory diagram for explaining the charge/discharge control when there is a load on the phase (U phase) that is interconnected to the grid, FIG. indicate the time.

When the power storage system 1 is discharged, as shown in FIG. 8A, a load with a power consumption of 2 [kW] is connected to the grid-connected phase (U phase), and the grid-unconnected phase ( W phase) is no load (power consumption 0 [W]), the current sensor 51 detects power purchase (supply of commercial power) to a load with power consumption 2 [kW] (current indicated by a thin arrow in the figure). Then, discharge control is performed from the power conditioner 20 (current indicated by a thick arrow in the figure). As a result, the power supplied by purchasing commercial power becomes 0 [A], and the discharge power from the power conditioner 20 is supplied to the load (discharge current of 20 [A] is supplied from the power conditioner 20). Thus, in the case shown in FIG. 8A, the load uses 2 [kW] of discharge power. The direction of power is determined by the direction (phase) of the voltage and current of each phase.

When the power storage system 1 is charged, as shown in FIG. 8B, a load of power consumption 2 [kW] is applied to the grid-connected phase (U-phase), and the grid-not-connected phase (W phase) is no load (power consumption 0 [W]), 40 [A] of charging current 20 [A] + load 20 [A] flows through the U phase, and 40 [A] also flows through the neutral wire. At this time, for example, by controlling the power conditioner 20 to limit the current in the neutral line to 30 [A], the current flowing in the neutral line is suppressed, while charging is also 1 [kW] (10 [A] ]). As a result, in the case shown in FIG. 8(b), a total of 3 [kW] of commercial power was used: 1 [kW] for charging the storage battery 10 and 2 [kW] for the load.

FIG. 9 is an explanatory diagram for explaining the charge/discharge control when the grid-connected phase (U-phase) has no load and the grid-not-connected phase (W phase) is connected to a load. FIG. 9(a) shows the state during discharging, and FIG. 9(b) shows the state during charging.

When the storage system 1 is discharged, as shown in FIG. 9A, the grid-connected phase (U phase) has no load, and the grid-not-connected phase (W phase) consumes 2 kW of power. ] is connected, the current sensor 52 detects a load with a power consumption of 2 [kW] (the current indicated by the thick arrow in the figure), and discharge control is performed from the power conditioner 20 (the thin arrow in the figure). current). In other words, the direction of the power is determined by the direction (phase) of the voltage and current of each phase, and the sum of the power of the U and W phases is zero at the connection point (position of the current sensors 51 and 52 (position of CT)). controlled to be

At this time, 20 [A] + 20 [A] = 40 [A] flows through the neutral wire. By controlling, the current flowing through the neutral wire is suppressed, while the discharge output from the power conditioner 20 becomes 1 [kW] (10 [A]) as indicated by the thin arrow in the figure. As a result, 1 [kW] of power is sold for the U phase and 2 [kW] is purchased for the W phase, resulting in a total of 1 [kW] of power being used (purchased) from the commercial power grid 150. .

When the power storage system 1 is charged, as shown in FIG. 9B, the grid-connected phase (U phase) has no load, and the grid-not-connected phase (W phase) consumes 2 kW of power. ] is connected, a charging current of 20 [A] flows through the U phase, but this cancels out the current of 20 [A] in the W phase, and the neutral wire becomes 0 [A]. Even if control is performed to limit the line current to 30 [A], the threshold is not reached. As a result, a total of 4 [kW] of commercial power, 2 [kW] for charging the storage battery 10 and 2 [kW] for load consumption, was used (purchased power).

According to the present embodiment configured in this way, it is possible to connect the system to one phase of the single-phase three-wire system by simply connecting it to an outlet, and the load 5 can be connected to the commercial power system 150 in a phase that is not connected to the commercial power system 150. , the current flowing through the neutral wire (O phase) can be suppressed. Therefore, the capacity of the breaker to be installed can be suppressed, and the wire diameter of the neutral wire can also be suppressed to a relatively small size, so that the cost and the handling of wire rods can be facilitated.

1 power storage system 2 power storage device 5 general load 6 autonomous load 10 storage battery 20 power conditioner 21 control circuit 22 converter 23 inverter 24 sensor value receiver 50 current/voltage detectors 51 and 52 current sensors 53 and 54 voltage sensor 55 sensor value transmission Machine 100 Distribution board 150 System power supply 200 Grounded outlet

Claims (6)

An electricity storage system including an electricity storage device,
A sensor for detecting U-phase and W-phase currents, a voltage between U and O phases and a voltage between W and O phases in a single-phase, three-wire distribution line of a commercial electric power system, and transmitting the sensor values detected by the sensors. A detection unit having a transmission means for
The power storage device is connected to either the U-phase O-phase or the W-phase O-phase of the single-phase three-wire distribution line via a grounded outlet, and a power conversion unit that charges and discharges a storage battery. , a power conditioner having a control circuit for controlling the power conversion unit; and receiving means for receiving the sensor value transmitted from the transmitting means,
The control circuit is
determining which connection terminal corresponds to the O phase by comparing the voltage with respect to the ground potential of one connection terminal and the voltage with respect to the ground potential of the other connection terminal in the grounded outlet;
The voltage or current information of the connection terminal not determined to correspond to the O phase is compared with the voltage or current information based on the sensor value received by the receiving means to determine whether the connection terminal corresponds to the U phase or the W phase. has a determination means for determining which of
A power storage system , wherein the charge/discharge operation by the power conversion unit is controlled based on the determination result of the determination means . 2. A receiving state of said receiving means is monitored, and when it is determined that transmission from said transmitting means has stopped, said power conversion section is stopped and/or said power conversion section is disconnected from a commercial power system. The electrical storage system described. the power storage device is interconnected to either the U phase or the W phase,
The sensors include a first current sensor that measures the current of the grid-connected phase, a second current sensor that measures the current of the phase that is not grid-connected, and a first voltage sensor that measures the voltage of the grid-connected phase. and a second voltage sensor that measures the voltage of the phase that is not interconnected,
The control circuit is
Based on the measured value of the first current sensor and the measured value of the second current sensor, the current value flowing through the O line is calculated, and the current value is controlled so as not to exceed a preset value. 3. The power storage system according to claim 1 or 2, characterized in that: a power conversion unit that is connected via a grounded outlet to either the U-phase O-phase or the W-phase O-phase of a single-phase three-wire distribution line of a commercial electric power system, and performs charging and discharging operations on a storage battery; a power conditioner having a control circuit that controls the power conversion unit;
receiving means for receiving a sensor value from a sensor for detecting the current of the U phase and the W phase, the voltage between the U phase and the O phase, and the voltage between the W phase and the O phase in the single-phase three-wire distribution line;
The control circuit is
determining which connection terminal corresponds to the O phase by comparing the voltage with respect to the ground potential of one connection terminal and the voltage with respect to the ground potential of the other connection terminal in the grounded outlet;
The voltage or current information of the connection terminal not determined to correspond to the O phase is compared with the voltage or current information based on the sensor value received by the receiving means to determine whether the connection terminal is the U phase or the W phase. has a determination means for determining whether it corresponds to
A power storage device, wherein the charge/discharge operation by the power conversion unit is controlled based on the determination result of the determination means . 5. The system according to claim 4 , wherein the receiving state of the receiving means is monitored, and when it is determined that the sensor value is no longer received, the power conversion unit is stopped and/or the power conversion unit is disconnected from the commercial power system. storage device. The system is connected to either the U phase or the W phase,
The control circuit calculates a current value flowing through the O line based on the sensor value received by the receiving means, and controls the current value so that it does not exceed a preset value. 6. The power storage device according to claim 4 or 5.

Images