JP7112982B2 - storage system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a technology for protecting an electricity storage system itself and an electric device such as a home appliance connected to the electricity storage system from a lightning surge.

In general, electric power sent from a commercial power system is supplied to electrical equipment via a power plug or the like. Conventionally, there is a power storage system that charges a storage battery with low-cost late-night power and uses the power charged in the storage battery during the daytime, when power prices are high, together with commercial power as needed to reduce electricity charges. In such a power storage system, it is possible to operate electric devices with power supplied from the storage battery when commercial power supply is not expected, such as during a power outage.

On the other hand, if the power outage is caused by a lightning strike, the lightning surge may enter the commercial power system and then enter the electrical equipment via the power plug, damaging the electrical equipment. In addition, the power storage system itself is generally equipped with lightning surge countermeasures, but if an unexpected lightning surge penetrates from the commercial power system, the power storage system itself will be damaged, and the storage battery will not be able to supply power during a power outage. do not have.

Therefore, for example, Patent Document 1 discloses means for detecting a surge current or voltage caused by lightning, means for interrupting the supply of commercial power to an electrical device when lightning is detected, and power supply from a storage battery to the electrical device. and a means for switching to a power storage system is disclosed. When a lightning strike occurs, the power supply from the commercial power system is cut off, so it is possible to prevent lightning surges from entering the electrical equipment and the power storage system, and thus prevent damage. In addition, even if the power supply from the commercial power system is cut off, the power supply from the storage battery can ensure the power supply to the electrical equipment.

JP 2001-197679

However, there is an upper limit to the battery capacity of a storage battery, and a storage battery with a large battery capacity is very expensive. Therefore, most of the storage batteries for home use have a low battery capacity from the viewpoint of economy. In this case, it is difficult to supply all the power required during the day with the power charged at midnight. In addition, as described above, the power of the storage battery is charged at night and consumed during the daytime. It may happen that there is almost no left.

If a lightning strike occurs while the storage battery is not sufficiently charged and the supply of commercial power is cut off to prevent a lightning surge from entering, the power remaining in the storage battery alone will not be sufficient to supply power from the commercial power grid. There is a risk that it will not be possible to ensure sufficient power supply to the electrical equipment at the time of interruption.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to prevent damage to an electricity storage system itself and electrical equipment connected to the electricity storage system due to the intrusion of a lightning surge, and to stably supply power when the power supply from the commercial power system is cut off. It is to provide a power storage system that can perform.

A power storage system according to the present invention includes a system input unit to which power sent from a commercial power system is input, a power storage circuit that charges and discharges a storage battery, and power supplied from at least one of the power system input unit and the power storage circuit. a power output unit for outputting to a load, a first state in which power can be supplied from the system input unit to the power storage circuit and the load, and the system input unit, the power storage circuit, and the power output unit being cut off, and a switching device capable of switching to a second state in which power can be supplied from the storage battery to the load; a discriminating circuit for discriminating between an initial stage and a second stage in which the risk of a lightning surge entering a commercial power system is higher than the initial stage; When the determination is made, the switching device is placed in the first state, the storage circuit is controlled so that charging of the storage battery is started by power supply from the system input unit, and the occurrence of lightning occurs in the second state. and a control circuit for controlling the storage circuit so that when the stage is determined, the switching device is placed in the second state and power is supplied from the storage battery to the load.

According to the above configuration, by charging the storage battery in advance when the occurrence of lightning is determined to be the initial stage in which there is a risk of a lightning surge entering the commercial power system, the occurrence of lightning can be prevented from the initial stage. At the time when it is determined that the second stage, in which there is a high risk of a lightning surge entering the commercial power system, there is a high possibility that the storage battery has already been charged with a sufficient amount of power. Therefore, when the occurrence of lightning is determined to be in the second stage, the switching device is placed in the second state, so that the power storage system and loads such as electrical equipment connected to the power storage system are damaged by the intrusion of the lightning surge. can be prevented, and power can be stably supplied from the storage battery to the load.

The power storage system further includes a lightning detection circuit that outputs to the determination circuit at least two-stage signals corresponding to an initial stage and a second stage, which differ depending on the risk of a lightning surge entering the commercial power system. It is preferable to have

The determination circuit may perform determination based on, for example, lightning information obtained from the Internet. However, when the Internet line is defective due to a power outage or the like, the determination circuit is delayed in acquiring lightning information, and the load cannot be sufficiently protected from lightning surges. Therefore, by incorporating a lightning detection circuit into the power storage system, it is possible to obtain lightning information reliably and quickly even in the event of a failure of the Internet line. Securing can be performed more reliably.

Further, in the power storage system, the control circuit checks the remaining battery level of the storage battery when the determination circuit determines that the occurrence of lightning is in an initial stage, and if the remaining battery level is equal to or less than a predetermined threshold, Preferably, the charging circuit is controlled such that charging of the storage battery is started.

As described above, daytime electricity is expensive, so from the viewpoint of reducing electricity costs, it is desirable to avoid charging the storage battery during hours other than midnight as much as possible. On the other hand, considering the risk of a lightning surge caused by a lightning strike entering the commercial power system, it is preferable that the remaining battery level of the storage battery that supplies power when the power supply from the system input is cut off is large. For example, when lightning occurs in the initial stage, if there is sufficient remaining battery power, the lightning occurrence is determined to be in the second stage, and the power supply from the system input unit is cut off. But the battery works well as a power source. However, when the battery level of the storage battery is insufficient, it is necessary to charge the storage battery in advance in order to stably supply power when the power supply from the system input unit is cut off.

Therefore, according to the above configuration, when it is determined that the occurrence of lightning is in the initial stage, charging is performed only when the remaining battery level of the storage battery is equal to or less than a predetermined threshold value, so that when the power supply from the grid is interrupted, etc. It is possible to avoid unnecessary expenses while suppressing the shortage of remaining battery power.

In the power storage system, the initial stage includes a caution stage and a warning stage in which the risk of a lightning surge entering a commercial power system is higher than the caution stage, and the second stage is a dangerous stage. wherein the discrimination circuit discriminates whether the occurrence of lightning is any of the non-occurrence state, the caution stage, the warning stage, and the danger stage, and the control circuit uses the discrimination circuit to When the occurrence of lightning is determined to be a warning stage, the remaining battery level of the storage battery is checked, and if the remaining battery level is equal to or less than a predetermined threshold, charging of the storage battery is started, and the remaining battery level reaches the predetermined threshold. is exceeded, the storage circuit is controlled so that charging is not performed, and when the occurrence of lightning is determined to be in the warning stage, charging of the storage battery is started regardless of the remaining battery level of the storage battery. It is preferable to control the storage circuit such that

In the above configuration, the power storage system further divides the initial stage into a caution stage and a caution stage. When the lightning situation is determined to be a caution stage, charging is performed by comparing the remaining amount of the storage battery with a predetermined threshold. determines the necessity of Then, at the time when the lightning occurrence situation is determined to be in the warning stage, there is a possibility that the lightning occurrence situation is subsequently determined to be in the dangerous stage (second stage), that is, the power supply from the system input section is cut off. Assuming that the possibility has increased, control is performed to start charging the storage battery regardless of the remaining battery level.

Therefore, according to the above configuration, the charging of the storage battery is started regardless of the remaining battery level of the storage battery in the alert stage, which is likely to be determined as the second stage in the near future. By charging the storage battery only, it is possible to avoid unnecessary expenses while minimizing the shortage of the remaining battery power when the power supply from the commercial power system is interrupted.

Further, in the power storage system, when the lightning generation state is no longer determined to be the second stage for a predetermined time or longer after the determination circuit determined that the lightning occurrence status is the second stage, the control circuit It is preferable to set the switching device to the first state.

Since the power supply from the storage circuit to the load stops when the remaining battery power runs out, there is a risk of lightning surges entering the commercial power system in order to continue supplying power to the load without interruption. It is desirable to quickly restart the power supply from the grid input section when it drops. According to the above configuration, the power supply from the system input unit can be automatically restarted at the time when the risk of lightning surge entering the commercial power system is considered to have decreased. As a result, it is possible to reduce the possibility that the power supply to the load will be interrupted due to the remaining battery power being depleted.

According to the present invention, it is possible to prevent the power storage system itself and electrical devices connected to the power storage system from being damaged by a lightning surge, and to stably supply power when the power supply from the commercial power system is interrupted. A power storage system can be provided.

1 is a block diagram of a power storage system according to one embodiment of the present invention; FIG. 4 is a flowchart showing a control operation of power supply when the power storage system shown in FIG. 1 detects lightning.

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

The power storage system 1 according to this embodiment is a system that supplies power to a load 100 connected to a self-supporting output unit (power output unit) 7 . As shown in FIG. 1, the power storage system 1 includes a lightning detection circuit 2, a determination circuit 3, a system input unit 4 connected to a commercial power system G, a power storage circuit 5, a switching device 6, and an independent output unit. 7 and a control circuit 8 . Moreover, the system input unit 4 and the storage circuit 5 are connected by a wiring 9 a that passes through the switching device 6 . The independent output unit 7 and the electric storage circuit 5 are connected by a wiring 9 b passing through the switching device 6 . The wiring 9a and the wiring 9b are connected by wiring 9c in the switching device 6 on the system input section 4 side of the relays 51 and 52 and on the independent output section 7 side of the relays 55 and 56 .

The lightning detection circuit 2 is a circuit for detecting lightning and is connected to the discrimination circuit 3 . Lightning is detected by detecting, for example, electromagnetic waves emitted when lightning occurs, an increase in current or voltage in the lightning detection circuit 2, the light and sound of lightning, and the like. In this embodiment, the lightning detection circuit 2 preferably outputs a discrete signal in any one of three or more stages according to the risk of a lightning surge entering the commercial power grid G. FIG. Note that the lightning detection circuit 2 may output continuous signals having different intensities depending on the risk of a lightning surge entering the commercial power system G. FIG.

The discriminating circuit 3 is connected to the lightning detection circuit 2 and the control circuit 8, and based on the signal from the lightning detection circuit 2, determines whether the lightning has occurred: non-occurrence state (undetected), caution stage, warning stage, Then, it determines which of the dangerous stages it is, and transmits determination information to the control circuit 8 . In this embodiment, each stage is defined as a caution stage, a caution stage, and a danger stage in order of decreasing risk of a lightning surge entering the commercial power grid G. FIG.

The determination as to which stage the lightning is occurring is based on the signal supplied from the lightning detection circuit 2 . For example, when the lightning detection circuit 2 outputs a continuous signal, the level is determined by comparing the intensity of the signal with a threshold corresponding to the boundary of the level. When the lightning detection circuit 2 outputs a discrete signal, the stage is determined based on a table that associates the discrete signal with each stage.

Power sent from the commercial power system G is input to the system input unit 4 . The power input to the system input unit 4 is supplied to the load 100 through the self-sustaining output unit 7 at night except when the determination circuit 3 determines that the occurrence of lightning is dangerous. and one used for charging the storage battery 22, which will be described later. During the daytime, the power charged in the storage battery 22 and the power input to the system input unit 4 as necessary are supplied to the load 100 via the independent output unit 7 .

The power storage circuit 5 has a bidirectional DC/DC converter 23 and a bidirectional inverter 24 , a noise filter 25 that removes noise generated from the power storage circuit 5 , and a relay 57 . Bidirectional DC/DC converter 23 has one end connected to storage battery 22 via relay 57 and the other end connected to bidirectional inverter 24 .

The bidirectional DC/DC converter 23 is a device that converts the voltage of DC power. In the present embodiment, the voltage on the storage battery 22 side and the voltage on the system input unit 4 side are mutually converted, It is a device that provides the optimum voltage. The bidirectional inverter 24 is a device that converts direct current to alternating current or vice versa. , converts the DC power discharged from the storage battery 22 into AC power, and supplies it to the load 100 . Bidirectional DC/DC converter 23 and bidirectional inverter 24 are connected to control circuit 8 and their operations are controlled by control circuit 8 .

In addition, when a power outage continues for a long period of time and there is a risk that the storage battery 22 is over-discharged, or when an abnormality occurs in the storage battery 22, the relay 57 is turned off to prevent the power from the storage battery 22 from being discharged. It is possible to cut off the supply and prevent overdischarge of the storage battery 22 .

Switching device 6 includes relays 51 and 52 arranged on wiring 9a connecting system input unit 4 and power storage circuit 5, and relays 53 and 53 arranged on wiring 9c connecting wiring 9a and wiring 9b. 54 , and relays 55 and 56 arranged on the wiring 9 b connecting the self-supporting output unit 7 and the storage circuit 5 . When no lightning occurs, the relays 51 to 54 are ON and the relays 55 and 56 are OFF, and the state of the switching device 6 at this time is referred to as a first state. During the daytime, power is supplied to the load 100 from the power storage circuit 5 and from the system input unit 4 as necessary. Also, at night or in the daytime, when the thunder situation is determined to be caution level and the battery level of the storage battery 22 is below a predetermined threshold, or when the thunder situation is determined to be caution level. , the storage battery 22 is charged from the system input unit 4 .

In addition, the switching device 6 turns off the relays 51 to 54 and turns on the relays 55 and 56 by the control circuit 8 when the occurrence of lightning is determined to be in a dangerous stage regardless of whether it is day or night. , the power storage circuit 5 and the self-supporting output unit 7 are cut off, and the second state is entered in which power can be supplied from the storage battery 22 to the load 100 via the self-supporting output unit 7 .

For example, if relays 51 and 52 as well as relays 55 and 56 are turned off during normal times, power supply from power storage circuit 5 during the daytime can be stopped. In this case, since the remaining battery capacity of the storage battery 22 can be secured, during a power failure, that is, when the power supply from the system input unit 4 is stopped and only the power supply from the storage circuit 5 is performed, power supply for a longer period of time is possible. It becomes possible. However, if the storage battery 22 that stores inexpensive nighttime power is not used during the daytime, the power supply to the load 100 in normal times must be covered by the daytime power from the system input unit 4, and the daytime power is considered as the nighttime power. Because it is more expensive than the conventional one, the electricity bill will increase.

The independent output unit 7 is connected to the load 100 via a power plug, a power cable, and the like, and outputs power supplied from at least one of the system input unit 4 and the storage circuit 5 to the load 100 .

The control circuit 8 is connected to the determination circuit 3 and the storage circuit 5, and is a circuit capable of reading lightning information output from the determination circuit 3 and checking the remaining battery capacity of the storage battery 22. The control circuit 8 switches ON/OFF the relays 51 to 57 and charges and discharges the storage battery 22 based on the stage of the occurrence of lightning determined by the determination circuit 3 and the remaining battery capacity of the storage battery 22. and other controls.

Next, a control operation of power supply when the power storage system 1 configured as described above detects lightning will be described.

FIG. 2 is a flowchart showing the control operation of power supply when the power storage system 1 detects lightning. When no lightning occurs, relays 51 to 54 and 57 of power storage system 1 are ON, and relays 55 and 56 are OFF. At this time, the switching device 6 is in the first state, and power is supplied to the load 100 from the system input unit 4 and/or the storage circuit 5 .

At the same time that the discriminating circuit 3 discriminates based on the output signal of the lightning detecting circuit 2 that the lightning is in a stage other than the lightning non-occurrence state (S1: YES), the discriminating circuit 3 determines whether the lightning occurrence state is the caution stage, the warning stage, or the It is determined whether it is in one of the dangerous stages (S2).

When the detected lightning occurrence state is determined to be the caution stage, the control circuit 8 checks whether the remaining battery level of the storage battery 22 is equal to or less than a predetermined threshold (first threshold) (S3).

Here, the predetermined threshold is 20% of the maximum capacity of the storage battery 22, for example. However, in the present invention, the predetermined threshold is freely set according to the user's needs. For example, for a user who prefers to reduce the cost of electricity, it is not preferable to charge the storage battery 22 during the daytime hours when prices are high. In this case, charging of the storage battery 22 can be avoided as much as possible by setting the predetermined threshold as low as possible, such as 5%. As a result, power costs can be reduced by sacrificing to some extent securing a stable power supply during power outages.
On the other hand, a user who wants to ensure a stable power supply in the event of a power failure would like to store as much power as possible in the storage battery 22 even at the expense of power costs. In this case, by setting the predetermined threshold value to a high value, such as 50%, it is possible to secure the power amount of the storage battery capable of always stably supplying power although the power cost increases.

When the remaining battery level of the storage battery 22 is equal to or less than a predetermined threshold value (first threshold value) (S3: YES), charging of the storage battery 22 is started (S4). Then, while the storage battery 22 is still charged, the process returns to step S1 and waits until the next lightning is detected. Note that charging may be stopped when the remaining battery level of the storage battery 22 becomes equal to or greater than another predetermined threshold value (second threshold value that is greater than the first threshold value) during standby. If the remaining battery level of the storage battery 22 is greater than the predetermined threshold (first threshold) (S3: NO), the storage battery 22 is not charged and the process returns to step S1.

Also, when the detected thunder occurrence state is determined to be in the warning stage, charging is forcibly started regardless of the remaining battery level of the storage battery 22 (S4), and the process returns to step S1. Also in this case, charging may be stopped when the remaining battery level of the storage battery 22 becomes equal to or greater than another predetermined threshold value (second threshold value) during standby.

Here, when charging the storage battery 22, commercial power supplied from the system input unit 4 is used. Since the commercial power is AC power, it is converted into DC power by the bidirectional inverter 24 . Also, the bidirectional DC/DC converter 23 converts the voltage into a voltage used for charging the storage battery 22 and charges the storage battery 22 . When discharging, that is, when supplying the load 100 with power stored in the storage battery 22, conversion opposite to that described above is performed. Also, these conversion controls are performed by the control circuit 8 .

When the detected lightning occurrence is determined to be in a dangerous stage, the control circuit 8 turns off the relays 51 to 54 to cut off the power supply from the system input unit 4, and then the relays 55 and 56 are turned off. By turning ON, the switching device 6 is switched to the second state (S5). When lightning in a critical stage is detected, a lightning surge entering from the commercial power system G may flow into the power storage circuit 5 side of the power storage system 1 and the load 100 . Therefore, relays 51 and 52 are turned off to disconnect system input unit 4 and power storage circuit 5 , and relays 53 and 54 are turned off to disconnect system input unit 4 and load 100 . In this state, commercial power is not supplied from the system input unit 4 to the load 100, so the relays 55 and 56 are turned ON so that power from the storage battery 22 can be supplied.

In general, thunderclouds are considered to approach gradually, so it is conceivable that the thundercloud will shift in stages from a caution stage to a warning stage to a danger stage. Therefore, when the critical stage is reached, the storage battery 22 is charged with a sufficient amount of electric power. However, it is conceivable that a thundercloud suddenly appears and the thunder in the dangerous stage is detected without going through the stages. In this case, prior to charging of the storage battery 22, the power supply from the system input unit 4 is cut off and the power supply is switched to the power supply only by the storage circuit 5. FIG.

Next, it is determined whether or not a predetermined time has passed since the lightning detecting circuit 2 no longer determines that the detected lightning occurrence state is in the dangerous stage (S6). If the lightning situation is in a dangerous stage or the elapsed time since it is no longer determined to be in a dangerous stage is less than the predetermined time (S6: NO), the process proceeds to step S6 while maintaining the power supply from the storage battery 22 at the time of power failure. return. If the time that has passed since the lightning situation was no longer determined to be in a dangerous stage is equal to or longer than a predetermined time (S6: YES), the relays 51 to 54 are turned ON, and the relays 55 and 56 are turned OFF. 6 is switched to the first state, power supply from the system input unit 4 is resumed, and power is supplied to the load 100 from the system input unit 4 or from both the system input unit 4 and the storage circuit 5 (S7).
It should be noted that "lightning is no longer determined to be in a dangerous stage" includes not only the caution stage and caution stage, but also the case where lightning itself is not detected, that is, the non-occurrence state.

Also, the predetermined time is, for example, 10 minutes. However, in the present invention, the predetermined time is freely set according to the user's needs. For example, if it is desired to give priority to protecting the electrical equipment and the power storage system from a lightning surge, the predetermined time is set long. On the other hand, a user who wants to secure a stable power supply even at the expense of the risk of a lightning surge may prefer power supplied from the system input unit 4 instead of the storage battery 22, which has a limited remaining battery capacity. is preferably used, in which case the predetermined time is set short. In the present invention, the predetermined time may be zero.

According to the above-described embodiment, when the occurrence of lightning is determined to be a warning stage, charging is performed only when the remaining battery level of the storage battery 22 is equal to or less than a predetermined threshold value. It is possible to avoid unnecessary expenses while suppressing the shortage of remaining battery power.

In addition, when the lightning occurrence state is determined to be in the warning stage, there is a possibility that the lightning occurrence state will be determined to be in the dangerous stage in the near future, that is, the power supply from the commercial power system G may be cut off. Control is made to start charging the storage battery 22 regardless of the remaining battery level. As a result, it is possible to minimize the shortage of the remaining battery power when the power supply from the commercial power system G is interrupted or the like.

When the occurrence of lightning is determined to be in a dangerous stage, the switching device 6 is placed in the second state, thereby preventing damage to the load 100 such as electrical equipment and the power storage system 1 due to the intrusion of a lightning surge. can. The occurrence of lightning is often judged to be in the danger stage after going through the caution stage or warning stage. Therefore, since there is a high possibility that a sufficient amount of electric power has been charged in the storage battery 22 at this time, the possibility that the storage battery 22 can stably supply power to the load 100 increases.

Further, in the control circuit 8 according to the present embodiment, after the determination circuit 3 determines that the lightning occurrence state is in the dangerous stage (second stage), the lightning occurrence state is not determined to be in the dangerous stage for a predetermined time or more. At this time, the switching device 6 is set to the first state.

Since the power supply from the power storage circuit 5 to the load 100 stops when the remaining battery capacity of the storage battery 22 runs out, in order to continuously supply power to the load 100 without interruption, the commercial power system G It is desirable to restart the power supply from the system input unit 4 promptly when the danger of intrusion into the system has decreased. According to the present embodiment, the power supply from the system input unit 4 can be automatically restarted when the risk of lightning surge entering the commercial power system G is considered to have decreased. As a result, it is possible to reduce the possibility that the power supply to the load 100 is interrupted due to the remaining battery power of the storage battery 22 running out.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these examples, and various modifications are possible within the scope of the claims.

For example, the determination circuit 3 determines whether lightning has not yet occurred, the initial stage when there is a risk of a lightning surge entering the commercial power system G, or the initial stage when a lightning surge may enter the commercial power system G You may discriminate|determine whether it is any of the 2nd stage with high risk of. In that case, when it is determined to be in the initial stage, charging of the storage battery 22 may be forcibly started regardless of the remaining battery level of the storage battery 22, or if the remaining battery level of the storage battery 22 is equal to or less than the first threshold. Otherwise, the charging of the storage battery 22 may be started, and the charging may not be started. However, in order to minimize the shortage of the remaining battery capacity of the storage battery 22 when the power supply from the grid is interrupted, it is necessary to determine whether it is in the non-occurrence state, caution stage, warning stage, or danger stage. It is preferable to discriminate. Further, the discriminating circuit 3 may discriminate which of four or more stages the occurrence of lightning is. In this case, for example, in S2, the attention stages may be further subdivided, and the remaining battery level threshold may be increased in stages where the risk of a lightning surge entering the commercial power system G is higher.

Moreover, the lightning detection circuit 2 may not be mounted on the power storage system 1 . In this case, for example, the power storage system 1 is connected to the Internet, and lightning information is acquired from the Internet. In this case, the determination of the occurrence of lightning by the determination circuit 3 may be performed based on the distance from the installation position of the power storage system 1 to the location of the occurrence of lightning. Caution stage, occurrence within a 20-km radius may be considered as a warning stage, and occurrence within a 10-km radius may be considered as a danger stage. Alternatively, it may be based on the lightning intensity, or by another index. In addition, based on a combination of multiple indicators, such as the combination of the distance to the location where the lightning occurred and the intensity of the lightning, the risk of a lightning surge entering the power system can be determined, and the stage at which it is occurring can be determined. can be determined. In the above-described embodiment, the lightning detection circuit 2 outputs at least three-stage signals to the determination circuit 3. In the present invention, the lightning detection circuit outputs two-stage A signal may be output to the discrimination circuit.

However, when the Internet line is defective due to a power outage or the like, the determination circuit is delayed in acquiring lightning information, and the load cannot be sufficiently protected from lightning surges. Therefore, in order to obtain lightning information reliably and quickly even in the event of a failure of the Internet line, and to more reliably secure the power supply when the power supply from the commercial power system is cut off and the lightning surge countermeasure, the lightning detection circuit 2 is preferably installed in the power storage system 1 .

Further, the determination circuit 3 may be included in the lightning detection circuit 2 or the control circuit 8. In this case, the lightning detection circuit 2 and the control circuit 8 are connected.

The noise generated from the power storage system during normal times and during power outages differs between normal times and during power outages, and two noise filters 25 may be installed in accordance with these noise differences. However, in this case, the cost of the power storage system 1 increases and the size increases, so it is preferable that there is one noise filter 25 .

Also, instead of the bidirectional DC/DC converter 23, two DC converters may be installed. In this case, one DC converter converts the voltage from the system input unit 4 side to the storage battery 22 side, and the other DC converter converts the voltage from the storage battery 22 side to the system input unit 4 side.

1 power storage system 2 lightning detection circuit 3 discrimination circuit 4 system input unit 5 power storage circuit 6 switching device 7 self-sustaining output unit (power output unit)
8 control circuits 9a, 9b, 9c wiring 22 storage battery 23 bidirectional DC/DC converter 24 bidirectional inverter 25 noise filter 100 load

Claims (5)

a system input unit to which power sent from a commercial power system is input;
a power storage circuit that charges and discharges a storage battery;
a power output unit that outputs power supplied from at least one of the system input unit and the power storage circuit to a load;
a first state in which power can be supplied from the power system input unit to the power storage circuit and the load; and power supply from the power storage battery to the load while the power system input unit, the power storage circuit, and the power output unit are cut off. a switching device capable of switching to and from a second state in which supply is possible;
At least, the state of occurrence of lightning is a non-occurrence state, an initial stage in which there is a risk of a lightning surge entering the commercial power system, and a second stage in which the risk of a lightning surge entering the commercial power system is higher than the initial stage. a determination circuit for determining which of
When the determination circuit determines that the occurrence of lightning is in the initial stage, the switching device is placed in the first state, and the electric power storage unit is configured so that charging of the storage battery is started by power supply from the system input unit. controlling the circuit to set the switching device to the second state when the occurrence of lightning is determined to be in the second stage, and to control the storage circuit so that power is supplied from the storage battery to the load; and a control circuit. further comprising a lightning detection circuit that outputs to the determination circuit at least two-stage signals corresponding to the initial stage and the second stage, which differ according to the risk of a lightning surge entering the commercial power system. The power storage system according to claim 1. The control circuit checks the remaining battery level of the storage battery when the determination circuit determines that the occurrence of lightning is in the initial stage, and starts charging the storage battery if the remaining battery level is equal to or less than a predetermined threshold. 3. The power storage system according to claim 1, wherein the power storage circuit is controlled so as to The initial stage consists of a caution stage and a caution stage in which there is a higher risk of a lightning surge entering the commercial power system than the caution stage,
The second stage is a critical stage,
the discrimination circuit discriminates whether the occurrence of lightning is any of the non-occurrence state, the caution stage, the warning stage, and the danger stage;
The control circuit checks the remaining battery level of the storage battery when the discrimination circuit determines that the lightning situation is in the caution stage, and starts charging the storage battery if the remaining battery level is equal to or less than a predetermined threshold. and controls the storage circuit so that charging is not performed if the remaining battery level exceeds the predetermined threshold, and when the lightning occurrence situation is determined to be in the warning stage, the remaining battery level of the storage battery 3. The power storage system according to claim 1, wherein the power storage circuit is controlled so that charging of the storage battery is started regardless of the state of the storage battery. The control circuit switches the switching device to the second stage when the lightning occurrence status is not determined to be the second stage for a predetermined time or longer after the determination circuit determines that the lightning occurrence status is the second stage. 5. The power storage system according to any one of claims 1 to 4, characterized in that one state is set.

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