JP2020171140A - Power storage system - Google Patents

Abstract

To prevent damage to a power storage system itself and an electric device connected to the power storage system due to the intrusion of lightning surges, and provide stable power supply in an event of a power outage.SOLUTION: A power storage system includes a determination circuit 3 that determines whether the lightning occurrence status is in a non-generated state, an initial stage, or a second stage, a system input unit 4, a power storage circuit 5 including a storage battery 22, and a switching device 6 that can switch to a first state in which power can be supplied from the system input unit 4 to the power storage battery 22 and a load 100, and a second state in which the system input unit 4, the power storage circuit 5, and a self-sustaining output unit 7 are cut off, and the power is supplied from the storage battery 5 to the load 100. A control circuit 8 controls the switching device 6 to be in the first state and starts charging the of power storage battery 22 when the lightning occurrence status is determined to be the initial stage, and controls the switching device to be in the second state and controls the power storage circuit 5 such that power is supplied from the power storage battery 22 to the load 100 when the lightning occurrence state is determined to be the second stage.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technique for protecting the power storage system itself and electrical equipment such as home appliances connected to the power storage system from lightning surges.

Generally, the electric power sent from the commercial power system is supplied to the electric device through a power plug or the like. Conventionally, there is a power storage system that charges a storage battery with low-priced midnight power and uses the power charged in the storage battery in the daytime when the power price is high in combination with commercial power as needed to reduce electricity charges. In such a power storage system, it is possible to operate an electric device by supplying power from a storage battery when commercial power cannot be expected to be supplied, for example, during a power outage.

On the other hand, when a power outage is caused by a lightning strike, a lightning surge may invade a commercial power system and further invade an electric device via a power plug, thereby damaging it. In addition, the power storage system itself is generally equipped with lightning surge countermeasures, but if a lightning surge that exceeds expectations invades from the commercial power system, the power storage system itself will be damaged and power can be supplied by the storage battery in the event of a power outage. Absent.

Therefore, for example, Patent Document 1 describes a means for detecting a surge current or voltage due to lightning, a means for cutting off the supply of commercial power to an electric device when a lightning is detected, and a power supply from a storage battery to the electric device. A power storage system including a means for switching to is disclosed. When a lightning strike occurs, the power supply from the commercial power system is cut off, so that lightning surges can be prevented from entering the electrical equipment and power storage system, and eventually damage can be prevented. Further, even if the power supply from the commercial power system is cut off, the power supply to the electric device can be secured by the power supply from the storage battery.

JP 2001-197679

However, there is an upper limit to the battery capacity of the storage battery, and a storage battery having a large battery capacity is very expensive. Therefore, most of the storage batteries for home use have a small battery capacity from the viewpoint of economy. In this case, it is difficult for the electric power charged at midnight to supply all the electric power required in the daytime. Further, as described above, the power of the storage battery is charged at night and consumed in the daytime. However, for example, the remaining power of the storage battery is used up in the evening, and the remaining power of the storage battery may be used depending on the time of day. It can happen if there is little left.

If a lightning strike occurs when the storage battery is not fully charged and the supply of commercial power is cut off to prevent the intrusion of lightning surges, the remaining power of the storage battery alone will supply power from the commercial power system. There is a risk that it will not be possible to secure sufficient power supply to electrical equipment when the power is cut off.

Therefore, an object of the present invention is to prevent damage to the power storage system itself and the electric equipment connected to the power 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 possible power storage system.

The power storage system according to the present invention receives power supplied from at least one of a system input unit for inputting power sent from a commercial power system, a power storage circuit for charging and discharging a storage battery, and the system input unit or the power storage circuit. The power output unit that outputs to the load, the 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 are cut off. In addition, a switching device that can switch to a second state in which power can be supplied from the storage battery to the load, and at least a state in which lightning has not occurred, and a risk of lightning surge intrusion into the commercial power system. A discriminant circuit that discriminates whether the initial stage has or a second stage in which there is a higher risk of lightning surge intrusion into the commercial power system than the initial stage, and the discriminant circuit determines the state of lightning generation as the initial stage. When the determination is made, the switching device is set to the first state, and the power storage circuit is controlled so that charging of the storage battery is started by the power supply from the system input unit, and the lightning generation state is the second state. When the stage is determined, the switching device is set to the second state, and the storage battery is provided with a control circuit that controls the power storage circuit so that power is supplied to the load.

According to the above configuration, when the lightning occurrence situation is determined to be the initial stage where there is a risk of invasion of the lightning surge into the commercial power system, the storage battery is charged in advance, so that the lightning generation situation is from the initial stage. When it is determined that the second stage has a high risk of lightning surge entering the commercial power system, it is highly possible that a sufficient amount of power has already been charged in the storage battery. Therefore, when the lightning occurrence status is determined to be the second stage, the switching device is in the second state, and the load of the power storage system and the electric equipment connected to the power storage system is damaged due to the intrusion of the lightning surge. Can be prevented, and power can be stably supplied from the storage battery to the load.

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

The discrimination circuit may perform discrimination based on, for example, lightning information acquired from the Internet. However, when the Internet line is defective due to the influence of a power outage or the like, the discrimination circuit is delayed in acquiring lightning information, and the load cannot be sufficiently protected from lightning surges. Therefore, by incorporating a lightning detection circuit in the power storage system, lightning information can be acquired reliably and quickly even when the Internet line is defective, and lightning surge countermeasures and power supply when the power supply from the system is cut off can be obtained. It can be secured more reliably.

Further, in the power storage system, the control circuit confirms the remaining battery level of the storage battery when the lightning generation state is determined to be the initial stage by the discrimination circuit, and if the remaining battery level is equal to or less than a predetermined threshold value. It is preferable to control the charging circuit so that charging of the storage battery is started.

As mentioned above, daytime electricity is expensive, so from the viewpoint of reducing electricity costs, it is desirable to avoid charging the storage battery at times other than midnight as much as possible. On the other hand, considering the risk of lightning surges caused by lightning strikes 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 unit is cut off is large. For example, when the lightning generation status is in the initial stage, if there is sufficient battery power remaining, then the lightning generation status is determined to be the second stage, and the power supply from the system input section is cut off. However, the storage battery works well as a power source. However, when the remaining battery level of the storage battery is insufficient, it is necessary to charge the storage battery in advance in order to provide a stable power supply when the power supply from the system input unit is cut off.

Therefore, according to the above configuration, when the lightning generation state is determined to be 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 system is cut off, etc. It is possible to avoid unnecessary expenses while suppressing the shortage of the remaining battery power.

Further, in the power storage system, the initial stage is composed of a caution stage and a warning stage in which there is a higher risk of lightning surge entering the commercial power system than the caution stage, and the second stage is a danger stage. Therefore, the discriminating circuit discriminates whether the lightning occurrence state is the non-occurrence state, the caution stage, the warning stage, or the danger stage, and the control circuit is determined by the discriminating circuit. When the occurrence status of lightning is determined to be the caution 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 value, charging of the storage battery is started and the remaining battery level is the predetermined threshold value. If it exceeds, the power storage circuit is controlled so that charging is not performed, and when the lightning occurrence state 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 power storage circuit as described above.

In the above configuration, the power storage system further divides the initial stage into a caution stage and a caution stage, and charges the battery by comparing the remaining amount of the storage battery with a predetermined threshold value when the lightning occurrence status is determined to be the caution stage. Judging the need for. Then, when the lightning occurrence status is determined to be the warning stage, the lightning occurrence status may be subsequently determined to be the dangerous stage (second stage), that is, the power supply from the system input unit is cut off. As the possibility has increased, it is controlled to start charging the storage battery regardless of the remaining battery level.

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

Further, in the power storage system, the control circuit is described when the lightning generation status is not determined to be the second stage for a predetermined time or more after the lightning generation status is determined to be the second stage by the discrimination circuit. It is preferable that the switching device is in the first state.

Since the power supply from the power storage circuit to the load is stopped when the remaining battery power is exhausted, there is a risk of lightning surge intrusion into the commercial power system in order to continue supplying power to the load without interruption. When it drops, it is desirable to promptly restart the power supply from the system input section. According to the above configuration, the power supply from the system input unit can be automatically restarted when the risk of lightning surge intrusion into the commercial power system is considered to be reduced. As a result, it is possible to suppress the possibility that the power supply to the load will be interrupted due to the exhaustion of the remaining battery level.

According to the present invention, it is possible to prevent damage to the power storage system itself and the electric equipment connected to the power 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. A power storage system can be provided.

It is a block diagram of the power storage system which concerns on one Embodiment of this invention. It is a flowchart which shows the control operation of the power supply when the power storage system shown in FIG. 1 detects lightning.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

The power storage system 1 according to the present embodiment is a system that supplies power to a load 100 connected to an independent output unit (power output unit) 7. As shown in FIG. 1, the power storage system 1 includes a lightning detection circuit 2, a discrimination 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. Further, the system input unit 4 and the power storage circuit 5 are connected by a wiring 9a via a switching device 6. The self-supporting output unit 7 and the power storage circuit 5 are connected by a wiring 9b via a switching device 6. The wiring 9a and the wiring 9b are connected by the wiring 9c in the switching device 6 on the system input unit 4 side of the relays 51 and 52 and on the independent output unit 7 side of the relays 55 and 56.

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

The discrimination 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, the lightning occurrence status is undetected (undetected), caution stage, warning stage, and so on. Then, it is determined which of the danger stages it is, and the discrimination information is transmitted to the control circuit 8. In the present embodiment, each stage is set as a caution stage, a caution stage, and a danger stage in ascending order of the risk of lightning surge entering the commercial power system G.

The stage at which the lightning generation status is determined is determined based on the signal supplied from the lightning detection circuit 2. For example, when the lightning detection circuit 2 outputs a continuous signal, the stage is determined by comparing the intensity with the threshold value corresponding to the boundary of the stage. When the lightning detection circuit 2 outputs a discrete signal, the stage is determined based on a table in which the discrete signal and each stage are associated with each other.

The electric power sent from the commercial power system G is input to the system input unit 4. At night, the electric power input to the system input unit 4 is supplied to the load 100 via the self-supporting output unit 7, except when the determination circuit 3 determines that the lightning occurrence condition is a dangerous state. And one used for charging the storage battery 22, which will be described later. Further, in the daytime, the charged electric power of the storage battery 22 and the electric power input to the system input unit 4 as needed are supplied to the load 100 via the self-supporting output unit 7.

The power storage circuit 5 includes a bidirectional DC / DC converter 23, a bidirectional inverter 24, a noise filter 25 for removing noise generated from the power storage circuit 5, and a relay 57. One end side of the bidirectional DC / DC converter 23 is connected to the storage battery 22 via a relay 57, and the other end side is connected to the bidirectional inverter 24.

The bidirectional DC / DC converter 23 is a device that converts the voltage of DC power, and 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 and converted into each. It is a device with the optimum voltage. Further, the bidirectional inverter 24 is a device that converts direct current into direct current or alternating current into direct current, and in the present embodiment, the alternating current power sent from the system input unit 4 side is converted into direct current power to be converted into a storage battery 22. Is a device that charges the DC power, converts the DC power discharged from the storage battery 22 into AC power, and supplies the DC power to the load 100. The bidirectional DC / DC converter 23 and the bidirectional inverter 24 are connected to the control circuit 8, and their respective operations are controlled by the control circuit 8.

Further, when there is a risk that the storage battery 22 will be over-discharged due to a continuous power failure for a long period of time, or when an abnormality occurs in the storage battery 22, the relay 57 can be turned off to generate power from the storage battery 22. The supply can be cut off to prevent over-discharging of the storage battery 22.

The switching device 6 includes relays 51 and 52 arranged on the wiring 9a connecting the system input unit 4 and the power storage circuit 5, and relays 53 and 52 arranged on the wiring 9c connecting the wiring 9a and the wiring 9b. It has 54 and relays 55 and 56 arranged on the wiring 9b connecting the self-supporting output unit 7 and the power storage circuit 5. When the lightning has not occurred, the relays 51 to 54 are in the ON state, the relays 55 and 56 are in the OFF state, and the state of the switching device 6 at this time is the first state. Then, in the daytime, electric power is supplied from the power storage circuit 5 and the system input unit 4 to the load 100 as needed. Further, at night or in the daytime, when the lightning occurrence status is determined to be in the caution stage and the remaining battery level of the storage battery 22 is equal to or less than a predetermined threshold value, or when the lightning occurrence status is determined to be in the caution stage. , The storage battery 22 is charged from the system input unit 4.

Further, in the switching device 6, when the lightning occurrence situation is determined to be a dangerous stage in both day and night, the relays 51 to 54 are turned off and the relays 55 and 56 are turned on by the control circuit 8, and the system input unit 4 And the power storage circuit 5 and the self-supporting output unit 7 are cut off, and a second state is established 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 the relays 51 and 52 as well as the relays 55 and 56 are turned off in the normal state, the power supply from the power storage circuit 5 in the daytime can be stopped. In this case, since the remaining battery level of the storage battery 22 can be secured, a longer-term power supply can be performed in the event of a power failure, that is, when the power supply from the system input unit 4 is stopped and only the power supply from the power storage circuit 5 is performed. It will be possible. However, when the storage battery 22 storing inexpensive nighttime power is not used in the daytime, all the power supply to the load 100 at normal times must be covered by the daytime power from the system input unit 4, and the daytime power is the nighttime power. Since it is more expensive than that, the electricity bill increases.

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

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

Next, the power supply control operation when the power storage system 1 having the above configuration detects lightning will be described.

FIG. 2 is a flowchart showing a power supply control operation when the power storage system 1 detects lightning. When the lightning is not generated, the relays 51 to 54 and 57 of the power storage system 1 are in the ON state, and the relays 55 and 56 are in the OFF state. At this time, the switching device 6 is in the first state, and the power supply to the load 100 is performed from the system input unit 4 and / or the power storage circuit 5.

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

When the detected lightning generation status is determined to be the caution stage, the control circuit 8 confirms whether or not the remaining battery level of the storage battery 22 is equal to or less than a predetermined threshold value (first threshold value) (S3).

Here, the predetermined threshold value is, for example, 20% of the maximum capacity of the storage battery 22. However, in the present invention, the predetermined threshold value is freely set according to the needs of the user. For example, if the user wants to prioritize the reduction of the electric power cost, it is not preferable to charge the storage battery 22 during the daytime when the price is high. In this case, charging of the storage battery 22 can be avoided as much as possible by setting a predetermined threshold value as low as possible, for example, 5%. As a result, it is possible to reduce the power cost by sacrificing the securing of a stable power supply in the event of a power outage to some extent.
On the other hand, if the user wants to secure a stable power supply in the event of a power failure, he / she wants to store as much power as possible in the storage battery 22 at the expense of the power cost. In this case, by setting the predetermined threshold value as high as, for example, 50%, the power cost increases, but the power amount of the storage battery capable of always stably supplying power can be secured.

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, with the storage battery 22 charged, the process returns to step S1 and waits until the next lightning detection. During standby, charging may be stopped when the remaining battery level of the storage battery 22 becomes equal to or higher than another predetermined threshold value (second threshold value larger than the first threshold value). When the remaining battery level of the storage battery 22 is larger than a predetermined threshold value (first threshold value) (S3: NO), the storage battery 22 is not charged and the process returns to step S1.

Further, when the detected lightning generation status 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 higher than another predetermined threshold value (second threshold value) during standby.

Here, when charging the storage battery 22, the 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. Further, the bidirectional DC / DC converter 23 converts the voltage into a voltage used for charging the storage battery 22 to charge the storage battery 22. At the time of discharging, that is, when the electric power stored in the storage battery 22 is supplied to the load 100, the conversion opposite to the above is performed. Further, these conversion controls are performed by the control circuit 8.

When the detected lightning occurrence status is determined to be 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 turns the relays 55 and 56. By turning it on, the switching device 6 is switched to the second state (S5). When a lightning strike at a dangerous stage is detected, a lightning surge that has entered 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, the relays 51 and 52 are turned off to disconnect the system input unit 4 and the power storage circuit 5, and the relays 53 and 54 are turned off to disconnect the system input unit 4 and the load 100. In this state, since the commercial power from the system input unit 4 is not supplied to the load 100, the relays 55 and 56 are turned on so that the power from the storage battery 22 can be supplied.

In general, thunderstorms are considered to approach gradually, so it is conceivable to shift to a caution stage, a caution stage, and a danger stage in stages. Therefore, when the danger stage is reached, the storage battery 22 is charged with a sufficient amount of electric power. However, it is assumed that a thunderstorm suddenly appears and a thunderstorm in a dangerous stage is detected without taking steps. In this case, prioritizing the charging of the storage battery 22, the power supply from the system input unit 4 is cut off and the power supply is switched only by the power storage circuit 5.

Subsequently, after the detected lightning generation status is determined to be the dangerous stage, it is determined whether or not a predetermined time has elapsed since the lightning detection circuit 2 no longer determines the lightning generation status to be the dangerous stage (S6). If the elapsed time from the occurrence of lightning is in the dangerous stage or is no longer determined as the dangerous stage is less than the predetermined time (S6: NO), step S6 is performed while maintaining the power supply in the event of a power failure by the storage battery 22. Return. When the elapsed time from when the lightning occurrence status is no longer determined as a dangerous stage is longer than a predetermined time (S6: YES), the switching device is switched by turning on the relays 51 to 54 and then turning off the relays 55 and 56. 6 is switched to the first state, the power supply from the system input unit 4 is restarted, and the power is supplied to the load 100 from the system input unit 4 or both the system input unit 4 and the power storage circuit 5 (S7).
In addition, "the occurrence status of lightning cannot be determined as a dangerous stage" includes not only the caution stage and the caution stage, but also the case where the lightning itself is not detected, that is, the non-occurrence state.

The predetermined time is, for example, 10 minutes. However, in the present invention, the predetermined time is freely set according to the needs of the user. For example, if priority is given to protecting electrical equipment and power storage systems from lightning surges, the predetermined time is set longer. On the other hand, if the user wants to secure a stable power supply even at the expense of the risk of lightning surge intrusion, the power supplied from the system input unit 4 instead of the storage battery 22 having a limited battery level. In this case, the predetermined time is set short. In the present invention, the predetermined time may be zero.

According to the above embodiment, when the lightning occurrence status is determined to be in the caution 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, so that when the power supply from the system is cut off, etc. It is possible to avoid unnecessary expenses while suppressing the shortage of the remaining battery power.

In addition, when the lightning occurrence status is determined to be the warning stage, the lightning occurrence status may be determined to be the dangerous stage in the near future, that is, the power supply from the commercial power system G may be cut off. Assuming that the price has increased, the storage battery 22 is controlled to start charging regardless of the remaining battery level. As a result, it is possible to suppress the shortage of the remaining battery power as much as possible when the power supply from the commercial power system G is cut off.

Then, when the lightning occurrence situation is determined to be a dangerous stage, the switching device 6 is in the second state, so that it is possible to prevent damage to the load 100 of the electric device and the power storage system 1 due to the intrusion of the lightning surge. it can. The occurrence of lightning is often determined to be a dangerous stage after passing through a caution stage or a warning stage. Therefore, since there is a high possibility that a sufficient amount of electric power is charged in the storage battery 22 at this time, there is a high possibility that the electric power can be stably supplied from the storage battery 22 to the load 100.

Further, in the control circuit 8 according to the present embodiment, after the lightning generation status is determined to be the dangerous stage (second stage) by the discrimination circuit 3, the lightning generation status is not determined to be 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 is stopped when the remaining battery level of the storage battery 22 is exhausted, in order to continuously supply the power to the load 100 without interruption, the commercial power system G of the lightning surge It is desirable to promptly restart the power supply from the system input unit 4 when the risk of intrusion into the system is reduced. According to the present embodiment, the power supply from the system input unit 4 can be automatically restarted when the risk of lightning surge intrusion into the commercial power system G is considered to be reduced. As a result, it is possible to suppress the possibility that the power supply to the load 100 is interrupted due to the exhaustion of the remaining battery level of the storage battery 22.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these examples, and various modifications can be made as long as they are described in the claims.

For example, in the discrimination circuit 3, the lightning occurrence state is not generated, the initial stage where there is a risk of lightning surge invading the commercial power system G, and the lightning surge invades the commercial power system G from the initial stage. It may be determined whether it is one of the second stages at high risk of. In that case, when it is determined to be 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 the remaining battery level of the storage battery 22 is equal to or less than the first threshold value. For example, charging of the storage battery 22 may be started, and charging may not be started otherwise. However, in order to prevent the storage battery 22 from running out of battery power when the power supply from the grid is cut off, it is necessary to determine whether the storage battery 22 is in the ungenerated state, the caution stage, the caution stage, or the dangerous stage. It is preferable to discriminate. Further, the discrimination circuit 3 may determine which of the four or more stages the lightning generation status is. In this case, for example, in S2, the attention stage may be further subdivided, and the threshold value of the remaining battery level may be increased as the risk of lightning surge entering the commercial power system G is higher.

Further, 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 lightning occurrence status by the discrimination circuit 3 may be performed based on the distance from the installation position of the power storage system 1 to the lightning generation point. For example, when the lightning is generated within 40 km. The caution stage, the case where it occurs within 20 km may be the caution stage, and the case where it occurs within 10 km may be the danger stage. Alternatively, it may be performed based on the intensity of lightning, or may be performed based on yet another index. In addition, the risk of lightning surge intrusion into the power system is determined based on the combination of multiple indicators, such as the combination of the distance to the lightning occurrence point and the intensity of lightning, and which stage it is in. You may discriminate. In the above-described embodiment, the lightning detection circuit 2 outputs a signal of at least three stages to the discrimination circuit 3, but in the present invention, the lightning detection circuit has two stages corresponding to the initial stage and the second stage. The signal may be output to the discrimination circuit.

However, when the Internet line is defective due to the influence of a power outage or the like, the discrimination circuit is delayed in acquiring lightning information, and the load cannot be sufficiently protected from lightning surges. Therefore, in order to acquire lightning information reliably and quickly even when the Internet line is defective, and to take measures against lightning surges and secure the power supply when the power supply from the commercial power system is cut off, the lightning detection circuit 2 Is preferably mounted on the power storage system 1.

Further, the discrimination 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 the normal time and the power failure is different between the normal time and the power failure, and two noise filters 25 may be installed according to the difference in the noise. However, in this case, since the cost of the power storage system 1 increases and the size increases, it is preferable to use one noise filter 25.

Further, two DC converters may be installed instead of the bidirectional DC / DC converter 23. 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 Independent 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)

The system input section where the power sent from the commercial power system is input, and
A power storage circuit that charges and discharges the storage battery,
A power output unit that outputs power supplied from at least one of the system input unit or the power storage circuit to a load, and
The first state in which power can be supplied from the system input unit to the power storage circuit and the load, the system input unit, the power storage circuit, and the power output unit are cut off, and the power from the storage battery to the load is cut off. A switching device that can switch to the second state where supply is possible, and
At least, the lightning occurrence status is not generated, the initial stage where there is a risk of lightning surge entering the commercial power system, and the second stage where the risk of lightning surge entering the commercial power system is higher than the initial stage. A discriminant circuit that discriminates which one is
When the lightning generation state is determined to be the initial stage by the discrimination circuit, the storage battery is stored so that the switching device is set to the first state and the storage battery is started to be charged by the power supply from the system input unit. The circuit is controlled, and when the lightning generation state is determined to be the second stage, the switching device is set to the second state, and the power storage circuit is controlled so that power is supplied from the storage battery to the load. A power storage system characterized by having a control circuit. Further provided with a lightning detection circuit that outputs signals of at least two stages corresponding to the initial stage and the second stage to the discrimination circuit, which differ depending on the risk of lightning surge entering the commercial power system. The power storage system according to claim 1. The control circuit confirms the remaining battery level of the storage battery when the lightning generation status is determined by the discrimination circuit to be the initial stage, and if the remaining battery level is equal to or less than a predetermined threshold value, charging of the storage battery is started. The power storage system according to claim 1 or 2, wherein the power storage circuit is controlled so as to be performed. The initial stage consists of a caution stage and a warning stage where there is a higher risk of lightning surges entering the commercial power system than the caution stage.
The second stage is a dangerous stage.
The discrimination circuit discriminates whether the lightning occurrence state is the non-occurrence state, the caution stage, the caution stage, or the danger stage.
The control circuit confirms the remaining battery level of the storage battery when the lightning occurrence status is determined by the discrimination circuit to be in the caution stage, and if the remaining battery level is equal to or less than a predetermined threshold, charging of the storage battery is started. The storage circuit is controlled so that charging is not performed if the remaining battery level exceeds the predetermined threshold value, and when the lightning occurrence status is determined to be the warning stage, the remaining battery level of the storage battery is reached. The power storage system according to claim 1 or 2, wherein the power storage circuit is controlled so that charging of the storage battery is started regardless of the above. The control circuit sets the switching device to the second stage when the lightning generation status is not determined to be the second stage for a predetermined time or more after the lightning generation status is determined to be the second stage by the discrimination circuit. The power storage system according to any one of claims 1 to 4, wherein the power storage system is in one state.

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