Opening / closing device and storage battery system including the opening / closing device

Abstract

To suppress that an opening / closing device provided in a storage battery system becomes an over specification.SOLUTION: An opening / closing device is an opening / closing device connected to a first power line that connects a commercial system and a load, and a second power line that connects a power conditioner and the load. The opening / closing device includes: a contact device; and a detection device. The contact device includes an opening / closing part that opens and closes a connection between the commercial system and the load, and a control part that controls the opening / closing part. The detection device detects an energization state of the second power line. When the supply of a power from the commercial system to the first power line is stopped, the opening / closing part of the contact device is switched from an ON state to an OFF state. The control part of the contact device switches the opening / closing part from the OFF state to the ON state according to the detection result of the detection device when the supply of the power from the commercial system to the first power line is stopped and the opening / closing part is in the OFF state, and reconnects the commercial system and the load.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a switching device and a storage battery system including the switching device. [Background technology]

[0002] Conventionally, a switchgear capable of switching a power supply system to a load between a commercial power supply and a distributed power supply has been known (see Patent Document 1). The distributed power supply is connected to the switchgear via a power conditioner and a storage battery. The power conditioner includes a switching unit that opens and closes the connection with the load. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-142487 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional switchgear includes a switching unit that is placed on the power line connecting the power conditioner and the load. As a result, the functions of the switching unit on the stand-alone side of the power conditioner and the switchgear are duplicated. Furthermore, since the stand-alone side mainly switches relatively small amounts of power compared to the grid side, matching the specifications of the switching unit on the stand-alone side of the switchgear to the grid side results in over-spec, which leads to increased costs.

[0005] An object of the present invention is to prevent a switching device provided in a storage battery system from becoming over-specified. [Means for solving the problem]

[0006] A switchgear according to one aspect of the present invention is connected to a first power line connecting a commercial grid and a load and a second power line connecting a power conditioner and the load. The switchgear includes a contact device and a detection device. The contact device includes a switching unit that opens and closes the connection between the commercial grid and the load, and a control unit that controls the switching unit. The detection device detects the conduction state of the second power line. When the supply of power from the commercial grid to the first power line is stopped, the switching unit of the contact device switches from an ON state to an OFF state. When the supply of power from the commercial grid to the first power line is stopped and the switching unit is in an OFF state, the control unit of the contact device switches the switching unit from an OFF state to an ON state in accordance with the detection result of the detection device, thereby reconnecting the commercial grid and the load.

[0007] In this switchgear, for example, if the commercial grid experiences a power outage, the switching unit of the contact device switches from an ON state to an OFF state, thereby disconnecting the load from the commercial grid. Furthermore, when the switching unit is in the OFF state, the control unit of the contact device switches the switching unit from an OFF state to an ON state in accordance with the detection result of the detection device, thereby reconnecting the load to the commercial grid. This allows the switchgear to have a switching unit only on the first power line, preventing the switchgear on the stand-alone side from overlapping in function with the switching unit of the power conditioner. This allows the switchgear to have a simple configuration, thereby preventing the switchgear from becoming over-specified. Furthermore, since it is no longer necessary to match the specifications of the switching unit on the stand-alone side of the switchgear to the grid side, as in the conventional case, this prevents the switchgear from becoming over-specified. As a result, it is possible to prevent an increase in the cost of the switchgear and to optimize it with the power conditioner.

[0008] The switching device may further include an auxiliary relay controlled by the control unit. The auxiliary relay may be arranged on a signal line that outputs a control signal for controlling the switching unit. In this case, the design flexibility of the switching device is expanded. Furthermore, if an abnormality occurs in the auxiliary relay, the switching unit cannot be switched from the OFF state to the ON state, so that when the switching device is arranged in a battery storage system, the safety of the battery storage system is improved.

[0009] The switching unit may include a plurality of a-contacts connected in series with each other. In this case, for example, even if one of the plurality of a-contacts is welded, the function as a switching device can be maintained.

[0010] A storage battery system according to another aspect of the present invention includes a power conditioner and the above-described switching device. In this storage battery system, the switching device can be configured simply, thereby preventing the switching device from becoming over-specified. Furthermore, in the storage battery system, an increase in the cost of the switching device can be prevented, and optimization with the power conditioner can be achieved. [Effects of the Invention]

[0011] According to the present invention, it is possible to prevent the switching device provided in the storage battery system from becoming over-specified. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a block diagram illustrating a schematic configuration of a battery system. [Figure 2] FIG. 2 is a block diagram schematically illustrating the configuration of a switching device. [Figure 3] 1 is a timing chart showing the operation timing of a switching device from when a commercial grid is powered down until power is restored. [Figure 4] 10A and 10B are diagrams illustrating modified examples of the opening and closing section. DETAILED DESCRIPTION OF THE INVENTION

[0013] A storage battery system 1 according to an embodiment will be described below with reference to the drawings. Fig. 1 is a block diagram schematically showing the configuration of the storage battery system 1. The storage battery system 1 includes a solar cell 2, a power conditioner 3, a storage battery 4, and a switching device 5.

[0014] The storage battery system 1 is configured to supply power to the load 7 from either a first power line L1 connecting the commercial grid 6 and the load 7, or a second power line L2 connecting the power conditioner 3 and the load 7. For example, when the commercial grid 6 is energized, power is supplied from the commercial grid 6 to the load 7 via the first power line L1, and when the commercial grid 6 experiences a power outage, power is supplied from the power conditioner 3 to the load 7 via the second power line L2. A smart meter 8 is arranged on the first power line L1.

[0015] The solar cell 2 includes a plurality of solar cell modules. The solar cell 2 receives sunlight to generate electric power and outputs the generated electric power to the power conditioner 3.

[0016] The power conditioner 3 converts DC power generated by the solar cell 2 into AC power. The power conditioner 3 is connected to a load 7 such as an electrical device via a transformer 10, a switchgear 5, and a distribution board 12.

[0017] The power conditioner 3 has a configuration similar to that of a conventional power conditioner, and includes circuits (not shown), such as a converter circuit, an inverter circuit, and a charge / discharge circuit. As shown in FIG. 1 , the power conditioner 3 also includes a linked operation circuit 3a and an isolated operation circuit 3b. The linked operation circuit 3a is a circuit that controls the connection with the commercial grid 6. The linked operation circuit 3a includes a mechanical relay that opens and closes the connection with the commercial grid 6. The isolated operation circuit 3b is a circuit that supplies the AC voltage generated by the inverter circuit to the load 7, for example, when the commercial grid 6 experiences a power outage. The isolated operation circuit 3b includes a mechanical relay that opens and closes the connection (second power line L2) between the power conditioner 3 and the load 7.

[0018] The power conditioner 3 operates in either a linked operation mode or an isolated operation mode. The linked operation mode is executed by the linked operation circuit 3a, and is a mode in which the power conditioner 3 is connected to the commercial grid 6 and operates. In the linked operation mode, power is supplied to the load 7 via the first power line L1. The isolated operation mode is executed by the isolated operation circuit 3b, and is a mode in which only the power conditioner 3 operates, for example, when the commercial grid 6 is experiencing a power outage. In the isolated operation mode, power is supplied to the load 7 via the second power line L2.

[0019] The power conditioner 3 includes a control circuit that switches the operation mode of the power conditioner 3 by controlling the opening and closing of mechanical relays in the linked operation circuit 3a and the isolated operation circuit 3b. The control circuit switches the operation mode of the power conditioner 3 according to the detection result of a detection circuit that detects whether or not power is being supplied from the commercial grid 6. The detection circuit detects the energized state of the first power line L1 and outputs a detection signal.

[0020] The storage battery 4 is connected to the power conditioner 3. The storage battery 4 stores the power supplied from the power conditioner 3. The storage battery 4 is capable of supplying the stored power to the power conditioner 3.

[0021] Fig. 2 is a block diagram showing a schematic configuration of the switchgear 5. As shown in Fig. 2, a first breaker 14 is provided on the first power line L1. The first breaker 14 shuts off the first power line L1 when an overcurrent, a ground fault, or the like is detected. A second breaker 15 is provided on the second power line L2. The second breaker 15 shuts off the second power line L2 when an overcurrent, a ground fault, or the like is detected.

[0022] The switchgear 5 is connected to the first power line L1 and the second power line L2. The switchgear 5 is arranged on the first power line L1 between the commercial grid 6 and the load 7. The switchgear 5 is arranged on the second power line L2 between the power conditioner 3 and the load 7.

[0023] The switchgear 5 is powered by power supplied from the commercial grid 6. The switchgear 5 opens and closes the connection between the commercial grid 6 and the load 7 by opening and closing the first power line L1. When the commercial grid 6 is energized, the switchgear 5 connects the commercial grid 6 and the load 7. When the commercial grid 6 experiences a power outage, the switchgear 5 cuts off the connection between the commercial grid 6 and the load 7. The switchgear 5 monitors the energization state of the second power line L2, and reconnects the commercial grid 6 and the load 7 depending on the energization state of the second power line L2.

[0024] The switching device 5 includes a contact device 20, a power supply circuit 22, a welding detection device 24, and a current flow detection device 26 (an example of a detection device). The contact device 20 is driven by power supplied from the commercial grid 6 via the power supply circuit 22.

[0025] The contact device 20 includes a switching unit 20a and a control unit 20b. The switching unit 20a switches the connection between the commercial grid 6 and the load 7. In this embodiment, the switching unit 20a includes three a-contacts connected in parallel to each other. The contact device 20 includes a coil (not shown), and the switching unit 20a closes when the coil is excited. When the supply of power from the commercial grid 6 to the first power line L1 is stopped, the power supply circuit 22 becomes inoperable and the switching unit 20a switches from the ON state to the OFF state (open state). In other words, when the commercial grid 6 experiences a power outage, the switching unit 20a switches to the OFF state, and the connection between the commercial grid 6 and the load 7 is interrupted.

[0026] The control unit 20b controls the switching unit 20a. The control unit 20b can independently control each contact of the switching unit 20a. The control unit 20b is configured to be able to switch the switching unit 20a from an OFF state to an ON state. When the supply of power from the commercial grid 6 to the first power line L1 is stopped and the switching unit 20a is in the OFF state, the control unit 20b switches the switching unit 20a from the OFF state to the ON state in accordance with the detection result of the current flow detection device 26, thereby reconnecting the commercial grid 6 and the load 7.

[0027] The control unit 20b is supplied with power from the power supply circuit 22 and can control the switching unit 20a only when power is being supplied to the first power line L1 from the commercial grid 6. In other words, when the commercial grid 6 recovers from a power outage, the control unit 20b can switch the switching unit 20a from an OFF state to an ON state.

[0028] The power supply circuit 22 is connected to the first power line L1. The power supply circuit 22 is supplied with power from the commercial power system 6. The power supply circuit 22 converts the power supplied from the commercial power system 6 and supplies the converted power to the contact device 20, the control unit 20b, and the welding detection device 24.

[0029] The control unit 20b includes an auxiliary relay 20c. The control unit 20b controls the opening and closing of the auxiliary relay 20c. The auxiliary relay 20c is arranged on a signal line through which a control signal for controlling the opening and closing unit is output. The control signal here is a signal for switching the opening and closing unit 20a of the contact device 20 from an OFF state to an ON state. The auxiliary relay 20c includes one a-contact. The control unit 20b outputs the control signal to the contact device 20 via the auxiliary relay 20c. Therefore, the control signal from the control unit 20b can be transmitted to the contact device 20 only when the auxiliary relay 20c is operating normally.

[0030] The welding detection device 24 is a circuit that detects welding of the switching unit 20a. The welding detection device 24 has a well-known configuration, and for example, detects welding of the switching unit 20a by using a detection element to detect the presence or absence of current flowing through the switching unit 20a. The welding detection device 24 includes, for example, a photocoupler and a transistor. The welding detection device 24 outputs a detection signal according to the detection result to the control unit 20b. The welding detection device 24 may detect welding of the switching unit 20a by detecting a voltage difference between the switching units 20a, or may detect welding of the switching unit 20a by providing an auxiliary contact for monitoring the state of the switching unit 20a.

[0031] The conduction detection device 26 is a circuit that detects the conduction state of the second power line L2. The conduction detection device 26 detects whether the second power line L2 is in a power outage state. The conduction detection device 26 is connected to the second power line L2 and, for example, detects an AC current flowing from the power conditioner 3 to the second power line L2 and outputs a detection signal corresponding to the detection result to the control unit 20b. The conduction detection device 26 may be configured to detect the AC voltage output from the power conditioner 3 to the second power line L2, or may be configured to detect the phase of the voltage or current. In other words, the conduction detection device 26 may be configured to detect whether the second power line L2 is in a power outage state. For example, the conduction detection device 26 may be configured to determine whether the second power line L2 is in a power outage state based on a signal output from the power conditioner 3.

[0032] 3 is a timing chart showing the operation timing of the switchgear 5 from when the commercial grid 6 experiences a power outage until power is restored. When the first power line L1 is energized, that is, when power is being supplied from the commercial grid 6 to the first power line L1, the second power line L2 experiences a power outage, and the auxiliary relay 20c and the switching unit 20a are in the ON state. When the first power line L1 experiences a power outage, the power supply circuit 22 becomes inoperable, and the auxiliary relay 20c and the switching unit 20a switch from the ON state to the OFF state.

[0033] When the power conditioner 3 detects that the first power line L1 is in a power outage state, it switches its operation mode from the linked operation mode to the independent operation mode. As a result, the second power line L2 becomes energized. When the power conditioner 3 detects that power has been restored to the commercial grid 6 while operating in the independent operation mode, it switches its operation mode from the independent operation mode to the linked operation mode. As a result, the second power line L2 changes from an energized state to a power outage state. As a result of the power being restored to the commercial grid 6, power is supplied from the commercial grid 6 to the power supply circuit 22.

[0034] When the second power line L2 changes from a conducting state to a power outage state, the control unit 20b determines, based on the detection result of the conduction detection device 26, that the second power line L2 has changed from a conducting state to a power outage state. The control unit 20b then determines, based on a detection signal corresponding to the detection result of the welding detection device 24, whether the switching unit 20a is welded. If the control unit 20b determines that the switching unit 20a is not welded, it controls the auxiliary relay 20c from an OFF state to an ON state and outputs a control signal for switching the switching unit 20a from an OFF state to an ON state. As a result, the switching unit 20a switches from an OFF state to an ON state, and the commercial grid 6 and the load 7 are reconnected.

[0035] In the switching device 5 of the storage battery system 1 described above, for example, when the commercial grid 6 experiences a power outage, the switching unit 20a of the contact device 20 switches from an ON state to an OFF state, thereby disconnecting the commercial grid 6 from the load 7. Furthermore, when the switching unit 20a is in the OFF state, the control unit 20b of the contact device 20 switches the switching unit 20a from an OFF state to an ON state in accordance with the detection result of the energization detection device 26, thereby reconnecting the commercial grid 6 to the load 7. This allows the switching unit 20a to be provided only on the first power line L1 in the switching device 5, preventing the switching device 5 from overlapping in function with the switching unit of the power conditioner 3 on the isolated side. This allows the switching device 5 to have a simple configuration, thereby preventing the switching device 5 from becoming over-specified. Furthermore, unlike the conventional method, it is no longer necessary to match the specifications of the switching unit on the isolated side of the switching device 5 with those on the grid side, thereby preventing the switching device 5 from becoming over-specified. As a result, it is possible to prevent an increase in the cost of the switching device 5 and to optimize the switching device with the power conditioner 3.

[0036] As shown in Fig. 4, the switching unit 20a may have two sets of three a-contacts arranged in series. Alternatively, the switching unit 20a may have three contacts that are simultaneously operated in conjunction with one input voltage. The switching unit 20a may include an auxiliary contact that is a b-contact. The contact device 20 may be a contactor. [Explanation of symbols]

[0037] 1: storage battery system, 3: power conditioner, 5: switching device, 20: contact device, 20a: switching unit, 20b: control unit, 20c: auxiliary relay, 24: welding detection device, 26: current detection device

Claims

1. A switching device connected to a first power line connecting a commercial grid and a load and a second power line connecting a power conditioner and the load, a contact device including a switch unit that opens and closes the connection between the commercial grid and the load, and a control unit that controls the switch unit; a detection device that detects a current-carrying state of the second power line; Equipped with the opening / closing unit of the contact device switches from an ON state to an OFF state when the supply of power from the commercial grid to the first power line is stopped; the control unit of the contact device switches the switching unit from the OFF state to the ON state in accordance with a detection result of the detection device when the supply of power from the commercial grid to the first power line is stopped and the switching unit is in the OFF state, thereby reconnecting the commercial grid and the load. Switchgear.

2. further comprising an auxiliary relay controlled by the control unit; The auxiliary relay is disposed on a signal line through which a control signal for controlling the opening and closing unit is output. The opening and closing device according to claim 1 .

3. The opening / closing unit includes a plurality of a-contacts connected in series with each other. The opening and closing device according to claim 1 .

4. A power conditioner, The opening and closing device according to claim 1; Equipped with Battery storage system

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