Power supply systems and automatic switching distribution boards

Abstract

To provide a power supply system capable of stably supplying power to a load even if failure occurs in a changeover switch for switching between a system output and an independent output.SOLUTION: A power supply system 1A includes a charging / discharging device 11 for charging / discharging a storage battery 12 and an automatic switching distribution panel 20A. The automatic switching distribution panel 20A includes: a first changeover switch SW1 for switching between a first system input end T11 and a first independent input end T12 and connecting them to a first output end T13; a second changeover switch SW2 for switching between a second system input end T21 and a second independence input end T22 and connecting them to a second output end T23; a third changeover switch SW3 for switching between a first system input end T31 and a second input end T32 and connecting them to a third output ends T33; and a control unit 22A for controlling the first changeover switch SW1, the second changeover switch SW2, and the third changeover switch SW3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power supply system and an automatic switching distribution board. Background Art

[0002] As a conventional power supply system, a full-load compatible system is known that can supply power to all loads (e.g., electric appliances) without distinguishing between important loads and general loads by switching between grid output and independent output (see, for example, Patent Document 1).

[0003] FIG. 7 shows the configuration of a full-load compatible power supply system 1D. The power supply system 1D includes a power storage system 10 and an automatic switching distribution board 20D. The power supply system 1D switches between grid output from the power grid 2 and the power storage system 10 and independent output from the power storage system 10 by the automatic switching distribution board 20D, and supplies power to a load 3 such as an electric appliance connected to a household outlet.

[0004] The power storage system 10 includes a charging / discharging device 11 and a storage battery 12. The charging / discharging device 11 is configured to charge and discharge the storage battery 12, and includes an AC terminal connected to a grid power line L11, and an independent output terminal connected to a power line for independent output (hereinafter referred to as an independent output line L12). When the power grid 2 is energized, the charging / discharging device 11 outputs the discharge power of the storage battery 12 to the grid power line L11 (grid output); when the power grid 2 experiences a power outage, the charging / discharging device 11 outputs the discharge power of the storage battery 12 to the independent output line L12 (independent output).

[0005] The automatic switching distribution board 20D includes a changeover switch 21D and a control unit 22D that controls the changeover switch 21D. The output side of the automatic switching distribution board 20D is connected to the load 3 via a general distribution board (not shown). Under the control of the control unit 22D, the changeover switch 21D is connected to the grid power line L11 side when the power grid 2 is energized, and is connected to the independent output line L12 side when the power grid 2 experiences a power outage. Prior Art Documents Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2019-198203 [Overview of the project] [Problems that the invention aims to solve]

[0007] In the automatic switching distribution panel 20D, a switching failure may occur in the changeover switch 21D. For example, if the changeover switch 21D becomes unable to switch while connected to the grid power line L11, the conventional power supply system 1D will be unable to supply the independent output of the charge / discharge device 11 to the load 3 during a power outage in the power grid 2.

[0008] Furthermore, if the changeover switch 21D becomes unable to switch while connected to the independent output line L12, the conventional power supply system 1D will be unable to supply the system output (system power of power system 2 or discharge power output from the AC terminal of the charge / discharge device 11) to the load 3 when power system 2 is energized. In this case, since the independent output of the charge / discharge device 11 is supplied to the load 3 when power system 2 is energized, there is a risk that the failure of the changeover switch 21D may go undetected for a long time.

[0009] Furthermore, if a breaker for independent output is installed on the independent output line L12, the breaker capacity of the independent output breaker is generally set to a value that matches the rated value of the independent output of the charge / discharge device 11, and the rated value of the independent output is smaller than the rated value of the grid output of the charge / discharge device 11. For this reason, if the changeover switch 21D becomes unable to switch while connected to the independent output line L12, in the conventional power supply system 1D, the power that can be supplied to the load 3 when the power grid 2 is energized will be limited to the rated value of the independent output of the charge / discharge device 11, and if the load 3 increases, the frequency of breaker trips may increase.

[0010] The present invention has been made in view of the above circumstances, and its objective is to provide a power supply system and an automatic switching distribution board that can stably supply power to a load even if a changeover switch that switches between grid output and independent output malfunctions. [Means for solving the problem]

[0011] To solve the above problems, the power supply system according to the present invention is A charge / discharge device comprising an AC terminal connected to a power grid, a DC terminal connected to a battery, and a standalone output terminal, wherein the standalone output terminal outputs the discharge power of the battery, An automatic switching distribution board is connected to one side of the power system and the standalone output terminal of the charge / discharge device, and to the other side of the load. A power supply system comprising, The aforementioned automatic switching distribution panel is A first changeover switch is provided, which switches between a state in which the first system input terminal and the first output terminal are electrically connected and a state in which the first system input terminal and the first output terminal are electrically connected. The device includes a second system input terminal connected to the power system, a second independent input terminal connected to the independent output terminal, and a second output terminal, and a second changeover switch that switches between a state in which the second system input terminal and the second output terminal are electrically connected and a state in which the second independent input terminal and the second output terminal are electrically connected. A third changeover switch is provided for switching between a state in which the first input terminal and the third output terminal are electrically connected and a state in which the second input terminal and the third output terminal are electrically connected, and a first input terminal connected to the first output terminal, a second input terminal connected to the second output terminal, and a third output terminal connected to the load, The system is characterized by comprising a control unit that controls the first changeover switch, the second changeover switch, and the third changeover switch so as to form a power supply path to the load.

[0012] In this configuration, the automatic changeover distribution panel has a first power supply path via a first changeover switch and a second power supply path via a second changeover switch, both connected in parallel. The first and second changeover switches are connected to both the power system and the independent output terminals of the charge / discharge device. Therefore, in this configuration, even if either the first or second changeover switch fails, it is possible to stably supply power to the load via either the first or second power supply path.

[0013] In the aforementioned power supply system, The aforementioned automatic switching distribution panel is A fourth changeover switch is interposed in the first power line connecting the first output terminal and the first input terminal, and switches the first power line between a conductive state and a non-conductive state. The system includes a fifth changeover switch interposed in a second power line connecting the second output terminal and the second input terminal, which switches the second power line between a conductive state and a non-conductive state, The control unit, The fourth changeover switch and the fifth changeover switch can be controlled to make either the first power line or the second power line conductive and the other non-conductive.

[0014] In the aforementioned power supply system, The control unit, If the first changeover switch fails to switch, the fourth changeover switch is controlled to de-conduct the first power line, while the fifth changeover switch is controlled to conduct the second power line. If the second changeover switch fails to switch, the fifth changeover switch can be controlled to de-conduct the second power line, while the fourth changeover switch can be controlled to conduct the first power line.

[0015] In the aforementioned power supply system, The control unit, In a case where the first changeover switch has a failure that disables switching when the first system input terminal is connected to the first output terminal, when the power system is in an energized state, the fourth changeover switch is controlled to bring the first power line into a conducting state, and In a case where the second changeover switch has a failure that disables switching when the second self-standing input terminal is connected to the second output terminal, when the power system is in a power outage state, the fifth changeover switch can be controlled to bring the second power line into a conducting state.

[0016] In the power supply system, the control unit includes: a first detection unit that detects a switching-disabling failure of the first changeover switch in accordance with voltages at a front stage and a rear stage of the first changeover switch, and controls the fourth changeover switch in accordance with the detection result; and a second detection unit that detects a switching-disabling failure of the second changeover switch in accordance with voltages at a front stage and a rear stage of the second changeover switch, and controls the fifth changeover switch in accordance with the detection result.

[0017] In the power supply system, the automatic transfer switchboard includes: a sixth changeover switch interposed in a third power line connecting the third output terminal and the load, the sixth changeover switch switching the third power line between a conducting state and a non-conducting state, wherein the control unit is configured to, when both the first changeover switch and the second changeover switch have a switching-disabling failure, control the sixth changeover switch to bring the third power line into a non-conducting state.

[0018] In the power supply system, the automatic transfer switchboard is configured to include a failure display unit that notifies a user of a failure by means of a light emitting means, a display means or an audio means when at least one of the first changeover switch and the second changeover switch has a switching-disabling failure.

[0019] Furthermore, in order to solve the above problems, the automatic switching distribution board according to the present invention is An automatic switching distribution panel in which the power grid and battery charging / discharging equipment are connected to one side, and the load is connected to the other side, The charging and discharging device is equipped with a self-contained output terminal that outputs the discharge power of the storage battery, The aforementioned automatic switching distribution panel is A first changeover switch is provided, which switches between a state in which the first system input terminal and the first output terminal are electrically connected and a state in which the first system input terminal and the first output terminal are electrically connected. The device includes a second system input terminal connected to the power system, a second independent input terminal connected to the independent output terminal, and a second output terminal, and a second changeover switch that switches between a state in which the second system input terminal and the second output terminal are electrically connected and a state in which the second independent input terminal and the second output terminal are electrically connected. A third changeover switch is provided for switching between a state in which the first input terminal and the third output terminal are electrically connected and a state in which the second input terminal and the third output terminal are electrically connected, and a first input terminal connected to the first output terminal, a second input terminal connected to the second output terminal, and a third output terminal connected to the load, The system is characterized by comprising a control unit that controls the first changeover switch, the second changeover switch, and the third changeover switch so as to form a power supply path to the load. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a power supply system and an automatic switching distribution board that can stably supply power to a load even if a changeover switch that switches between grid output and independent output malfunctions. [Brief explanation of the drawing]

[0021] [Figure 1] This is a diagram showing a power supply system according to the first embodiment of the present invention. [Figure 2]This is a status table showing the control status of each switch SW1 to SW5 in the first embodiment. [Figure 3] This figure shows a power supply system according to a second embodiment of the present invention. [Figure 4] This is a status table showing the control status of each switch SW1 to SW5 in the second embodiment. [Figure 5] This figure shows a power supply system according to a third embodiment of the present invention. [Figure 6] This figure shows an automatic switching distribution panel according to a third embodiment of the present invention. [Figure 7] This is a diagram showing a conventional power supply system. [Modes for carrying out the invention]

[0022] Hereinafter, embodiments of the power supply system and automatic switching distribution board according to the present invention will be described with reference to the attached drawings.

[0023] [First Embodiment] Figure 1 shows a power supply system 1A according to a first embodiment of the present invention. The power supply system 1A is a household power supply system and comprises a battery storage system 10 and an automatic switching distribution board 20A. The power supply system 1A is also a full-load type and supplies power to load 3 by switching between the grid output of the power system 2 and / or the battery storage system 10 and the standalone output of the battery storage system 10 using the automatic switching distribution board 20A.

[0024] Power system 2 is an AC power source that supplies AC grid power to the grid power line L11 connecting power system 2 and power supply system 1A. Power system 2 is connected to power supply system 1A, for example, via a three-phase three-wire high-voltage power line, a pole-mounted transformer, and a single-phase three-wire low-voltage (AC100 / 200V) power line.

[0025] Load 3 is a general term for devices that consume electricity. Load 3 includes, for example, electrical appliances such as refrigerators, air conditioners, washing machines, personal computers, and televisions, and these Load 3s are connected, for example, from a household outlet to a single-phase three-wire power line. Since the power supply system 1A is a full-load compatible type, Load 3 in this embodiment includes all loads without distinguishing between critical loads (loads that are to be operated even when the power system 2 is down) and general loads (loads other than critical loads). In the case of a critical load compatible power supply system, Load 3 becomes a critical load, and general loads are connected to the system power line L11 without going through the automatic switching distribution board 20A.

[0026] The energy storage system 10 comprises a charge / discharge device 11 and a battery 12. When the power grid 2 is powered, the energy storage system 10 charges the battery 12 with inexpensive nighttime electricity supplied from the power grid 2, and by using the electricity stored in the battery 12 during the day, it can save on electricity costs. In addition, the energy storage system 10 can supply the electricity stored in the battery 12 to the load 3 even in the event of a power outage in the power grid 2.

[0027] The charge / discharge device 11 comprises an AC terminal Ta, a DC terminal Tb, and an independent output terminal Tc, a switching unit 11a, a power conversion unit 11b, and a control unit 11c.

[0028] The AC terminal Ta is connected to power system 2 and automatic switching distribution board 20A via the grid power line L11. The DC terminal Tb is connected to the battery 12. The standalone output terminal Tc is connected to automatic switching distribution board 20A via the standalone output power line (hereinafter referred to as standalone output line L12).

[0029] The switching unit 11a comprises a first switch SW11, a second switch SW12, a third switch SW13, and a fourth switch SW14. When the power system 2 is energized, the first switch SW11 and the second switch SW12 are closed (ON state), and the third switch SW13 and the fourth switch SW14 are open (OFF state). On the other hand, when the power system 2 is de-energized, the first switch SW11 and the second switch SW12 are open (OFF state), and the third switch SW13 and the fourth switch SW14 are closed (ON state). Each switch SW11 to SW14 is composed of a relay that opens and closes under the control of the control unit 11c, for example.

[0030] The power conversion unit 11b includes a bidirectional AC / DC inverter and a bidirectional DC / DC converter. The AC side of the bidirectional AC / DC inverter is connected to the switch 11a, and the DC side is connected to one DC side of the bidirectional DC / DC converter. The other DC side of the bidirectional DC / DC converter is connected to the DC terminal Tb. Under the control of the control unit 11c, the power conversion unit 11b performs charging and discharging operations on the battery 12. During charging, the power conversion unit 11b supplies DC charging power to the battery 12. During discharging, the power conversion unit 11b extracts DC discharge power from the battery 12, converts it to AC power, and outputs it.

[0031] The control unit 11c comprises an on / off control unit that controls the on / off unit 11a and a power conversion control unit that controls the power conversion unit 11b. The power conversion control unit may be composed of a digital circuit using, for example, a microcontroller or a DSP, or it may be composed of a circuit that combines a digital circuit and an analog circuit. The control unit 11c further comprises a detection unit. The detection unit includes, for example, a current sensor and / or a voltage sensor that detect current values ​​and / or voltage values ​​necessary for controlling the control unit 11c.

[0032] The control unit 11c sets the operating mode of the charge / discharge device 11. The operating modes include a grid-connected operation mode, which is set when the power system 2 is energized, and an independent operation mode, which is set when the power system 2 is in a power outage state. In grid-connected operation mode, the control unit 11c closes the first switch SW11 and the second switch SW12 (opens the third switch SW13 and the fourth switch SW14) and causes the power conversion unit 11b to provide grid output from the AC terminal Ta and independent output from the independent output terminal Tc. On the other hand, in independent operation mode, the control unit 11c closes the third switch SW13 and the fourth switch SW14 (opens the first switch SW11 and the second switch SW12) and causes the power conversion unit 11b to provide only independent output from the independent output terminal Tc.

[0033] The battery storage system 12 is a stationary battery storage system installed and used in a predetermined location, and includes at least one rechargeable battery configured to be rechargeable and dischargeable, and a battery management system for managing the rechargeable battery. For example, a lithium-ion rechargeable battery is used as the rechargeable battery, but a rechargeable battery other than a lithium-ion rechargeable battery may also be used.

[0034] Furthermore, a breaker for independent output may be installed in the independent output line L12 of the energy storage system 10. The breaker capacity of the independent output breaker is set to a value that matches the rated value of the independent output of the charge / discharge device 11, and the rated value of the independent output is smaller than the rated value of the grid output of the charge / discharge device 11.

[0035] The automatic switching distribution panel 20A comprises a switch unit 21A and a control unit 22A that controls the switch unit 21A. One side of the automatic switching distribution panel 20A (AC input side) is connected to the power system 2 and the energy storage system 10 via the grid power line L11, and is also connected to the energy storage system 10 via the independent output line L12. The other side of the automatic switching distribution panel 20A (AC output side) is connected to the load 3 via a general distribution panel (not shown).

[0036] The switch section 21A includes a first changeover switch SW1, a second changeover switch SW2, a third changeover switch SW3, a fourth changeover switch SW4, and a fifth changeover switch SW5, and switches between grid output and standalone output. Each of the switches SW1 to SW5 may consist of at least one relay or at least one semiconductor switch.

[0037] The grid output input to the switch unit 21A is the AC grid power supplied from the power system 2 and / or the AC power output from the AC terminal Ta of the charge / discharge device 11. The standalone output input to the switch unit 21A is the AC power output from the standalone output terminal Tc of the charge / discharge device 11.

[0038] The first changeover switch SW1 includes a first system input terminal T11 connected to the system power line L11, a first independent input terminal T12 connected to the independent output line L12, and a first output terminal T13 connected to the first power line L1. Under the control of the control unit 22A, the first changeover switch SW1 switches between a state in which the first system input terminal T11 and the first output terminal T13 are electrically connected and a state in which the first independent input terminal T12 and the first output terminal T13 are electrically connected. In other words, the first changeover switch SW1 switches between a state in which the system output is supplied to the first power line L1 and a state in which the independent output is supplied to the first power line L1.

[0039] The second changeover switch SW2 includes a second system input terminal T21 connected to the system power line L11, a second independent input terminal T22 connected to the independent output line L12, and a second output terminal T23 connected to the second power line L2. Under the control of the control unit 22A, the second changeover switch SW2 switches between a state in which the second system input terminal T21 and the second output terminal T23 are electrically connected and a state in which the second independent input terminal T22 and the second output terminal T23 are electrically connected. In other words, the second changeover switch SW2 switches between a state in which the system output is supplied to the second power line L2 and a state in which the independent output is supplied to the second power line L2.

[0040] The third changeover switch SW3 includes a first input terminal T31 connected to the first power line L1, a second input terminal T32 connected to the second power line L2, and a third output terminal T33 connected to the third power line L3. Under the control of the control unit 22A, the third changeover switch SW3 switches between a state in which the first input terminal T31 and the third output terminal T33 are electrically connected (hereinafter referred to as the "upper state") and a state in which the second input terminal T32 and the third output terminal T33 are electrically connected (hereinafter referred to as the "lower state"). In other words, the third changeover switch SW3 switches between a state in which AC power supplied from the first power line L1 is supplied to the third power line L3 (upper state) and a state in which AC power supplied from the second power line L2 is supplied to the third power line L3 (lower state).

[0041] The fourth changeover switch SW4 is installed in the first power line L1. Under the control of the control unit 22A, the fourth changeover switch SW4 switches between an ON state and an OFF state. When it is in the ON state, it makes the first power line L1 conductive, while when it is in the OFF state, it makes the first power line L1 non-conductive.

[0042] The fifth changeover switch SW5 is installed in the second power line L2. Under the control of the control unit 22A, the fifth changeover switch SW5 switches between an ON state and an OFF state. When it is in the ON state, it makes the second power line L2 conductive, while when it is in the OFF state, it makes the second power line L2 non-conductive.

[0043] The control unit 22A includes a mode determination unit that determines the operating mode of the charge / discharge device 11, a fault determination unit that determines a failure in the first changeover switch SW1 and the second changeover switch SW2 to be switchable, and a switch control unit that controls each of the switches SW1 to SW5.

[0044] The mode determination unit determines the operating mode by communicating with the control unit 11c of the energy storage system 10, or by detecting the grid power supplied from the power grid 2. In the former case, the mode determination unit includes communication means for communicating with the control unit 11c, and obtains the operating mode from the control unit 11c using this communication means. In the latter case, the mode determination unit includes a voltage sensor, and determines that the system is in grid-connected operation mode if the voltage of the first system input terminal T11 or the second system input terminal T21 detected by the voltage sensor falls within a predetermined normal range, and determines that it is in standalone operation mode if it does not fall within the normal range. The mode determination unit outputs the determined operating mode to the switch control unit.

[0045] The fault detection unit uses a voltage sensor to detect the voltage at the first output terminal T13 before and after the switching of the operating mode, thereby determining if the first changeover switch SW1 is unable to switch, and detects the voltage at the second output terminal T23 before and after the switching of the operating mode, thereby determining if the second changeover switch SW2 is unable to switch.

[0046] When the fourth changeover switch SW4 is in the ON position, the fifth changeover switch SW5 is in the OFF position, and the third changeover switch SW3 is in the up position, the fault detection unit determines that the first changeover switch SW1 is unable to be switched as follows (1) and (2). (1) In grid-connected operation mode, if the voltage at the first output terminal T13 is within a predetermined first normal range, and when switching from grid-connected operation mode to independent operation mode, the voltage change at the first output terminal T13 before and after the switch remains outside a predetermined second normal range for a predetermined period of time, the fault determination unit determines that a fault has occurred in which the first changeover switch SW1 is fixed to the first system input terminal T11 side and switching is impossible. (2) In the independent operation mode, if the voltage at the first output terminal T13 is within a predetermined third normal range, and when switching from the independent operation mode to the grid-connected operation mode, the voltage change at the first output terminal T13 before and after the switch remains outside a predetermined fourth normal range for a predetermined period of time, the fault determination unit determines that the first changeover switch SW1 is fixed to the first independent input terminal T12 side and has become unable to switch, resulting in a fault.

[0047] If the fourth changeover switch SW4 is in the OFF state, the fifth changeover switch SW5 is in the ON state, and the third changeover switch SW3 is in the down state, the fault detection unit will determine that the second changeover switch SW2 is unable to be switched as follows (3) and (4). (3) In grid-connected operation mode, if the voltage at the second output terminal T23 is within a predetermined first normal range, and when switching from grid-connected operation mode to independent operation mode, the voltage change at the second output terminal T23 before and after the switch remains outside the predetermined second normal range for a predetermined period of time, the fault determination unit determines that a fault has occurred in which the second changeover switch SW2 is fixed to the second system input terminal T21 side and switching is not possible. (4) In the independent operation mode, if the voltage at the second output terminal T23 is within a predetermined third normal range, and when switching from the independent operation mode to the grid-connected operation mode, the voltage change at the second output terminal T23 before and after the switch remains outside the predetermined fourth normal range for a predetermined period of time, the fault determination unit determines that the second changeover switch SW2 is fixed to the second independent input terminal T22 side and has become unable to switch, resulting in a fault.

[0048] The first to fourth normal ranges can be appropriately set by the control unit 22A based on the rated value of the system output of the charge / discharge device 11, the rated value of the standalone output of the charge / discharge device 11, and the difference between these rated values. The fault detection unit outputs the detection result to the switch control unit.

[0049] The switch control unit controls each switch SW1 to SW5 based on the determination results of the mode determination unit and the fault determination unit. Specifically, the switch control unit controls each switch SW1 to SW5 as shown in Figure 2. In the following, a fault that prevents switching will simply be referred to as a fault, and the same will apply to the second and third embodiments.

[0050] (State 1-1) In state 1-1, the operating mode of the charge / discharge device 11 is the grid-connected operation mode, and neither the first changeover switch SW1 nor the second changeover switch SW2 is malfunctioning.

[0051] In grid-connected operation mode, the grid output (grid voltage and / or AC voltage output from AC terminal Ta) is applied to the first grid input terminal T11 and the second grid input terminal T21, while the independent output (AC voltage output from independent output terminal Tc) is applied to the first independent input terminal T12 and the second independent input terminal T22.

[0052] The control unit 22A sets the first changeover switch SW1 to a state where the first input terminal T11 and the first output terminal T13 are electrically connected, and sets the second changeover switch SW2 to a state where the second input terminal T21 and the second output terminal T23 are electrically connected. Furthermore, the control unit 22A sets the fourth changeover switch SW4 to the ON state, the fifth changeover switch SW5 to the OFF state, and the third changeover switch SW3 to the up state, or sets the fourth changeover switch SW4 to the OFF state, the fifth changeover switch SW5 to the ON state, and the third changeover switch SW3 to the down state. The control unit 22A can pre-set whether switches SW3 to SW5 should be in the former state or the latter state.

[0053] (State 1-2) In state 1-2, the charging / discharging device 11 is in the independent operation mode, and neither the first changeover switch SW1 nor the second changeover switch SW2 is malfunctioning.

[0054] In standalone operation mode, no system output is applied to the first system input terminal T11 and the second system input terminal T21, while standalone output is applied to the first standalone input terminal T12 and the second standalone input terminal T22.

[0055] The control unit 22A sets the first changeover switch SW1 to a state where the first independent input terminal T12 and the first output terminal T13 are electrically connected, and sets the second changeover switch SW2 to a state where the second independent input terminal T22 and the second output terminal T23 are electrically connected. Furthermore, the control unit 22A sets the fourth changeover switch SW4 to the ON state, the fifth changeover switch SW5 to the OFF state, and the third changeover switch SW3 to the up state, or sets the fourth changeover switch SW4 to the OFF state, the fifth changeover switch SW5 to the ON state, and the third changeover switch SW3 to the down state.

[0056] (States 1-3) In state 1-3, the charging / discharging device 11 is in the self-sustaining operation mode, the first changeover switch SW1 is faulty, and the second changeover switch SW2 is not faulty. In state 1-3, the first changeover switch SW1 is faulty while fixed to the first system input terminal T11 side, but even if the first changeover switch SW1 is faulty while fixed to the first self-sustaining input terminal T12 side, the control unit 22A will perform the same control.

[0057] The control unit 22A sets the second changeover switch SW2 to a state where the second independent input terminal T22 and the second output terminal T23 are electrically connected, sets the fourth changeover switch SW4 to the OFF state, the fifth changeover switch SW5 to the ON state, and the third changeover switch SW3 to the down state. As a result, the independent output is supplied to the load 3 via the power supply path through the second changeover switch SW2.

[0058] (States 1-4) In state 1-4, the operating mode of the charge / discharge device 11 is grid-connected operation mode, the first changeover switch SW1 is faulty, and the second changeover switch SW2 is not faulty. In state 1-4, the first changeover switch SW1 is faulty while fixed to the first system input terminal T11 side, but even if the first changeover switch SW1 is faulty while fixed to the first independent input terminal T12 side, the control unit 22A will perform the same control.

[0059] The control unit 22A sets the second changeover switch SW2 to a state where the second system input terminal T21 and the second output terminal T23 are electrically connected, sets the fourth changeover switch SW4 to the OFF state, the fifth changeover switch SW5 to the ON state, and the third changeover switch SW3 to the down state. As a result, the system output is supplied to the load 3 via the power supply path through the second changeover switch SW2.

[0060] (States 1-5) In state 1-5, the charging / discharging device 11 is in the independent operation mode, the second changeover switch SW2 is faulty, and the first changeover switch SW1 is not faulty. In state 1-5, the second changeover switch SW2 is faulty while fixed to the second system input terminal T21 side, but even if the second changeover switch SW2 is faulty while fixed to the second independent input terminal T22 side, the control unit 22A will perform the same control.

[0061] The control unit 22A sets the first changeover switch SW1 to a state where the first independent input terminal T12 and the first output terminal T13 are electrically connected, sets the fourth changeover switch SW4 to the ON state, the fifth changeover switch SW5 to the OFF state, and the third changeover switch SW3 to the up state. As a result, the independent output is supplied to the load 3 via the power supply path through the first changeover switch SW1.

[0062] (States 1-6) In state 1-6, the operating mode of the charge / discharge device 11 is grid-connected operation mode, the second changeover switch SW2 is faulty, and the first changeover switch SW1 is not faulty. The second changeover switch SW2 is faulty while fixed to the second system input terminal T21 side, but even if the second changeover switch SW2 is faulty while fixed to the second independent input terminal T22 side, the control unit 22A will perform the same control.

[0063] The control unit 22A sets the first changeover switch SW1 to a state where the first system input terminal T11 and the first output terminal T13 are electrically connected, sets the fourth changeover switch SW4 to the ON state, the fifth changeover switch SW5 to the OFF state, and the third changeover switch SW3 to the up state. As a result, the system output is supplied to the load 3 via the power supply path through the first changeover switch SW1.

[0064] As described above, in the power supply system 1A according to this embodiment, a first power supply path (first power line L1) via the first changeover switch SW1 and a second power supply path (second power line L2) via the second changeover switch SW2 are formed in parallel in the automatic changeover distribution board 20A, and each of the first changeover switch SW1 and the second changeover switch SW2 is connected to both the grid power line L11 and the independent output line L12. Therefore, in the power supply system 1A according to this embodiment, even if either the first changeover switch SW1 or the second changeover switch SW2 fails, it is possible to stably supply power to the load 3 via either the first power supply path (first power line L1) or the second power supply path (second power line L2).

[0065] In this embodiment, the fault detection unit is configured to detect whether switches SW1 and SW2 are fixed to either the grid power line L11 side or the independent output line L12 side when a fault occurs. However, in the power supply system 1A according to this embodiment, if either the first changeover switch SW1 or the second changeover switch SW2 fails, power is supplied to the load 3 via the power supply path through the other switch that is not faulty. Therefore, if a fault in either switch SW1 or SW2 can be detected, it is not necessary to detect whether the fault is fixed to either the grid power line L11 side or the independent output line L12 side. Thus, the fault detection unit in this embodiment can be simplified in its configuration.

[0066] [Second Embodiment] Figure 3 shows a power supply system 1B according to a second embodiment of the present invention. The power supply system 1B comprises a power storage system 10 and an automatic switching distribution board 20B. The power storage system 10 has the same configuration as in the first embodiment.

[0067] The automatic switching distribution board 20B comprises a switch unit 21B and a control unit 22B that controls the switch unit 21B. The switch unit 21B has the same configuration as the switch unit 21A in the first embodiment.

[0068] The control unit 22B includes a mode determination unit that determines the operating mode of the charge / discharge device 11, a fault determination unit that determines a failure in the first changeover switch SW1 and the second changeover switch SW2 to be switchable, and a switch control unit that controls each of the switches SW1 to SW5. The control unit 22B has the same configuration as the control unit 22A of the first embodiment, except for the control performed by the switch control unit.

[0069] The switch control unit controls each switch SW1 to SW5 based on the determination results of the mode determination unit and the fault determination unit. Specifically, the switch control unit controls each switch SW1 to SW5 as shown in Figure 4.

[0070] (State 2-1) In state 2-1, the operating mode of the charge / discharge device 11 is grid-connected operation mode, and neither the first changeover switch SW1 nor the second changeover switch SW2 is malfunctioning. The control unit 22B sets the first changeover switch SW1 to a state where the first system input terminal T11 and the first output terminal T13 are electrically connected, and the second changeover switch SW2 to a state where the second system input terminal T21 and the second output terminal T23 are electrically connected, and sets the fourth changeover switch SW4 to the ON state, the fifth changeover switch SW5 to the OFF state, and the third changeover switch SW3 to the up state.

[0071] (State 2-2) In state 2-2, the charging / discharging device 11 is in the self-sustaining operation mode, and neither the first changeover switch SW1 nor the second changeover switch SW2 is malfunctioning. The control unit 22B sets the first changeover switch SW1 to a state where the first self-sustaining input terminal T12 and the first output terminal T13 are electrically connected, and the second changeover switch SW2 to a state where the second self-sustaining input terminal T22 and the second output terminal T23 are electrically connected, and sets the fourth changeover switch SW4 to the OFF state, the fifth changeover switch SW5 to the ON state, and the third changeover switch SW3 to the down state.

[0072] (State 2-3) State 2-3 is the same as state 1-3 in the first embodiment. That is, the control unit 22B performs the same control as the control unit 22A in the first embodiment.

[0073] (State 2-4) In state 2-4, the charging / discharging device 11 is in grid-connected operation mode, the first changeover switch SW1 is faulty and fixed to the first system input terminal T11, and the second changeover switch SW2 is not faulty. The control unit 22B sets the second changeover switch SW2 to a state where the second system input terminal T21 and the second output terminal T23 are electrically connected, sets the fourth changeover switch SW4 to the ON state, the fifth changeover switch SW5 to the OFF state, and the third changeover switch SW3 to the up state. As a result, the grid output is supplied to the load 3 via the first power supply path through the faulty first changeover switch SW1.

[0074] (States 2-5) State 2-5 is the same as state 1-5 in the first embodiment. That is, the control unit 22B performs the same control as the control unit 22A in the first embodiment.

[0075] (States 2-6) State 2-6 is the same as state 1-6 in the first embodiment. That is, the control unit 22B performs the same control as the control unit 22A in the first embodiment.

[0076] (State 2-7) State 2-7 is when the charging / discharging device 11 is in the self-sustaining operation mode, the first changeover switch SW1 is faulty and fixed to the first self-sustaining input terminal T12, and the second changeover switch SW2 is not faulty. In this case, the control unit 22B performs the same control on the non-faulty switches SW2 to SW5 as in state 2-3 (state 1-3 of the first embodiment).

[0077] (State 2-8) State 2-8 is when the charging / discharging device 11 is in grid-connected operation mode, the first changeover switch SW1 is faulty and fixed to the first independent input terminal T12, and the second changeover switch SW2 is not faulty. In this case, the control unit 22B performs the same control on the non-faulty switches SW2 to SW5 as in state 1-4 of the first embodiment.

[0078] (State 2-9) In state 2-9, the charging / discharging device 11 is in the self-sustaining operation mode, the second changeover switch SW2 is faulty and fixed to the second self-sustaining input terminal T22, and the first changeover switch SW1 is not faulty. The control unit 22B sets the first changeover switch SW1 to a state where the first self-sustaining input terminal T12 and the first output terminal T13 are electrically connected, sets the fourth changeover switch SW4 to the OFF state, the fifth changeover switch SW5 to the ON state, and the third changeover switch SW3 to the down state. As a result, the self-sustaining output is supplied to the load 3 via the second power supply path through the faulty second changeover switch SW2.

[0079] (State 2-10) In state 2-10, the operating mode of the charge / discharge device 11 is the grid-connected operation mode, the second changeover switch SW2 is faulty and fixed to the second independent input terminal T22 side, and the first changeover switch SW1 is not faulty. In this case, the control unit 22B performs the same control as in state 2-6 (state 1-6 of the first embodiment) for the switches SW1, SW3 to SW5 that are not faulty.

[0080] As described above, in the power supply system 1B according to this embodiment, a first power supply path (first power line L1) via the first changeover switch SW1 and a second power supply path (second power line L2) via the second changeover switch SW2 are formed in parallel in the automatic changeover distribution board 20B, and each of the first changeover switch SW1 and the second changeover switch SW2 is connected to both the grid power line L11 and the independent output line L12. Therefore, in the power supply system 1B according to this embodiment, even if either the first changeover switch SW1 or the second changeover switch SW2 fails, it is possible to stably supply power to the load 3 via either the first power supply path (first power line L1) or the second power supply path (second power line L2).

[0081] Furthermore, in the power supply system 1B according to this embodiment, if the operating mode of the charge / discharge device 11 is grid-connected operation mode and the first changeover switch SW1 is fixed to the first system input terminal T11 side and has failed (state 2-4), the grid output is supplied to the load 3 via the first power supply path through the failed first changeover switch SW1. In this way, by performing the same control on the non-faulty switches SW2 to SW5 as when the first changeover switch SW1 has not failed (state 2-1), the complexity of the control can be suppressed.

[0082] Similarly, in the power supply system 1B according to this embodiment, if the operating mode of the charge / discharge device 11 is in the independent operation mode and the second changeover switch SW2 is fixed to the second independent input terminal T22 side and has failed (in the case of state 2-9), the independent output is supplied to the load 3 via the second power supply path through the failed second changeover switch SW2. In this way, by performing the same control on the non-faulty switches SW1, SW3 to SW5 as when the second changeover switch SW2 is not faulty (in the case of state 2-2), the complexity of the control can be suppressed.

[0083] [Third Embodiment] Figure 5 shows a power supply system 1C according to a third embodiment of the present invention. The power supply system 1C comprises a power storage system 10C and an automatic switching distribution board 20C.

[0084] The energy storage system 10C comprises a charge / discharge device 11C and a battery 12. The charge / discharge device 11C differs from the first embodiment in that it provides grid output without providing independent output during grid-connected operation mode (for example, the configuration of the switching unit differs from the first embodiment), but otherwise has the same configuration as the first embodiment. The battery 12 has the same configuration as the first embodiment.

[0085] The automatic switching distribution board 20C comprises a switch unit 21C and a control unit 22C that controls the switch unit 21C. The switch unit 21C has the same configuration as the switch unit 21A of the first embodiment, except that a sixth changeover switch SW6 is interposed on the third power line L3. In this embodiment, the fourth changeover switch SW4, the fifth changeover switch SW5, and the sixth changeover switch SW6 are relay switches (contacts).

[0086] The sixth changeover switch SW6 switches between an ON state and an OFF state under the control of the control unit 22C. When it is ON, it makes the third power line L3 conductive, and when it is OFF, it makes the third power line L3 non-conductive. The sixth changeover switch SW6 is OFF when both the first changeover switch SW1 and the second changeover switch SW2 are faulty, and is ON when only one of them is faulty or when neither is faulty.

[0087] As shown in Figure 6, the control unit 22C includes a mode determination unit 23, a switch control unit 24, a first detection unit 25, a second detection unit 26, a fault determination unit 27, and a fault display unit 28.

[0088] The mode determination unit 23 has the same configuration as the mode determination unit of the first embodiment and determines the operating mode of the charge / discharge device 11C. The mode determination unit 23 outputs the determined operating mode to the switch control unit 24.

[0089] The switch control unit 24 controls each switch SW1 to SW3 according to the determination result of the mode determination unit 23 and whether or not the first changeover switch SW1 and the second changeover switch SW2 are faulty. Specifically, the switch control unit 24 controls each switch SW1 to SW3 in the same manner as in the first embodiment (as shown in Figure 2).

[0090] The first detection unit 25 detects whether or not the first changeover switch SW1 is faulty, and controls the fourth changeover switch SW4 according to the detection result. The first detection unit 25 turns the fourth changeover switch SW4 ON if it has not detected a fault in the first changeover switch SW1, and turns the fourth changeover switch SW4 OFF if it has detected a fault in the first changeover switch SW1.

[0091] The first detection unit 25 comprises logic circuits C1 to C5, a transistor TR1, and a drive coil RC1 for the fourth changeover switch SW4. Logic circuit C1 is a NAND circuit, logic circuits C2, C3, and C5 are AND circuits, and logic circuit C4 is an OR circuit. These logic circuits are composed of analog and / or digital circuits. Transistor TR1 is an NPN bipolar transistor, and the drive coil RC1 is connected to the collector of transistor TR1. The output signal (voltage signal) from the connection point P1 between transistor TR1 and drive coil RC1 is output to the fault determination unit 27 and the switch control unit 24. Furthermore, at the input sections of logic circuits C1 to C3, AC power (system output and independent output) is converted into DC detection signals by detection circuits (system output detection circuit and independent output detection circuit) not shown, which are installed on the power lines (system power line L11 and independent output line L12). As a result, signals (system output signal and independent output signal) that have been binarized (for example, input present: 1, input absent: 0) are input depending on whether or not AC power is being input.

[0092] When the charge / discharge device 11C is in grid-connected operation mode, the voltage signals input to the first detection unit 25 and the second detection unit 26 from the grid power line L11 are high-level signals, while the voltage signals input to the first detection unit 25 and the second detection unit 26 from the independent output line L12 are low-level signals. When the charge / discharge device 11C is in independent operation mode, the voltage signals input to the first detection unit 25 and the second detection unit 26 from the grid power line L11 are low-level signals, while the voltage signals input to the first detection unit 25 and the second detection unit 26 from the independent output line L12 are high-level signals.

[0093] In the first detection unit 25, the voltage level at the first output terminal T13 of the first changeover switch SW1 is high when the first changeover switch SW1 is not faulty, and low when the first changeover switch SW1 is faulty. The output of logic circuit C1 is high regardless of whether the first changeover switch SW1 is faulty or not. When the first changeover switch SW1 is not faulty, the output of logic circuit C4 is high, the output of logic circuit C5 is also high, transistor TR1 turns ON and current flows to the drive coil RC1, and the fourth changeover switch SW4 is turned ON. As a result, the output from connection point P1 (voltage level at connection point P1) is low. On the other hand, when the first changeover switch SW1 is faulty, the output of logic circuit C4 is low, the output of logic circuit C5 is also low, transistor TR1 turns OFF and no current flows to the drive coil RC1, and the fourth changeover switch SW4 is turned OFF. As a result, the output from connection point P1 is high.

[0094] The second detection unit 26 detects whether or not the second changeover switch SW2 is faulty and controls the fifth changeover switch SW5 according to the detection result. The second detection unit 26 turns the fifth changeover switch SW5 ON if it has not detected a fault in the second changeover switch SW2, and turns the fifth changeover switch SW5 OFF if it has detected a fault in the second changeover switch SW2.

[0095] The second detection unit 26 comprises logic circuits C6 to C10, a transistor TR2, and a drive coil RC2 for the fifth changeover switch SW5. Logic circuit C6 is a NAND circuit, logic circuits C7, C8, and C10 are AND circuits, and logic circuit C9 is an OR circuit. These logic circuits consist of analog and / or digital circuits. Transistor TR2 is an NPN bipolar transistor, and the drive coil RC2 is connected to the collector of transistor TR2. The output signal (voltage signal) from the connection point P2 between transistor TR2 and drive coil RC2 is output to the fault determination unit 27 and the switch control unit 24. Furthermore, at the input sections of logic circuits C6 to C8, AC power (system output and independent output) is converted into DC detection signals by detection circuits (system output detection circuit and independent output detection circuit) not shown, which are installed on the power lines (system power line L11 and independent output line L12). As a result, signals (system output signal and independent output signal) that have been binarized (for example, input present: 1, input absent: 0) are input depending on whether or not AC power is being input.

[0096] In the second detection unit 26, the voltage level at the second output terminal T23 of the second changeover switch SW2 is high when the second changeover switch SW2 is not faulty, and low when the second changeover switch SW2 is faulty. The output of logic circuit C6 is high regardless of whether the second changeover switch SW2 is faulty or not. When the second changeover switch SW2 is not faulty, the output of logic circuit C9 is high, the output of logic circuit C10 is also high, transistor TR2 turns ON and current flows to the drive coil RC2, and the fifth changeover switch SW5 is in the ON state. As a result, the output from connection point P2 (voltage level at connection point P2) is low. On the other hand, when the second changeover switch SW2 is faulty, the output of logic circuit C9 is low, the output of logic circuit C10 is also low, transistor TR2 turns OFF and no current flows to the drive coil RC2, and the fifth changeover switch SW5 is in the OFF state. As a result, the output from connection point P2 is high.

[0097] The fault detection unit 27 turns the sixth changeover switch SW6 ON if it has not detected a fault in the first changeover switch SW1 or the second changeover switch SW2, while turning the sixth changeover switch SW6 OFF if it has detected faults in both the first changeover switch SW1 and the second changeover switch SW2.

[0098] The fault detection unit 27 comprises a logic circuit C11, a transistor TR3, and a drive coil RC3 for the sixth changeover switch SW6. The logic circuit C11 is a NAND gate and consists of an analog circuit and / or a digital circuit. The transistor TR3 is an NPN bipolar transistor, and the drive coil RC3 is connected to the collector of the transistor TR3.

[0099] The logic circuit C11 receives output signals from connection point P1 and connection point P2. When both the first changeover switch SW1 and the second changeover switch SW2 are functioning correctly (P1 is low level, P2 is low level), when only the first changeover switch SW1 is faulty (P1 is high level, P2 is low level), or when only the second changeover switch SW2 is faulty (P1 is low level, P2 is high level), the output of the logic circuit C11 becomes high level, transistor TR3 turns ON, current flows to the drive coil RC3, and the sixth changeover switch SW6 becomes ON. On the other hand, when both the first changeover switch SW1 and the second changeover switch SW2 are faulty (P1 is high level, P2 is high level), the output of the logic circuit C11 becomes low level, transistor TR3 turns OFF, no current flows to the drive coil RC3, and the sixth changeover switch SW6 becomes OFF.

[0100] The fault indicator unit 28 is configured to notify the user of a fault when at least one of the first changeover switch SW1 and the second changeover switch SW2 is faulty. In this embodiment, the fault indicator unit 28 comprises a logic circuit C12, a transistor TR4, a light-emitting diode LED1, and a resistor R1. The logic circuit C12 is a NAND gate and consists of an analog circuit and / or a digital circuit. The transistor TR4 is an NPN bipolar transistor, and a series circuit of the resistor R1 and the light-emitting diode LED1 is connected to the collector of the transistor TR4. The light-emitting diode LED1 is at least one light-emitting diode that emits visible light.

[0101] The output signals of logic circuit C4 and logic circuit C9 are input to logic circuit C12. If the first changeover switch SW1 and the second changeover switch SW2 are not faulty (when the output of C4 and the output of C9 are both high levels), the output of logic circuit C12 will be low level, transistor TR4 will turn OFF, no current will flow to the light-emitting diode LED1, and LED1 will not light up. On the other hand, if at least one of the first changeover switch SW1 and the second changeover switch SW2 is faulty (when at least one of the outputs of C4 and C9 is low level), the output of logic circuit C12 will be high level, transistor TR4 will turn ON, current will flow to LED1, and LED1 will light up. This allows the user to be notified of a fault and to detect the fault early.

[0102] In this embodiment, the user is notified of a malfunction in at least one of the first changeover switch SW1 and the second changeover switch SW2 using a light-emitting means (light-emitting diode LED1). However, in addition to this, or instead, the malfunction may be indicated using a display means such as a touch panel, or the malfunction may be notified by voice using any voice means.

[0103] [Differentiation] The embodiments of the power supply system and automatic switching distribution board according to the present invention have been described above, but the present invention is not limited to the above embodiments.

[0104] The power supply system according to the present invention comprises a charge / discharge device having an AC terminal connected to a power grid, a DC terminal connected to a storage battery, and an independent output terminal, and outputting discharge power from the storage battery from the independent output terminal, and an automatic switching distribution board having the power grid and the independent output terminal of the charge / discharge device connected to one side, and a load connected to the other side, wherein the automatic switching distribution board has a first system input terminal connected to the power grid, a first independent input terminal connected to the independent output terminal, and a first output terminal, and a first changeover switch that switches between a state in which the first system input terminal and the first output terminal are electrically connected and a state in which the first independent input terminal and the first output terminal are electrically connected, and a second system input terminal connected to the power grid, and the independent output terminal The configuration can be modified as appropriate, provided that the system includes a second independent input terminal and a second output terminal connected to the power terminal, a second changeover switch that switches between a state in which the second system input terminal and the second output terminal are electrically connected and a state in which the second independent input terminal and the second output terminal are electrically connected; a third changeover switch that switches between a state in which the first input terminal and the third output terminal are electrically connected and a state in which the second input terminal and the third output terminal are electrically connected, and a control unit that controls the first changeover switch, the second changeover switch and the third changeover switch so as to form a power supply path to the load.

[0105] For example, the power supply systems 1A to 1C according to each of the above embodiments do not necessarily have a fourth changeover switch SW4 and a fifth changeover switch SW5.

[0106] The charging and discharging device of the present invention may also be a charging and discharging device (for example, a V2H device) that charges and discharges a storage battery installed in an electric vehicle or the like.

[0107] The power supply system of the present invention may include a power conversion unit (e.g., a power conditioner unit) of a power generation device using renewable energy (e.g., a solar power generation device). If the power conversion unit of the power generation device has an independent output terminal that can output AC power as an independent output, the independent output terminal can be connected to the output side of an automatic switching distribution board (e.g., the third power line L3 in the above embodiment). [Explanation of Symbols]

[0108] 1A~1C Power Supply System 2 Power system 3 load 10, 10C energy storage system 11, 11C charge / discharge device 11a Opening / closing part 11b Power conversion section 11c Control Unit 12 Storage batteries 20A~20C Automatic Switching Distribution Board 21A~21C Switch section 22A~22C Control Unit 23 Mode determination unit 24 Switch control unit 25 First detection unit 26 Second detection unit 27 Failure determination section 28 Fault display section

Claims

1. A charge / discharge device comprising an AC terminal connected to a power grid, a DC terminal connected to a storage battery, and a self-contained output terminal, wherein the self-contained output terminal outputs the discharge power of the storage battery, An automatic switching distribution board is connected to one side of the power system and the standalone output terminal of the charge / discharge device, and to the other side of the load. A power supply system comprising, The aforementioned automatic switching distribution panel is A first changeover switch is provided, which switches between a state in which the first system input terminal and the first output terminal are electrically connected and a state in which the first system input terminal and the first output terminal are electrically connected. The device includes a second system input terminal connected to the power system, a second independent input terminal connected to the independent output terminal, and a second output terminal, and a second changeover switch that switches between a state in which the second system input terminal and the second output terminal are electrically connected and a state in which the second independent input terminal and the second output terminal are electrically connected. The system includes a first input terminal connected to the first output terminal, a second input terminal connected to the second output terminal, and a third output terminal connected to the load, and a third changeover switch that switches between a state in which the first input terminal and the third output terminal are electrically connected and a state in which the second input terminal and the third output terminal are electrically connected. The system includes a control unit that controls the first changeover switch, the second changeover switch, and the third changeover switch so that a power supply path to the load is formed, The aforementioned automatic switching distribution panel is A fourth changeover switch is interposed in the first power line connecting the first output terminal and the first input terminal, and switches the first power line between a conductive state and a non-conductive state. The system further includes a fifth changeover switch interposed in a second power line connecting the second output terminal and the second input terminal, which switches the second power line between a conductive state and a non-conductive state, The control unit, The fourth changeover switch and the fifth changeover switch are controlled to make either the first power line or the second power line conductive and the other non-conductive. A power supply system characterized by the following features.

2. The control unit, If the first changeover switch fails to switch, the fourth changeover switch is controlled to de-conduct the first power line, while the fifth changeover switch is controlled to conduct the second power line. If the second changeover switch fails to switch, the fifth changeover switch is controlled to de-conduct the second power line, while the fourth changeover switch is controlled to conduct the first power line. The power supply system according to claim 1.

3. The control unit, When the first system input terminal is connected to the first output terminal and the first changeover switch is malfunctioning and unable to switch, if the power system is energized, the fourth changeover switch is controlled to make the first power line conductive, When the second independent input terminal is connected to the second output terminal, and the second changeover switch fails to switch, and the power system is in a power outage state, the fifth changeover switch is controlled to make the second power line conductive. The power supply system according to claim 1.

4. The control unit, A first detection unit detects a failure of the first changeover switch to be unable to switch based on the voltages before and after the first changeover switch, and controls the fourth changeover switch according to the detection result. The system includes a second detection unit that detects a failure of the second changeover switch to be unable to switch based on the voltages before and after the second changeover switch, and controls the fifth changeover switch according to the detection result. The power supply system according to claim 1.

5. A charge / discharge device comprising an AC terminal connected to a power grid, a DC terminal connected to a storage battery, and a self-contained output terminal, wherein the self-contained output terminal outputs the discharge power of the storage battery, An automatic switching distribution board is connected to one side of the power system and the standalone output terminal of the charge / discharge device, and to the other side of the load. A power supply system comprising, The aforementioned automatic switching distribution panel is A first changeover switch is provided, which switches between a state in which the first system input terminal and the first output terminal are electrically connected and a state in which the first system input terminal and the first output terminal are electrically connected. The device includes a second system input terminal connected to the power system, a second independent input terminal connected to the independent output terminal, and a second output terminal, and a second changeover switch that switches between a state in which the second system input terminal and the second output terminal are electrically connected and a state in which the second independent input terminal and the second output terminal are electrically connected. The system includes a first input terminal connected to the first output terminal, a second input terminal connected to the second output terminal, and a third output terminal connected to the load, and a third changeover switch that switches between a state in which the first input terminal and the third output terminal are electrically connected and a state in which the second input terminal and the third output terminal are electrically connected. The system includes a control unit that controls the first changeover switch, the second changeover switch, and the third changeover switch so that a power supply path to the load is formed, The aforementioned automatic switching distribution panel is The system further includes a sixth changeover switch interposed in the third power line connecting the third output terminal and the load, which switches the third power line between a conductive state and a non-conductive state. The control unit, If both the first and second changeover switches fail to switch, the sixth changeover switch is controlled to de-conduct the third power line. A power supply system characterized by the following features.

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