Switcher, power distribution board and power system

Abstract

To eliminate the need of a configuration for detecting an abnormality which occurs in a distributed power source in addition to a switcher.SOLUTION: A switcher 2 comprises a first connection section (movable contact 243), a second connection section (stationary contact 242), a third connection section (stationary contact 241), a voltage detection section 26 and a control section 25. A load is connected to the first connection section. A distributed power source is connected to the second connection section. A system power source is connected to the third connection section. The voltage detection section 26 is at least one of a first voltage detection section which detects a first voltage to be applied to the first connection section and a second voltage detection section which detects a second voltage to be applied to the second connection section. In a case where a detection voltage of the voltage detection section 26 exceeds a first threshold or a detection voltage of the voltage detection section 26 is below a second threshold, the control section 25 switches a connection destination of the first connection section from the second connection section to the other connection section which is different from the second connection section.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a switch, a distribution board, and a power system. More particularly, the present disclosure relates to a switch having a plurality of connections, a distribution board including the switch, and a power system including the switch. [Background technology]

[0002] Patent Document 1 describes a grid interconnection system in which a commercial power source and a distributed power source are connected to the terminals of a changeover switch, and the current path of the power system to the load can be switched. In the grid interconnection system described in Patent Document 1, a ground fault circuit interrupter is provided on the primary side of the distributed power source connection part of the changeover switch. [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] The grid interconnection system (power system) described in Patent Document 1 required a configuration (earth leakage switch) for detecting abnormalities occurring in the distributed power source (distributed power source) in addition to the changeover switch (switch).

[0005] An object of the present disclosure is to provide a switch, a distribution board, and a power system that do not require a configuration separate from the switch for detecting abnormalities occurring in distributed power sources. [Means for solving the problem]

[0006] A switch according to one aspect of the present disclosure includes a first connection unit, a second connection unit, a third connection unit, a voltage detection unit, and a control unit. A load is connected to the first connection unit. A distributed power source is connected to the second connection unit. A grid power source is connected to the third connection unit. The voltage detection unit is at least one of a first voltage detection unit that detects a first voltage applied to the first connection unit and a second voltage detection unit that detects a second voltage applied to the second connection unit. When the detected voltage of the voltage detection unit exceeds a first threshold or when the detected voltage of the voltage detection unit falls below a second threshold that is lower than the first threshold, the control unit switches the connection destination of the first connection unit from the second connection unit to another connection unit different from the second connection unit.

[0007] A distribution board according to an aspect of the present disclosure includes the switch and a cabinet. The cabinet houses the switch.

[0008] A power system according to one aspect of the present disclosure includes the switch and the distributed power source. [Effects of the Invention]

[0009] The switch, distribution board, and power system according to one aspect of the present disclosure have the advantage that no configuration separate from the switch is required to detect abnormalities occurring in distributed power sources. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a distribution board and a power system according to an embodiment. [Figure 2] FIG. 2 is a front view of the distribution board. [Figure 3] FIG. 3 is a schematic diagram showing the configuration of a switch in the distribution board. [Figure 4] FIG. 4 is a schematic diagram illustrating a configuration of a switch in a distribution board according to a first modification of the embodiment. [Figure 5] FIG. 5 is a schematic diagram illustrating a configuration of a switch in a distribution board according to a second modification of the embodiment. [Figure 6] FIG. 6 is a schematic diagram showing the configuration of a switch in a distribution board according to a third modification of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a switch, a distribution board, and a power system according to embodiments will be described with reference to the drawings. The drawings referred to in the following embodiments are schematic diagrams, and the sizes and thicknesses of the components in the drawings do not necessarily reflect the actual dimensions, and the ratios of sizes and thicknesses between the components do not necessarily reflect the actual dimensional ratios.

[0012] (Embodiment) (1) Overview First, an overview of a switch 2, a distribution board 100, and a power system 200 according to the embodiment will be described with reference to FIGS. 1 to 3. FIG.

[0013] As shown in FIG. 1, a power system 200 according to an embodiment is a system that supplies power supplied from a commercial power system CS or power supplied from a distributed power source DS to multiple loads L1 provided within a facility. The facility may be, for example, a residential facility such as a detached house or each dwelling unit in an apartment building, or a non-residential facility such as a factory, store, office building, commercial building, hospital, or school. In this embodiment, as an example, the facility is a detached house. As shown in FIG. 1, the power system 200 includes a distribution board 100, a commercial power system CS, a distributed power source DS, and multiple loads L1.

[0014] The distribution board 100 is attached to a building material such as a wall. As shown in Fig. 1, the distribution board 100 includes a main breaker 1, a switch 2, a plurality of (three in the illustrated example) conductive bars 3, a plurality of (14 in the illustrated example) branch breakers 4, an interconnection breaker 5, and a cabinet C1. As shown in Figs. 1 and 2, the cabinet C1 houses the main breaker 1, the switch 2, the plurality of conductive bars 3, the plurality of branch breakers 4, and the interconnection breaker 5.

[0015] The switch 2 is a device that switches power supplied to multiple loads L1 provided in a facility between power supplied from a commercial power grid CS and power supplied from a distributed power source DS. As shown in FIG. 3 , the switch 2 includes a movable contact 243 (first connection), a fixed contact 242 (second connection), a fixed contact 241 (third connection), a voltage detection unit 26, and a control unit 25. The movable contact 243 is connected to the load L1. The fixed contact 242 is connected to a distributed power source DS. The fixed contact 241 is connected to the commercial power grid CS. The voltage detection unit 26 detects a second voltage applied to the fixed contact 242. The control unit 25 switches the connection destination of the movable contact 243 from the fixed contact 242 to the fixed contact 241 when the detected voltage of the voltage detection unit 26 exceeds a first threshold or falls below a second threshold that is lower than the first threshold.

[0016] As described above, the switch 2 according to the embodiment includes the voltage detection unit 26 that detects the second voltage applied to the fixed contact 242 by the distributed power source DS, and therefore does not require a configuration for detecting the second voltage, separate from the switch 2. That is, the switch 2 according to the embodiment has the advantage that it does not require a configuration for detecting an abnormality occurring in the distributed power source DS, separate from the switch 2.

[0017] (2)Details Next, details of the switch 2, distribution board 100, and power system 200 according to the embodiment will be described with reference to Figs. 1 to 3. In the following description, unless otherwise specified, the longitudinal direction of the cabinet C1 is defined as the left-right direction, the short side direction (width direction) of the cabinet C1 is defined as the up-down direction, and the thickness direction (depth direction) of the cabinet C1 is defined as the front-rear direction. However, these directions are not intended to limit the directions in which the distribution board 100 is used. Furthermore, the arrows indicating "up," "down," "left," and "right" in Fig. 2 are merely shown for the purpose of explanation and do not have any physical substance.

[0018] A power system 200 according to the embodiment is, for example, a grid-connected system that can switch the power supply system to a load L1 between a commercial power system CS and a distributed power source DS. As shown in Fig. 1, the power system 200 according to the embodiment includes a distribution board 100, a commercial power system CS, a distributed power source DS, and a plurality of loads L1.

[0019] (2.1) Distribution board The distribution board 100 is, for example, a residential distribution board (so-called residential board) used in a single-phase three-wire power distribution system. However, the distribution board 100 is not limited to a residential board, and may be a cabinet-type distribution board or the like used in a three-phase three-wire or three-phase four-wire power distribution system.

[0020] The distribution board 100 includes a cabinet C1 that houses internal devices (see FIGS. 1 and 2). The cabinet C1 is a rectangular box with an open front, and is attached to a building material such as a wall. In FIGS. 1 and 2, illustrations of a cover or the like that can be attached to the opening on the front of the cabinet C1 in an openable / closable or detachable manner are omitted.

[0021] The distribution board 100 includes, as internal devices housed in a cabinet C1, a main breaker (main switch) 1, a switch 2, a plurality of (three in the illustrated example) conductive bars 3, a plurality of (14 in the illustrated example) branch breakers 4, and an interconnection breaker 5. These internal devices are attached to the cabinet C1 directly or indirectly via attachment parts or the like. That is, the distribution board 100 according to the embodiment includes the switch 2 and a cabinet C1 that houses the switch 2. Furthermore, the power system 200 according to the embodiment includes the switch 2 and a distributed power source DS.

[0022] (2.1.1) Main breaker The main breaker 1 is disposed inside the cabinet C1, slightly to the left of the center in the left-right direction. Three primary terminals 11 (see FIG. 2) are provided at the top end of the case 10 of the main breaker 1, and three secondary terminals 12 (see FIG. 2) are provided at the right end of the case 10 of the main breaker 1. In the following description, when it is necessary to distinguish between the three primary terminals 11, the three primary terminals 11 may be referred to as primary terminals 11a, 11b, and 11c, respectively. Similarly, when it is necessary to distinguish between the three secondary terminals 12, the three secondary terminals 12 may be referred to as secondary terminals 12a, 12b, and 12c, respectively.

[0023] The main breaker 1 has contacts in a case 10 that electrically connect and disconnect the primary terminal 11 and the secondary terminal 12. The main breaker 1 also has an operating lever 13 on the front of the case 10 for turning the contacts on and off. The main breaker 1 has a function for detecting overcurrent abnormalities, in which an overcurrent such as a short-circuit current or an overload current flows through the contacts, and opens the contacts when an overcurrent abnormality is detected. That is, when the main breaker 1 detects an overcurrent abnormality, it cuts off the power supply to the secondary circuit of the main breaker 1. The main breaker 1 may also have a limiter function that opens the contacts when a current exceeding a predetermined limit value flows. The main breaker 1 may also have a function for opening the contacts when it detects a ground fault current, an open-phase neutral state, or the like.

[0024] A single-phase three-wire electric wire W1 drawn in from a commercial power system CS is connected to the primary side terminal 11. More specifically, a power supply line of a first voltage pole (L1 phase) of the electric wire W1 is connected to the primary side terminal 11a. Furthermore, a power supply line of a second voltage pole (L2 phase) of the electric wire W1 is connected to the primary side terminal 11b. Furthermore, a power supply line of a neutral pole (N phase) of the electric wire W1 is connected to the primary side terminal 11c. In other words, commercial power is supplied to the primary side terminal 11.

[0025] Electrical conduction and interruption is established between primary side terminal 11a and secondary side terminal 12a via the contacts of main breaker 1. Electrical conduction and interruption is established between primary side terminal 11b and secondary side terminal 12b via the contacts of main breaker 1. Electrical conduction and interruption is established between primary side terminal 11c and secondary side terminal 12c via the contacts of main breaker 1. A first input terminal 21 of switch 2 is connected to secondary side terminal 12.

[0026] (2.1.2) Switch The switch 2 is disposed inside the cabinet C1 to the right of the main breaker 1. Three first input terminals 21 (see FIG. 2) are provided at the left end of the case 20 of the switch 2, and three output terminals 22 (see FIG. 2) are provided at the right end of the case 20 of the switch 2. Three second input terminals 23 (see FIG. 2) are provided at the bottom end of the case 20 of the switch 2. The switch 2 has a c-contact structure that electrically connects either the first input terminal 21 or the second input terminal 23 to the output terminal 22. In the following description, when it is necessary to distinguish between the three first input terminals 21, the three first input terminals 21 may be referred to as first input terminals 21a, 21b, and 21c, respectively. Similarly, when it is necessary to distinguish between the three output terminals 22, the three output terminals 22 may be referred to as output terminals 22a, 22b, and 22c, respectively. Similarly, when it is necessary to distinguish between the three second input terminals 23, the three second input terminals 23 may be referred to as second input terminals 23a, 23b, and 23c, respectively.

[0027] The contact mechanism shown in FIG. 3 is housed inside the case 20 of the switch 2. The contact mechanism of the switch 2 has three c contacts 24. Each c contact 24 includes two fixed contacts 241 and 242 and one movable contact 243. The movable contact 243 comes into contact with either the fixed contacts 241 or 242 depending on the energized state of the coil of the contact mechanism. Specifically, the movable contact 243 comes into contact with the fixed contact 241 when the coil is not energized, and comes into contact with the fixed contact 242 when the coil is energized. In the following description, when it is necessary to distinguish between the three c contacts 24, the three c contacts 24 will be referred to as c contacts 24a, 24b, and 24c, respectively.

[0028] At contact c 24a, fixed contact 241 is connected to first input terminal 21a, fixed contact 242 is connected to second input terminal 23a, and movable contact 243 is connected to output terminal 22a. At contact c 24b, fixed contact 241 is connected to first input terminal 21b, fixed contact 242 is connected to second input terminal 23b, and movable contact 243 is connected to output terminal 22b. At contact c 24c, fixed contact 241 is connected to first input terminal 21c, fixed contact 242 is connected to second input terminal 23c, and movable contact 243 is connected to output terminal 22c.

[0029] That is, when the movable contact 243 is in contact with the fixed contact 241, electrical continuity is established between the first input terminal 21 and the output terminal 22, and electrical disconnection is established between the second input terminal 23 and the output terminal 22. When the movable contact 243 is in contact with the fixed contact 242, electrical continuity is established between the second input terminal 23 and the output terminal 22, and electrical disconnection is established between the first input terminal 21 and the output terminal 22.

[0030] The first input terminal 21 is connected to the secondary terminal 12 of the main breaker 1. The output terminal 22 is connected to the conductive bar 3. The second input terminal 23 is electrically connected to the isolated output terminal T2 of the distributed power supply DS via an electric wire W3. That is, the switch 2 selectively supplies either commercial power supplied from the commercial power system CS or isolated power, which is power output from the isolated output terminal T2 of the distributed power supply DS, from the output terminal 22 to the conductive bar 3. The isolated power is supplied by a single-phase three-wire power distribution system.

[0031] In this embodiment, the commercial power system CS is connected to a fixed contact 241 of the c-contact 24 of the switch 2 via the main breaker 1, and the fixed contact 241 corresponds to a third connection part to which the system power supply (commercial power system CS) is connected. Also, in this embodiment, a distributed power source DS is connected to a fixed contact 242 of the c-contact 24 of the switch 2, and the fixed contact 242 corresponds to a second connection part to which the distributed power source DS is connected. Also, in this embodiment, a load L1 is connected to a movable contact 243 of the c-contact 24 of the switch 2 via the conductive bar 3 and the branch breaker 4, and the movable contact 243 corresponds to a first connection part to which the load L1 is connected. That is, the switch 2 according to this embodiment includes a first connection part (movable contact 243) to which the load L1 is connected, a second connection part (fixed contact 242) to which the distributed power source DS is connected, and a third connection part (fixed contact 241) to which the system power supply (commercial power system CS) is connected.

[0032] As shown in FIG. 3, the switch 2 further includes a control unit 25 and a voltage detection unit 26. As shown in FIG. 3, the voltage detection unit 26 detects a voltage (second voltage) applied to a fixed contact 242 (second connection portion) by a distributed power source DS. More specifically, the voltage detection unit 26 detects, for example, a voltage applied to the fixed contact 242 to which a power line of a second voltage pole (L2 phase) of the electric wire W3 is connected. That is, in this embodiment, the voltage detection unit 26 corresponds to a second voltage detection unit that detects the second voltage applied to the second connection portion (fixed contact 242). In short, the switch 2 according to this embodiment includes a second voltage detection unit (voltage detection unit 26) that detects the second voltage applied to the second connection portion (fixed contact 242).

[0033] The control unit 25 can be realized, for example, by a computer system having one or more processors and one or more memories. That is, the one or more processors execute a program recorded in one or more memories of the computer system, thereby functioning as the control unit 25. Here, the program is pre-recorded in the memory of the computer system, but it may also be provided via a telecommunications line such as the Internet, or may be provided by recording it on a non-transitory recording medium such as a memory card.

[0034] The control unit 25 switches the three c contacts 24 depending on whether or not there is a power outage in the commercial power system CS. In this embodiment, a voltage detection unit (not shown) that detects the voltage (system voltage) of the commercial power system CS may be installed either inside or outside the cabinet C1. The control unit 25 determines whether or not there is a power outage in the commercial power system CS based on the detection result of the voltage detection unit, and switches the three c contacts 24 based on the determination result.

[0035] Specifically, during normal operation when the commercial power system CS is not experiencing a power outage, the control unit 25 brings the movable contact 243 into contact with the fixed contact 241. That is, the switch 2 connects the first input terminal 21 and the output terminal 22, and disconnects the second input terminal 23 and the output terminal 22, thereby outputting the commercial power supplied from the commercial power system CS from the output terminal 22 to the conductive bar 3. The commercial power is supplied to the load L1 from the conductive bar 3 via the branch breaker 4 and the electric wire W4.

[0036] Furthermore, during a power outage in which the commercial power system CS is out, the control unit 25 brings the movable contact 243 into contact with the fixed contact 242. That is, the switch 2 connects the second input terminal 23 to the output terminal 22, disconnects the first input terminal 21 from the output terminal 22, and outputs the independent power supplied from the independent output terminal T2 of the distributed power source DS from the output terminal 22 to the conductive bar 3. The independent power is supplied to the load L1 from the conductive bar 3 via the branch breaker 4 and the electric wire W4.

[0037] Furthermore, the control unit 25 controls switching of the three c-contacts 24 based on the magnitude of the voltage detected by the voltage detection unit 26. As described above, the voltage detection unit 26 detects the voltage applied to the fixed contact 242 to which the power line of the second voltage pole (L2 phase) of the electric wire W3 is connected. In the present embodiment, as an example, the voltage detection unit 26 detects an overvoltage caused by a neutral conductor open-phase state. When the voltage detected by the voltage detection unit 26 exceeds a preset first threshold value in a state in which independent power is supplied from the distributed power source DS, the control unit 25 switches the connection destination of the movable contact 243 from the fixed contact 242 to the fixed contact 241. In the present embodiment, the fixed contact 241 (third connection portion) corresponds to another connection portion different from the fixed contact 242 (second connection portion). In other words, the other connection portion is the third connection portion (fixed contact 241).

[0038] When an overvoltage is detected at fixed contact 242 to which the power line of the second voltage pole (L2 phase) of electric wire W3 is connected, a low voltage (for example, a voltage less than 100 V) is applied to fixed contact 242 to which the power line of the first voltage pole (L1 phase) of electric wire W3 is connected. Therefore, when voltage detection unit 26 detects the voltage applied to fixed contact 242 to which the power line of the first voltage pole (L1 phase) of electric wire W3 is connected, control unit 25 can also determine that a neutral wire open-phase state has occurred when the detected voltage of voltage detection unit 26 falls below a second threshold value that is smaller than the first threshold value. Therefore, the switch 2 of the embodiment is equipped with a control unit 25 that switches the connection destination of the first connection part (movable contact 243) from the second connection part (fixed contact 242) to another connection part (fixed contact 241) different from the second connection part when the detected voltage of the voltage detection part 26 exceeds the first threshold value or when the detected voltage of the voltage detection part 26 falls below a second threshold value that is smaller than the first threshold value.

[0039] (2.1.3) Conductive Bar Each of the three conductive bars 3 is formed into a long plate shape using a conductive material. Each conductive bar 3 is arranged inside the cabinet C1 to the right of the switch 2 so as to extend in the left-right direction. In the following description, when it is necessary to distinguish between the three conductive bars 3, the three conductive bars 3 may be referred to as conductive bars 3a, 3b, and 3c, respectively.

[0040] Each of the three conductive bars 3 is connected to an output terminal 22 of the switch 2. More specifically, the left end of the conductive bar 3a is connected to the output terminal 22a, the left end of the conductive bar 3b is connected to the output terminal 22b, and the left end of the conductive bar 3c is connected to the output terminal 22c. That is, the conductive bar 3a is the first voltage pole (L1 phase), the conductive bar 3b is the second voltage pole (L2 phase), and the conductive bar 3c is the neutral pole (N phase).

[0041] (2.1.4) Branch breaker The plurality of branch breakers 4 are arranged in the cabinet C1 in front of the conductive bar 3 on the upper and lower sides, with a plurality of each on each side lined up in the left-right direction.

[0042] Each of the branch breakers 4 has a pair of primary terminals and a pair of secondary terminals. Each branch breaker 4 has contacts in the case 40 that electrically connect and disconnect the primary terminals and secondary terminals. Each branch breaker 4 also has an operating lever 41 on the front surface of the case 40 for turning the contacts on and off.

[0043] The branch breakers 4 are available for 100V and 200V. The pair of primary terminals of the 100V branch breaker 4 are connected to one of the conductive bars 3a of the first voltage pole and the conductive bar 3b of the second voltage pole, and to the neutral conductive bar 3c. The pair of primary terminals of the 200V branch breaker 4 are connected to the conductive bar 3a of the first voltage pole and the conductive bar 3b of the second voltage pole, respectively. A load L1 is electrically connected to the pair of secondary terminals of the branch breaker 4 via an electric wire W4. The load L1 includes, for example, electrical appliances such as lighting fixtures and hot water supply equipment, as well as wiring devices such as outlets and wall switches.

[0044] The branch breaker 4 has a function to detect an overcurrent abnormality, in which an overcurrent such as a short circuit current or an overload current flows through the contacts, and when an overcurrent abnormality is detected, the branch breaker 4 opens the contacts. In other words, when an overcurrent abnormality is detected, the branch breaker 4 cuts off the power supply to the load L1. As described above, the branch breaker 4 makes and breaks electrical conduction between the conductive bar 3 and the load L1.

[0045] (2.1.5) Grid-connected breaker The interconnection breaker 5 is disposed inside the cabinet C1 to the left of the main breaker 1. Three primary terminals 51 (see FIG. 2) are provided at the upper end of the case 50 of the interconnection breaker 5, and three secondary terminals 52 (see FIG. 2) are provided at the lower end of the case 50 of the interconnection breaker 5. In the following description, when it is necessary to distinguish between the three primary terminals 51, the three primary terminals 51 may be referred to as primary terminals 51a, 51b, and 51c, respectively. Similarly, when it is necessary to distinguish between the three secondary terminals 52, the three secondary terminals 52 may be referred to as secondary terminals 52a, 52b, and 52c, respectively.

[0046] The interconnection breaker 5 has contacts in a case 50 that electrically connect and disconnect between a primary terminal 51 and a secondary terminal 52. The interconnection breaker 5 also has an operating lever 53 on the front surface of the case 50 for turning the contacts on and off. The interconnection breaker 5 has a function to detect overcurrent abnormalities in which an overcurrent such as a short-circuit current or an overload current flows through the contacts, and opens the contacts when an overcurrent abnormality is detected. The interconnection breaker 5 may also have a function to open the contacts when it detects a leakage current, an open-phase neutral wire, or the like.

[0047] The primary side terminal 51 is electrically connected to a single-phase three-wire electric wire W1 of the commercial power system CS. More specifically, the primary side terminal 51a is electrically connected to a power supply line of a first voltage pole (L1 phase) of the electric wire W1. The primary side terminal 51b is electrically connected to a power supply line of a second voltage pole (L2 phase) of the electric wire W1. The primary side terminal 51c is electrically connected to a power supply line of a neutral pole (N phase) of the electric wire W1.

[0048] The secondary-side terminal 52 is electrically connected to the grid-connection output terminal T1 of the distributed power source DS via the electric wire W2. That is, when the contacts of the grid-connection breaker 5 are on, the power output from the grid-connection output terminal T1 of the distributed power source DS is supplied to the electric wire W1 as a grid-connection output. The distributed power source DS controls the power output from the grid-connection output terminal T1 so that it is connected to the commercial power grid CS. Furthermore, when the contacts of the grid-connection breaker 5 are off, the distributed power source DS is disconnected from the commercial power grid CS.

[0049] (2.1.6) Distributed power generation The distributed power source DS includes a power generation device or a power storage device. Examples of the power generation device include a solar power generation device, a wind power generation device, a hydroelectric power generation device, a biomass power generation device, a geothermal power generation device, a hydrogen-based power generation device, or a fossil fuel-based power generation device. The power storage device is not limited to a stationary type, but also includes a storage battery mounted on an electric vehicle. The distributed power source DS converts the power generated by the power generation device or the power discharged from the power storage device into single-phase three-wire power and outputs it from the grid-connected output terminal T1 or the isolated output terminal T2. The distributed power source DS outputs power connected to the commercial power grid CS from the grid-connected output terminal T1. If the contacts of the grid-connected breaker 5 are on, the power output from the grid-connected output terminal T1 is supplied to the electric wire W1 as a grid-connected output. The distributed power source DS also outputs isolated power from the isolated output terminal T2. If the switch 2 establishes electrical continuity between the second input terminal 23 and the output terminal 22, the isolated power is supplied to the conductive bar 3.

[0050] The distributed power source DS detects, for example, the voltage at the grid-connected output terminal T1 as the voltage (grid voltage) of the commercial power grid CS. The distributed power source DS determines whether or not the commercial power grid CS has experienced a power outage based on the grid voltage. Based on the determination result, the distributed power source DS controls the output of the grid-connected output terminal T1 and the output of the isolated output terminal T2.

[0051] Specifically, during normal times when the commercial power grid CS is not experiencing a power outage, the distributed power source DS outputs grid-connected output from the grid-connected output terminal T1 and does not output independent power from the independent output terminal T2. On the other hand, during a power outage when the commercial power grid CS is experiencing a power outage, the distributed power source DS outputs independent power from the independent output terminal T2 and does not output grid-connected output from the grid-connected output terminal T1.

[0052] (3) Switch operation (3.1) First action First, a first operation of the switch 2 according to the embodiment will be described. The first operation is an operation of switching the c contact 24 of the switch 2 in response to a power outage in the commercial power system CS.

[0053] During normal operation when the commercial power system CS is not experiencing a power outage, the control unit 25 of the switch 2 establishes conduction between the first input terminal 21 and the output terminal 22 and cuts off conduction between the second input terminal 23 and the output terminal 22. Commercial power from the commercial power system CS is supplied to a load L1 via the main breaker 1, the switch 2, the conductive bar 3, the branch breaker 4, and the electric wire W4. The load L1 operates on the commercial power. Furthermore, if the interconnection breaker 5 is on, the interconnection output output from the interconnection output terminal T1 of the distributed power source DS is supplied to the commercial power system CS via the interconnection breaker 5. The interconnection output is supplied to the load L1 via the main breaker 1, the switch 2, the conductive bar 3, the branch breaker 4, and the electric wire W4.

[0054] During a power outage in which the commercial power system CS is out of service, the control unit 25 of the switch 2 connects the second input terminal 23 to the output terminal 22 and disconnects the first input terminal 21 from the output terminal 22. The isolated power output from the isolated output terminal T2 of the distributed power source DS is supplied to the load L1 via the switch 2, the conductive bar 3, the branch breaker 4, and the electric wire W4. The load L1 operates on the isolated power. To efficiently and effectively utilize the isolated power, it is preferable to turn on only the branch breaker 4 to which the load L1 required during the power outage is connected, and to keep the other branch breakers 4 off.

[0055] (3.2)Second operation Next, a second operation of the switch 2 according to the embodiment will be described. The second operation is an operation of switching the contact c24 of the switch 2 based on the magnitude of the voltage detected by the voltage detection unit .

[0056] During a power outage in which the commercial power system CS is out of service, the control unit 25 of the switch 2 connects the second input terminal 23 to the output terminal 22 and cuts off the connection between the first input terminal 21 and the output terminal 22. The isolated power output from the isolated output terminal T2 of the distributed power source DS is supplied to the load L1 via the switch 2, the conductive bar 3, the branch breaker 4, and the electric wire W4. The load L1 operates on the isolated power.

[0057] When the detected voltage of the voltage detection unit 26 is greater than or equal to the second threshold and less than or equal to the first threshold, the control unit 25 of the switch 2 maintains a state in which conduction is established between the second input terminal 23 and the output terminal 22 and a state in which conduction is interrupted between the first input terminal 21 and the output terminal 22.

[0058] When the voltage detected by the voltage detection unit 26 exceeds the first threshold value or falls below the second threshold value, the control unit 25 of the switch 2 connects the first input terminal 21 to the output terminal 22 and disconnects the second input terminal 23 from the output terminal 22. In other words, when the control unit 25 detects an overvoltage caused by a neutral phase loss, it switches the connection destination of the load L1 from the distributed power source DS to the commercial power grid CS. This makes it possible to protect the load L1 even when a neutral phase loss occurs in the distributed power source DS.

[0059] (4) Effects As described above, the switch 2 according to the embodiment includes the voltage detection unit 26 that detects the voltage (second voltage) applied to the fixed contact 242 (second connection portion) by the distributed power source DS, and therefore does not require a configuration for detecting the voltage, separate from the switch 2. That is, the switch 2 according to the embodiment has the advantage that it does not require a configuration, separate from the switch 2, for detecting an abnormality occurring in the distributed power source DS.

[0060] In the switch 2 according to the embodiment, the other connection part is the third connection part (fixed contact 241). As a result, when an abnormality occurring in the distributed power source DS is detected, the connection destination of the first connection part (movable contact 243) is switched to the third connection part, so that it is possible to protect the load L1 from an abnormality (for example, an overvoltage) occurring in the distributed power source DS.

[0061] Furthermore, since the distribution board 100 and the power system 200 according to the embodiment are provided with the switch 2, there is an advantage in that a configuration separate from the switch 2 for detecting abnormalities occurring in the distributed power sources DS is not required.

[0062] (5) Variations The above-described embodiment is merely one of various embodiments of the present disclosure. The above-described embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Modifications of the above-described embodiment are listed below. The modifications described below can be applied in appropriate combinations.

[0063] (5.1) Variation 1 In the above-described embodiment, the switch 2 includes a voltage detection unit 26 (second voltage detection unit) that detects a voltage (second voltage) applied to the fixed contact 242 (second connection portion), as shown in Fig. 3. In contrast, the switch 2A according to Modification 1 includes a voltage detection unit 27 (first voltage detection unit) that detects a voltage (first voltage) applied to the movable contact 243 (first connection portion), as shown in Fig. 4. The switch 2A according to Modification 1 will be described below with reference to Fig. 4.

[0064] As shown in FIG. 4 , the switch 2A according to the first modification includes three c-contacts 24, a control unit 25, and a voltage detection unit 27. The voltage detection unit 27 detects, for example, a voltage applied to a movable contact 243 to which a power line of the second voltage pole (L2 phase) of the electric wire W3 is connected via a fixed contact 242. In the first modification, the voltage detection unit 27 also detects an overvoltage caused by a neutral conductor open-phase state. When the voltage detected by the voltage detection unit 27 exceeds a predetermined first threshold value while independent power is being supplied from the distributed power source DS, the control unit 25 switches the connection destination of the movable contact 243 from the fixed contact 242 to the fixed contact 241. In the first modification, the fixed contact 241 (third connection portion) corresponds to another connection portion different from the fixed contact 242 (second connection portion). That is, the other connection portion is the third connection portion (fixed contact 241).

[0065] Here, when an overvoltage is detected at the fixed contact 242 to which the power line of the second voltage pole (L2 phase) of the electric wire W3 is connected, a low voltage is applied to the fixed contact 242 to which the power line of the first voltage pole (L1 phase) of the electric wire W3 is connected. Therefore, when the voltage detection unit 27 detects the voltage applied to the fixed contact 242 to which the power line of the first voltage pole (L1 phase) of the electric wire W3 is connected, the control unit 25 can determine that a neutral conductor open-phase state has occurred when the detected voltage of the voltage detection unit 27 falls below a second threshold value that is smaller than the first threshold value. Therefore, the switch 2A according to the first modification includes the control unit 25 that switches the connection destination of the first connection unit (movable contact 243) from the second connection unit (fixed contact 242) to another connection unit (third connection unit) different from the second connection unit when the detected voltage of the voltage detection unit 27 exceeds the first threshold value or falls below a second threshold value that is smaller than the first threshold value.

[0066] The switch 2A according to the first modification, like the switch 2 according to the embodiment, has the advantage that a configuration for detecting an abnormality (e.g., overvoltage) occurring in the distributed power source DS is not required, separate from the switch 2. Furthermore, like the switch 2 according to the embodiment, the switch 2A according to the first modification can protect the load L1 from an abnormality occurring in the distributed power source DS. Furthermore, the switch 2A according to the first modification can also protect the load L1 from an abnormality (e.g., overvoltage) occurring in the commercial power system CS.

[0067] Furthermore, in the switch 2A according to the first modification, the voltage detection unit 27 detects the voltage applied to the fixed contact 241, and therefore can also detect a neutral phase loss state when commercial power is being supplied from the commercial power system CS.

[0068] In the first modification, the switch 2A may further include a voltage detection unit 26 in addition to the voltage detection unit 27. That is, the switch 2A according to the first modification may include both the voltage detection unit 27 (first voltage detection unit) that detects the voltage (first voltage) applied to the movable contact 243 (first connection portion) and the voltage detection unit 26 (second voltage detection unit) that detects the voltage (second voltage) applied to the fixed contact 242 (second connection portion).

[0069] (5.2) Variation 2 In the above-described embodiment, as shown in Fig. 3, a voltage detection unit 26 (second voltage detection unit) is provided that detects the voltage (second voltage) applied to the fixed contact 242 (second connection portion). In contrast, as shown in Fig. 5, a switch 2B according to Modification 2 further includes, in addition to the voltage detection unit 26, a voltage detection unit 28 (third voltage detection unit) that detects the voltage (third voltage) applied to the fixed contact 241 (third connection portion). Hereinafter, the switch 2B according to Modification 2 will be described with reference to Fig. 5.

[0070] 5, the switch 2B according to the second modification includes three c-contacts 24, a control unit 25, and two voltage detection units 26 and 28. The voltage detection unit 26 detects, for example, the voltage applied to a fixed contact 242 to which the power line of the second voltage pole (L2 phase) of the electric wire W3 is connected. The voltage detection unit 28 detects, for example, the voltage applied to a fixed contact 241 to which the power line of the second voltage pole (L2 phase) of the electric wire W1 is connected.

[0071] In the second modification, the voltage detection unit 26 detects, for example, an overvoltage caused by a neutral wire open-phase state. When the voltage detected by the voltage detection unit 26 exceeds a preset first threshold value in a state in which independent power is supplied from the distributed power source DS, the control unit 25 switches the connection destination of the movable contact 243 from the fixed contact 242 to the fixed contact 241. In the second modification, the fixed contact 241 (third connection portion) corresponds to another connection portion different from the fixed contact 242 (second connection portion). In other words, the other connection portion is the third connection portion (fixed contact 241).

[0072] Furthermore, in Modification 2, voltage detection unit 28 detects, for example, an overvoltage associated with a neutral wire open-phase state. When commercial power is supplied from commercial power system CS and the detected voltage of voltage detection unit 28 exceeds a preset third threshold, control unit 25 switches the connection destination of movable contact 243 from fixed contact 241 to fixed contact 242. In Modification 2, fixed contact 242 (second connection portion) corresponds to a specific connection portion different from fixed contact 241 (third connection portion). In other words, the specific connection portion is the second connection portion (fixed contact 242).

[0073] Here, when an overvoltage is detected at fixed contact 241 to which the power line of the second voltage pole (L2 phase) of electric wire W1 is connected, a low voltage (for example, a voltage less than 100 V) is applied to fixed contact 241 to which the power line of the first voltage pole (L1 phase) of electric wire W1 is connected. Therefore, when voltage detection unit 28 detects the voltage applied to fixed contact 241 to which the power line of the first voltage pole (L1 phase) of electric wire W1 is connected, control unit 25 can also determine that a neutral wire open-phase state has occurred when the detected voltage of voltage detection unit 28 falls below a fourth threshold value that is smaller than the third threshold value. That is, in switch 2B according to Modification 2, control unit 25 switches the connection destination of first connection unit (movable contact 243) from third connection unit (fixed contact 241) to a specific connection unit (second connection unit) different from the third connection unit when the detected voltage of voltage detection unit 28 exceeds the third threshold value or falls below a fourth threshold value that is smaller than the third threshold value. Also, switch 2B according to Modification 2 further includes voltage detection unit 28 (third voltage detection unit) that detects a third voltage applied to the third connection unit.

[0074] In the switch 2B according to the second modification, when the load L1 is connected to the distributed power source DS, the control unit 25 switches the connection destination of the movable contact 243 (first connection part) from the fixed contact 242 (second connection part) to the fixed contact 241 (third connection part) when the detected voltage of the voltage detection unit 26 exceeds the first threshold value or the detected voltage falls below the second threshold value.

[0075] In addition, in the switch 2B according to the second modification, when the load L1 is connected to the commercial power system CS, the control unit 25 switches the connection destination of the movable contact 243 (first connection part) from the fixed contact 241 (third connection part) to the fixed contact 242 (second connection part) when the detected voltage of the voltage detection unit 28 exceeds the third threshold value or the detected voltage falls below the fourth threshold value.

[0076] The switch 2B according to the second modification, like the switch 2 according to the embodiment, has the advantage that a configuration for detecting an abnormality (e.g., overvoltage) occurring in the distributed power source DS is not required, separate from the switch 2. Furthermore, the switch 2B according to the second modification, like the switch 2 according to the embodiment, can protect the load L1 from an abnormality occurring in the distributed power source DS. Furthermore, like the switch 2A according to the first modification, the switch 2B according to the second modification can protect the load L1 from an abnormality (e.g., overvoltage) occurring in the commercial power system CS.

[0077] (5.3) Variation 3 In the above-described embodiment, as shown in Fig. 3, each c contact 24 includes two fixed contacts 241, 242 and one movable contact 243. In contrast, in a switch 2C according to Modification 3, as shown in Fig. 6, each c contact 24 includes three fixed contacts 241, 242, 244 and one movable contact 243. The switch 2C according to Modification 3 will be described below with reference to Fig. 6.

[0078] As shown in Fig. 6, the switch 2C according to the third modification includes three c-contacts 24, a control unit 25, and a voltage detection unit 26. Each of the three c-contacts 24 includes three fixed contacts 241, 242, and 244, and a movable contact 243. As shown in Fig. 6, the fixed contact 244 is not connected to any of the load L1, the distributed power source DS, and the commercial power grid CS. That is, the switch 2C according to the third modification further includes a fourth connection unit (fixed contact 244) that is not connected to any of the load L1, the distributed power source DS, and the commercial power grid CS.

[0079] In the switch 2C according to the third modification, when the voltage detected by the voltage detector 26 exceeds the first threshold value or falls below a second threshold value that is smaller than the first threshold value in a state in which independent power is supplied from the dispersed power source DS, the controller 25 switches the connection destination of the movable contact 243 from the fixed contact 242 to the fixed contact 244. That is, in the switch 2C according to the third modification, the other connection part is the fourth connection part (fixed contact 244).

[0080] The switch 2C according to the third modification, like the switch 2 according to the embodiment, has the advantage that it does not require a configuration for detecting an abnormality (e.g., overvoltage) occurring in the distributed power source DS, separate from the switch 2. Furthermore, like the switch 2 according to the embodiment, the switch 2C according to the third modification can protect the load L1 from an abnormality occurring in the distributed power source DS.

[0081] (5.4) Other Modifications Other variations of the embodiment are listed below.

[0082] In the above embodiment, an open phase in the neutral conductor is exemplified as an abnormality in the distributed power source DS, but the abnormality in the distributed power source DS is not limited to an open phase in the neutral conductor, and may be, for example, a short circuit, an overload, or a leakage current.

[0083] In the above embodiment, the switch 2 is provided inside the cabinet C1 of the distribution board 100, but the switch 2 may be provided inside the housing of the distributed power source DS, for example.

[0084] In the above-described embodiment and modifications 1 and 2, a fourth connection part (fixed contact 244) may be provided. That is, each of the switch 2 according to the embodiment, the switch 2A according to modification 1, and the switch 2B according to modification 2 may further include a fourth connection part (fixed contact 244) that is not connected to any of the load L1, the distributed power source DS, and the commercial power system CS. In this case, the other connection part is the fourth connection part.

[0085] In the above-described embodiment and modifications 1 and 3, a voltage detection unit 28 (third voltage detection unit) may be further provided. That is, the switch 2 according to the embodiment, the switch 2A according to modification 1, and the switch 2C according to modification 3 may each further include a voltage detection unit 28 (third voltage detection unit) that detects a voltage (third voltage) applied to the fixed contact 241 (third connection portion). When the detected voltage of the voltage detection unit 28 exceeds a third threshold value or falls below a fourth threshold value that is lower than the third threshold value, the control unit 25 switches the connection destination of the movable contact 243 (first connection portion) from the fixed contact 241 (third connection portion) to the fixed contact 242 (second connection portion, specific connection portion). In this case, the specific connection portion is the fixed contact 242 (second connection portion).

[0086] (Aspect) The present specification discloses the following aspects.

[0087] The switch (2; 2A; 2B; 2C) according to the first aspect includes a first connection unit (243), a second connection unit (242), a third connection unit (241), voltage detection units (26; 27), and a control unit (25). A load (L1) is connected to the first connection unit (243). A distributed power source (DS) is connected to the second connection unit (242). A system power source (CS) is connected to the third connection unit (241). The voltage detection units (26; 27) are at least one of a first voltage detection unit (27) that detects a first voltage applied to the first connection unit (243) and a second voltage detection unit (26) that detects a second voltage applied to the second connection unit (242). The control unit (25) switches the connection destination of the first connection unit (243) from the second connection unit (242) to another connection unit (241; 244) different from the second connection unit (242) when the detected voltage of the voltage detection unit (26; 27) exceeds a first threshold value or when the detected voltage of the voltage detection unit (26; 27) falls below a second threshold value that is smaller than the first threshold value.

[0088] This embodiment has the advantage that there is no need for a configuration for detecting abnormalities occurring in the distributed generation (DS) apart from the switches (2; 2A; 2B; 2C).

[0089] In the switch (2; 2A; 2B) according to the second aspect, the other connection part (241) in the first aspect is the third connection part (241).

[0090] According to this aspect, by switching the connection destination of the first connection part (243) to the third connection part (241), it is possible to protect the load (L1) from an abnormality occurring in the distributed generation (DS).

[0091] The switch (2C) according to the third aspect is the same as the switch (2C) according to the first aspect, but further includes a fourth connection part (244). The fourth connection part (244) is not connected to any of the load (L1), the distributed power source (DS), and the system power source (CS). The other connection part (244) is the fourth connection part (244).

[0092] According to this aspect, by switching the connection destination of the first connection part (243) to the fourth connection part (244), it is possible to protect the load (L1) from an abnormality occurring in the distributed generation (DS).

[0093] A switch (2B) according to a fourth aspect is the same as any one of the first to third aspects, and further includes a third voltage detection unit (28). The third voltage detection unit (28) detects a third voltage applied to the third connection unit (241). When the voltage detected by the third voltage detection unit (28) exceeds a third threshold value or falls below a fourth threshold value that is lower than the third threshold value, the control unit (25) switches the connection destination of the first connection unit (243) from the third connection unit (241) to specific connection units (242; 244) different from the third connection unit (241).

[0094] This embodiment has the advantage that there is no need for a configuration for detecting an abnormality occurring in the system power supply (CS) apart from the switches (2; 2A; 2B; 2C).

[0095] In a switch (2B) according to a fifth aspect, the specific connection part (242) in the fourth aspect is the second connection part (242).

[0096] According to this embodiment, by switching the connection destination of the first connector (243) to the second connector (242), it is possible to protect the load (L1) from an abnormality occurring in the system power supply (CS).

[0097] A switch (2C) according to a sixth aspect is the fourth aspect, and further includes a fourth connection part (244). The fourth connection part (244) is not connected to any of the load (L1), the distributed power source (DS), and the system power source (CS). The specific connection part (244) is the fourth connection part (244).

[0098] According to this embodiment, by switching the connection destination of the first connector (243) to the fourth connector (244), it is possible to protect the load (L1) from an abnormality occurring in the system power supply (CS).

[0099] A distribution board (100) according to a seventh aspect includes a switch (2; 2A; 2B; 2C) according to any one of the first to sixth aspects and a cabinet (C1). The cabinet (C1) houses the switch (2; 2A; 2B; 2C).

[0100] This embodiment has the advantage that there is no need for a configuration for detecting abnormalities occurring in the distributed generation (DS) apart from the switches (2; 2A; 2B; 2C).

[0101] A power system (200) according to an eighth aspect includes a switch (2; 2A; 2B; 2C) according to any one of the first to sixth aspects, and a distributed power source (DS).

[0102] This embodiment has the advantage that there is no need for a configuration for detecting abnormalities occurring in the distributed generation (DS) apart from the switches (2; 2A; 2B; 2C).

[0103] The configurations according to the second to sixth aspects are not essential for the switches (2; 2A; 2B; 2C) and can be omitted as appropriate. [Explanation of symbols]

[0104] 2,2A,2B,2C switch 25 Control Unit 26 Voltage detection unit (second voltage detection unit) 27 Voltage detection unit (first voltage detection unit) 28 Voltage detection unit (third voltage detection unit) 100 Distribution board 200 Power Systems 241 Fixed contact (third connection, other connection) 242 Fixed contact (secondary connection, specific connection) 243 Movable contact (first connection part) 244 Fixed contacts (fourth connection, other connection, specific connection) C1 Cabinet CS Commercial power system (grid power supply) DS Distributed Power L1 load

Claims

1. a first connection portion to which a load is connected; a second connection portion to which the distributed power source is connected; a third connection part to which a system power supply is connected; a voltage detection unit that is at least one of a first voltage detection unit that detects a first voltage applied to the first connection part and a second voltage detection unit that detects a second voltage applied to the second connection part; a control unit that switches a connection destination of the first connection unit from the second connection unit to another connection unit different from the second connection unit when the detected voltage of the voltage detection unit exceeds a first threshold value or when the detected voltage of the voltage detection unit falls below a second threshold value that is smaller than the first threshold value, Switch.

2. The other connection portion is the third connection portion. The switch according to claim 1 .

3. a fourth connection part that is not connected to any of the load, the distributed power source, and the system power source; The other connection portion is the fourth connection portion. The switch according to claim 1 .

4. a third voltage detection unit that detects a third voltage applied to the third connection unit; the control unit switches the connection destination of the first connection unit from the third connection unit to a specific connection unit different from the third connection unit when the detected voltage of the third voltage detection unit exceeds a third threshold or when the detected voltage of the third voltage detection unit falls below a fourth threshold that is lower than the third threshold. The switch according to claim 1 .

5. the specific connection portion is the second connection portion, The switch according to claim 4 .

6. a fourth connection part that is not connected to any of the load, the distributed power source, and the system power source; the specific connection portion is the fourth connection portion, The switch according to claim 4 .

7. A switch according to any one of claims 1 to 6; a cabinet that houses the switch; Distribution board.

8. A switch according to any one of claims 1 to 6; The distributed power source. Power system.

Images