Power conditioner system

Abstract

To provide a power conditioner system capable of verifying details of an arc detection event by an arc detection device at a location remote from a site where the arc detection device is set.SOLUTION: The power conditioner system includes: a power conditioner for converting direct-current power output from a string into alternating-current power; and an arc detection device for detecting occurrence of an arc in an electric path connecting the string and the power conditioner. The arc detection device includes: a current sensor, an arc determination unit, a recording unit, and a communication unit. The current sensor detects a current flowing through the electric path. The arc determination unit outputs a first control signal for switching a switching device from a closed state to an open state when the arc determination unit determines that an arc has occurred. The recording unit records determination data used by the arc determination unit for determining occurrence of the arc. The communication unit transmits the determination result of the arc determination unit and the determination data when the arc determination unit determines that the arc has occurred.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a power conditioner system. [Background technology]

[0002] A power conditioner system equipped with an arc detection device is known. When the arc detection device determines that an arc is occurring, it activates a breaker via a breaker control unit, thereby interrupting the electrical path connecting the solar cell module and the power conditioner. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7117630 Summary of the Invention [Problem to be solved by the invention]

[0004] In a conventional power conditioner system, when a circuit connecting a solar cell module and a power conditioner is interrupted by a breaker, the cause must be identified at the site where the arc detection device is installed, and the administrator of the power conditioner system cannot verify the details of the arc detection event at a location away from the site where the arc detection device is installed. In other words, it is difficult for the administrator of the power conditioner system to immediately grasp the urgency and situation of the event at the site where the arc detection device is installed.

[0005] An object of the present invention is to provide a power conditioner system that makes it possible to verify the details of an event in which an arc is detected by an arc detection device at a location away from the site where the arc detection device is installed. [Means for solving the problem]

[0006] A power conditioner system according to one aspect of the present invention is a power conditioner system for outputting power output from at least one string including a plurality of solar cell modules to a load or a power grid. The power conditioner system includes a power conditioner, an arc detection device, and a switching device. The power conditioner converts DC power output from the at least one string into AC power. The arc detection device detects the occurrence of an arc in an electric circuit connecting the at least one string and the power conditioner. The switching device includes a switching unit and opens and closes the electric circuit. The at least one arc detection device includes a current sensor, an arc determination unit, a recording unit, and a communication unit. The current sensor detects a current flowing in the electric circuit. The arc determination unit determines the occurrence of an arc based on the detection result of the current sensor, and outputs a first control signal for switching the switching unit from a closed state to an open state when it determines that an arc has occurred. The recording unit records determination data used by the arc determination unit to determine the occurrence of an arc. The communication unit transmits the determination result and the determination data of the arc determination unit when the arc determination unit determines that an arc has occurred.

[0007] In this power conditioner system, the determination result of the arc determination unit and the determination data used by the arc determination unit to determine the occurrence of an arc are transmitted by the communication unit. As a result, for example, an administrator of the power conditioner system can receive the data transmitted from the communication unit and verify the details of the event in which the arc detection device detected an arc at a location away from the site where the arc detection device is installed.

[0008] The switching device may further include a control unit that controls the switching unit. The control unit may be capable of receiving a second control signal output from an external device for switching the switching unit from an open state to a closed state. In this case, for example, if an administrator examines the details of the event in which the arc detection device detected an arc and determines that the arc detection device malfunctioned, the administrator can operate the external device to send the second control signal to the control unit, thereby restoring the switching device.

[0009] The switching device may include a holding circuit for holding the switching unit in an open state. In this case, when the switching unit is switched from a closed state to an open state as determined by the arc determination unit, the open state of the switching unit can be held by the holding circuit.

[0010] The power conditioner may convert DC power output from multiple strings including a first string and a second string into AC power. The at least one arc detection device may include a first arc detection device that detects the occurrence of an arc in an electric circuit connecting the first string and the power conditioner, and a second arc detection device that detects the occurrence of an arc in a second electric circuit connecting the second string and the power conditioner. In this case, it is possible to shut off only the string in which an arc is detected, thereby reducing downtime of the power conditioner.

[0011] The determination result of the arc determination unit of the second arc detection device and the determination data recorded by the recording unit of the second arc detection device may be output via the communication unit of the first arc detection device. In this case, the communication line with the external device can be unified using the communication unit of the first arc detection device.

[0012] The current sensor of at least one of the arc detection devices may also serve as a current sensor for detecting the output current of the power conditioner, which can reduce the cost of the power conditioner system. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a power conditioner system that makes it possible to verify the details of an event in which an arc is detected by an arc detection device at a location away from the site where the arc detection device is installed. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a block diagram schematically illustrating a configuration of a power conditioner system. [Figure 2] FIG. 2 is a block diagram schematically illustrating the configuration of a first arc detection device. [Figure 3] FIG. 3 is a block diagram schematically showing the configuration of a first opening and closing device. [Figure 4] FIG. 10 is a block diagram schematically illustrating a configuration of a power conditioner system according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, a power conditioner system 1 according to an embodiment will be described with reference to the drawings. Fig. 1 is a block diagram schematically showing the configuration of the power conditioner system 1. The power conditioner system 1 is a system for outputting power output from at least one string including a plurality of solar cell modules to a load or a power grid.

[0016] The power conditioner system 1 includes a plurality of strings 2, a power conditioner 3, an arc detection device 4, and a switching device 5.

[0017] Each of the plurality of strings 2 has a plurality of solar cell modules connected in series. Each of the solar cell modules includes a plurality of solar cell cells (not shown) connected in series. The plurality of strings 2 constitute a solar cell array 10. The plurality of strings 2 are connected to a power conditioner 3 via a junction box 13. In this embodiment, the plurality of strings 2 include four strings, namely, first to fourth strings 2a to 2d.

[0018] The power conditioner 3 converts DC power output from the plurality of strings 2 into AC power and outputs the AC power. The power conditioner 3 is connected to a load and a power grid 8 (not shown).

[0019] The power conditioner 3 has a conventional configuration and includes circuits (not shown) such as a converter circuit, an inverter circuit, and a charge / discharge circuit. The power conditioner 3 also includes a linked operation circuit that controls connection with the power grid 8, and an independent operation circuit that supplies the AC voltage generated by the inverter circuit to a load when, for example, the power grid 8 experiences a power outage.

[0020] The arc detector 4 detects the occurrence of an arc in an electric path connecting the multiple strings 2 and the power conditioner 3. In this embodiment, the arc detector 4 is disposed in each output path of the strings 2a to 2d. That is, in this embodiment, the arc detector 4 includes four arc detectors, namely, first to fourth arc detectors 4a to 4d. The arc detector 4 is disposed in the connection box 13.

[0021] 2 is a block diagram showing a schematic configuration of first arc detector 4a. First arc detector 4a detects the occurrence of an arc in first electric circuit 30a connecting first string 2a and power conditioner 3.

[0022] First arc detection device 4 a includes current sensor 21 , amplifier 22 , filter 23 , A / D conversion unit 24 , arc determination unit 25 , recording unit 26 , and communication unit 27 .

[0023] The current sensor 21 detects the current flowing through the first electrical circuit 30a connecting the first string 2a and the power conditioner 3. The amplifier 22 amplifies the current detected by the current sensor 21. The filter 23 is a band-pass filter (BPF) that passes only current within a predetermined frequency range from the current output from the amplifier 22. For example, the frequency range passed by the filter 23 is 40 kHz to 100 kHz. The A / D converter 24 converts the analog current signal that has passed through the filter 23 into a digital signal and outputs the digital signal to the arc determination unit 25.

[0024] Arc determination unit 25 is a functional configuration realized by a CPU, and is realized by the CPU executing a program stored in a ROM, a RAM, etc. Arc determination unit 25 determines the occurrence of an arc in first electric circuit 30a based on the detection result of current sensor 21, and outputs a first control signal S1 for switching switchgear 5 from a closed state to an open state when it determines that an arc has occurred.

[0025] Arc determination unit 25 performs FFT on the digital signal output from A / D conversion unit 24 to generate a power spectrum of the current, and uses the generated power spectrum to determine whether an arc has occurred. Arc determination unit 25 may also use the frequency spectrum of the current signal obtained by Fourier transforming the time waveform of the current signal output from current sensor 21 to determine whether an arc has occurred.

[0026] Recording unit 26 is a non-volatile memory, such as an EEPROM. Recording unit 26 records determination data related to the determination result of arc determination unit 25. The determination data is data used by arc determination unit 25 to determine whether an arc has occurred. The determination data includes data related to the current signal output from current sensor 21 and data generated based on the current signal. The determination data includes, for example, the arc current value during the period in which it was determined that an arc has occurred, the FFT calculation value, the analysis results of the power spectrum, and data related to the number of times the occurrence of an arc has been detected.

[0027] When the arc determination unit 25 determines that an arc has occurred, the communication unit 27 transmits the determination result of the arc determination unit 25 and the determination data stored in the recording unit 26. The communication unit 27 transmits the determination result of the arc determination unit 25 and the determination data stored in the recording unit 26 to, for example, a management terminal 40 (an example of an external device) that manages the power conditioner system 1. In this case, the communication unit 27 is connected to the management terminal 40 so as to be able to communicate via wired or wireless communication using a serial communication method or the like. The determination result of the arc determination unit 25 and the determination data stored in the recording unit 26 may be transmitted from the communication unit 27 to the management terminal 40 via the power conditioner 3. The communication unit 27 may transmit the determination result of the arc determination unit 25 and the determination data stored in the recording unit to a communication terminal (an example of an external device) used by a user of the power conditioner system 1.

[0028] The second arc detector 4b detects the occurrence of an arc in the second electric circuit 30b connecting the second string 2b and the power conditioner 3. The third arc detector 4c detects the occurrence of an arc in the third electric circuit 30c connecting the third string 2c and the power conditioner 3. The fourth arc detector 4d detects the occurrence of an arc in the fourth electric circuit 30d connecting the fourth string 2d and the power conditioner 3.

[0029] The first to fourth arc detectors 4a to 4d have the same functional configuration except that they detect arcs in different strings, and therefore detailed description of the second to fourth arc detectors 4b to 4d will be omitted.

[0030] The switching devices 5 are arranged in the first to fourth electric circuits 30a to 30d, respectively. The switching devices 5 are relays or contactors. The switching devices 5 include first to fourth switching devices 5a to 5d.

[0031] 3 is a block diagram illustrating the configuration of the first switching device 5a. The first switching device 5a opens and closes the first electric circuit 30a. The first switching device 5a includes a switching unit 51 and a control unit 52. The switching unit 51 can be in a closed state in which the first string 2a is connected to the power conditioner 3, or in an open state in which the connection between the first string 2a and the power conditioner 3 is cut off.

[0032] The control unit 6 controls the switching unit 51. The control unit 52 is supplied with power from a control power supply 42. The control power supply 42 may be generated from power generated by a solar cell, or may also serve as the control power supply for the power conditioner 3. The control power supply for the power conditioner 3 may be supplied from the power grid 8, or may be generated from power generated by the multiple strings 2. In this embodiment, the arc detection device 4 is supplied with power from the control power supply 42.

[0033] The control unit 52 switches the switching unit 51 from a closed state to an open state in response to a first control signal S1 output from the arc determination unit 25. The control unit 6 is capable of receiving a second control signal S2 for switching the switching unit 51 from an open state to a closed state, which is output from the management terminal 40. The control unit 52 switches the switching unit 51 from an open state to an open state in response to the second control signal S2.

[0034] The first switching device 5a includes a holding circuit 53 for holding the switching unit 51 in an open state. The holding circuit 53 includes a latch relay. The switching unit 51 operates in conjunction with the latch relay. The control unit 52 outputs a signal for switching the latch relay from an on state to an off state in response to a first control signal S1 output from the arc determination unit 25. As a result, the latch relay turns off, switching the switching unit 51 from a closed state to an open state, and the holding circuit 53 holds the switching unit 51 in an open state. The control unit 52 outputs a signal for switching the latch relay from an off state to an on state in response to a second control signal S2. As a result, the latch relay turns on, switching the switching unit 51 from an open state to a closed state.

[0035] The second switching device 5b opens and closes the second electric circuit 30b. The third switching device 5c opens and closes the third electric circuit 30c. The fourth switching device 5d opens and closes the fourth electric circuit 30d. The first to fourth switching devices 5a to 5d have the same functions except that they open and close different electric circuits. Therefore, detailed description of the second to fourth switching devices 5b to 5d will be omitted.

[0036] In the above-described power conditioner system 1, the determination result of arc determination unit 25 and determination data used by arc determination unit 25 to determine the occurrence of an arc are transmitted by communication unit 27. As a result, for example, an administrator of power conditioner system 1 can receive the data transmitted from communication unit 27 and verify the details of the event in which the arc was detected by arc detection device 4 (e.g., determine the urgency, etc.) at a location remote from the site where arc detection device 4 is installed. Furthermore, if the administrator determines that arc detection device 4 has malfunctioned based on the data transmitted from communication unit 27, the administrator can restore the switch without going to the site where arc detection device 4 is installed.

[0037] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention.

[0038] The number of strings in the power conditioner system 1 may be one or more. The connection box 13 may be omitted. In this case, the arc detection device 4 and the switchgear 5 may be disposed in the power conditioner 3. In addition, the control power supply 42 and the management terminal 40 may be disposed in the power conditioner 3.

[0039] The arc detection device 4 may be configured to collectively detect the occurrence of arcs in a plurality of strings 2. The switchgear 5 may be configured by one switchgear including four switch units 51, for example.

[0040] The current sensor 21 may also serve as a current sensor that detects the output current of the power conditioner 3.

[0041] As shown in FIG. 4, the second arc detection device 4b may be communicatively connected to the first arc detection device 4a via wired or wireless communication using a serial communication system or the like. That is, the communication unit 27 of the second arc detection device 4b may be configured to be communicable with the first arc detection device 4a. In this case, the determination result of the arc determination unit 25 of the second arc detection device 4b and the determination data recorded by the recording unit 26 of the second arc detection device 4b may be output via the communication unit 27 of the first arc detection device 4a. The third arc detection device 4c and the fourth arc detection device 4d may also be communicatively connected to the first arc detection device 4a. The first arc detection device 4a functions as a master with respect to the second to fourth arc detection devices 4b to 4d, and the second to fourth arc detection devices 4b to 4d function as slaves with respect to the first arc detection device 4a. That is, the arc detection device 4a may be configured to monitor the second to fourth arc detection devices 4b to 4d. [Explanation of symbols]

[0042] 1: Power conditioner system, 2: String, 3: Power conditioner, 4: Arc detection device, 5: Switching device, 21: Current sensor, 25: Arc determination unit, 27: Communication unit, 51: Switching unit, 52: Control unit, 53: Holding circuit

Claims

1. A power conditioner system for outputting power output from at least one string including a plurality of solar cell modules to a load or a power grid, a power conditioner that converts DC power output from the at least one string into AC power; At least one arc detection device that detects an arc occurrence in an electric path connecting the at least one string and the power conditioner; a switching device including a switching unit for switching the electric circuit; Equipped with the at least one arc detection device; a current sensor for detecting a current flowing through the electrical path; an arc determination unit that determines the occurrence of an arc based on a detection result of the current sensor, and outputs a first control signal for switching the switching unit from a closed state to an open state when it determines that the arc has occurred; a recording unit that records determination data used by the arc determination unit to determine the occurrence of an arc; a communication unit that transmits the determination result and the determination data of the arc determination unit when the arc determination unit determines that the arc has occurred; Including, Power conditioner system.

2. The opening and closing device further includes a control unit that controls the opening and closing unit, the control unit is capable of receiving a second control signal output from an external device for switching the opening / closing unit from the open state to the closed state. The power conditioner system according to claim 1 .

3. The opening and closing device includes a holding circuit for holding the opening and closing unit in the open state. The power conditioner system according to claim 1 or 2.

4. The power conditioner converts DC power output from a plurality of strings including a first string and a second string into AC power; The at least one arc detection device includes a first arc detection device that detects an arc occurrence in an electric circuit that connects the first string and the power conditioner, and a second arc detection device that detects an arc occurrence in a second electric circuit that connects the second string and the power conditioner. The power conditioner system according to claim 1 or 2.

5. the determination result of the arc determination unit of the second arc detection device and the determination data recorded by the recording unit of the second arc detection device are output via the communication unit of the first arc detection device. The power conditioner system according to claim 4.

6. The current sensor of the at least one arc detection device also serves as a current sensor that detects an output current of the power conditioner. The power conditioner system according to claim 1 or 2.

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