DC Cable Monitoring System in Photovoltaic Power Generation Equipment

Abstract

Provided is a DC cable monitoring system in a photovoltaic power generation facility capable of determining whether an abnormality in a DC cable to be monitored is due to theft or a defect such as a failure. 【Solution means】A resistance value measuring means 20 capable of measuring the resistance value of a DC cable 6 connecting an aggregation unit 4 that aggregates DC power generated by a solar cell unit 3 and a power conditioner 5, and based on the normal resistance value NR of the DC cable 6, an abnormal resistance value setting means 30 for setting a first lower limit value L1 as the lower limit value of the normal resistance value and a second lower limit value L2 having a resistance value smaller than the first lower limit value L1; and when monitoring the cable, when the resistance value of the DC cable 6 is less than or equal to the first lower limit value L1 and greater than or equal to the second lower limit value L2, it is determined that a cut has occurred in the DC cable 6, and when it is less than the second lower limit value L2, an abnormal state determining means 50 for determining that a defect other than a cut has occurred in the DC cable 6 is provided.

Description

Technical Field

[0001] The present invention relates to a DC cable monitoring system in a photovoltaic power generation facility. More specifically, it relates to a DC cable monitoring system in a photovoltaic power generation facility that can determine whether an abnormality in a DC cable to be monitored is due to theft (cutting) or a defect such as a failure.

Background Art

[0002] Conventionally, for example, a technique as disclosed in Patent Document 1 is known.

[0003] <Patent Document 1> Japanese Patent Application Laid-Open No. 2016-131470 Patent Document 1 states that "An object is to provide an abnormality detection system for a photovoltaic power generation facility that can surely detect an abnormality such as theft even at night with a low cost and a simple system configuration." "In an abnormality detection system for a photovoltaic power generation facility including a lower unit that aggregates DC power generated by a solar cell unit and an upper unit that aggregates the DC power collected by the lower unit, the lower units are connected in parallel to the upper unit, and a measuring device for measuring impedance is provided in each wiring cable connecting each of these lower units and the upper unit. Further, upstream of each of these measuring units, a determination unit for detecting the abnormality based on the measurement result during non-generation of the solar cell unit is provided. In the measuring device, as the impedance, the combined impedance aggregated by all the lower units connected in parallel to the upper unit is measured." An abnormality detection system for a photovoltaic power generation facility is described (in the summary section of the same document).

[0004] Also, in paragraph 0030 of the same document, "(ST3) In the determination unit 12, the resistance values (R1 to R3) of the electric circuits aggregated by each lower unit are stored in advance as initial setting values. The determination unit 12 compares ···omitted in the middle···, and if Z1 = 1 / (1 / R1 + 1 / R2 + 1 / R3), it makes a normal determination (a determination that it is in a "normal state" without theft, failure, etc.), and here, the routine for abnormal detection is terminated. is described, and in the same paragraph 0031, “(ST4) In cases other than Z1 = 1 / (1 / R1 + 1 / R2 + 1 / R3), an abnormal determination is made and a warning display is performed.” is described.

[0005] That is, according to the technology described in this Patent Document 1, it is understood that it is possible to determine whether the electric circuit (wiring cable) to be determined is in a "normal state" without theft, failure, etc., or in an abnormal state.

[0006] However, with the technology described in this Patent Document 1, it is not possible to determine whether the abnormal state is due to theft or due to a failure or the like.

[0007]

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] The problem to be solved by the present invention is to provide a DC cable monitoring system in a photovoltaic power generation facility that can determine whether an abnormality in a DC cable to be monitored is due to theft or due to a defect such as a failure.

Means for Solving the Problems

[0010] In order to solve the above problems, the DC cable monitoring system in the photovoltaic power generation facility of the present invention a solar cell unit, an aggregation unit that aggregates the DC power generated by this solar cell unit, a power conditioner that converts the DC power from this aggregation unit into AC, in a solar power generation facility including a DC cable that connects the aggregation unit and the power conditioner, resistance value measuring means capable of measuring the resistance value of the DC cable connecting the aggregation unit and the power conditioner, abnormal resistance value setting means for setting a first lower limit value as the lower limit value of the normal resistance value and a second lower limit value that is a resistance value smaller than this first lower limit value, based on the normal resistance value of the DC cable measured by this resistance value measuring means, when monitoring the cable, when the resistance value of the DC cable measured by the resistance value measuring means is less than or equal to the first lower limit value and greater than or equal to the second lower limit value, it is determined that a cut has occurred in the DC cable, and when it is less than the second lower limit value, it is determined that a problem other than a cut has occurred in the DC cable, abnormal state determination means, power conditioner position information storage means for storing the installation position of the power conditioner as power conditioner position information including at least latitude and longitude, a drone equipped with a camera capable of flying to the installation position of the power conditioner based on the power conditioner position information stored in this power conditioner position information storage means as a destination and capable of taking an image of the periphery of the installation position of the power conditioner including the DC cable connected to the power conditioner, and image transmission means capable of transmitting the image taken by this camera, characterized by comprising.

[0011] Since it has the above configuration, the following operational effects can be obtained according to the DC cable monitoring system in this solar power generation facility.

[0012] The resistance value measuring means can measure the resistance value of the DC cable connecting the aggregation unit and the power conditioner. Based on the normal resistance value of the DC cable measured by the resistance value measuring means, the abnormal resistance value setting means sets a first lower limit value as the lower limit value of the normal resistance value and a second lower limit value which is a resistance value smaller than the first lower limit value. During cable monitoring, the abnormal state determination means makes the following determination. (a) When the resistance value of the DC cable measured by the resistance value measuring means is less than or equal to the first lower limit value and greater than or equal to the second lower limit value, it is determined that a break has occurred in the DC cable. (b) When the resistance value of the DC cable measured by the resistance value measuring means is less than the second lower limit value, it is determined that a problem other than a break has occurred in the DC cable.

[0013] Therefore, according to the DC cable monitoring system in this photovoltaic power generation facility, it is possible to determine whether the abnormality of the DC cable to be monitored is due to theft (cutting) or a problem such as a failure (for example, a problem such as a connection cable ground fault or an accident due to flooding). Furthermore, the DC cable monitoring system in this photovoltaic power generation facility includes a power conditioner position information storage means for storing the installation position of the power conditioner as power conditioner position information including at least latitude and longitude, a drone equipped with a camera capable of flying to the installation position of the power conditioner based on the power conditioner position information stored in the power conditioner position information storage means as the destination and capable of taking an image of the periphery of the installation position of the power conditioner including the DC cable connected to the power conditioner, and an image transmission means capable of transmitting the image taken by this camera, Since it is equipped with [the relevant device], the drone is made to fly to the installation location of the power conditioner to which the abnormal DC cable is connected, and the video around the installation location of the power conditioner including the DC cable is taken, so that it is possible to visually determine in real time whether the abnormality of the DC cable is due to theft (cutting) or a malfunction such as a failure (for example, a problem such as a connection cable ground fault or an accident due to submersion, etc.). Since the countermeasures in the case where the abnormality of the DC cable is due to theft are different from those in the case of a malfunction such as a failure, according to the present invention, appropriate countermeasures can be taken.

[0014] In addition, in order to solve the above problems, the DC cable monitoring system in the solar power generation facility of the present invention is a solar cell unit, a plurality of aggregation units that aggregate the DC power generated by this solar cell unit, a power conditioner that aggregates the DC power from these plurality of aggregation units, in a solar power generation facility including a plurality of DC cables that respectively connect the plurality of aggregation units and the power conditioner, resistance value measuring means capable of measuring the resistance value of the entire plurality of DC cables connecting each aggregation unit and the power conditioner; abnormal resistance value setting means for setting a first lower limit value as the lower limit value of the normal resistance value and a second lower limit value that is a resistance value smaller than the first lower limit value, based on the normal resistance value of the entire DC cable measured by this resistance value measuring means; abnormal state determination means for determining that a cut has occurred in the DC cable when the resistance value of the entire DC cable measured by the resistance value measuring means during cable monitoring is less than or equal to the first lower limit value and greater than or equal to the second lower limit value, and determining that a malfunction other than a cut has occurred in the DC cable when it is less than the second lower limit value; Power conditioner position information storage means for storing the installation position of each of the plurality of power conditioners as power conditioner position information including at least latitude and longitude. A drone equipped with a camera capable of flying to the installation position of the power conditioner based on the power conditioner position information stored in the power conditioner position information storage means as a destination and capable of taking an image of the periphery of the installation position of the power conditioner including the DC cable connected to the power conditioner, and an image transmission means capable of transmitting the image taken by this camera. It is characterized by comprising the above.

[0015] Since it has the above configuration, the following operational effects can be obtained according to the DC cable monitoring system in this photovoltaic power generation facility.

[0016] The resistance value measuring means can measure the resistance value of the entire DC cable connecting the aggregation unit and the power conditioner. The abnormal resistance value setting means sets a first lower limit value as the lower limit value of the normal resistance value and a second lower limit value smaller than the first lower limit value based on the normal resistance value of the entire DC cable measured by the resistance value measuring means. During cable monitoring, the abnormal state determination means makes the following determination. (a) When the resistance value of the entire DC cable measured by the resistance value measuring means is less than or equal to the first lower limit value and greater than or equal to the second lower limit value, it is determined that a break has occurred in the DC cable. (b) When the resistance value of the entire DC cable measured by the resistance value measuring means is less than the second lower limit value, it is determined that a problem other than a break has occurred in the DC cable.

[0017] Therefore, according to the DC cable monitoring system in this solar power generation facility, it is possible to determine whether the abnormality of the DC cable to be monitored is due to theft (cutting) or due to malfunctions such as failures (for example, malfunctions such as ground fault of the connection cable or accidents due to flooding, etc.). Furthermore, the DC cable monitoring system in this solar power generation facility a power conditioner position information storage means for storing the installation position of each of the plurality of power conditioners as power conditioner position information including at least latitude and longitude, a drone equipped with a camera capable of flying to the installation position of the power conditioner based on the power conditioner position information stored in the power conditioner position information storage means as a destination and capable of taking an image of the periphery of the installation position of the power conditioner including the DC cable connected to the power conditioner, and an image transmission means capable of transmitting the image taken by this camera, is provided. Therefore, by flying the drone to the installation position of the power conditioner to which the abnormal DC cable is connected as the destination and taking an image of the periphery of the installation position of the power conditioner including the DC cable, it is possible to visually determine in real time whether the abnormality of the DC cable is due to theft (cutting) or due to malfunctions such as failures (for example, malfunctions such as ground fault of the connection cable or accidents due to flooding, etc.). Since the countermeasures in the case where the abnormality of the DC cable is due to theft are different from the countermeasures in the case of malfunctions such as failures, according to the present invention, appropriate countermeasures can be taken.

[0018] In the DC cable monitoring system in this solar power generation facility, furthermore, when the abnormality determination means determines that a cut has occurred in the DC cable, an alarm transmission means for transmitting a cut occurrence alarm indicating that the DC cable has been cut, and when it is determined that a malfunction other than a cut has occurred in the DC cable, a malfunction occurrence alarm indicating that a malfunction has occurred in the DC cable is transmitted, When the abnormal state determination means determines that a disconnection has occurred in the DC cable, or when it determines that a problem other than disconnection has occurred in the DC cable, for the drone, the flight instruction means that instructs the drone to fly to the installation position of the power conditioner where it is determined that a disconnection has occurred in the DC cable or a problem other than disconnection has occurred. It can be configured to include. With this configuration, the alarm transmission means can issue an alarm indicating that an abnormality has occurred in the DC cable to be monitored and whether the abnormality is due to theft (disconnection) or a problem such as a malfunction (for example, a problem such as a connection cable grounding or an accident due to flooding). At the same time, the flight instruction means causes the drone to fly to the installation position of the power conditioner where it is determined that a disconnection has occurred in the DC cable or a problem other than disconnection has occurred, and by taking an image of the vicinity of the installation position of the power conditioner including the DC cable, it is possible to visually determine in real time whether the abnormality of the DC cable is due to theft (disconnection) or a problem such as a malfunction (for example, a problem such as a connection cable grounding or an accident due to flooding).

[0019] In this DC cable monitoring system for a solar power generation facility, At least the resistance value measuring means, the abnormal state determination means, and the alarm transmission means are incorporated in the power conditioner. Furthermore, it is provided at a location separated from the power conditioner, and includes a management device that wirelessly receives the disconnection occurrence alarm or problem occurrence alarm from the alarm transmission means and the image from the drone. This management device can be configured to transmit the above alarms and images to a predetermined notification destination. With this configuration, it becomes possible to immediately take appropriate measures corresponding to the problem for the cable where the problem has occurred.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments of a DC cable monitoring system in a photovoltaic power generation facility according to the present invention will be described with reference to the drawings. In each figure, the same parts or corresponding parts are denoted by the same reference numerals.

[0022] As shown in FIG. 1, the DC cable monitoring system 1 in the photovoltaic power generation facility of this embodiment includes a solar cell unit 3, a plurality of aggregation units 4 that aggregate the DC power generated by this solar cell unit 3, a power conditioner 5 that aggregates the DC power from these plurality of aggregation units 4, and a plurality of DC cables 6 that connect the plurality of aggregation units 4 and the power conditioner 5 respectively, and is applicable to a photovoltaic power generation facility 2. Note that, as will be described later, it is also applicable when there is only one DC cable 6 instead of a plurality of DC cables.

[0023] As also shown in FIG. 2, the DC cable monitoring system 1 in the photovoltaic power generation facility of this embodiment includes resistance value measuring means 20 capable of measuring the resistance value of the entire plurality of DC cables 6T connecting each aggregation unit 4 and the power conditioner 5, abnormal resistance value setting means 30 that sets, based on the normal resistance value NRT of the entire DC cable 6T measured by this resistance value measuring means 20, a first lower limit value L1T as the lower limit value of the normal resistance value, and a second lower limit value L2T that is a resistance value smaller than this first lower limit value, When monitoring the cable, when the resistance value of the entire DC cable 6T measured by the resistance value measuring means 20 is equal to or less than the first lower limit value L1T and equal to or greater than the second lower limit value L2T, it is determined that a break has occurred in one or more of the DC cables 6. When it is less than the second lower limit value L2T, an abnormality state determination means 50 that determines that a failure other than a break has occurred in one or more of the DC cables 6, Power conditioner position information storage means (storage means) 42 that stores the installation positions P(1 to n) of the plurality of power conditioners 5 as power conditioner position information PI including at least latitude and longitude, A drone (flying object that flies independently upon receiving an instruction) 300 equipped with a camera 301 (FIG. 3) that can fly to the installation position P(1 to n) of the power conditioner 5 based on the power conditioner position information PI stored in the power conditioner position information storage means 42 and can capture an image of the periphery of the installation position of the power conditioner 5 including the DC cable 6 connected to the power conditioner 5, and an image transmission means 302 (FIG. 3) that can transmit the image captured by the camera 301, is provided.

[0024] This system 1 further includes, When the abnormality state determination means 50 determines that a break has occurred in the DC cable 6, an alarm transmission means 60 that transmits a break occurrence alarm CA indicating that the DC cable 6 has been broken, and when it is determined that a failure other than a break has occurred in the DC cable 6, transmits a failure occurrence alarm FA indicating that a failure has occurred in the DC cable 6, When the abnormality state determination means 50 determines that a break has occurred in the DC cable 6, or when it is determined that a failure other than a break has occurred in the DC cable 6, a flight instruction means 80 that instructs the drone 300 to fly to the installation position P(1 to n) of the power conditioner 5 where it is determined that a break has occurred or a failure other than a break has occurred in the DC cable 6, is provided.

[0025] In this system 1, the resistance value measuring means 20, the abnormal state determination means 50, and the alarm transmitting means 60 are configured as a unit 110 and incorporated in the power conditioner 5 (see FIG. 1).

[0026] This system 1 is installed at a location separated from the power conditioner 5, and includes a management device 100 that wirelessly receives a disconnection occurrence alarm CA or a malfunction occurrence alarm FA from the alarm transmitting means 60 and an image (image signal) V from the drone 300. This management device 100 transmits the above-mentioned alarm and image to a predetermined notification destination 200.

[0027] With the above configuration, the following operational effects can be obtained according to the DC cable monitoring system in this photovoltaic power generation facility.

[0028] The resistance value measuring means 20 can measure the resistance value of the entire DC cable 6T connecting the aggregation unit 4 and the power conditioner 5.

[0029] Based on the normal resistance value NRT of the entire DC cable 6T measured by the resistance value measuring means 20, the abnormal resistance value setting means 30 sets a first lower limit value L1T as the lower limit value of the normal resistance value and a second lower limit value L2T that is smaller than the first lower limit value L1T.

[0030] During cable monitoring, the abnormal state determination means 50 makes the following determination.

[0031] (a) When the resistance value RT of the entire DC cable 6T measured by the resistance value measuring means 20 is less than or equal to the first lower limit value L1T and greater than or equal to the second lower limit value L2T, it is determined that a disconnection has occurred in one or more of the DC cables 6.

[0032] When the resistance value RT of the entire DC cable 6T measured by the resistance measurement means 20 is less than the second lower limit value L2T, it is determined that a problem other than a cut has occurred in one or more of the DC cables 6.

[0033] Therefore, according to the DC cable monitoring system in this photovoltaic power generation facility, it is possible to determine whether the abnormality of the DC cable 6 to be monitored is due to theft (cutting) or due to problems such as failures (for example, problems such as connection cable grounding or accidents due to flooding, etc.). Furthermore, the DC cable monitoring system in this photovoltaic power generation facility Power conditioner position information storage means 42 that stores the installation positions P(1~n) of each of the plurality of power conditioners 5 as power conditioner position information PI including at least latitude and longitude, A drone 300 equipped with a camera 301 that can fly to the installation positions P(1~n) of the power conditioner as the destination based on the power conditioner position information PI stored in the power conditioner position information storage means 42 and can capture an image V of the periphery of the installation position of the power conditioner 5 including the DC cable 6 connected to the power conditioner 5, and an image transmission means 302 that can transmit the image V captured by the camera 301, Since it is provided with, the drone 300 is flown to the installation positions P(1~n) of the power conditioner 5 to which the abnormal DC cable 6 is connected as the destination, and the image of the periphery of the installation position of the power conditioner 5 including the DC cable 6 is captured, so that it is possible to visually determine in real time whether the abnormality of the DC cable 6 is due to theft (cutting) or due to problems such as failures (for example, problems such as connection cable grounding or accidents due to flooding, etc.).

[0034] Since the countermeasures in the case where the abnormality of the DC cable 6 is due to theft are different from the countermeasures in the case of problems such as failures, according to this system, appropriate countermeasures can be taken promptly.

[0035] Since the DC cable monitoring system in this photovoltaic power generation facility further includes the alarm transmitting means 60, the alarm transmitting means 60 can issue an alarm indicating that an abnormality has occurred in the DC cable 6 to be monitored, and whether the abnormality is caused by theft (cutting) or a malfunction such as a fault. That is, it can transmit a cutting occurrence alarm CA or a malfunction occurrence alarm FA. At the same time, the flight instruction means 80 causes the drone 300 to fly to the installation position P(1 - n) of the power conditioner 5 where it is determined that a cut has occurred in the DC cable 6 or a malfunction other than cutting has occurred, and images around the installation position of the power conditioner 5 including the DC cable 6 are taken, enabling real-time visualization and determination of whether the abnormality of the DC cable is caused by theft (cutting) or a malfunction such as a fault (for example, a fault such as a connection cable ground fault or an accident such as waterlogging).

[0036] Also, in the DC cable monitoring system of this photovoltaic power generation facility, at least the resistance value measuring means 20, the abnormal state determination means 50, and the alarm transmitting means 60 are incorporated into the power conditioner 5. Further, a management device 100 is installed at a location separated from the power conditioner 5. This management device 100 wirelessly receives the cutting occurrence alarm CA or the malfunction occurrence alarm FA from the alarm transmitting means 60 and the image V from the drone 300, and transmits these alarms and images to a predetermined notification destination 200, enabling immediate and appropriate measures to be taken for the cable 6 with the problem.

[0037] This will be further described in detail below. The solar cell unit 3 can be composed of a known group of solar panels. Each aggregation unit 4 can be composed of a known appropriate aggregation unit, for example, a known junction box.

[0038] Each solar cell unit 3 and the aggregation unit 4 are connected by a known DC cable 3c. The DC power generated by the solar cell unit 3 is aggregated to each aggregation unit 4 through this DC cable 3c. This DC cable 3c is a thinner cable compared to the DC cable 6.

[0039] The power conditioner 5 can be configured by a known appropriate power conditioner. In this embodiment, it is configured by a central type power conditioner.

[0040] Each aggregation unit 4 and the power conditioner 5 are connected by a known DC cable 6, and the DC power from each aggregation unit 4 is aggregated to the power conditioner 5 through this DC cable 6. This DC cable 6 is a thicker cable compared to the DC cable 3c.

[0041] Both the DC cable 3c and the DC cable 6 have a current flow of approximately 0V after sunset. However, since the DC cable 6 is a thicker cable compared to the DC cable 3c, it is more likely to be a target of theft compared to the DC cable 3c. Even when the DC cable 3c is cut (stolen), the measured resistance value of the DC cable 6 changes. Therefore, according to this system, as a result, even when the DC cable 3c is stolen, it can be detected.

[0042] The power of the power conditioner 5 will be supplied to a predetermined facility through the AC cable 5c and the associated facility 7. However, since an AC voltage of about 380 - 600V is applied to the AC cable 5c except during a power outage, it is less likely to be a target of theft.

[0043] In FIG. 2, 6(1), 6(2), ··· 6(n) are the aforementioned DC cables 6. Relay 21(1 - n) is connected to each of these DC cables 6, and a resistance value measuring device 24 is connected via relay 21(1 - n). Note that 6f is the terminal of cable 6, and 6b is the connection terminal block.

[0044] 22 is a PCS input voltage measuring means for measuring the input voltage to the power conditioner 5, and measures the input voltage to the power conditioner 5 by being connected to an appropriate position of the power conditioner 5.

[0045] 23 is a relay operation control means for controlling the operation of the above relay 21(1~n), inputs the measurement result from the PCS input voltage measuring means 22, and when the voltage nV which is the measurement result becomes almost 0 (that is, when the power generation by the solar cell unit 3 becomes almost 0 due to sunset), sequentially operates the above relay 21(1~n) to sequentially connect each DC system cable 6(1~n) to the resistance value measuring device 24, and issues a relay operation signal to each relay 21(1~n) to cause the resistance value measuring device 24 to measure the resistance value R(1~n) of each DC system cable 6(1~n).

[0046] Due to the operation of the above relay 21(1~n), the resistance values R(1~n) of the DC system cables 6(1~n) sequentially measured by the resistance value measuring device 24 are sequentially sent from the resistance value measuring device 24 to the control unit 81, and the control unit 81 accumulates these resistance values R(1~n) and determines the cumulative value as the resistance value RT of the entire plurality of DC cables 6.

[0047] Prior to cable monitoring, the abnormal resistance value setting means 30 is based on the normal resistance value NRT of the resistance value RT of the entire plurality of DC cables 6 measured by the resistance value measuring means 20, and sets a first lower limit value L1T as the lower limit value of the normal resistance value, and a second lower limit value L2T which is a resistance value smaller than the first lower limit value L1T. These first lower limit value L1T and second lower limit value L2T are stored in the storage unit 41 via, for example, the transmission and reception means 71, 72, and the control unit 81 described later.

[0048] Specifically, for example, when the normal resistance value NRT of the total resistance value RT of the plurality of DC cables 6 measured by the resistance value measuring means 20 is 6 MΩ, based on this 6 MΩ, a first lower limit value L1T as the lower limit value of the normal resistance value is set to, for example, 5 MΩ, and a second lower limit value L2T, which is a resistance value smaller than the first lower limit value L1T, is set to, for example, 100 Ω. As described above, these values are stored in the storage unit 41.

[0049] During cable monitoring (at sunset), due to the operation of the relays 21(1~n), the resistance values R(1~n) of the DC cables 6(1~n) sequentially measured by the resistance measuring device 24 are accumulated by the control unit 81, and the accumulated value is determined as the total resistance value RT of the plurality of DC cables 6 and sent to the abnormal state determination means 50.

[0050] When the abnormal state determination means 50 determines that the total resistance value RT of the DC cables 6 is less than or equal to the first lower limit value L1T set by the abnormal resistance value setting means 30 and greater than or equal to the second lower limit value L2T, it determines that a break has occurred in one or more of the DC cables 6. When it is less than the second lower limit value L2T, it determines that a malfunction other than a break has occurred in the DC cable 6.

[0051] For example, when the abnormal state determination means 50 determines that the total resistance value RT of the DC cables 6 is 5 MΩ, it determines that the DC cable 6 has been cut. When it is 0 Ω, it determines that a malfunction other than a break has occurred in the DC cable 6. This determination signal is sent to the alarm transmitting means 60(61) and sent to the management device 100 of this system 1 via the transmission and reception means 71.

[0052] The alarm transmitting means 60 receives the determination signal from the abnormal state determination means 50. When the abnormal state determination means 50 determines that the DC cable 6 has been cut, it transmits a break occurrence alarm CA indicating that the cable has been cut. When it determines that a malfunction other than a break has occurred in the DC cable 6, it transmits a malfunction occurrence alarm FA indicating that a malfunction has occurred in the cable 6.

[0053] In this embodiment, the resistance value measuring means 20, the abnormal state determination means 50, the alarm transmitting means 61(60), and the transmission / reception means 71 described above are configured as a unit 110 and incorporated into the power conditioner 5 (see FIG. 1).

[0054] The management device 100 includes unit identification information providing means 10. The unique unit identification information UI for each of the provided units 110 by this unit identification information providing means 10 is stored in the storage unit 41 for each unit 110 via the transmission / reception means 71, 72 and the control means 81 for each unit 110, and is also stored in the storage means 42 provided in the management device 100 via the control means (CPU) 82 provided in the management device 100.

[0055] In this embodiment, the power conditioner position information PI including at least latitude and longitude is formed as a part of the unique unit identification information UI for each unit 110. Therefore, the storage means 42 provided in the management device 100 constitutes power conditioner position information storage means for storing the installation positions P(1 to n) of each power conditioner 5 as power conditioner position information PI including at least latitude and longitude. Note that altitude information to be reached by the drone 300 can be included as the power conditioner position information PI.

[0056] The signal from the alarm transmitting means 61 is sent to the transmission / reception means 72 provided in the management device 100 of this system 1 via the transmission / reception means 71 together with the unit identification information UI (that is, the identification information of the unit to which the cable 6 where disconnection or malfunction has occurred is connected). Both of these transmission / reception means 71, 72 can be configured by known transmission / reception means operable in a wireless communication environment (including a wireless LAN, Wi-Fi environment).

[0057] The unit 110 is provided with control means (for example, MCU) 81 for controlling the above-described respective means 22, 23, 24, 50, 61, 71 within the unit 110.

[0058] The management device 100 can be configured as a known personal computer including a control means (e.g., CPU) for controlling each means of the device 100, and input means (not shown) such as a keyboard and a mouse, and a display (not shown).

[0059] When the management device 100 receives the unit identification information UI(1~n) including the above power conditioner position information PI and the malfunction occurrence alarm FA (or disconnection occurrence alarm CA) from the unit 110, it transmits these alarms to a predetermined notification destination (e.g., a failure response department, a theft response department, etc.) 200, and at the same time, the flight instruction means 80 instructs the drone 300 via the transmission / reception means 72 to fly to the installation position P(1~n) of the power conditioner 5 where the above malfunction occurrence alarm FA (or disconnection occurrence alarm CA) is issued as the destination.

[0060] The basic configuration of the drone 300 itself can be configured as a known drone with a GPS function. In addition to the above basic configuration, the drone 300 of this embodiment includes a position information storage unit 303 that stores at least the power conditioner position information PI (installation position P(1~n)) and the position information of the storage to be described later, which are given from the management device 100, a transmission / reception means 304 that enables the transmission and reception of various information including video signals between the management device 100 and the storage 400 to be described later, and a control means 305 that controls these respective parts (including the respective parts to be described later). When receiving a flight instruction to the installation position P(any one of 1~n) of the power conditioner 5 from the above flight instruction means 80, it reads out the information of the destination corresponding to the flight command (e.g., the installation position P(1) of the power conditioner 5(1)) from the position information storage unit 303 and flies toward the installation position.

[0061] The drone 300 has a comparison and determination means 306 that compares the current position of the drone with the installation position and determines that the destination has been reached when both positions reach within a predetermined range (for example, within a range of 1 m in terms of both latitude, longitude and distance conversion). When the comparison and determination means 306 determines that the destination has been reached, the control means 305 activates the camera 301 based on the arrival signal. The camera 301 is composed of a camera having a moving object detection function. The camera 301 captures an image V around the installation position of the power conditioner 5 and sends the image (image signal) V to the management device 100. The management device 100 sends this image to a predetermined notification destination 200. This enables the visualization of the cable situation where a problem has occurred in real time and appropriate countermeasures can be taken accordingly. Note that the image (image signal) V from the camera 301 may be directly sent to a predetermined notification destination 200 without passing through the management device 100.

[0062] This DC cable monitoring system 1 includes a storage (storage box) 400 for storing the drone 300. As shown in FIG. 3, the storage 400 includes a storage body 401, a door 402 provided on the upper part of the storage body 401 so as to be openable and closable, a door opening and closing drive mechanism 403 for opening and closing the door 402, and a charging device 405 for performing non-contact charging on a driving battery (not shown) of the drone 300.

[0063] The door opening and closing drive mechanism 403 has a communication means (not shown) with the drone 300. When receiving a signal that can be transmitted from the drone 300 inside the storage body 401, the door 402 is opened to enable the takeoff of the drone 300, and when the flying drone 300 lands inside the storage body 401, the door 402 is closed upon receiving a landing signal from the drone 300.

[0064] The storage 400 is installed at an appropriate location within the area to which this DC cable monitoring system 1 is applied. The opening and closing drive mechanism 403 for opening and closing the door 402 can use a known mechanism (for example, the mechanism disclosed as the roof opening and closing device 4 in Japanese Patent No. 7200324). The charging device 405 can also be configured by a known appropriate charging device. As the power supply for the devices in the storage 400 and the charging device 405, a configuration including a backup power supply (UPS) that can be activated even during a power outage is adopted. The drone 300 can store the position information (latitude, longitude) of the storage 400 in the position information storage unit 303. As the communication means between the drone 300 and the storage 400, a mobile router can also be used.

[0065] A series of operations related to the drone 300 as described above are as follows. <Standby> During standby (normal time when no abnormality has occurred in the DC cable), the drone 300 is inside the storage 400 and is being charged as needed by the charging device 405. <When an abnormal situation occurs> (1) When receiving a flight instruction to a destination of the installation position P (any one of 1 to n) of the power conditioner 5 from the flight instruction means 80, it enters the start preparation. It reads out the information of the destination corresponding to the flight instruction (for example, the installation position P(1) of the power conditioner 5(1)) from the position information storage unit 303. When the start preparation is completed, a transmission enable signal is sent to the door opening and closing drive mechanism 403. (2) The door opening and closing drive mechanism 403 that has received the transmission enable signal opens the door 402. (3) The drone 300 starts upon receiving the door opening signal of the door 402 and flies toward the above destination. (4) When arriving at the destination, the camera 301 is activated, and it takes an image V including the DC cable around the installation position of the power conditioner 5 to which the abnormal DC cable is connected, and sends the image (image signal) V to the management device 100. When the moving object detection by the camera 301 stops or when a predetermined time elapses, the camera 301 stops shooting and returns to the storage 400. Note that the drone 300 may be configured to directly issue a return command signal from the management device 100. (6) When the drone 300 lands on the storage 400, upon receiving the landing signal from the drone 300, the door opening / closing drive mechanism 403 closes the door 402, and the standby state is entered.

[0066] The cable monitoring operation as described above is repeated, for example, until the measured voltage by the voltage measuring means 22 becomes a predetermined voltage of 0 or more due to sunrise.

[0067] As described above, the embodiments of the present invention have been explained. However, the present invention is not limited to the above embodiments, and can be appropriately modified within the scope of the gist of the present invention. For example, in the above embodiment, the case where there are a plurality of power conditioners 5 has been described, but it is also applicable to the case of a single one. Similarly, it is also applicable when there is one cable 6. In this case, in the above embodiment, the resistance value measuring means 20 is configured to measure the resistance value of a single DC cable 6 connecting the aggregation unit (4) and the power conditioner (5), the abnormal resistance value setting means 30 is configured to set, based on the normal resistance value NR of the DC cable 6 measured by the resistance value measuring means 20, a first lower limit value L1 as the lower limit value of the normal resistance value and a second lower limit value L2 that is smaller than the first lower limit value L1, the abnormal state determination means 50 is configured to determine that a cut has occurred in the DC cable 6 when the resistance value of the DC cable 6 measured by the resistance value measuring means 20 during cable monitoring is less than or equal to the first lower limit value L1 and greater than or equal to the second lower limit value L2, and to determine that a problem other than a cut has occurred in the DC cable 6 when it is less than the second lower limit value L2, whereby it is applicable.

Explanation of reference numerals

[0068] 3: Solar cell unit 4: Aggregation unit 5: Power conditioner 5 6: DC cable 20: Resistance value measurement means 30: Abnormal resistance value setting means 50: Abnormal state determination means 300: Drone

Claims

1. A solar cell unit (3), An aggregation unit (4) that aggregates the DC power generated by this solar cell unit (3), A power conditioner (5) that converts the DC power from this aggregation unit (4) into AC, In a solar power generation facility (2) comprising a DC cable (6) that connects the aggregation unit (4) and the power conditioner (5), Resistance value measuring means (20) capable of measuring the resistance value of the DC cable (6) connecting the aggregation unit (4) and the power conditioner (5) and the devices connected to this DC cable (6), Based on the normal resistance value (NR) of the DC cable (6) measured by this resistance value measuring means (20) and the devices connected to this DC cable (6), abnormal resistance value setting means (30) for setting a lower limit value (L2) that is a resistance value smaller than the normal resistance value, When monitoring the cable, when the resistance value of the DC cable (6) measured by the resistance value measuring means (20) and the devices connected to this DC cable (6) is less than the lower limit value (L2), abnormal state determination means (50) for determining that a malfunction other than disconnection has occurred in the DC cable (6), Power conditioner position information storage means (42) for storing the installation position (P(1 - n)) of the power conditioner (5) as power conditioner position information (PI) including at least latitude and longitude, A drone (300) equipped with a camera (301) capable of flying to the installation position (P(1 - n)) of the power conditioner (5) based on the power conditioner position information (PI) stored in this power conditioner position information storage means (42) as a destination and capable of taking images of the vicinity of the installation position of the power conditioner (5) including the DC cable (6) connected to the power conditioner (5), and image transmission means (302) capable of transmitting the images taken by this camera (301), Alarm transmission means (60) for transmitting a malfunction occurrence alarm (FA) indicating that a malfunction other than disconnection has occurred in the DC cable (6) when the abnormal state determination means (50) determines that a malfunction other than disconnection has occurred in the DC cable (6), At least the resistance value measuring means (20), the abnormal state determination means (50), and the alarm transmission means (60) are incorporated in the power conditioner (5), Furthermore, it is provided with a management device (100) installed at a location separated from the power conditioner (5) and wirelessly receiving a malfunction occurrence warning (FA) from the warning transmission means (60). This management device (100) is a DC cable monitoring system in a photovoltaic power generation facility, characterized by transmitting the above warning to a predetermined notification destination (200).

2. A solar cell unit (3), A plurality of aggregation units (4) that aggregate the DC power generated by this solar cell unit (3), A power conditioner (5) that aggregates the DC power from these plurality of aggregation units (4), In a photovoltaic power generation facility (2) comprising a plurality of DC cables (6) that connect the plurality of aggregation units (4) and the power conditioner (5) in parallel with each other, Resistance value measuring means (20) capable of measuring the total resistance value obtained by summing the individual resistance values of the plurality of DC cables (6) connecting each aggregation unit (4) and the power conditioner (5) and the devices connected to this DC cable (6); Abnormal resistance value setting means (30) that sets a lower limit value (L2T), which is a resistance value smaller than the normal resistance value, based on the total normal resistance value (NRT) of the DC cable (6) and the devices connected to this DC cable (6) measured by this resistance value measuring means (20); When the total resistance value of the DC cable (6) and the devices connected to this DC cable (6) measured by the resistance value measuring means (20) is less than the lower limit value (L2T) during cable monitoring, abnormal state determination means (50) that determines that a malfunction other than disconnection has occurred in the DC cable (6); Power conditioner position information storage means (42) that stores the installation positions (P(1 to n)) of the plurality of power conditioners (5) as power conditioner position information (PI) including at least latitude and longitude. A drone (300) equipped with a camera (301) capable of flying to the installation position (P(1-n)) of the power conditioner (5) based on the power conditioner position information (PI) stored in the power conditioner position information storage means (42), and capable of taking images of the area around the installation position of the power conditioner (5) including the DC cable (6) connected to the power conditioner (5), and an image transmission means (302) capable of transmitting the images taken by this camera (301). When the abnormality determination means (50) determines that a problem other than a cut has occurred in the DC cable (6), an alarm transmission means (60) that transmits a problem occurrence alarm (FA) indicating that a problem other than a cut has occurred in the DC cable (6). At least the resistance value measurement means (20), the abnormality determination means (50), and the alarm transmission means (60) are incorporated in the power conditioner (5). Furthermore, a management device (100) is provided, which is installed at a location separated from the power conditioner (5) and wirelessly receives the problem occurrence alarm (FA) from the alarm transmission means (60). This management device (100) is a DC cable monitoring system for a solar power generation facility, characterized in that it transmits the above alarm to a predetermined notification destination (200).

3. In Claim 1 or 2, further When the abnormality determination means (50) determines that a problem other than a cut has occurred in the DC cable (6), a flight instruction means (80) that instructs the drone (300) to fly to the installation position (P(1-n)) of the power conditioner (5) where a problem other than a cut has been determined to have occurred as the destination A DC cable monitoring system for a solar power generation facility, characterized by comprising.

4. In Claim 3 The management device (100) is a management device that wirelessly receives images from the drone (300). This management device (100) is a DC cable monitoring system for a solar power generation facility, characterized in that it transmits the above alarm and images to a predetermined notification destination (200).

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