DC cable monitoring system for solar power generation facilities

Abstract

This invention provides a DC cable monitoring system for solar power generation facilities that can determine whether an abnormality in a monitored DC cable is due to theft or a malfunction such as a failure. [Solution] The system includes a resistance value measuring means 20 that can measure the resistance value of a DC cable 6 connecting a power conditioner 5 to a power aggregation unit 4 that aggregates the DC power generated by the solar cell unit 3; an abnormal resistance value setting means 30 that sets a first lower limit L1 as the lower limit of the normal resistance value, and a second lower limit L2 which is a resistance value smaller than the first lower limit L1, based on the normal resistance value NR of the DC cable 6; and an abnormal condition determination means 50 that, when monitoring the cable, determines that a break has occurred in the DC cable 6 when the resistance value of the DC cable 6 is less than or equal to the first lower limit L1 and greater than or equal to the second lower limit L2, and determines that a malfunction other than a break has occurred in the DC cable 6 when the resistance value is less than the second lower limit L2.

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 "to provide an abnormality detection system for a photovoltaic power generation facility that can surely detect abnormalities such as theft at night with a low cost and a simple system configuration" as an issue, "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 aggregated by the lower unit, the lower unit is 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 respectively." 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) ... and if Z1 = 1 / (1 / R1 + 1 / R2 + 1 / R3), it makes a normal determination (determining that it is in a "normal state" without theft, malfunction, etc.), and at this point, it terminates the abnormality detection routine. It is stated that, and paragraph 0031 says, (ST4) If Z1 is anything other than 1 / (1 / R1 + 1 / R2 + 1 / R3), an abnormality is detected and a warning is displayed. It is stated as follows.

[0005] In other words, according to the technology described in Patent Document 1, it is possible to determine whether the electrical circuit (wiring cable) to be judged is in a "normal state" free from theft, malfunction, etc., or in an abnormal state.

[0006] However, the technology described in Patent Document 1 cannot determine whether the abnormal condition is due to theft or a malfunction.

[0007] [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2016-131470 [Overview of the project] [Problems that the invention aims to solve]

[0009] The problem that this invention aims to solve is to provide a DC cable monitoring system for solar power generation equipment that can determine whether an abnormality in the monitored DC cable is due to theft or a malfunction such as a failure. [Means for solving the problem]

[0010] To solve the above problems, the DC cable monitoring system for solar power generation equipment of the present invention is Solar cell unit and This solar cell unit generates DC power which is then aggregated into an aggregation unit, This power conditioner converts the DC power from this aggregation unit into AC power, In a solar power generation system comprising a DC cable connecting the aforementioned aggregation unit and a power conditioner, A resistance measurement means capable of measuring the resistance value of the DC cable connecting the aforementioned aggregation unit and the power conditioner, An abnormal resistance value setting means sets a first lower limit as the lower limit of the normal resistance value, and a second lower limit which is a resistance value smaller than the first lower limit, based on the normal resistance value of the DC cable measured by this resistance value measuring means. An abnormal condition determination means determines that, when monitoring a cable, if the resistance value of the DC cable measured by the resistance value measuring means is less than or equal to the first lower limit and greater than or equal to the second lower limit, a break has occurred in the DC cable; and if it is less than the second lower limit, a malfunction other than a break has occurred in the DC cable. A power conditioner location information storage means that stores the installation location of the power conditioner as power conditioner location information including at least latitude and longitude, A drone equipped with a camera capable of flying to the installation location of a power conditioner based on power conditioner location information stored in a power conditioner location information storage means, and capable of capturing images of the area around the installation location of the power conditioner, including the DC cable connected to the power conditioner, and a video transmission means capable of transmitting the images captured by the camera, It is characterized by having the following features.

[0011] Given the above configuration, the following effects and benefits can be obtained from this DC cable monitoring system in the solar power generation facility.

[0012] The resistance value of the DC cable connecting the aggregation unit and the power conditioner can be measured using the resistance value measuring means. The abnormal resistance value setting means sets a first lower limit as the lower limit of the normal resistance value, and a second lower limit which is a resistance value smaller than the first lower limit, based on the normal resistance value of the DC cable measured by the resistance value measuring means. During cable monitoring, the abnormal condition determination means determines the following: (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, it is determined that a problem other than breakage has occurred in the DC cable.

[0013] Therefore, this DC cable monitoring system for solar power generation facilities can determine whether an abnormality in the monitored DC cable is due to theft (cutting) or a malfunction such as a fault (for example, a ground fault in the connecting cable, or a malfunction due to an accident such as submersion). Furthermore, the DC cable monitoring system in this solar power generation facility is A power conditioner location information storage means that stores the installation location of the power conditioner as power conditioner location information including at least latitude and longitude, A drone equipped with a camera capable of flying to the installation location of a power conditioner based on power conditioner location information stored in a power conditioner location information storage means, and capable of capturing images of the area around the installation location of the power conditioner, including the DC cable connected to the power conditioner, and a video transmission means capable of transmitting the images captured by the camera, Since it has [the relevant component], 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 due to malfunctions such as failures (for example, ground faults of the connection cable or accidents such as submersion). 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 malfunctions such as failures, according to this invention, appropriate countermeasures can be taken.

[0014] Also, in order to solve the above problems, the DC cable monitoring system in the solar power generation equipment 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 equipment 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 is less than or equal to the first lower limit value and greater than or equal to the second lower limit value during cable monitoring, 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 of the entire DC cable measured by the resistance value measuring means, 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 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, this DC cable monitoring system for solar power generation facilities can determine whether an abnormality in the monitored DC cable is due to theft (cutting) or a malfunction such as a fault (for example, a ground fault in the connecting cable, or a malfunction due to an accident such as submersion). Furthermore, the DC cable monitoring system in this solar power generation facility is A power conditioner location information storage means that stores the installation location of each of the aforementioned plurality of power conditioners as power conditioner location information including at least latitude and longitude, A drone equipped with a camera capable of flying to the installation location of a power conditioner based on power conditioner location information stored in a power conditioner location information storage means, and capable of capturing images of the area around the installation location of the power conditioner, including the DC cable connected to the power conditioner, and a video transmission means capable of transmitting the images captured by the camera, Because it is equipped with this feature, by flying a drone to the installation location of the power conditioner to which the DC cable experiencing the abnormality is connected, and having the drone capture video of the area around the installation location of the power conditioner, including the DC cable, it is possible to visualize and determine in real time whether the abnormality in the DC cable is due to theft (cutting) or a malfunction such as failure (for example, a ground fault in the connecting cable, or a malfunction due to an accident such as submersion). Since the way to deal with a DC cable malfunction differs depending on whether it is due to theft or a failure, this invention allows for appropriate action to be taken.

[0018] In this DC cable monitoring system for solar power generation facilities, further, When the abnormal condition determination means determines that a break has occurred in the DC cable, it issues a break occurrence alarm indicating that the DC cable has been broken, and when it determines that a malfunction other than a break has occurred in the DC cable, it issues a malfunction occurrence alarm indicating that a malfunction has occurred in the DC cable. When the abnormal condition determination means determines that a break has occurred in the DC cable, or when it determines that a malfunction other than a break has occurred in the DC cable, the flight instruction means instructs the drone to fly to the location where the power conditioner is installed and where the break in the DC cable or the malfunction other than a break was determined to occur is located. It can be configured to include the following features. With this configuration, the alarm issuing mechanism can trigger an alarm indicating that an abnormality has occurred in the monitored DC cable, and whether the abnormality is due to theft (cutting) or a malfunction such as a fault (for example, a ground fault in the connecting cable, or a malfunction due to an accident such as submersion). At the same time, the flight instruction means can instruct the drone to fly to the installation location of the power conditioner where it has been determined that a DC cable has been cut or that a malfunction other than a cut has occurred. By capturing video of the area around the installation location of the power conditioner, including the DC cable, it becomes possible to visualize and determine in real time whether the abnormality in the DC cable is due to theft (cutting) or a malfunction such as a failure (for example, a ground fault in the connecting cable, or a malfunction due to an accident such as submersion).

[0019] In this DC cable monitoring system for solar power generation facilities, At a minimum, the resistance value measuring means, the abnormal state determination means, and the alarm signaling means are incorporated into the power conditioner. Furthermore, the system includes a management device installed at a distance from the power conditioner, which wirelessly receives disconnection alarms or malfunction alarms from the alarm transmission means and video footage from the drone. This management device can be configured to transmit the above-mentioned alarms and video to a designated recipient. This configuration allows for immediate and appropriate action to be taken when a problem occurs with a cable. [Brief explanation of the drawing]

[0020] [Figure 1] A system configuration diagram showing an embodiment of the DC cable monitoring system in a solar power generation facility according to the present invention. [Figure 2] A block diagram showing an example of the main components of the system. [Figure 3] A schematic diagram showing an example of a drone and drone storage facility. [Modes for carrying out the invention]

[0021] Hereinafter, embodiments of the DC cable monitoring system for a solar 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 Figure 1, the DC cable monitoring system 1 in this embodiment of the solar power generation facility is Solar cell unit 3, Multiple aggregation units 4 collect the DC power generated by this solar cell unit 3, A power conditioner 5 aggregates the DC power from these multiple aggregation units 4, This method is applicable to a solar power generation system 2 that includes multiple DC cables 6 connecting multiple aggregation units 4 and power conditioners 5, respectively. It is also applicable when there is only one DC cable 6, as will be described later.

[0023] As shown in Figure 2, the DC cable monitoring system 1 in this embodiment of the solar power generation facility is A resistance measurement means 20 that can measure the total resistance of the multiple DC cables 6T connecting each aggregation unit 4 and the power conditioner 5, The abnormal resistance value setting means 30 sets a first lower limit L1T as the lower limit of the normal resistance value, and a second lower limit L2T which is a resistance value smaller than the first lower limit, based on the normal resistance value NRT of the entire DC cable 6T measured by the resistance value measuring means 20. An abnormal condition determination means 50 determines that a break has occurred in one or more DC cables 6 when the resistance value of the entire DC cable 6T measured by the resistance value measuring means 20 is less than or equal to the first lower limit L1T and greater than or equal to the second lower limit L2T during cable monitoring, and determines that a malfunction other than a break has occurred in one or more DC cables 6 when the resistance value is less than the second lower limit L2T. A power conditioner location information storage means (storage means) 42 stores the installation positions P(1~n) of each of the plurality of power conditioners 5 as power conditioner location information PI, which includes at least latitude and longitude. A drone (an autonomous flying object that receives commands) 300 is equipped with a camera 301 (Figure 3) capable of capturing images of the area around the installation location of the power conditioner 5, including the DC cable 6 connected to the power conditioner 5, and a video transmission means 302 (Figure 3) capable of transmitting the images captured by the camera 301, which can fly to the installation location P(1~n) of the power conditioner 5 based on the power conditioner location information PI stored in the power conditioner location information storage means 42, and a video transmission means 302 (Figure 3) capable of transmitting the images captured by the camera 301. It is equipped with.

[0024] This system 1 further, An alarm transmitting means 60 that, when the abnormal condition determination means 50 determines that a break has occurred in the DC cable 6, transmits a break occurrence alarm CA indicating that the DC cable 6 has been broken, and when it determines that a malfunction other than a break has occurred in the DC cable 6, transmits a malfunction occurrence alarm FA indicating that a malfunction has occurred in the DC cable 6. When the abnormal condition determination means 50 determines that a break has occurred in the DC cable 6, or when it determines that a malfunction other than a break has occurred in the DC cable 6, the flight instruction means 80 instructs the drone 300 to fly to the installation position P(1~n) of the power conditioner 5 where it was determined that a break had occurred in the DC cable 6 or that a malfunction other than a break had occurred. It is equipped with.

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

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

[0027] Given the above configuration, the following effects and benefits can be obtained from this DC cable monitoring system in the solar power generation facility.

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

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

[0030] During cable monitoring, the abnormal condition 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 L1T and greater than or equal to the second lower limit L2T, it is determined that a break has occurred in one or more of the DC cables 6.

[0032] (b) When the resistance value RT of the entire DC cable 6T measured by the resistance value measuring means 20 is less than the second lower limit value L2T, it is determined that a malfunction other than a break has occurred in the DC cable 6 (or any one or more of them).

[0033] Therefore, this DC cable monitoring system in the solar power generation facility can determine whether an abnormality in the monitored DC cable 6 is due to theft (cutting) or a malfunction such as a fault (for example, a ground fault in the connecting cable, or a malfunction due to an accident such as submersion). Furthermore, the DC cable monitoring system in this solar power generation facility is A power conditioner location information storage means 42 stores the respective installation locations P(1~n) of multiple power conditioners 5 as power conditioner location information PI, which includes at least latitude and longitude. A drone 300 is equipped with a camera 301 capable of flying to the installation location P(1~n) of a power conditioner based on the power conditioner location information PI stored in the power conditioner location information storage means 42, and capable of capturing video V of the area around the installation location of the power conditioner 5, including the DC cable 6 connected to the power conditioner 5, and a video transmission means 302 capable of transmitting the video V captured by the camera 301. Since it is equipped with this feature, the drone 300 can be flown to the installation location P(1~n) of the power conditioner 5 to which the abnormal DC cable 6 is connected as its destination, and by having it capture video of the area around the installation location of the power conditioner 5, including the DC cable 6, it is possible to visualize and determine in real time whether the abnormality in the DC cable 6 is due to theft (cutting) or a malfunction such as failure (for example, a ground fault in the connecting cable, or a malfunction due to an accident such as submersion).

[0034] Since the procedures for dealing with an abnormality in DC cable 6 due to theft and the procedures for dealing with a malfunction such as a failure are different, this system allows for prompt and appropriate action to be taken.

[0035] The DC cable monitoring system in this solar power generation facility is further equipped with the alarm transmitting means 60, which can issue an alarm when an abnormality occurs in the DC cable 6 being monitored, and whether the abnormality is due to theft (cutting) or a malfunction such as a failure. In other words, it can issue a cut occurrence alarm CA or a malfunction occurrence alarm FA. At the same time, the flight instruction means 80 instructs the drone 300 to fly to the installation location P(1~n) of the power conditioner 5 where it has been determined that a DC cable 6 has been cut or that a malfunction other than a cut has occurred. By capturing video of the area around the installation location of the power conditioner 5, including the DC cable 6, it becomes possible to visualize and determine in real time whether the abnormality in the DC cable is due to theft (cutting) or a malfunction such as a failure (for example, a ground fault in the connecting cable, or a malfunction due to an accident such as submersion).

[0036] Furthermore, in this solar power generation facility, the DC cable monitoring system includes at least a resistance value measuring means 20, an abnormal condition determination means 50, and an alarm transmission means 60, all of which are incorporated into the power conditioner 5. In addition, a management device 100 is installed at a location separated from the power conditioner 5. This management device 100 wirelessly receives disconnection alarms CA or malfunction alarms FA from the alarm transmission means 60 and video V from the drone 300, and transmits these alarms and video to a predetermined notification destination 200. This makes it possible to immediately take appropriate action regarding the cable 6 that has a problem.

[0037] Further details are provided below. The solar cell unit 3 can be composed of a group of known solar panels. Each aggregation unit 4 can be composed of a known and suitable 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 units 3 is aggregated to each aggregation unit 4 through this DC cable 3c. This DC cable 3c is thinner than the DC cable 6.

[0039] The power conditioner 5 can be composed of any known and suitable power conditioner. In this embodiment, it is composed of 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 thicker than the aforementioned DC cable 3c.

[0041] Both DC cables 3c and 6 have a current of approximately 0V after sunset, but DC cable 6 is thicker than DC cable 3c and therefore more susceptible to theft. Furthermore, even if DC cable 3c is cut (stolen), the measured resistance value of DC cable 6 will change, so this system can detect the theft of DC cable 3c as well.

[0042] The power from the power conditioner 5 is supplied to the designated equipment via the AC cable 5c and the interconnection equipment 7. However, since the AC cable 5c has an AC voltage of approximately 380-600V applied to it except during power outages, it is unlikely to be a target for theft.

[0043] In Figure 2, 6(1), 6(2), ... 6(n) are the DC cables 6 mentioned earlier. Relays 21(1~n) are connected to each of these DC cables 6, and resistance measuring instruments 24 are connected via relays 21(1~n). Note that 6f is a terminal of cable 6, and 6b is a connection terminal block.

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

[0045] 23 is a relay operation control means that controls the operation of the relays 21(1~n) described above. It receives the measurement result from the PCS input voltage measurement means 22, and when the measured voltage nV becomes approximately 0 (i.e., when power generation by the solar cell unit 3 becomes approximately 0 due to sunset), it sequentially operates the relays 21(1~n) to sequentially connect each DC cable 6(1~n) to the resistance meter 24, and sends a relay operation signal to each relay 21(1~n) to cause the resistance meter 24 to measure the resistance value R(1~n) of each DC cable 6(1~n).

[0046] When the relays 21(1~n) are activated, the resistance values ​​R(1~n) of the DC cables 6(1~n) measured sequentially by the resistance meter 24 are sent sequentially from the resistance meter 24 to the control unit 81. The control unit 81 accumulates these resistance values ​​R(1~n) and determines the accumulated value as the total resistance value RT of the multiple DC cables 6.

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

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

[0049] During cable monitoring (at sunset), the relay 21(1~n) is activated, and the resistance values ​​R(1~n) of the DC cables 6(1~n) measured sequentially by the resistance meter 24 are accumulated in the control unit 81. This accumulated value is determined as the total resistance value RT of the multiple DC cables 6 and sent to the abnormal condition determination means 50.

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

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

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

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

[0054] The management device 100 includes a unit identification information assignment means 10. The unique unit identification information UI assigned to each unit 110 by this unit identification information assignment means 10 is stored in the storage unit 41 for each unit 110 via the transmitting and receiving means 71, 72 and the control means 81 for each unit 110, and is also stored in the storage means 42 of the management device 100 via the control means (CPU) 82 of the management device 100.

[0055] In this embodiment, the power conditioner location information PI, which includes at least latitude and longitude, is formed as part of the unique unit identification information UI for each unit 110. Therefore, the storage means 42 of the management device 100 constitutes a power conditioner location information storage means that stores the respective installation locations P(1~n) of the power conditioners 5 as power conditioner location information PI, which includes at least latitude and longitude. The power conditioner location information PI can also include altitude information that the drone 300 should reach.

[0056] The signal from the alarm transmission means 61 is sent via the transmission / reception means 71 to the transmission / reception means 72 of the management device 100 of this system 1, along with the unit identification information UI (i.e., the identification information of the unit to which the disconnected or malfunctioning cable 6 is connected). Both of these transmission / reception means 71 and 72 can be composed of known transmission / reception means that can operate in a wireless communication environment (including wireless LAN and Wi-Fi environments).

[0057] Unit 110 is provided with a control means (e.g., an MCU) 81 that controls each of the means 22, 23, 24, 50, 61, and 71 within Unit 110.

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

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

[0060] The basic configuration of the Drone 300 can be made up of known GPS-equipped drones. In addition to the basic configuration described above, the drone 300 of this embodiment includes a location information storage unit 303 that stores at least power conditioner location information PI (installation location P(1~n)) and hangar location information, which will be described later, provided by 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 hangar 400, which will be described later; and a control means 305 that controls these parts (including the parts described later). When the drone receives a flight instruction from the flight instruction means 80 with the installation location P(1~n) of the power conditioner 5 as its destination, it reads the destination information corresponding to the flight instruction (for example, the installation location P(1) of the power conditioner 5(1)) from the location information storage unit 303 and flies toward that installation location.

[0061] The drone 300 has a comparison and determination means 306 that compares the drone's current position with the installation position and determines that the destination has been reached when both positions are within a predetermined range (for example, within a range of 1m when converted to distance in both latitude and longitude). 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. Camera 301 consists of cameras equipped with motion detection capabilities. Camera 301 captures video (video signal) V around the installation location of the power conditioner 5 and sends the video (video signal) V to the management device 100. The control device 100 sends this video to a designated notification destination 200. This allows for real-time visualization of the status of problematic cables and enables appropriate countermeasures to be taken accordingly. The video (video signal) V from camera 301 may be sent directly to a predetermined notification destination 200 without going through the management device 100.

[0062] This DC cable monitoring system 1 is equipped with a hangar (storage box) 400 for housing the drone 300. As shown in Figure 3, the hangar 400 comprises a hangar body 401, a door 402 that is openable and closable and located on the top of the hangar body 401, a door opening and closing drive mechanism 403 for opening and closing the door 402, and a charging device 405 for contactless charging of the drone 300's drive battery (not shown).

[0063] The door opening / closing drive mechanism 403 has a means of communication (not shown) with the drone 300. When it receives a signal from the drone 300 inside the hangar body 401 that it is ready to transmit, it opens the door 402 to allow the drone 300 to launch. When the drone 300 lands inside the hangar body 401 after flight, it receives a landing signal from the drone 300 and closes the door 402.

[0064] The hangar 400 is installed at a suitable 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 be a known mechanism (for example, the mechanism disclosed as a roof opening and closing device 4 in Japanese Patent Publication No. 7200324). The charging device 405 can also be configured with a known and suitable charging device. The power supply for the equipment and charging device 405 inside the hangar 400 will be configured to include a backup power supply (UPS) to enable startup even in the event of a power outage. The drone 300 can store the location information (latitude and longitude) of the hangar 400 in the location information storage unit 303. A mobile router can also be used as a means of communication between the drone 300 and the hangar 400.

[0065] The sequence of operations for the Drone 300 described above is as follows: <In standby mode> During standby (when there is no abnormality in the DC cable), the drone 300 is located inside the hangar 400 and receives charging as needed from the charging device 405. <In case of an emergency> (1) When the aircraft receives a flight instruction from the flight instruction means 80 with the installation position P (any of 1 to n) of the power conditioner 5 as the destination, it enters a launch preparation phase. The aircraft reads destination information 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, and once the launch preparation is complete, it sends a signal ready to launch to the door opening / closing drive mechanism 403. (2) The door opening / closing drive mechanism 403, upon receiving the signal to transmit, opens the door 402. (3) Upon receiving the signal to open door 402, the drone 300 is launched and flies toward the destination mentioned above. (4) Upon arrival at the destination, camera 301 is activated and captures video V including the DC cable around the installation location of the power conditioner 5 to which the malfunctioning DC cable is connected, and sends the video (video signal) V to the management device 100. (5) When motion detection by the camera 301 ceases, or when a predetermined time has elapsed, the camera 301 stops taking pictures and returns to the storage compartment 400. The control device 100 may also be configured to directly issue a return command signal to the drone 300. (6) When the drone 300 lands in the storage compartment 400, the door opening / closing drive mechanism 403 receives a landing signal from the drone 300 and closes the door 402, returning to the standby state described above.

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

[0067] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and can be appropriately modified and implemented within the scope of the gist of the present invention. For example, although the above embodiment described a case where there are multiple power conditioners 5, it is also applicable to the case where there is only one. Similarly, this method is also applicable when there is only one cable 6. In this case, in the above embodiment, The resistance measurement means 20 is configured to measure the resistance 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 a first lower limit value L1 as the lower limit of the normal resistance value and a second lower limit value L2 which is a resistance value smaller than the first lower limit value L1, based on the normal resistance value NR of the DC cable 6 measured by the resistance value measuring means 20. The abnormal condition determination means 50 is applicable by configuring it so that, when monitoring the cable, if the resistance value of the DC cable 6 measured by the resistance value measuring means 20 is less than or equal to the first lower limit L1 and greater than or equal to the second lower limit L2, it is determined that a break has occurred in the DC cable 6, and if it is less than the second lower limit L2, it is determined that a malfunction other than a break has occurred in the DC cable 6. [Explanation of symbols]

[0068] 3: Solar cell unit 4: Aggregation Unit 5: Power Conditioner 5 6: DC cable 20: Resistance measurement means 30: Abnormal resistance value setting means 50: Abnormal State Determination Method 300: Drone

Claims

1. Solar cell unit (3), This solar cell unit (3) generates DC power which is then aggregated by an aggregation unit (4), A power conditioner (5) converts the DC power from this aggregation unit (4) to AC power, In a solar power generation system (2) comprising a DC cable (6) connecting the aggregation unit (4) and a power conditioner (5), A resistance measurement means (20) that can measure the resistance value of the DC cable (6) connecting the aggregation unit (4) and the power conditioner (5), An abnormal resistance value setting means (30) sets a first lower limit value (L1) as the lower limit of the normal resistance value and a second lower limit value (L2) which is a resistance value smaller than the first lower limit value (L1), based on the normal resistance value (NR) of the DC cable (6) measured by this resistance value measuring means (20). An abnormal condition determination means (50) determines that a break 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 determines that a malfunction other than a break has occurred in the DC cable (6) when the resistance value is less than the second lower limit value (L2), A power conditioner location information storage means (42) stores the installation location (P(1 to n)) of the power conditioner (5) as power conditioner location information (PI) including at least latitude and longitude, A drone (300) is equipped with a camera (301) capable of capturing images of the area around the installation location of the power conditioner (5), including the DC cable (6) connected to the power conditioner (5), and a video transmission means (302) capable of transmitting the images captured by the camera (301), which is capable of flying to the installation location (P(1 to n)) of the power conditioner (5) based on the power conditioner location information (PI) stored in the power conditioner location information storage means (42), and the drone (300) is equipped with a camera (301) capable of capturing images of the area around the installation location of the power conditioner (5), including the DC cable (6) connected to the power conditioner (5), and a video transmission means (302) capable of transmitting the images captured by the camera (301). A DC cable monitoring system for solar power generation facilities, characterized by having the following features.

2. Solar cell unit (3), Multiple aggregation units (4) collect the DC power generated by this solar cell unit (3), A power conditioner (5) aggregates the DC power from these multiple aggregation units (4), In a solar power generation system (2) comprising multiple DC cables (6) connecting the multiple aggregation units (4) and the power conditioner (5), A resistance measurement means (20) that can measure the total resistance of multiple DC cables (6) connecting each aggregation unit (4) and the power conditioner (5), An abnormal resistance value setting means (30) sets a first lower limit (L1T) as the lower limit of the normal resistance value, and a second lower limit (L2T) which is a resistance value smaller than the first lower limit (L1T), based on the normal resistance value (NRT) of the entire DC cable (6) measured by this resistance value measuring means (20). An abnormal condition determination means (50) determines that a break has occurred in the DC cable (6) when the total 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 (L1T) and greater than or equal to the second lower limit value (L2T), and determines that a malfunction other than a break has occurred in the DC cable (6) when it is less than the second lower limit value (L2T), A power conditioner location information storage means (42) stores the installation locations (P(1 to n)) of each of the plurality of power conditioners (5) as power conditioner location information (PI) including at least latitude and longitude, A drone (300) is equipped with a camera (301) capable of capturing images of the area around the installation location of the power conditioner (5), including the DC cable (6) connected to the power conditioner (5), and a video transmission means (302) capable of transmitting the images captured by the camera (301), which is capable of flying to the installation location (P(1 to n)) of the power conditioner (5) based on the power conditioner location information (PI) stored in the power conditioner location information storage means (42), and the drone (300) is equipped with a camera (301) capable of capturing images of the area around the installation location of the power conditioner (5), including the DC cable (6) connected to the power conditioner (5), and a video transmission means (302) capable of transmitting the images captured by the camera (301). A DC cable monitoring system for solar power generation facilities, characterized by having the following features.

3. In claim 1 or 2, further, When the abnormal condition determination means (50) determines that a break has occurred in the DC cable (6), the alarm issuing means (60) issues a break occurrence alarm (CA) indicating that the DC cable (6) has been broken, and when it determines that a malfunction other than a break has occurred in the DC cable (6), the alarm issuing means (60) issues a malfunction occurrence alarm (FA) indicating that a malfunction has occurred in the DC cable (6). When the abnormal condition determination means (50) determines that a break has occurred in the DC cable (6), or when it determines that a malfunction other than a break has occurred in the DC cable (6), the flight instruction means (80) instructs the drone (300) to fly to the installation location (P(1 to n)) of the power conditioner (5) where it was determined that a break had occurred in the DC cable (6) or that a malfunction other than a break had occurred. A DC cable monitoring system for solar power generation facilities, characterized by having the following features.

4. In claim 3, At least the resistance value measuring means (20), the abnormal state determination means (50), and the alarm signaling means (60) are incorporated into the power conditioner (5). Furthermore, the system includes a management device (100) installed at a distance from the power conditioner (5) that wirelessly receives disconnection alarms (CA) or malfunction alarms (FA) from the alarm transmission means (60) and video from the drone (300). This management device (100) is a DC cable monitoring system for a solar power generation facility, characterized by transmitting the above-mentioned alarms and video to a predetermined notification destination (200).

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