DC cable monitoring system for solar power generation facilities

Abstract

To provide a DC cable monitoring system for a photovoltaic power generation facility capable of determining whether an abnormality in a DC cable to be monitored is due to theft or a malfunction such as a breakdown. [Solution] The system includes a resistance value measuring means 20 capable of measuring the resistance of a DC cable 6 connecting an aggregation unit 4 that aggregates DC power generated by a solar cell unit 3 to a power conditioner 5 and the resistance of the equipment connected to the DC cable 6, an abnormal resistance value setting means 30 that sets an upper limit L1 and a lower limit L2 of the normal resistance value based on the normal resistance value NR of the DC cable 6, and an abnormal state determination means 50 that, when monitoring the cable, determines that a break has occurred in the DC cable 6 if the resistance value of the DC cable 6 and the equipment connected to the DC cable 6 is equal to or greater than the upper limit L1, and determines that a malfunction other than a break has occurred in the DC cable 6 and / or the equipment connected to the DC cable 6 if the resistance value is less than the lower limit L2.

Description

[Technical Field]

[0001] The present invention relates to a DC cable monitoring system for a photovoltaic power generation facility, and more particularly to a DC cable monitoring system for a photovoltaic power generation facility that can determine whether an abnormality in the DC cable being monitored is due to theft (cutting) or a malfunction such as a breakdown. [Background technology]

[0002] Conventionally, a technique such as that shown in Patent Document 1 has been known.

[0003] <Patent Document 1> JP 2016-131470 A Patent Document 1 states: The objective of the project is to provide a solar power generation facility anomaly detection system that can reliably detect anomalies such as theft even at night, at low cost and with a simple system configuration. "In an abnormality detection system for photovoltaic power generation equipment that includes a lower unit that aggregates the DC power generated by the solar cell units and an upper unit that aggregates the DC power aggregated in the lower unit, multiple lower units are connected in parallel to the upper unit, and a measuring instrument that measures impedance is provided on each distribution cable connecting each of these lower units to the upper unit, and a judgment unit that detects the abnormality based on the results of the measurement when the solar cell units are not generating power is provided upstream of each of these measuring units, and the measuring instrument measures the composite impedance aggregated in each of all of the lower units connected in parallel to the upper unit as the impedance." An abnormality detection system for solar power generation equipment is described (abstract of the same document).

[0004] Furthermore, paragraph 0030 of the same document states: "(ST3) The determining unit 12 stores in advance the resistance values ​​(R1 to R3) of the electric circuits integrated into each of the lower units as initial setting values. The determination unit 12 compares ... and if Z1 = 1 / (1 / R1 + 1 / R2 + 1 / R3), it determines that the vehicle is normal (determines that the vehicle is in a "normal state" with no theft or malfunction, etc.), and terminates the abnormality detection routine. and paragraph 0031 of the same article states: "(ST4) If Z1 is not equal to 1 / (1 / R1+1 / R2+1 / R3), an abnormality is detected and a warning is displayed. It is stated that:

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

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

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

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-131470 Summary of the Invention [Problem to be solved by the invention]

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

[0010] In order to solve the above problems, the DC cable monitoring system for a photovoltaic power generation facility of the present invention comprises: A solar cell unit; An aggregation unit that aggregates the DC power generated by this solar cell unit, A power conditioner converts DC power from this aggregation unit into AC power, A photovoltaic power generation facility including a DC cable connecting the aggregation unit and a power conditioner, A DC cable connecting the aggregation unit and the power conditioner and the equipment connected to this DC cable a resistance value measuring means for measuring the resistance value of the The DC cable measured by this resistance value measuring means and the equipment connected to this DC cable The normal resistance value is used as the reference. Upper limit of value, and Normal resistance value an abnormal resistance value setting means for setting a lower limit value; DC cable resistance measured by the resistance measuring means during cable monitoring and the equipment connected to this DC cable The resistance value of upper limit If the value is equal to or greater than the predetermined value, it is determined that a break has occurred in the DC cable. Below When the limit value is less than the limit value, the DC cable and / or any equipment connected to this DC cable an abnormality determination means for determining that a malfunction other than disconnection has occurred; a power conditioner position information storage means for storing the installation location of the power conditioner as power conditioner position information including at least latitude and longitude; a drone that can fly to a destination of the installation location of the power conditioner based on the power conditioner position information stored in the power conditioner position information storage means, and that is equipped with a camera that can capture images of the area around the installation location of the power conditioner including the DC cable connected to the power conditioner, and an image transmission means that can transmit the images captured by the camera; The present invention is characterized by the following features.

[0011] With the above-described configuration, the DC cable monitoring system for the photovoltaic power generation facility can provide the following advantages.

[0012] The resistance value measuring means measures the resistance of the DC cable connecting the aggregation unit and the power conditioner. and the equipment connected to this DC cable The resistance value of the resistor can be measured. The abnormal resistance value setting means sets the resistance value of the DC cable measured by the resistance value measuring means in the normal state as a reference. upper limit value, and Normal A lower limit value and are set. When the cable is monitored, the abnormal state determining means determines whether the cable is abnormal or not as follows. (a) DC cable measured by the resistance value measuring means and the equipment connected to this DC cable The resistance value of upper limit If the value is equal to or greater than the threshold, it is determined that a break has occurred in the DC cable. (b) DC cable measured by the resistance value measuring means and the equipment connected to this DC cable The resistance value of Below When the limit value is less than the limit value, the DC cable and / or any equipment connected to this DC cable It is determined that a malfunction other than disconnection has occurred.

[0013] Therefore, with this DC cable monitoring system for solar power generation equipment, it is possible to determine whether an abnormality in the DC cable being monitored is due to theft (disconnection) or a malfunction such as a breakdown (for example, a ground fault in the connecting cable, or a malfunction such as an accident caused by submersion in water, etc.). Furthermore, the DC cable monitoring system for this solar power generation facility: a power conditioner position information storage means for storing the installation location of the power conditioner as power conditioner position information including at least latitude and longitude; a drone that can fly to a destination of the installation location of the power conditioner based on the power conditioner position information stored in the power conditioner position information storage means, and that is equipped with a camera that can capture images of the area around the installation location of the power conditioner including the DC cable connected to the power conditioner, and an image transmission means that can transmit the images captured by the camera; Therefore, by flying a drone to the installation location of the power conditioner to which the DC cable with an abnormality is connected as its destination and taking images 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 (disconnection) or a malfunction such as a breakdown (for example, a ground fault in the connecting cable, or a malfunction such as an accident caused by submersion in water, etc.). Since the measures to be taken when the abnormality in the DC cable is due to theft are different from the measures to be taken when the abnormality is due to a malfunction such as a breakdown, the present invention allows appropriate measures to be taken.

[0014] In order to solve the above problems, the DC cable monitoring system for a photovoltaic power generation facility of the present invention comprises: A solar cell unit; a plurality of aggregation units that aggregate the DC power generated by the solar cell units; a power conditioner that aggregates DC power from these multiple aggregation units; The plurality of aggregation units and the power conditioner are Connect them in parallel A solar power generation facility including a plurality of DC cables, Multiple DC cables connecting each aggregation unit to the power conditioner and the sum of the individual resistance values ​​of the devices connected to this DC cable a resistance value measuring means capable of measuring the overall resistance value; The DC cable measured by this resistance value measuring means and the equipment connected to this DC cable The normal resistance value is used as the reference. Upper limit of value, and Below normal resistance an abnormal resistance value setting means for setting a limit value; DC cable resistance measured by the resistance measuring means during cable monitoring and the equipment connected to this DC cable The overall resistance is Above the upper limit When the above condition is met, it is determined that a break has occurred in the DC cable. Below When the limit value is less than the limit value, the DC cable and / or any equipment connected to this DC cable an abnormality determination means for determining that a malfunction other than disconnection has occurred; a power conditioner position information storage means for storing the installation positions of the plurality of power conditioners as power conditioner position information including at least latitude and longitude; a drone that can fly to a destination of the installation location of the power conditioner based on the power conditioner position information stored in the power conditioner position information storage means, and that is equipped with a camera that can capture images of the area around the installation location of the power conditioner including the DC cable connected to the power conditioner, and an image transmission means that can transmit the images captured by the camera; The present invention is characterized by the following features.

[0015] With the above-described configuration, the DC cable monitoring system for the photovoltaic power generation facility can provide the following advantages.

[0016] The resistance value measuring means measures the resistance of the DC cable connecting the aggregation unit and the power conditioner. and the sum of the individual resistance values ​​of the devices connected to this DC cable The overall resistance can be measured. The abnormal resistance value setting means sets the resistance value of the DC cable measured by the resistance value measuring means. and the equipment connected to this DC cable The normal resistance value of the whole is used as the standard. upper limit value, and Below normal resistance A limit value is set. When the cable is monitored, the abnormal state determining means determines whether the cable is abnormal or not as follows. (a) DC cable measured by the resistance value measuring means and the equipment connected to this DC cable The overall resistance is upper limit If the value is equal to or greater than the threshold, it is determined that a break has occurred in the DC cable. (b) DC cable measured by the resistance value measuring means and the equipment connected to this DC cable The overall resistance is Below When the limit value is less than the limit value, the DC cable and / or any equipment connected to this DC cable It is determined that a malfunction other than disconnection has occurred.

[0017] Therefore, with this DC cable monitoring system for solar power generation equipment, it is possible to determine whether an abnormality in the DC cable being monitored is due to theft (disconnection) or a malfunction such as a breakdown (for example, a ground fault in the connecting cable, or a malfunction such as an accident caused by submersion in water, etc.). Furthermore, the DC cable monitoring system for this solar power generation facility: a power conditioner position information storage means for storing the installation positions of the plurality of power conditioners as power conditioner position information including at least latitude and longitude; a drone that can fly to a destination of the installation location of the power conditioner based on the power conditioner position information stored in the power conditioner position information storage means, and that is equipped with a camera that can capture images of the area around the installation location of the power conditioner including the DC cable connected to the power conditioner, and an image transmission means that can transmit the images captured by the camera; Therefore, by flying a drone to the installation location of the power conditioner to which the DC cable with an abnormality is connected as its destination and taking images 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 (disconnection) or a malfunction such as a breakdown (for example, a ground fault in the connecting cable, or a malfunction such as an accident caused by submersion in water, etc.). Since the measures to be taken when the abnormality in the DC cable is due to theft are different from the measures to be taken when the abnormality is due to a malfunction such as a breakdown, the present invention allows appropriate measures to be taken.

[0018] The DC cable monitoring system for this solar power generation facility further includes: When the abnormality determination means determines that a cut has occurred in the DC cable, it issues a cut occurrence alarm to the effect that the DC cable has been cut, and and / or any equipment connected to this DC cable When it is determined that a fault other than a break has occurred in the DC cable, and / or any equipment connected to this DC cable an alarm issuing means for issuing a malfunction occurrence alarm to notify that a malfunction has occurred; a flight instruction means for instructing the drone to fly to a destination of an installation location of a power conditioner where it has been determined that a cut has occurred in the DC cable or a malfunction other than a cut has occurred in the DC cable when the abnormality determination means determines that a cut has occurred in the DC cable or a malfunction other than a cut has occurred in the DC cable; The configuration may include the following. With this configuration, the alarm issuing means can issue an alarm that an abnormality has occurred in the DC cable being monitored, and whether the abnormality is due to theft (disconnection) or a malfunction such as a breakdown (for example, a ground fault in the connecting cable, or a malfunction such as an accident caused by submersion in water, etc.). At the same time, the flight instruction means causes the drone to fly to the installation location of a power conditioner where it has been determined that a cut has occurred in the DC cable or that a malfunction other than a cut has occurred, and 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 (cut) or a malfunction such as a breakdown (for example, a ground fault in the connecting cable, or a malfunction due to an accident such as submersion in water).

[0019] In this DC cable monitoring system for solar power generation facilities, At least the resistance value measuring means, the abnormal state determining means, and the alarm issuing means are incorporated into the power conditioner, Further, a management device is provided which is installed at a location away from the power conditioner and wirelessly receives the disconnection occurrence alarm or malfunction occurrence alarm from the alarm issuing means and the image from the drone, The management device can be configured to transmit the alarm and video to a predetermined notification destination. With this configuration, it becomes possible to immediately take appropriate measures depending on the problem with the cable in question. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a system configuration diagram showing an embodiment of a DC cable monitoring system in a photovoltaic power generation facility according to the present invention; [Figure 2] FIG. 2 is a block diagram showing an example of the main parts of the system. [Figure 3] FIG. 1 is a schematic diagram showing an example of a drone and a drone storage facility. DETAILED DESCRIPTION OF THE INVENTION

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

[0022] As shown in FIG. 1, a DC cable monitoring system 1 in a solar power generation facility according to this embodiment includes: a solar cell unit 3; a plurality of aggregation units 4 that aggregate the DC power generated by the solar cell units 3; a power conditioner 5 that aggregates DC power from the multiple aggregation units 4; A plurality of aggregation units 4 and power conditioners 5 are Connect them in parallel The present invention is applicable to a photovoltaic power generation facility 2 that includes a plurality of DC cables 6. As will be described later, the present invention is also applicable to a photovoltaic power generation facility 2 that includes a single DC cable 6 instead of a plurality of DC cables 6.

[0023] As shown in FIG. 2, the DC cable monitoring system 1 in the solar power generation facility according to this embodiment includes: A plurality of DC cables connecting each aggregation unit 4 and the power conditioner 5 and the sum of the individual resistance values ​​of the devices (mainly the aggregation unit 4 and the power conditioner 5) connected to this DC cable 6 a resistance value measuring means 20 capable of measuring the resistance value of the entire 6T; DC cable measured by this resistance value measuring means 20 and the equipment connected to this DC cable 6 The normal resistance value NRT of the entire 6T is used as the reference. upper limit The value L1T, Normal resistance valuean abnormal resistance value setting means 30 for setting a lower limit value L2T; During cable monitoring, the resistance value of the DC cable 6 measured by the resistance value measuring means 20 and the equipment connected to this DC cable 6 The resistance value of the entire 6T is upper limit Value L1 T or more When the condition is above, it is determined that a break has occurred in one or more of the DC cables 6, and Below When the limit value is less than L2T, DC cable 6 (one or more) and / or the equipment connected to this DC cable 6 an abnormality determination means 50 for determining that a malfunction other than disconnection has occurred; a 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 (a flying object that flies autonomously under command) 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 as its destination and that can capture 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 (FIG. 3) that can transmit the images captured by the camera 301; It is equipped with:

[0024] This system 1 further includes: When the abnormal state determination means 50 determines that a cut has occurred in the DC cable 6, a cut occurrence alarm CA is issued to notify that the DC cable 6 has been cut, and the DC cable 6 and / or the equipment connected to this DC cable 6 When it is determined that a fault other than a break has occurred in DC cable 6, and / or the equipment connected to this DC cable 6 alarm issuing means 60 for issuing a malfunction occurrence alarm FA to notify that a malfunction has occurred; a flight instruction means 80 that, when the abnormal state determination means 50 determines that a cut has occurred in the DC cable 6 or that a malfunction other than a cut has occurred in the DC cable 6, instructs the drone 300 to fly to the installation position P (1 to n) of the power conditioner 5 where it has been determined that a cut has occurred in the DC cable 6 or that a malfunction other than a cut has occurred, as its destination; It is equipped with:

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

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

[0027] With the above-described configuration, the DC cable monitoring system for the photovoltaic power generation facility can provide the following advantages.

[0028] The resistance value measuring means 20 measures the resistance of the DC cable 6 connecting the aggregation unit 4 and the power conditioner 5. and the sum of the individual resistance values ​​of the devices connected to this DC cable 6 The resistance value of the entire 6T can be measured.

[0029] The abnormal resistance value setting means 30 determines the resistance value of the DC cable 6 measured by the resistance value measuring means 20. and the sum of the resistance values ​​of the devices connected to this DC cable 6 The normal resistance value NRT of the entire 6T is used as the reference. upper limit The value L1T, Normal resistance value A lower limit L2T is set.

[0030] When monitoring the cable, the abnormal state determining means 50 determines whether the cable is in an abnormal state as follows.

[0031] (a) DC cable 6 measured by resistance measurement means 20 and the sum of the individual resistance values ​​of the devices connected to this DC cable 6 The resistance value RT of the entire 6T is upper limit If the value is equal to or greater than L1T, it is determined that a break has occurred in (one or more of) the DC cables 6.

[0032] (b) DC cable 6 measured by resistance measurement means 20 and the sum of the individual resistance values ​​of the devices connected to this DC cable 6 The resistance value RT of the entire 6T is Below When the limit value is less than L2T, DC cable 6 (one or more) and / or the equipment connected to this DC cable 6 It is determined that a malfunction other than disconnection has occurred.

[0033] Therefore, according to the DC cable monitoring system for the photovoltaic power generation facility, it is possible to determine whether an abnormality in the DC cable 6 to be monitored is due to theft (cutting), or a malfunction such as a breakdown (for example, a ground fault in the connection cable, or Failures such as accidents caused by the submersion of the connection between the cable 6 and the equipment, or the submersion of part or all of the equipment in water. ) can be determined. Furthermore, the DC cable monitoring system for this solar power generation facility: a 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 a destination of the installation position P (1 to n) of the power conditioner based on the power conditioner position information PI stored in the power conditioner position information storage means 42, and capable of capturing an image V of the periphery of the installation position of the power conditioner 5 (including the periphery of the aggregation unit 4) including the DC cable 6 connected to the power conditioner 5, and an image transmission means 302 capable of transmitting the image V captured by the camera 301; Therefore, the drone 300 is flown to the installation position P (1 to n) of the power conditioner 5 to which the DC cable 6 where the abnormality has occurred is connected as the destination, and the drone 300 is made to take an image of the surroundings of the installation position of the power conditioner 5 including the DC cable 6, and it is possible to determine whether the abnormality of the DC cable 6 is due to theft (cutting), a malfunction such as a breakdown (for example, a ground fault in the connection cable, or The connection between the cable 6 and the device may be submerged in water, or the device may be damaged in part or in whole. It is possible to visualize and determine in real time whether the problem is due to an accident such as submersion in water or other malfunctions.

[0034] Since the measures to be taken when the abnormality in the DC cable 6 is due to theft are different from the measures to be taken when the abnormality is due to a malfunction such as a breakdown, this system makes it possible to take appropriate measures.

[0035] The DC cable monitoring system in this solar power generation facility further includes the alarm issuing means 60, and the DC cable 6 and / or the equipment connected to this DC cable 6 It is possible to issue an alarm that an abnormality has occurred in the system and whether the abnormality is due to theft (disconnection) or a malfunction such as a breakdown. In other words, it is possible to issue a disconnection 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 location P (1 to n) of the power conditioner 5 where it has been determined that the DC cable 6 has been cut or that a malfunction other than a cut has occurred, and 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 breakdown.

[0036] In addition, the DC cable monitoring system in this solar power generation facility has at least a resistance value measuring means 20, an abnormal state determining means 50, and an alarm issuing means 60 incorporated into the power conditioner 5, and furthermore, a management device 100 installed in a location separate from the power conditioner 5, and this management device 100 wirelessly receives a disconnection occurrence alarm CA or a malfunction occurrence alarm FA from the alarm issuing means 60 and video V from the drone 300, and transmits these alarms and video to a specified notification destination 200, making it possible to immediately take appropriate measures according to the problem for the cable 6 in which a problem has occurred.

[0037] This will be explained in more detail below. The solar cell unit 3 can be configured with a group of known solar panels. Each aggregation unit 4 can be configured as 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 and known connection structures The DC power generated by the solar cell units 3 is collected to each collection unit 4 through this DC cable 3c. This DC cable 3c is a thinner cable than the DC cable 6.

[0039] The power conditioner 5 can be configured as an appropriate known power conditioner, and in this embodiment is configured as a central type power conditioner.

[0040] Each aggregation unit 4 and the power conditioner 5 are connected to a known DC cable 6 and a known connection structure The DC power from each aggregation unit 4 is aggregated to the power conditioner 5 via this DC cable 6. This DC cable 6 is a thicker cable than the DC cable 3c.

[0041] The current flowing through both the DC cable 3c and the DC cable 6 becomes approximately 0V after sunset, but the DC cable 6 is a thicker cable than the DC cable 3c, so it is more likely to be the target of theft than the DC cable 3c. Even if the DC cable 3c is cut (stolen), Measured by resistance measuring means 20 Since the resistance value changes, this system can consequently detect theft of the DC cable 3c.

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

[0043] In Fig. 2, 6(1), 6(2), ..., 6(n) are the DC cables 6 mentioned above. Relays 21(1 to n) are connected to these DC cables 6, respectively, and resistance value measuring devices 24 are connected via the relays 21(1 to n). Note that 6f is a terminal of the cable 6, and 6b is a connection terminal block.

[0044] Reference numeral 22 denotes a PCS input voltage measuring means for measuring the input voltage to the power conditioner 5, and is connected to the power conditioner 5 at an appropriate position to measure the input voltage to the power conditioner 5.

[0045] Reference numeral 23 denotes a relay operation control means for controlling the operation of the relays 21(1 to n), which receives the measurement result from the PCS input voltage measurement means 22, and when the voltage nV, which is the measurement result, becomes almost 0 (i.e., when the power generation by the solar cell unit 3 becomes almost 0 due to sunset), operates the relays 21(1 to n) in sequence, connects each DC system cable 6(1 to n) in sequence to a resistance value measuring device 24, and and the equipment connected to this DC cable 6 In order to have the resistance value measuring device 24 measure the resistance values ​​R(1 to n), a relay actuation signal is issued to each of the relays 21(1 to n).

[0046] By the operation of the relays 21 (1 to n), the DC cables 6 (1 to n) sequentially measured by the resistance measuring device 24 and the equipment connected to this DC cable 6 The resistance values ​​R(1 to n) 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 to n) and outputs the accumulated value to the plurality of DC cables 6. and the equipment connected to this DC cable 6 Determine the overall resistance value RT.

[0047] Prior to cable monitoring, the abnormal resistance value setting means 30 sets the resistance values ​​of the DC cables 6 measured by the resistance value measuring means 20. and the equipment connected to this DC cable 6 The normal resistance value NRT of the overall resistance value RT is used as the reference. upper limit The value L1T, Normal resistance value The lower limit L2T of these upper limit Value L1T and below The limit value L2T is stored in the storage unit 41 via, for example, the transmission / reception means 71, 72 and the control unit 81, which will be described later.

[0048] Specifically, for example, the resistance of a plurality of DC cables 6 measured by the resistance value measuring means 20 is and the equipment connected to this DC cable 6 If the normal resistance NRT of the overall resistance RT is 6MΩ, then the upper limit L1T of the normal resistance is set to, for example, 6MΩ. 6.3 MΩ ,under For example, the limit L2T is 0.5M Ω. As described above, these values ​​are stored in the storage unit 41. For example, if the normal combined resistance value RT is 6 MΩ as described above, the percentages of the upper limit value L1T and lower limit value L2T relative to the normal combined resistance value RT will vary depending on the equipment configuration, cable size, and number of connected circuits, so it is difficult to set a uniform value.However, if the number of circuits is small, the increase in resistance when one cable is cut will be 15% to 30%, and if the number of circuits is large, the increase in resistance when one cable is cut will be approximately 3% to 5%, so the upper limit value L1T can be set to, for example, 6.3 MΩ, which is a value approximately 5% higher than the normal value. On the other hand, if an accident other than cable disconnection occurs (short circuit, ground fault, submersion in water), the combined resistance value RT will become unmeasurable (it will drop significantly from the normal value and become very close to 0Ω), so the lower limit value L2T can be set to, for example, 0.5MΩ. In addition, when installing an alarm system at an actual site, it is advisable to disconnect one of the connected circuits, check the increase in resistance, and then set the alarm range, i.e., the upper limit L1T and lower limit L2T.

[0049] During cable monitoring (at sunset), the relays 21 (1 to n) are activated to measure the resistance of the DC cables 6 (1 to n) sequentially by the resistance measuring instrument 24. and the equipment connected to this DC cable 6 The resistance values ​​R(1 to n) are accumulated in the control unit 81, and the accumulated value is used for the plurality of DC cables 6 and the equipment connected to this DC cable 6 The total resistance value RT is determined and sent to the abnormal state determination means 50.

[0050] The abnormal state determination means 50 detects the DC cable 6 and the equipment connected to this DC cable 6 The total resistance value RT is set by the abnormal resistance value setting means 30. upper limit Value L1 T or more When the above condition is met, it is determined that a break has occurred in the DC cable 6 (one or more cables). ,under When the limit value L2T is less than the limit value L2T, the DC cable 6 and / or the equipment connected to this DC cable 6 It is determined that a malfunction other than disconnection has occurred.

[0051] For example, the abnormal state determination means 50 may and the equipment connected to this DC cable 6 The total resistance RT is 6.4 When the resistance is MΩ, it is determined that DC cable 6 is disconnected. When the resistance is 0Ω, it is determined that DC cable 6 is disconnected. and / or the equipment connected to this DC cable 6 It is determined that a malfunction other than disconnection has occurred. This determination signal is sent to the alarm issuing means 60 (61) and then sent to the management device 100 of this system 1 via the transmitting / receiving means 71.

[0052] The alarm issuing means 60 receives a determination signal from the abnormal state determining means 50, and when the abnormal state determining means 50 determines that the DC cable 6 has been cut, issues a cut occurrence alarm CA to indicate that the cable has been cut, and and / or the equipment connected to this DC cable 6 When it is determined that a fault other than a break has occurred in cable 6, and / or the equipment connected to this DC cable 6 A malfunction alarm FA is sent to indicate that a malfunction has occurred.

[0053] In this embodiment, the resistance value measuring means 20, abnormal state determining means 50, alarm issuing means 61 (60), and transmitting / receiving means 71 described above are configured as a unit 110 and are incorporated into the power conditioner 5 (see FIG. 1). The management device 100 is provided with a unit identification information assigning means 10, and the unique unit identification information UI assigned to each unit 110 by this unit identification information assigning means 10 is stored in the memory unit 41 of each unit 110 via the transmitting / receiving means 71, 72 and the control unit 81 of each unit 110.

[0054] In this embodiment, the power conditioner position information PI, which includes at least latitude and longitude, is formed as part of unit identification information UI unique to each unit 110. Therefore, the storage means 42 included in the management device 100 constitutes a power conditioner position information storage means that stores the installation positions P (1 to n) of each power conditioner 5 as power conditioner position information PI, which includes at least latitude and longitude. Note that the power conditioner position information PI can also include altitude information that the drone 300 should reach.

[0055] The signal from the alarm issuing means 61 is sent together with unit identification information UI (i.e., identification information of the unit to which the disconnected or defective cable 6 is connected) via the transmitting / receiving means 71 to the transmitting / receiving means 72 provided in the management device 100 of this system 1. Both of these transmitting / receiving means 71 and 72 can be configured with known transmitting / receiving means that can operate in a wireless communication environment (including wireless LAN and Wi-Fi environments).

[0056] The unit 110 is provided with a control means (for example, an MCU) 81 that controls the above-mentioned means 22, 23, 24, 50, 61, and 71 within the unit 110.

[0057] The management device 100 can be configured as a known personal computer equipped with a control means (e.g., a CPU) that controls each means possessed by the device 100, input means such as a keyboard and mouse (not shown), a display (not shown), etc.

[0058] When the management device 100 receives unit identification information UI (1 to n) including the power conditioner position information PI and a malfunction alarm FA (or a disconnection alarm CA) from the unit 110, it transmits these alarms to a predetermined notification destination (e.g., a malfunction response department, a theft response department, etc.) 200, and instructs the drone 300, via the transmission / reception means 72, to fly to the installation location P (1 to n) of the power conditioner 5 for which the malfunction alarm FA (or disconnection alarm CA) was issued, as its destination, using the flight instruction means 80.

[0059] 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 is equipped with a position information memory unit 303 that stores at least the power conditioner position information PI (installation position P(1 to n)) and the position information of the hangar described later, which are provided by the management device 100, a transmission / reception means 304 that enables transmission and reception of various information including video signals between the management device 100 and the hangar 400 described later, and a control means 305 that controls each of these units (including each unit described later).When the drone 300 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 its destination, it reads out the destination information corresponding to the flight command (for example, the installation position P(1) of the power conditioner 5(1)) from the position information memory unit 303 and flies toward that installation position.

[0060] The drone 300 has a comparison and judgment means 306 that compares the drone's current position with the installation position and judges that the destination has been reached when both positions are within a predetermined range (for example, within a range of 1 m in both latitude and longitude when converted into distance), and when this comparison and judgment means 306 judges that the destination has been reached, the control means 305 activates the camera 301 based on the arrival signal. The camera 301 is configured with a camera having a moving object detection function. The camera 301 captures an image V of the area around the installation position of the power conditioner 5, and transmits the image V (image signal) to the management device 100. The management device 100 sends this video to a predetermined notification destination 200. This allows the status of problematic cables to be visualized in real time, making it possible to take appropriate action accordingly. The video (video signal) V from the camera 301 may be sent directly to the predetermined notification destination 200 without going through the management device 100.

[0061] This DC cable monitoring system 1 includes a hangar (storage box) 400 for storing drones 300 . As shown in Figure 3, the hangar 400 includes a hangar main body 401, a door 402 that can be opened and closed at the top of the hangar main body 401, a door opening and closing drive mechanism 403 that opens and closes the door 402, and a charging device 405 that performs contactless charging on the driving battery (not shown) of the drone 300.

[0062] The door opening / closing drive mechanism 403 has a means of communication (not shown) with the drone 300, and when it receives a signal indicating that it can send a message from the drone 300 inside the hangar main body 401, it opens the door 402 to allow the drone 300 to take off, and when the drone 300 lands inside the hangar main body 401 after flight, it receives a landing signal from the drone 300 and closes the door 402.

[0063] The hangar 400 is installed at an appropriate location within the area where the DC cable monitoring system 1 is to be applied. The opening / closing drive mechanism 403 that opens and closes the door 402 can be a known mechanism (for example, the mechanism disclosed as the roof opening / closing device 4 in Japanese Patent No. 7200324). The charging device 405 can also be configured as a known appropriate charging device. The power source for the devices and charging device 405 in the storage facility 400 is a backup power supply (UPS) that allows them to be started even in the event of a power outage. The drone 300 can store the location information (latitude, 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.

[0064] The series of operations related to the drone 300 described above is as follows. <Standby> During standby (normal times when no abnormalities occur in the DC cable), the drone 300 is inside the hangar 400 and is charged by the charging device 405 as needed. <When an abnormal situation occurs> (1) When a flight instruction is received from the flight instruction means 80 specifying the installation location P (any of 1 to n) of the power conditioner 5 as the destination, the means 80 begins preparation for departure, reads out information on the destination corresponding to the flight command (for example, the installation location P(1) of the power conditioner 5(1)) from the position information memory unit 303, and when the preparation for departure is complete, sends a signal indicating that the aircraft is ready to send to the door opening / closing drive mechanism 403. (2) Upon receiving the transmission enable signal, the door opening / closing drive mechanism 403 opens the door 402. (3) Upon receiving the signal from the door 402 to open, the drone 300 takes off and flies toward the destination. (4) Upon arrival at the destination, the camera 301 is activated and captures an image V including the DC cable having the abnormality around the installation location of the power conditioner 5 to which the DC cable is connected, and sends the image (video signal) V to the management device 100. (5) When the camera 301 no longer detects a moving object or when a predetermined time has elapsed, the camera 301 stops capturing images and returns to the storage facility 400. Note that the management device 100 may be configured to issue a return command signal directly to the drone 300. (6) When the drone 300 lands on the storage shed 400, the door opening / closing drive mechanism 403 receives a landing signal from the drone 300 and closes the door 402, thereby entering the standby state.

[0065] The above-described cable monitoring operation is repeated until the voltage measured by the voltage measuring means 22 reaches a predetermined voltage of 0 or more, for example, at sunrise.

[0066] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made 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 the present invention is also applicable to the case where there is a single power conditioner. Similarly, the present invention can also be applied to a case where there is only one cable 6. In this case, in the above embodiment, The resistance value measuring means 20 measures the resistance of a single DC cable 6 connecting the aggregation unit (4) and the power conditioner (5). and the equipment connected to this DC cable The resistance value of The abnormal resistance value setting means 30 sets the normal resistance value NR of the DC cable 6 measured by the resistance value measuring means 20 as a reference. upper limit Value L1 and ,under A limit value L2 is set, The abnormal state determination means 50 determines the resistance of the DC cable 6 measured by the resistance value measurement means 20 during cable monitoring. and the equipment connected to this DC cable The resistance value of Upper limit L1 or higher When the above condition is met, it is determined that a break has occurred in the DC cable 6. Below When the limit value L2 is less than the limit value L2, the DC cable 6 and / or the equipment connected to this DC cable 6 This can be applied by determining that a problem other than a disconnection has occurred. [Explanation of symbols]

[0067] 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 means 300: Drone

Claims

1. A solar cell unit; An aggregation unit that aggregates the DC power generated by this solar cell unit, A power conditioner converts DC power from this aggregation unit into AC power, A photovoltaic power generation facility including a DC cable connecting the aggregation unit and a power conditioner, a resistance value measuring means for measuring the resistance value of a DC cable connecting the aggregation unit and a power conditioner and of a device connected to the DC cable; an abnormal resistance value setting means for setting an upper limit and a lower limit of the normal resistance value based on the normal resistance value of the DC cable and the device connected to the DC cable measured by the resistance value measuring means; an abnormality determination means for determining that a break has occurred in the DC cable when the resistance value of the DC cable and the equipment connected to the DC cable measured by the resistance value measurement means is equal to or greater than the upper limit value during cable monitoring, and determining that a malfunction other than a break has occurred in the DC cable and / or the equipment connected to the DC cable when the resistance value is less than the lower limit value; a power conditioner position information storage means for storing the installation location of the power conditioner as power conditioner position information including at least latitude and longitude; a drone that can fly to a destination of the installation location of the power conditioner based on the power conditioner position information stored in the power conditioner position information storage means, and that is equipped with a camera that can capture images of the area around the installation location of the power conditioner including the DC cable connected to the power conditioner, and an image transmission means that can transmit the images captured by the camera; A DC cable monitoring system for a solar power generation facility, comprising:

2. A solar cell unit; a plurality of aggregation units that aggregate the DC power generated by the solar cell units; a power conditioner that aggregates DC power from these multiple aggregation units; a plurality of DC cables connecting the plurality of aggregation units and the power conditioner in parallel to each other, a resistance value measuring means for measuring an overall resistance value obtained by adding up the individual resistance values ​​of a plurality of DC cables connecting each aggregation unit and the power conditioner and of devices connected to the DC cables; an abnormal resistance value setting means for setting an upper limit and a lower limit of the normal resistance value based on the normal resistance value of the DC cable and the devices connected to the DC cable measured by the resistance value measuring means; an abnormality determination means for determining that a break has occurred in the DC cable when the total resistance value of the DC cable and the devices connected to the DC cable measured by the resistance value measurement means is equal to or greater than the upper limit value during cable monitoring, and determining that a malfunction other than a break has occurred in the DC cable and / or the devices connected to the DC cable when the total resistance value is less than the lower limit value; a power conditioner position information storage means for storing the installation positions of the plurality of power conditioners as power conditioner position information including at least latitude and longitude; a drone that can fly to a destination of the installation location of the power conditioner based on the power conditioner position information stored in the power conditioner position information storage means, and that is equipped with a camera that can capture images of the area around the installation location of the power conditioner including the DC cable connected to the power conditioner, and an image transmission means that can transmit the images captured by the camera; A DC cable monitoring system for a solar power generation facility, comprising:

3. In claim 1 or 2, further comprising: an alarm issuing means for issuing a disconnection occurrence alarm to the effect that the DC cable has been disconnected when the abnormal state determining means determines that a disconnection has occurred in the DC cable, and for issuing a malfunction occurrence alarm to the effect that a malfunction has occurred in the DC cable and / or in the equipment connected to the DC cable when the abnormal state determining means determines that a malfunction other than a disconnection has occurred in the DC cable and / or in the equipment connected to the DC cable; a flight instruction means for instructing the drone to fly to a destination of an installation location of a power conditioner where it has been determined that a cut has occurred in the DC cable or a malfunction other than a cut has occurred in the DC cable when the abnormality determination means determines that a cut has occurred in the DC cable or a malfunction other than a cut has occurred in the DC cable; A DC cable monitoring system for a solar power generation facility, comprising:

4. In claim 3, At least the resistance value measuring means, the abnormal state determining means, and the alarm issuing means are incorporated into the power conditioner, Further, a management device is provided which is installed at a location away from the power conditioner and wirelessly receives the disconnection occurrence alarm or malfunction occurrence alarm from the alarm issuing means and the image from the drone, This management device is a DC cable monitoring system for a photovoltaic power generation facility, characterized in that it transmits the alarm and video to a predetermined notification destination.

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