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; 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.). Since the measures to be taken when the DC cable abnormality is due to theft are different from the measures to be taken when the DC cable 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; 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.). Since the measures to be taken when the DC cable abnormality is due to theft are different from the measures to be taken when the DC cable 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 The device may be configured to include an alarm issuing means for issuing an alarm to notify the user that a malfunction has occurred. 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.).

[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 the malfunction occurrence alarm from the alarm issuing means, The management device may be configured to transmit the alarm 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. 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 value an 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 above condition is met, it is determined that a break has occurred in the DC cable 6 (or one or more of the cables), 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 and an abnormal state determination means 50 for determining that a malfunction other than disconnection has occurred.

[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 The system is provided with an alarm issuing means 60 for issuing a malfunction alarm FA to notify the user that a malfunction has occurred.

[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 remote from the power conditioner 5 and wirelessly receives a disconnection occurrence alarm CA or a malfunction occurrence alarm FA from the alarm issuing means 60, The management device 100 transmits the alarm 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 individual 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.

[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.

[0036] In addition, in the DC cable monitoring system for this solar power generation facility, at least the resistance value measuring means 20, the abnormal state determining means 50, and the alarm issuing means 60 are incorporated into the power conditioner 5, and further, a management device 100 is installed in a location separate from the power conditioner 5, and this management device 100 wirelessly receives the disconnection occurrence alarm CA or the malfunction occurrence alarm FA from the alarm issuing means 60 and transmits these alarms 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 by 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) measured in sequence by the resistance measuring instrument 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 The overall resistance value is determined as 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 is set. 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 is true, 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, the abnormal state determining means 50, the alarm issuing means 61 (60), and the transmitting / receiving means 71 are configured as a unit 110 and incorporated into the power conditioner 5 (see FIG. 1 ). The management device 100 includes a unit identification information assigning means 10, and the unique unit identification information UI assigned to each unit 110 by the unit identification information assigning means 10 is stored in the memory 41 via the transmitting / receiving means 71, 72, and the control unit 81. A signal from the alarm issuing means 61 is sent together with the 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 included in the management device 100 of the system 1. Both of these transmitting / receiving means 71, 72 can be configured as known transmitting / receiving means capable of operating in a wireless communication environment (including a wireless LAN or Wi-Fi environment).

[0054] 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.

[0055] 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.

[0056] When the management device 100 receives the unit identification information UI (1 to n) and the malfunction occurrence alarm FA (or disconnection occurrence alarm CA) from the unit 110, it transmits these alarms to a predetermined notification destination (e.g., a malfunction response department, a theft response department, etc.) 200. This allows for appropriate measures to be taken immediately in response to the problem on the cable in question.

[0057] 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.

[0058] 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]

[0059] 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

Claims

1. a solar cell unit (3); an aggregation unit (4) that aggregates the DC power generated by the solar cell unit (3); a power conditioner (5) that converts DC power from the aggregation unit (4) into AC power; In a solar power generation facility (2) including a DC cable (6) connecting the aggregation unit (4) and a power conditioner (5), a resistance value measuring means (20) capable of measuring the resistance value of a DC cable (6) connecting the aggregation unit (4) and a power conditioner (5) and of devices connected to the DC cable (6); an abnormal resistance value setting means (30) for setting an upper limit (L1) of the normal resistance value and a lower limit (L2) of the normal resistance value based on the normal resistance value (NR) of the DC cable (6) and the devices connected to the DC cable (6) measured by the resistance value measuring means (20); an abnormality determination means (50) for determining that a break has occurred in the DC cable (6) when the resistance value of the DC cable (6) and the equipment connected to the DC cable (6) measured by the resistance value measurement means (20) during cable monitoring is equal to or greater than the upper limit value (L1), and determining that a malfunction other than a break has occurred in the DC cable (6) and / or the equipment connected to the DC cable (6) when the resistance value is less than the lower limit value (L2); and Equipped with The resistance value measuring means (20), the abnormal state determining means (50), and the control means (81) for controlling each of these means are configured as a unit (110) and incorporated into the power conditioner (5), and the DC cable (6) is connected to the resistance value measuring means (20) in the unit (110).

2. 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 plurality of aggregation units (4); In a solar power generation facility (2) including a plurality of DC cables (6) that connect the plurality of aggregation units (4) and the power conditioners (5) in parallel with each other, a resistance value measuring means (20) capable of measuring an overall resistance value obtained by adding up the individual resistance values ​​of a plurality of DC cables (6) connecting each aggregation unit (4) and a power conditioner (5) and of devices connected to the DC cables (6); an abnormal resistance value setting means (30) for setting an upper limit (L1T) of the normal resistance value and a lower limit (L2T) of the normal resistance value based on the normal resistance value (NRT) of the DC cable (6) and the devices connected to the DC cable (6) measured by the resistance value measuring means (20); an abnormality determination means (50) for determining that a break has occurred in the DC cable (6) when the total resistance value of the DC cable (6) and the devices connected to the DC cable (6) measured by the resistance value measurement means (20) during cable monitoring is equal to or greater than the upper limit value (L1T), and determining that a malfunction other than a break has occurred in the DC cable (6) and / or the devices connected to the DC cable (6) when the total resistance value is less than the lower limit value (L2T); Equipped with The resistance value measuring means (20), the abnormal state determining means (50), and the control means (81) for controlling each of these means are configured as a unit (110) and incorporated into the power conditioner (5), and the DC cable (6) is connected to the resistance value measuring means (20) in the unit (110).

3. In claim 1 or 2, further comprising: alarm issuing means (60) for issuing a disconnection occurrence alarm (CA) to the effect that the DC cable (6) has been disconnected when the abnormal state determining means (50) determines that a disconnection has occurred in the DC cable (6), and for issuing a malfunction occurrence alarm (FA) to the effect that a malfunction has occurred in the DC cable (6) and / or in the equipment connected to the DC cable (6) when it determines that a malfunction other than a disconnection has occurred in the DC cable (6) and / or in the equipment connected to the DC cable (6); This DC cable monitoring system for a solar power generation facility is characterized in that the alarm issuing means (60) is configured as a unit (110) together with a control means (81) that also controls the resistance value measuring means (20), the abnormal state determining means (50), and the alarm issuing means (60).

4. In claim 3, Further, a management device (100) is provided which 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 issuing means (60), This management device (100) transmits the alarm to a predetermined notification destination (200). This is a DC cable monitoring system for a photovoltaic power generation facility.

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