WO2015015835A1 - Système de génération d'énergie solaire - Google Patents

Système de génération d'énergie solaire Download PDF

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Publication number
WO2015015835A1
WO2015015835A1 PCT/JP2014/059198 JP2014059198W WO2015015835A1 WO 2015015835 A1 WO2015015835 A1 WO 2015015835A1 JP 2014059198 W JP2014059198 W JP 2014059198W WO 2015015835 A1 WO2015015835 A1 WO 2015015835A1
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Prior art keywords
power generation
ground fault
solar cell
unit
fault detection
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PCT/JP2014/059198
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English (en)
Japanese (ja)
Inventor
吉富政宣
石井隆文
佐藤真也
福田靖
Original Assignee
Ｊｘ日鉱日石エネルギー株式会社
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Publication of WO2015015835A1 publication Critical patent/WO2015015835A1/fr

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
    • H02S50/00—Monitoring or testing of PV systems, e.g. load balancing or fault identification
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/16—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to fault current to earth, frame or mass
    • H02H3/17—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to fault current to earth, frame or mass by means of an auxiliary voltage injected into the installation to be protected
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

Definitions

  • JP2013-158870 application number filed in Japan on July 31, 2013.
  • the contents described in JP2013-158870 are incorporated into the present application.
  • One embodiment of the present invention relates to a solar power generation system, for example, a solar power generation system in which a PID (Potential Induced Degradation) measure is taken.
  • a PID Pultential Induced Degradation
  • a photovoltaic power generation system that generates power using sunlight
  • a plurality of solar cell modules are connected in series and in parallel, and the generated power that has become a large voltage and a large current is a power conditioner or the like.
  • a power conditioner or the like are supplied to a commercial power system and the like.
  • a plurality of solar cell modules are connected in series to form a solar cell string.
  • a plurality of solar cell strings are connected in parallel to form a solar cell array.
  • FIGS. 9A and 9B are conceptual diagrams for explaining an example of the PID phenomenon.
  • 9A and 9B show one solar cell string 502 as an example of the solar cell array of the photovoltaic power generation system.
  • FIG. 9A the case where a p-type semiconductor is used for the bulk of a solar cell is shown as an example.
  • FIG. 9B shows an example in which an n-type semiconductor is used for the bulk of the solar cell.
  • the performance may be deteriorated at a positive potential rather than the ground potential.
  • FIGS. 10A and 10B are conceptual diagrams for explaining an example of a countermeasure technique for the PID phenomenon.
  • a countermeasure method against the PID phenomenon it has been considered to take a countermeasure on the solar cell module and the cell itself, but as a reliable technique, it is considered to ground the negative electrode or the positive electrode of the photovoltaic power generation system.
  • FIG. 10A the case where a p-type semiconductor is used for the bulk of a solar cell is shown as an example. In such a case, the negative electrode side of the solar cell string 502 is grounded in a state where the solar power generation system is constructed in a system insulated from a commercial power system or the like.
  • the entire solar cell string 502 can be prevented from having a negative potential with respect to the ground potential.
  • Such measures can avoid the PID phenomenon.
  • FIG. 10B the case where an n-type semiconductor is used for the bulk of a solar cell is shown as an example.
  • the positive electrode side of the solar cell string 502 is grounded in a state where the solar power generation system is constructed in a system insulated from a commercial power system or the like. Thereby, it can prevent that the solar cell string 502 whole becomes a positive electric potential rather than the electric potential of the earth.
  • Such measures can avoid the PID phenomenon.
  • FIG. 11 is a conceptual diagram for explaining an example of the ground fault countermeasure of the photovoltaic power generation system in which the PID countermeasure is taken.
  • FIG. 11 shows a case where the negative electrode side of the solar cell string 502 is grounded.
  • FIG. 11 shows a configuration in which an ammeter or / and a fuse are arranged at the grounding location 530 for PID countermeasures for ground fault countermeasures.
  • FIG. 11 for example, when a ground fault occurs in the middle of the solar cell string 502 or on the positive electrode side, a closed loop circuit is formed between the grounding point 530 for PID countermeasures and the ground fault point 600. As a result, a large current flows to the outside.
  • FIG. 12 is a conceptual diagram for explaining an example of a blind spot for detecting a ground fault in a photovoltaic power generation system in which a PID countermeasure is taken.
  • a first ground fault occurs on the negative electrode side of the solar cell string 502
  • no potential difference is generated between the ground location 530 and the ground fault location 602 for PID countermeasures. Therefore, it is difficult to detect such a first ground fault with an ammeter or / and a fuse arranged at the grounding location 530 for PID countermeasures. Therefore, the solar power generation system continues normal operation.
  • one aspect of the present invention provides a photovoltaic power generation system that can overcome the above-described problems and eliminate a blind spot where ground fault detection is difficult while grounding for PID countermeasures is performed. Objective.
  • the photovoltaic power generation system of one embodiment of the present invention is A power generation unit configured using one or more solar cell modules that generate power using sunlight; and A load device that consumes or converts the power generated by the power generation unit while being insulated from the power generation unit side or the ground; and A grounding portion for grounding the negative electrode or the positive electrode of the power generation unit; An exclusion unit arranged to be able to eliminate the influence on the ground potential of the power generation unit caused by the grounding by the grounding unit; In the state where the influence on the ground potential of the power generation unit caused by the grounding by the grounding unit is excluded by the exclusion unit, the ground potential of the power generation unit is detected by controlling the ground potential of the power generation unit to two or more different potentials.
  • a ground fault detector It is provided with.
  • a photovoltaic power generation system configured using one or more solar cell modules that generate power using sunlight; and A load device that consumes or converts the power generated by the power generation unit while being insulated from the power generation unit side or the ground; and A grounding portion for grounding the negative electrode or the positive electrode of the power generation unit;
  • An exclusion unit arranged to be able to eliminate the influence on the ground potential of the power generation unit caused by the grounding by the grounding unit;
  • a current monitoring unit that is disposed on the grounding unit and monitors a current flowing through the grounding unit to detect a ground fault of the power generation unit; In a state where the influence on the ground potential of the power generation unit caused by grounding by the grounding unit is excluded by the exclusion unit, the ground potential of the power generation unit is controlled to a ground potential different from that when grounded by the grounding unit, and the ground of the power generation unit is controlled.
  • a ground fault detector for detecting a fault, It is provided with.
  • FIG. 1 is a configuration diagram showing a configuration of a photovoltaic power generation system in Embodiment 1.
  • FIG. It is a block diagram which shows the structure of the ground fault inspection apparatus of the solar energy power generation system in Embodiment 1.
  • FIG. It is a block diagram which shows the structure of the ground fault inspection apparatus of the solar energy power generation system in Embodiment 1.
  • FIG. It is a block diagram which shows the structure of the solar energy power generation system in Embodiment 2.
  • It is a block diagram which shows the structure of the ground fault inspection apparatus of the solar energy power generation system in Embodiment 2.
  • FIG. It is a block diagram which shows the structure of the ground fault inspection apparatus of the solar energy power generation system in Embodiment 2.
  • FIG. It is a block diagram which shows the structure of the ground fault inspection apparatus of the solar energy power generation system in Embodiment 2.
  • FIG. 10 is a configuration diagram showing a configuration of a photovoltaic power generation system in a third embodiment. It is a block diagram which shows the structure of the ground fault inspection apparatus of the solar energy power generation system in Embodiment 3.
  • FIG. It is a block diagram which shows the structure of the ground fault inspection apparatus of the solar energy power generation system in Embodiment 3.
  • FIG. It is a block diagram which shows the structure of the ground fault inspection apparatus of the solar energy power generation system in Embodiment 3.
  • FIG. It is a block diagram which shows the structure of the ground fault inspection apparatus of the solar energy power generation system in Embodiment 3.
  • FIG. 10 is a configuration diagram showing a configuration of a photovoltaic power generation system in a third embodiment. It is a block diagram which shows the structure of the ground fault inspection apparatus of the solar energy power generation system in Embodiment 3.
  • FIG. It is a block diagram which shows the structure of the ground fault inspection apparatus of the solar energy power generation system in Embodiment 3.
  • FIG. It is
  • FIG. 10 is a configuration diagram showing a configuration of a photovoltaic power generation system in a fifth embodiment. It is a block diagram which shows the structure of the ground fault inspection apparatus of the solar energy power generation system in Embodiment 5. It is a block diagram which shows the structure of the ground fault inspection apparatus of the solar energy power generation system in Embodiment 5.
  • FIG. 10 is a configuration diagram showing a configuration of a solar power generation system in a sixth embodiment. It is a block diagram which shows the structure of the ground fault inspection apparatus of the solar energy power generation system in Embodiment 6.
  • FIG. 10 is a block diagram which shows the structure of the ground fault inspection apparatus of the solar energy power generation system in Embodiment 6.
  • FIG. 10 is a configuration diagram illustrating a configuration of a solar power generation system in a seventh embodiment.
  • FIG. 10 is a configuration diagram illustrating a configuration of a solar power generation system in a seventh embodiment. It is a figure for demonstrating the switch operation
  • FIG. It is a conceptual diagram for demonstrating an example of a PID phenomenon. It is a conceptual diagram for demonstrating an example of a PID phenomenon. It is a conceptual diagram for demonstrating an example of the countermeasure method to a PID phenomenon. It is a conceptual diagram for demonstrating an example of the countermeasure method to a PID phenomenon. It is a conceptual diagram for demonstrating an example of the ground fault countermeasure of the solar power generation system in which the PID countermeasure was taken. It is a conceptual diagram for demonstrating an example of the blind spot of the ground fault detection of the photovoltaic power generation system with which the PID countermeasure was taken.
  • FIG. 1A is a configuration diagram showing the configuration of the photovoltaic power generation system in the first embodiment.
  • 1B to 1C are configuration diagrams illustrating the configuration of the photovoltaic power generation system according to Embodiment 1.
  • a solar power generation system 100 is a system that generates power using solar energy.
  • the solar power generation system 100 includes a solar cell array 300 (an example of a power generation unit) and a load device 400.
  • a plurality of solar cell modules 10a to 10e (an example of a power generation unit) electrically connected in series constitute a solar cell string 12 (an example of a power generation unit).
  • Each solar cell module 10 is a module that uses sunlight to convert solar energy into electrical energy and output it as DC power.
  • the solar cell array 300 includes a plurality of solar cell strings 12a to 12c arranged in parallel.
  • the plurality of solar cell strings 12a to 12c are electrically connected in parallel inside the solar cell array 300.
  • each solar cell string 12 is configured by five solar cell modules 10a to 10e connected in series, but is not limited thereto.
  • the number in series may be two, three, four, or six or more. What is necessary is just to set suitably.
  • the solar cell array 300 is configured by three solar cell strings 12a to 12c connected in parallel, but is not limited thereto.
  • the number in parallel may be one, two, or four or more. What is necessary is just to set suitably.
  • the power generation unit is configured using one or more solar cell modules that generate power using sunlight.
  • each solar cell string 12a-c the positive electrode (+) and the negative electrode (-) of each solar cell string 12a-c are connected to the solar cell strings 12a-c from the system or connected to the system, respectively. Is connected.
  • one end of the switch device 102a is connected to the negative electrode wiring of the solar cell string 12a, and one end of the switch device 102b is connected to the positive electrode wiring.
  • a backflow prevention diode 20a is connected to the other side of both ends of the switch device 102b.
  • one end of the switch device 102c is connected to the negative electrode wiring of the solar cell string 12b, and one end of the switch device 102d is connected to the positive electrode wiring.
  • a backflow prevention diode 20b is connected to the other side of both ends of the switch device 102d.
  • one end of the switch device 102e is connected to the negative electrode wiring of the solar cell string 12c, and one end of the switch device 102f is connected to the positive electrode wiring.
  • a backflow prevention diode 20c is connected to the other side of both ends of the switch device 102f.
  • Each of the backflow prevention diodes 20a to 20c is arranged such that the current flowing from the corresponding solar cell string 12a to 12c flows in the forward direction.
  • the number of switch devices 102 that can be arranged on both poles of the solar cell string 12 is arranged.
  • Each switch device 102 is preferably a switch capable of automatically controlling the opening / closing operation electrically.
  • a ground fault when a ground fault is detected in the solar cell, it may be a mechanical switch that allows the system to be disconnected and stopped in string units, but it is more preferable to use a semiconductor switch or the like, for example. It is.
  • a MOSFET Metal Oxide Semiconductor Field Effect Transistor
  • the backflow prevention diode 20 is disposed only on the positive electrode side of each solar cell string 12, but the present invention is not limited to this.
  • the backflow prevention diode 20 may be disposed only on the negative electrode side of each solar cell string 12.
  • the backflow prevention diode 20 may be arrange
  • each backflow prevention diode 20 is arranged such that the direction in which the current supplied from the corresponding solar cell string 12 flows is the forward direction.
  • each of the solar cell strings 12a to 12c is connected in parallel on the other side of the switch device 102, one of which is connected to the negative electrode of the corresponding solar cell string 12, and one of the corresponding solar cell strings 12
  • the other side of the backflow prevention diode 20 connected to the positive electrode side is connected in parallel.
  • the plurality of solar cell strings 12a to 12c are connected in parallel to form the solar cell array 300.
  • a fuse can be used instead of the backflow prevention diode. In this case, although a reverse current cannot be prevented completely, a solar cell array capable of preventing an excessive reverse current can be configured.
  • the negative electrode wiring (negative electrode bus) of the solar cell array 300 is connected to a switch 402 such as a circuit breaker or disconnector, and the positive electrode wiring (positive electrode bus) is connected to a switch 404 such as a circuit breaker or disconnector.
  • the switches 402 and 404 are connected to the load device 400, respectively.
  • the positive electrode (+) side of the solar cell array 300 is connected to the load device 400 via the switch 404
  • the negative electrode ( ⁇ ) side is connected to the load device 400 via the switch 402.
  • the load device 400 has an insulating transformer inside or on the output side thereof, and prevents the solar cell array from being electrically connected to the ground on the load side. Examples of the load device 400 include a power conditioner.
  • the DC power supplied from the solar cell array 300 to the load device 400 is converted into, for example, three-phase AC power in the load device 400 and supplied to, for example, a commercial power system.
  • the load device 400 consumes or converts the power generated by the solar cell array 300 while being insulated from the solar cell array 300 (power generation unit) side or the ground.
  • a ground wire 40 (an example of a ground portion) branched from the negative electrode wiring (negative electrode bus) of the solar cell array 300 is grounded.
  • the negative electrode wiring is grounded.
  • the positive electrode wiring (positive electrode bus) is grounded.
  • a switch device 44 (an example of an exclusion unit) that disconnects or connects the ground location 41 and the photovoltaic power generation system 100 is disposed in the middle of the ground wire 40.
  • the switch device 44 uses a switch capable of automatically controlling the opening / closing operation electrically.
  • a mechanical switch may be used, it is more preferable to use, for example, a semiconductor switch.
  • a MOSFET MOSFET
  • a current monitoring unit 42 capable of monitoring the current flowing through the ground line 40 is disposed.
  • the current monitoring unit 42 is disposed between the negative electrode of the solar cell array 300 (the positive electrode when an n-type semiconductor is used for the bulk of the solar cell) and the ground location 41 by the ground wire 40.
  • the current monitoring unit 42 for example, an ammeter connected in series to the ground line 40 and / or a fuse is preferably used.
  • the current may be monitored by providing a separate resistor (not shown) in the middle of the ground line 40 as the current monitoring unit 42 and monitoring the voltage at both ends thereof.
  • a ground fault detection device 36 (an example of a ground fault detection unit or a first ground fault detection unit) is further arranged.
  • the wiring branched from the negative electrode wiring (negative electrode bus) of the solar cell array 300 is connected to the ground fault detection device 36 via the switch device 33.
  • the wiring branched from the positive electrode wiring (positive electrode bus) of the solar cell array 300 is connected to the ground fault detection device 36 via the switch device 31.
  • the switch devices 31 and 33 that connect the ground fault detection device 36 to the solar power generation system 100 from the solar power generation system 100 are arranged.
  • the switch devices 31 and 33 use switches capable of automatically controlling the opening / closing operation electrically.
  • the ground fault detection unit 36 is arranged to be disconnected from the solar power generation system 100 and connectable to the solar power generation system 100.
  • the solar power generation system 100 as described above is operated as follows.
  • Each switch device 102, switch device 44, and switches 402 and 404 driven by control from a control system (not shown) are all in an ON state (closed), and switch devices 31 and 33 are in an OFF state (open).
  • Normal operation is performed. That is, during normal operation, the negative electrode of the photovoltaic power generation system 100 is grounded. Thereby, the negative electrode of each solar cell string 12a-c can be controlled to the ground potential, and the PID phenomenon can be avoided.
  • the current monitoring unit 42 (second ground fault detection unit) detects the ground fault of the solar cell array 300 during the normal operation of the solar power generation system 100.
  • the current monitoring unit 42 is disposed on the ground line 40 as described above, and monitors the current flowing through the ground line 40 to detect a ground fault in the power generation unit. As described with reference to FIG. 11, during such normal operation, for example, when a ground fault occurs in the middle of one of the solar battery strings 12 or on the positive electrode side, between the grounding location 41 for PID countermeasures and the ground fault location. As a result, a closed loop circuit is formed, and a large current flows to the outside. Therefore, the current is monitored by the current monitoring unit 42 as a measurement value based on such current, and by monitoring whether a current determined to be dangerous is flowing, a current that is equal to or greater than a threshold before a large current flows to the outside.
  • the control system (not shown) can determine that there is a ground fault and can stop the photovoltaic power generation system 100 in an emergency. However, in this configuration, as described above, a blind spot portion (detection dead zone) for ground fault detection is generated.
  • the ground fault detection device 36 periodically performs ground fault detection. For example, the ground fault is detected every time the photovoltaic power generation system 100 is started or periodically during operation.
  • the ground fault detection unit 36 is connected to the negative electrode of the solar cell array 300 (when an n-type semiconductor is used for the bulk of the solar cell) by a switch device 44 (an example of an exclusion unit) that is driven by control from a control system (not shown) In the state separated from the positive electrode), ground fault detection is performed in units of 300 solar cell arrays.
  • the switch device 44 is arranged so as to eliminate the influence on the potential of the negative electrode of the solar cell array 300 (positive electrode when an n-type semiconductor is used for the bulk of the solar cell) caused by grounding by the ground wire 40.
  • the switch device 44 is disposed so as to be able to eliminate the influence on the ground potential of the power generation unit caused by the grounding by the grounding wire 40.
  • the ground fault detection device 36 detects the ground fault of the solar cell array 300 in a state where the influence on the negative electrode potential of the solar cell array 300 caused by the grounding by the ground wire 40 is eliminated by the switch device 44.
  • the ground fault detection device 36 changes the ground potential of the power generation unit to two or more different potentials in a state where the influence on the ground potential of the power generation unit caused by the grounding by the ground line 40 is eliminated by the switch device 44.
  • Control to detect a ground fault of the power generation unit The switch devices 31 and 33 driven by control from a control system (not shown) are turned on (closed).
  • the ground fault detection unit 36 is connected to the solar power generation system 100 when detecting the ground fault of the solar cell array 300. Further, the switches 402 and 404 may be turned off (open), and in this case, the influence from the load device 400 can be eliminated.
  • the negative electrode wiring of the solar cell array 300 (“negative electrode bus” connecting the negative electrode of the solar cell array 300 and the negative electrode of the load device 400) and the positive electrode wiring (the positive electrode of the solar cell array 300 and the positive electrode of the load device 400).
  • An example of a ground fault detection device connected to both of the “positive electrode bus” connecting the two is shown.
  • a changeover switch 80, a resistor 84, and a voltage monitoring unit 86 are disposed in the ground fault detection device 36.
  • One of the resistors 84 is connected to the changeover switch 80 and the other is grounded. Further, the voltage monitoring unit 86 monitors the potential difference (voltage) at both ends of the resistor 84.
  • the voltage monitoring unit 86 for example, a voltmeter electrically connected in parallel with the resistor 84 can be used. Further, the other of the changeover switch 80, one of which is connected to the resistor 84, has a wiring branched from the negative electrode wiring (negative electrode bus) of the solar cell array 300 and a wiring branched from the positive electrode wiring (positive electrode bus) of the solar cell array 300. And are connected to be switchable. When detecting a ground fault, the changeover switch 80 connects the resistor 84 to, for example, the negative electrode wiring (negative electrode bus) side of the solar cell array 300. In this state, the voltage monitoring unit 86 measures the voltage V ⁇ b> 1 across the resistor 84.
  • the resistor 84 is connected to the positive electrode wiring (positive electrode bus) side of the solar cell array 300, for example.
  • the voltage monitoring unit 86 measures the voltage V ⁇ b> 2 applied across the resistor 84.
  • a control system not shown.
  • the solar power generation system 100 can be stopped urgently.
  • such a ground fault can be detected even if a ground fault accident (insulation failure or the like) occurs in any part of the solar cell array 300.
  • the switch device 44 is opened to eliminate the influence of the ground wire 40 for PID countermeasures, and then connected to the solar cell array 300 (switch device 31, 31 is closed), and by switching the changeover switch 80, the ground position of the solar cell array 300 is switched between the positive electrode wiring and the negative electrode wire, and the ground potential of the solar cell array 300 is controlled to two different potentials. Both-end voltages V1 and V2 are monitored to determine the ground fault. Therefore, ground fault detection becomes possible at the stage when the first ground fault accident (first ground fault accident) occurs, and a blind spot location for ground fault detection by the current monitoring unit 42 during normal operation can be eliminated. Therefore, when using the ground fault detection apparatus shown in FIG. 1B, the current monitoring unit 42 may be omitted.
  • FIG. 1C shows another example of the ground fault detection device connected to both the negative electrode wiring (negative electrode bus) and the positive electrode wiring (positive electrode bus) of the solar cell array 300.
  • the ground fault detection device 36 two resistors 83a and 83b, a resistor 84, and a voltage monitoring unit 86 are arranged.
  • resistors 83a and 83b for example, resistors having the same resistance value may be used.
  • One end of the resistor 83a is connected to a wiring branched from the negative electrode wiring (negative electrode bus) of the solar cell array 300.
  • One of the resistors 83b is connected to a wiring branched from the positive electrode wiring (positive electrode bus) of the solar cell array 300.
  • the other of the resistors 83 a and 83 b is connected to one of the resistors 84.
  • the other end of the resistor 84 is grounded.
  • the middle point obtained by dividing the voltage (potential difference) between the two electrodes of the solar cell array 300 by the resistors 83 a and 83 b is connected to the ground via the resistor 84.
  • the voltage monitoring unit 86 monitors the voltage at both ends of the resistor 84.
  • the voltage monitoring unit 86 for example, a voltmeter electrically connected in parallel with the resistor 84 can be used. In this state, the voltage monitoring unit 86 measures the voltage V applied across the resistor 84.
  • a control system determines that there is a ground fault. And the solar power generation system 100 can be stopped urgently.
  • the current monitoring unit 42 described above can determine the ground fault during normal operation. That is, when monitoring is performed by the ground fault detection device shown in FIG. 1C, the ground potential of the solar cell array 300 is controlled by controlling the ground potential of the solar cell array 300 to a potential different from that when the current monitoring unit 42 performs monitoring. I do.
  • the ground fault detection device 36 is configured when the ground potential of the power generation unit is grounded by the ground line 40 in a state where the influence on the ground potential of the power generation unit caused by grounding by the ground line 40 is eliminated by the switch device 44.
  • the ground potential of the power generation unit is detected by controlling to a ground potential different from the above. Therefore, even if a ground fault occurs in any part of the solar cell array 300, the ground fault is reliably detected by either the current monitoring unit 42 or the ground fault detection device. Therefore, it becomes possible to detect a ground fault at the stage when the first ground fault accident (first ground fault accident) occurs, and it is possible to eliminate the blind spot of ground fault detection by the current monitoring unit 42 during normal operation.
  • FIG. 2A is a configuration diagram showing the configuration of the photovoltaic power generation system in the second embodiment.
  • 2B to 2E are configuration diagrams illustrating the configuration of the ground fault inspection apparatus for the photovoltaic power generation system according to the second embodiment.
  • solar power generation system 100 in Embodiment 2 is the same as FIG. 1A except that ground fault detection device 36 is connected only from the positive electrode wiring (positive electrode bus) of solar cell array 300.
  • the contents other than those described in particular are the same as those in the first embodiment.
  • the photovoltaic power generation system 100 is operated as follows.
  • the switch device 102, the switch device 44, and the switches 402 and 404 that are driven by control from a control system (not shown) are all in the ON (closed) state, and the switch device 31 is in the OFF (open) state. Is done. That is, during normal operation, the negative electrode of the photovoltaic power generation system 100 is grounded. Thereby, the negative electrode of each solar cell string 12a-c can be controlled to ground potential, and the PID phenomenon can be avoided. Then, the current monitoring unit 42 (second ground fault detection unit) detects the ground fault of the solar cell array 300 during the normal operation of the solar power generation system 100. As described with reference to FIG.
  • the ground fault detection device 36 periodically performs ground fault detection. For example, the ground fault is detected every time the photovoltaic power generation system 100 is started or periodically during operation.
  • the ground fault detection unit 36 is connected to the negative electrode of the solar cell array 300 (when an n-type semiconductor is used for the bulk of the solar cell) by a switch device 44 (an example of an exclusion unit) that is driven by control from a control system (not shown). In the state separated from the positive electrode), ground fault detection is performed in units of 300 solar cell arrays.
  • the switch device 31 driven by control from a control system (not shown) is turned on (closed).
  • the ground fault detection unit 36 is connected to the solar power generation system 100 when detecting a ground fault of the solar cell array 300. Further, in order to eliminate the influence from the load device 400, the switches 402 and 404 are turned OFF (open).
  • FIG. 2B shows an example of a ground fault detection device connected only from the positive electrode wiring (positive electrode bus) of the solar cell array 300.
  • a resistor 84 and a voltage monitoring unit 86 are disposed in the ground fault detection device 36.
  • One of the resistors 84 is connected to a wiring branched from the positive electrode wiring (positive electrode bus) of the solar cell array 300, and the other is grounded.
  • the voltage monitoring unit 86 monitors the voltage at both ends of the resistor 84. In this state, the voltage monitoring unit 86 measures the voltage V applied across the resistor 84. When the voltage V exceeds a preset threshold value, a control system (not shown) determines that there is a ground fault. And the solar power generation system 100 can be stopped urgently.
  • the above-mentioned current monitoring unit 42 can determine the ground fault during normal operation. That is, when the ground fault detection device shown in FIG. 2B performs monitoring, the ground potential of the solar cell array 300 is different from that when the current monitoring unit 42 performs monitoring. Even if this occurs, the ground fault is reliably detected by either the current monitoring unit 42 or the ground fault detection device.
  • the ground fault detection device 36 is configured when the ground potential of the power generation unit is grounded by the ground line 40 in a state where the influence on the ground potential of the power generation unit caused by grounding by the ground line 40 is eliminated by the switch device 44.
  • the ground potential of the power generation unit is detected by controlling to a ground potential different from the above. Therefore, ground fault detection becomes possible at the stage when the first ground fault accident (first ground fault accident) occurs, and a blind spot location for ground fault detection by the current monitoring unit 42 during normal operation can be eliminated.
  • FIG. 2C shows another example of the ground fault detection device connected only from the positive electrode wiring (positive electrode bus) of the solar cell array 300.
  • a changeover switch 81 In the ground fault detection device 36, a changeover switch 81, a DC power source 85, a resistor 84, and a voltage monitoring unit 86 are arranged.
  • One of the resistors 84 is connected to the changeover switch 81 and the negative electrode of the DC power supply 85, and the other is grounded. Further, the voltage monitoring unit 86 monitors the voltage at both ends of the resistor 84.
  • One of the changeover switches 81 is connected to a wiring branched from the positive electrode wiring (positive electrode bus) of the solar cell array 300, and the other is connected so that the resistor 84 and the positive electrode of the DC power supply 85 can be switched.
  • the DC power supply 85 applies a voltage so that, for example, the ground potential of the negative electrode of the solar cell array 300 becomes almost zero when the positive electrode of the solar cell array 300 is connected to the ground via the DC power supply 85 and the resistor 84. It is preferable.
  • the changeover switch 81 connects the resistor 84 to, for example, the positive electrode wiring (positive electrode bus) side of the solar cell array 300 without using the DC power supply 85.
  • the voltage monitoring unit 86 measures the voltage V ⁇ b> 1 across the resistor 84.
  • the resistor 84 is connected to the positive electrode wiring (positive electrode bus) side of the solar cell array 300 via the DC power source 85, for example.
  • the voltage monitoring unit 86 measures the voltage V ⁇ b> 2 applied across the resistor 84.
  • the voltage monitoring unit 86 measures the voltage V ⁇ b> 2 applied across the resistor 84.
  • the voltages V2 of the voltage V1 exceeds a preset threshold value, it is determined that there is a ground fault by a control system (not shown). And the solar power generation system 100 can be stopped urgently.
  • the example (D) of the ground fault detection device illustrated in FIG. 2C even when a ground fault accident (insulation failure or the like) occurs in any part of the solar cell array 300, the ground fault can be detected.
  • the ground fault is detected by controlling the ground potential of the solar cell array 300 to two different potentials. Therefore, ground fault detection becomes possible at the stage when the first ground fault accident (first ground fault accident) occurs, and a blind spot location for ground fault detection by the current monitoring unit 42 during normal operation can be eliminated. Therefore, when using the ground fault detection apparatus shown in FIG. 2C, the current monitoring unit 42 may be omitted.
  • FIG. 2D shows another example of the ground fault detection device connected only from the positive electrode wiring (positive electrode bus) of the solar cell array 300.
  • An AC power supply 87, a resistor 84, and a voltage monitoring unit 86 are disposed in the ground fault detection device 36.
  • One of the resistors 84 is connected to the wiring branched from the positive electrode wiring (positive electrode bus) of the solar cell array 300 via the AC power supply 87, and the other is grounded.
  • the voltage monitoring unit 86 monitors the voltage at both ends of the resistor 84. In this state, the voltage monitoring unit 86 measures the voltage V in phase with the AC power supply 87 applied to both ends of the resistor 84 in synchronization with the phase of the AC power supply 87.
  • a control system determines that a ground fault has occurred. And the solar power generation system 100 can be stopped urgently.
  • a potential difference occurs between both ends of the resistor 84 even when a ground fault (insulation failure or the like) occurs in any part of the solar cell array 300. Can be detected.
  • the ground fault detection is performed by controlling the ground potential of the solar cell array 300 to two or more different potentials by the AC power source 87.
  • ground fault detection becomes possible at the stage when the first ground fault accident (first ground fault accident) occurs, and a blind spot location for ground fault detection by the current monitoring unit 42 during normal operation can be eliminated. Therefore, when the ground fault detection apparatus shown in FIG. 2D is used, the current monitoring unit 42 may be omitted.
  • FIG. 2E shows another example of the ground fault detection device connected only from the positive electrode wiring (positive electrode bus) of the solar cell array 300.
  • a DC power supply 89, a resistor 84, and a voltage monitoring unit 86 are disposed in the ground fault detection device 36.
  • One end of the resistor 84 is connected to the positive electrode of the DC power supply 89, and is connected to a wiring branched from the positive electrode wiring (positive electrode bus) of the solar cell array 300 via the DC power supply 89.
  • the other end of the resistor 84 is grounded.
  • the DC power supply 89 applies a voltage so that the ground potential of the positive electrode of the solar cell array 300 becomes negative.
  • the voltage monitoring unit 86 monitors the voltage at both ends of the resistor 84.
  • the voltage monitoring unit 86 measures the voltage V applied across the resistor 84.
  • a control system (not shown) determines that there is a ground fault.
  • the solar power generation system 100 can be stopped urgently.
  • a potential difference is generated at both ends of the resistor 84 even when a ground fault (insulation failure or the like) occurs in any part of the solar cell array 300. Can be detected. Therefore, ground fault detection becomes possible at the stage when the first ground fault accident (first ground fault accident) occurs, and a blind spot location for ground fault detection by the current monitoring unit 42 during normal operation can be eliminated.
  • a blind spot where it is difficult to detect a ground fault can be eliminated or reduced while grounding for PID countermeasures is performed.
  • FIG. 3A is a configuration diagram showing the configuration of the photovoltaic power generation system according to Embodiment 3.
  • 3B to 3E are configuration diagrams illustrating the configuration of the ground fault inspection apparatus for the photovoltaic power generation system according to Embodiment 3. 3A
  • solar power generation system 100 in Embodiment 3 is the same as FIG. 1A except that ground fault detection device 36 is connected only from the negative electrode wiring (negative electrode bus) of solar cell array 300.
  • the contents other than those described in particular are the same as those in the first embodiment.
  • the photovoltaic power generation system 100 is operated as follows.
  • the switch device 102, the switch device 44, and the switches 402 and 404 that are driven by control from a control system (not shown) are all in an ON (closed) state, and the switch device 33 is in an OFF (open) state. Is done. That is, during normal operation, the negative electrode of the photovoltaic power generation system 100 is grounded. Thereby, the negative electrode of each solar cell string 12a-c can be controlled to ground potential, and the PID phenomenon can be avoided. Then, the current monitoring unit 42 (second ground fault detection unit) detects the ground fault of the solar cell array 300 during the normal operation of the solar power generation system 100. As described with reference to FIG.
  • a control system (not shown) can determine that there is a ground fault and can stop the photovoltaic power generation system 100 urgently.
  • a blind spot portion for ground fault detection is generated.
  • the ground fault detection device 36 periodically performs ground fault detection. For example, the ground fault is detected every time the photovoltaic power generation system 100 is started or periodically during operation.
  • the ground fault detection unit 36 is connected to the negative electrode of the solar cell array 300 (when an n-type semiconductor is used for the bulk of the solar cell) by a switch device 44 (an example of an exclusion unit) that is driven by control from a control system (not shown). In the state separated from the positive electrode), ground fault detection is performed in units of 300 solar cell arrays.
  • the switch device 33 driven by control from a control system (not shown) is turned on (closed).
  • the ground fault detection unit 36 is connected to the solar power generation system 100 when detecting a ground fault of the solar cell array 300. Further, the switches 402 and 404 may be turned off (open). In this case, the influence from the load device 400 can be eliminated.
  • FIG. 3B shows an example of a ground fault detection device connected only from the negative electrode wiring (negative electrode bus) of the solar cell array 300.
  • a DC power supply 90, a resistor 84, and a voltage monitoring unit 86 are disposed in the ground fault detection device 36.
  • One end of the resistor 84 is connected to the positive electrode of the DC power supply 90, and is connected to a wiring branched from the negative electrode wiring (negative electrode bus) of the solar cell array 300 via the DC power supply 90.
  • the other end of the resistor 84 is grounded.
  • the DC power supply 90 applies a voltage so that the ground potential of the positive electrode of the solar cell array 300 is almost zero.
  • the voltage monitoring unit 86 monitors the voltage at both ends of the resistor 84.
  • the voltage monitoring unit 86 measures the voltage V applied across the resistor 84.
  • a control system (not shown) determines that there is a ground fault. And the solar power generation system 100 can be stopped urgently.
  • the above-mentioned current monitoring unit 42 can determine the ground fault during normal operation. That is, when monitoring is performed by the ground fault detection device illustrated in FIG.
  • the ground potential of the solar cell array 300 (power generation unit) is different from that when the current monitoring unit 42 performs monitoring, Even if a ground fault occurs at a location, the ground fault is reliably detected by monitoring either the current monitoring unit 42 or the ground fault detection device.
  • the ground fault detection device 36 is configured when the ground potential of the power generation unit is grounded by the ground line 40 in a state where the influence on the ground potential of the power generation unit caused by grounding by the ground line 40 is eliminated by the switch device 44.
  • the ground potential of the power generation unit is detected by controlling to a ground potential different from the above. Therefore, ground fault detection becomes possible at the stage when the first ground fault accident (first ground fault accident) occurs, and a blind spot location for ground fault detection by the current monitoring unit 42 during normal operation can be eliminated.
  • FIG. 3C shows another example of the ground fault detection device connected only from the negative electrode wiring (negative electrode bus) of the solar cell array 300.
  • a changeover switch 81 In the ground fault detection device 36, a changeover switch 81, a DC power supply 91, a resistor 84, and a voltage monitoring unit 86 are arranged.
  • One of the resistors 84 is connected to the changeover switch 81 and the positive electrode of the DC power supply 91, and the other is grounded. Further, the voltage monitoring unit 86 monitors the voltage at both ends of the resistor 84.
  • One of the changeover switches 81 is connected to a wiring branched from the negative electrode wiring (negative electrode bus) of the solar cell array 300, and the other is connected so that the resistor 84 and the negative electrode of the DC power supply 91 can be switched.
  • the DC power supply 91 applies a voltage so that, for example, the ground potential of the positive electrode of the solar cell array 300 becomes almost zero when the negative electrode of the solar cell array 300 is connected to the ground via the DC power supply 91 and the resistor 84. It is preferable.
  • the changeover switch 81 connects the resistor 84 to the negative electrode wiring (negative electrode bus) side of the solar cell array 300 without using the DC power supply 91, for example.
  • the voltage monitoring unit 86 measures the voltage V ⁇ b> 1 across the resistor 84.
  • the resistor 84 is connected to the negative electrode wiring (negative electrode bus) side of the solar cell array 300 via the DC power supply 85, for example.
  • the voltage monitoring unit 86 measures the voltage V ⁇ b> 2 applied across the resistor 84.
  • a control system not shown.
  • the solar power generation system 100 can be stopped urgently.
  • a potential difference occurs between both ends of the resistor 84 even when a ground fault (insulation failure or the like) occurs in any part of the solar cell array 300. Such a ground fault can be detected.
  • FIG. 3D shows another example of the ground fault detection device connected only from the negative electrode wiring (negative electrode bus) of the solar cell array 300.
  • An AC power supply 87, a resistor 84, and a voltage monitoring unit 86 are disposed in the ground fault detection device 36.
  • One of the resistors 84 is connected to the wiring branched from the negative electrode wiring (negative electrode bus) of the solar cell array 300 via the AC power supply 87, and the other is grounded.
  • the voltage monitoring unit 86 monitors the voltage at both ends of the resistor 84. In this state, the voltage monitoring unit 86 measures the voltage V in phase with the AC power supply 87 applied to both ends of the resistor 84 in synchronization with the phase of the AC power supply 87.
  • a control system determines that a ground fault has occurred. And the solar power generation system 100 can be stopped urgently.
  • a potential difference occurs between both ends of the resistor 84 even when a ground fault (such as an insulation failure) occurs in any part of the solar cell array 300. Can be detected. Therefore, ground fault detection becomes possible at the stage when the first ground fault accident (first ground fault accident) occurs, and a blind spot location for ground fault detection by the current monitoring unit 42 during normal operation can be eliminated.
  • FIG. 3E shows another example of the ground fault detection device connected only from the negative electrode wiring (negative electrode bus) of the solar cell array 300.
  • a DC power source 92 In the ground fault detection device 36, a DC power source 92, a resistor 84, and a voltage monitoring unit 86 are arranged.
  • One end of the resistor 84 is connected to the negative electrode of the DC power supply 92, and is connected to a wiring branched from the negative electrode wiring (negative electrode bus) of the solar cell array 300 via the DC power supply 92.
  • the other end of the resistor 84 is grounded.
  • the DC power source 92 applies a voltage so that the ground potential of the negative electrode of the solar cell array 300 is positive.
  • the voltage monitoring unit 86 monitors the voltage at both ends of the resistor 84.
  • the voltage monitoring unit 86 measures the voltage V applied across the resistor 84.
  • a control system (not shown) determines that there is a ground fault.
  • the solar power generation system 100 can be stopped urgently.
  • a potential difference occurs between both ends of the resistor 84 even when a ground fault (insulation failure or the like) occurs in any part of the solar cell array 300. Can be detected. Therefore, ground fault detection becomes possible at the stage when the first ground fault accident (first ground fault accident) occurs, and a blind spot location for ground fault detection by the current monitoring unit 42 during normal operation can be eliminated.
  • the ground fault detection may be performed in units of 12 solar cell strings.
  • the ground fault detection may be performed in units of 12 solar cell strings.
  • the two switch devices 102 connected to the detection target solar cell string 12 are turned off (open)
  • the two switch devices 31 and 33 of the detection target solar cell string 12 are turned on (closed).
  • each of the two switch devices 102 of the remaining solar cell string 12 is turned on (closed), and the two switch devices 31 and 33 of the remaining solar cell string 12 are turned off (open). What is necessary is just to perform the ground fault detection of the content.
  • ground fault detection can be performed about the solar cell string 12 to be detected while each solar cell string 12 other than the solar cell string 12 to be detected is normally operated.
  • FIG. 4A is a configuration diagram showing the configuration of the photovoltaic power generation system according to Embodiment 4.
  • FIG. 4B is a configuration diagram illustrating a configuration of a ground fault inspection apparatus for a photovoltaic power generation system according to Embodiment 4.
  • a current monitoring unit 42 that monitors a point connected to each of the wirings branched from both the negative electrode wiring and the positive electrode wiring of the battery string 12, a point where the switch device 44 is not connected to the ground line 40, and a current flowing through the ground line 40.
  • the points are the same as in FIG.
  • the negative electrode wiring connected to the ground fault detection device 36 is branched from between the negative electrodes of the solar cell strings 12a to 12c and the switch devices 102a, c, e.
  • the positive wiring connected to the ground fault detection device 36 is branched from between the positive electrodes of the solar cell strings 12a to 12c and the switch devices 102b, e, and f.
  • the wiring branched from the negative electrode wiring that connects the negative electrode of the solar cell string 12a and the switch device 102a is connected to the ground fault detection device 36 via the switch device 33a.
  • the wiring branched from the positive electrode wiring which connects the positive electrode of the solar cell string 12a and the switch apparatus 102b is connected to the ground fault detection apparatus 36 via the switch apparatus 31a.
  • the wiring branched from the negative electrode wiring which connects the negative electrode of the solar cell string 12b and the switch apparatus 102c is connected to the ground fault detection apparatus 36 via the switch apparatus 33b.
  • the wiring branched from the positive electrode wiring which connects the positive electrode of the solar cell string 12b and the switch apparatus 102d is connected to the ground fault detection apparatus 36 via the switch apparatus 31b.
  • the wiring branched from the negative electrode wiring which connects the negative electrode of the solar cell string 12c and the switch apparatus 102e is connected to the ground fault detection apparatus 36 via the switch apparatus 33c.
  • the wiring branched from the positive electrode wiring which connects the positive electrode of the solar cell string 12c and the switch apparatus 102f is connected to the ground fault detection apparatus 36 via the switch apparatus 31c.
  • the connection from each solar cell string 12 to the ground fault detection device 36 is connected in parallel as shown in FIG. 4A.
  • a ground wire 40 (an example of a ground portion) branched from the negative electrode wiring (negative electrode bus) of the solar cell array 300 is grounded.
  • a solar cell using a p-type semiconductor for the bulk of the solar cell or a transparent conductive film is shown as an example. Therefore, the negative electrode wiring is grounded.
  • the positive electrode wiring (positive electrode bus) is grounded.
  • the solar power generation system 100 as described above is operated as follows.
  • Each switch device 102 and the switches 402 and 404 driven by control from a control system (not shown) are all in an ON (closed) state, and each switch device 31 and 33 is in an OFF (open) state, and normal operation is performed. Done. That is, during normal operation, the negative electrode of the photovoltaic power generation system 100 is grounded. Thereby, the negative electrode of each solar cell string 12a-c can be controlled to ground potential, and the PID phenomenon can be avoided.
  • the ground fault detection is not performed in units of the solar cell array 300 during the normal operation of the photovoltaic power generation system 100. In the fourth embodiment, ground fault detection is performed in units of 12 solar cell strings.
  • the two switch devices 31 and 33 of the detection target solar cell string 12 are turned on (closed).
  • the ground fault detection may be performed in a state where each of the two switch devices 102 of the remaining solar cell strings 12 is left ON (closed). Thereby, ground fault detection can be performed about the solar cell string 12 to be detected while each solar cell string 12 other than the solar cell string 12 to be detected is normally operated.
  • the ground fault detection is periodically performed by the ground fault detection device 36 for each solar cell string 12.
  • the ground fault is detected every time the photovoltaic power generation system 100 is started or periodically during operation.
  • the ground fault detection unit 36 is driven by control from a control system (not shown), and the ground line 40 is detected by the positive and negative switch devices 102 (an example of an exclusion unit) of the solar cell string 12 to be detected.
  • the ground fault is detected in units of the solar cell string 12 in a state of being disconnected from the negative electrode of the battery string 12 (positive electrode when an n-type semiconductor is used for the bulk of the solar cell).
  • the plurality of switch devices 102a to 102f individually disconnect the ground wire 40 (ground portion) from the plurality of solar cell strings 12a to 12c.
  • the switch device 102 on the negative electrode side of the solar cell string 12 to be detected is the negative electrode of the solar cell string 12 to be detected caused by the grounding by the ground wire 40 (when an n-type semiconductor is used for the bulk of the solar cell).
  • the ground fault detection apparatus 36 is the state of the solar cell string 12 of detection object in the state by which the influence on the electric potential of the negative electrode of the solar cell string 12 of detection object produced by the earthing
  • the detection target solar cell string 12 is disconnected from the system by turning off (opening) the two switch devices 102 of the detection target solar cell string 12.
  • the switch devices 31 and 33 that are connected to the positive and negative electrodes of the solar cell string 12 to be detected and are driven by control from a control system (not shown) are turned on (closed).
  • the ground fault detection unit 36 is connected to the solar power generation system 100 when detecting a ground fault of the solar cell string 12 to be detected.
  • the two switch devices 102 connected to the positive and negative electrodes other than the detection target solar cell string 12 and driven by control from a control system (not shown) are turned on (closed) and driven by control from a control system (not shown).
  • the switch devices 31 and 33 are OFF (open).
  • the switches 402 and 404 are turned on (closed).
  • FIG. 4B shows an example of a ground fault detection device connected to both the negative electrode wiring and the positive electrode wiring of the solar cell string 12 to be detected.
  • the configuration of the ground fault detection device 36 is the same as that in FIG. 1B.
  • the changeover switch 80 connects the resistor 84 to, for example, the negative electrode wiring side of the solar cell string 12 to be detected.
  • the voltage monitoring unit 86 measures the voltage V ⁇ b> 1 across the resistor 84.
  • the resistor 84 is connected to the positive electrode wiring side of the solar cell string 12 to be detected, for example.
  • the voltage monitoring unit 86 measures the voltage V ⁇ b> 2 applied across the resistor 84.
  • the ground fault can be determined by the voltage V2.
  • a ground fault can be determined based on the voltage V1 and the voltage V2. Therefore, ground fault detection becomes possible at the stage when the first ground fault accident (first ground fault accident) occurs, and the blind spot location for ground fault detection can be eliminated.
  • FIG. 5A is a configuration diagram showing the configuration of the photovoltaic power generation system according to Embodiment 5.
  • 5B to 5D are configuration diagrams illustrating the configuration of the ground fault inspection apparatus for the photovoltaic power generation system according to Embodiment 5.
  • 5A the solar power generation system 100 in Embodiment 5 is the same as FIG. 4A except that the ground fault detection device 36 is connected only from the positive electrode wiring of each solar cell string 12. Further, the contents other than those specifically described are the same as those in the fourth embodiment.
  • the photovoltaic power generation system 100 is operated as follows.
  • Each switch device 102 driven by control from a control system (not shown) and the switches 402 and 404 are both in an ON (closed) state, and each switch device 31 is in an OFF (open) state, and a normal operation is performed. . That is, during normal operation, the negative electrode of the photovoltaic power generation system 100 is grounded. Thereby, the negative electrode of each solar cell string 12a-c can be controlled to ground potential, and the PID phenomenon can be avoided.
  • the ground fault detection is not performed in units of the solar cell array 300. In the fifth embodiment, ground fault detection is performed in units of 12 solar cell strings.
  • the ground fault detection device 36 periodically performs ground fault detection. For example, the ground fault is detected every time the photovoltaic power generation system 100 is started or periodically during operation.
  • the ground fault detection unit 36 is driven by control from a control system (not shown), and the ground line 40 of the detection target solar cell string 12 is detected by the bipolar switch device 102 (an example of an exclusion unit) of the detection target solar cell string 12.
  • Ground fault detection is performed in units of 12 solar cell strings in a state separated from the negative electrode (positive electrode when an n-type semiconductor is used for the bulk of the solar cell).
  • the switch device 31 of the solar cell string 12 to be detected that is driven by control from a control system (not shown) is set to ON (closed).
  • the ground fault detection unit 36 is connected to the solar power generation system 100 when detecting a ground fault of the solar cell string 12 to be detected.
  • FIG. 5B shows another example of the ground fault detection device connected only from the positive electrode wiring of the solar cell string 12 to be detected.
  • the configuration of the ground fault detection device 36 is the same as that in FIG. 2C.
  • the changeover switch 81 connects the resistor 84 to, for example, the positive electrode wiring (positive electrode bus) side of the solar cell array 300 without using the DC power supply 85.
  • the voltage monitoring unit 86 measures the voltage V ⁇ b> 1 across the resistor 84.
  • the resistor 84 is connected to the positive electrode wiring side of the solar cell string 12 to be detected via the DC power source 85, for example. In this state, the voltage monitoring unit 86 measures the voltage V ⁇ b> 2 applied across the resistor 84.
  • the ground fault can be determined by the voltage V1.
  • a ground fault can be determined based on the voltage V1 and the voltage V2. Therefore, ground fault detection becomes possible at the stage when the first ground fault accident (first ground fault accident) occurs, and the blind spot location for ground fault detection can be eliminated.
  • FIG. 5C shows another example of the ground fault detection device connected only from the positive electrode wiring of the solar cell string 12 to be detected.
  • the configuration of the ground fault detection device 36 is the same as that in FIG. 2D.
  • the voltage monitoring unit 86 measures the voltage V in phase with the AC power supply 87 applied to both ends of the resistor 84 in synchronization with the phase of the AC power supply 87.
  • a control system (not shown) determines that a ground fault has occurred. Then, the detection target solar cell string 12 or the photovoltaic power generation system 100 can be urgently stopped.
  • E the example of the ground fault detection device shown in FIG.
  • FIG. 5D shows another example of the ground fault detection device connected only from the positive electrode wiring (positive electrode bus) of the solar cell array 300.
  • the configuration of the ground fault detection device is the same as that shown in FIG. 2E.
  • the voltage monitoring unit 86 measures the voltage V applied across the resistor 84.
  • a control system (not shown) determines that there is a ground fault.
  • the detection target solar cell string 12 or the photovoltaic power generation system 100 can be urgently stopped.
  • a potential difference occurs between both ends of the resistor 84 even when a ground fault (insulation failure or the like) occurs in any part of the solar cell array 300. Can be detected. Therefore, it becomes possible to detect a ground fault at the stage when the first ground fault accident (first ground fault accident) occurs, and it is possible to eliminate the blind spot of ground fault detection by the current monitoring unit 42 during normal operation.
  • FIG. 6A is a configuration diagram showing the configuration of the photovoltaic power generation system in the sixth embodiment.
  • 6B to 6D are configuration diagrams illustrating the configuration of the ground fault inspection apparatus for the photovoltaic power generation system according to Embodiment 6.
  • the photovoltaic power generation system 100 according to Embodiment 6 is the same as FIG. 4A except that the ground fault detection device 36 is connected only from the positive electrode wiring of each solar cell string 12. Further, the contents other than those specifically described are the same as those in the fourth embodiment.
  • the photovoltaic power generation system 100 is operated as follows.
  • Each switch device 102 driven by control from a control system (not shown) and the switches 402 and 404 are both in an ON (closed) state, and each switch device 33 is in an OFF (open) state, and a normal operation is performed. . That is, during normal operation, the negative electrode of the photovoltaic power generation system 100 is grounded. Thereby, the negative electrode of each solar cell string 12a-c can be controlled to ground potential, and the PID phenomenon can be avoided.
  • the ground fault detection is not performed for each solar cell array 300 during the normal operation of the photovoltaic power generation system 100. In the sixth embodiment, ground fault detection is performed in units of 12 solar cell strings.
  • the ground fault detection device 36 periodically performs ground fault detection. For example, the ground fault is detected every time the photovoltaic power generation system 100 is started or periodically during operation.
  • the ground fault detection unit 36 is driven by control from a control system (not shown), and the ground line 40 of the detection target solar cell string 12 is detected by the bipolar switch device 102 (an example of an exclusion unit) of the detection target solar cell string 12.
  • Ground fault detection is performed in units of 12 solar cell strings in a state separated from the negative electrode (positive electrode when an n-type semiconductor is used for the bulk of the solar cell).
  • the switch device 33 of the solar cell string 12 to be detected that is driven by control from a control system (not shown) is set to ON (closed).
  • the ground fault detection unit 36 is connected to the solar power generation system 100 when detecting a ground fault of the solar cell string 12 to be detected.
  • FIG. 6B shows an example of a ground fault detection device connected only from the negative electrode wiring of the solar cell string 12 to be detected.
  • the configuration of the ground fault detection device 36 is the same as that shown in FIG. 3C.
  • the changeover switch 81 connects the resistor 84 to the negative electrode wiring side of the solar cell string 12 to be detected without using the DC power supply 91, for example.
  • the voltage monitoring unit 86 measures the voltage V ⁇ b> 1 across the resistor 84.
  • the resistor 84 is connected to the negative electrode wiring side of the solar cell string 12 to be detected via the DC power source 85, for example.
  • the voltage monitoring unit 86 measures the voltage V ⁇ b> 2 applied across the resistor 84.
  • FIG. 6C shows another example of the ground fault detection device connected only from the negative electrode wiring of the solar cell string 12 to be detected.
  • the configuration of the ground fault detection device 36 is the same as that in FIG. 3D.
  • the voltage monitoring unit 86 measures the voltage V in phase with the AC power supply 87 applied to both ends of the resistor 84 in synchronization with the phase of the AC power supply 87.
  • a control system (not shown) determines that a ground fault has occurred. Then, the detection target solar cell string 12 or the solar power generation system 100 can be urgently stopped.
  • E the example of the ground fault detection device shown in FIG.
  • FIG. 6D shows another example of the ground fault detection device connected only from the negative electrode wiring of the solar cell string 12 to be detected.
  • the configuration of the ground fault detection device 36 is the same as that shown in FIG. 3E.
  • the voltage monitoring unit 86 measures the voltage V applied across the resistor 84.
  • a control system (not shown) determines that there is a ground fault.
  • the detection target solar cell string 12 or the solar power generation system 100 can be urgently stopped.
  • a potential difference occurs between both ends of the resistor 84 even when a ground fault (insulation failure or the like) occurs at any location of the solar cell string 12 to be detected.
  • Such a ground fault can be detected. Therefore, ground fault detection becomes possible at the stage when the first ground fault accident (first ground fault accident) occurs, and the blind spot location for ground fault detection can be eliminated.
  • the ground wire 40 is branched from the negative electrode bus of the solar cell array 300 (a positive bus when an n-type semiconductor is used for the bulk of the solar cell) and is grounded. It is not a thing.
  • the ground line 40 is branched and grounded from the negative electrode (positive electrode when an n-type semiconductor is used for the bulk of the solar cell) for each solar cell string 12 will be described.
  • the contents other than those specifically described are the same as those of the fourth embodiment.
  • FIG. 7A and 7B are configuration diagrams showing the configuration of the photovoltaic power generation system according to the seventh embodiment.
  • the ground lines 40a to 40c are branched from the negative electrode wirings of the solar cell strings 12a to 12c, respectively.
  • 4A is the same as FIG. 4A except that diodes 46a to 46c for preventing backflow are respectively connected in the middle of the ground lines 40a to 40c and that switch devices 48a to 48f are provided for the solar cell strings 12a to 12c. is there. As shown in FIG.
  • the diodes 46a to 46c are connected with the direction from the ground (ground) toward the negative electrodes of the solar cell strings 12a to 12c as the forward direction.
  • the negative electrode of the solar cell string 12 has a lower potential than the ground, and PID may not be prevented.
  • Each diode 46a-c also arranges switch devices 48a, c, e between the connection points of the negative lines of solar cell strings 12a-c and corresponding ground lines 40a-c. Further, the switch devices 48b, e, f are arranged between the positive electrodes of the solar cell strings 12a-c and the corresponding switch devices 102b, e, f.
  • the negative electrode wiring connected to the ground fault detection device 36 is branched from between the negative electrodes of the solar cell strings 12a to 12c and the switch devices 48a, c, e.
  • the positive wiring connected to the ground fault detection device 36 is branched from between the positive electrodes of the solar cell strings 12a to 12c and the switch devices 48b, e, and f.
  • the switch device 48 uses a switch that can automatically control the opening / closing operation electrically. Although a mechanical switch may be used, it is more preferable to use, for example, a semiconductor switch. For example, it is preferable to use a MOSFET.
  • the solar power generation system 100 as described above is operated as follows.
  • Each switch device 102, each switch device 48, and switches 402 and 404 driven by control from a control system (not shown) are all in an ON (closed) state, and each switch device 31 and 33 is in an OFF (open) state.
  • normal operation is performed.
  • the negative electrodes of the solar cell strings 12a to 12c are grounded.
  • the negative electrode of each solar cell string 12a-c can be controlled to ground potential, and the PID phenomenon can be avoided.
  • the ground fault detection is not performed in units of the solar cell array 300.
  • ground fault detection is performed in units of 12 solar cell strings.
  • FIG. 8 is a diagram for explaining the switch operation in the case where the ground fault detection of the photovoltaic power generation system according to the seventh embodiment is performed.
  • ground fault detection is periodically performed by the ground fault detection device 36.
  • the ground fault is detected every time the photovoltaic power generation system 100 is started or periodically during operation.
  • the ground fault detection unit 36 is driven by control from a control system (not shown), and the positive and negative switch devices 48 (for example, the switch devices 48a and 48b) of the solar cell string 12 to be detected (for example, the solar cell string 12a) ( In the state where the ground wire 40 (for example, the ground wire 40a) is separated from the negative electrode of the solar cell string 12 to be detected (positive electrode when an n-type semiconductor is used for the bulk of the solar cell) by the example of the exclusion unit, Ground fault detection is performed in units of 12 solar cell strings.
  • the plurality of switch devices 48a to 48f individually disconnect the ground lines 40a to 40c (ground portions) from the plurality of solar cell strings 12a to 12c.
  • the switch device 48 on the negative electrode side of the solar cell string 12 to be detected is provided with the negative electrode of the solar cell string 12 to be detected caused by grounding by the ground wire 40 (when an n-type semiconductor is used for the bulk of the solar cell Are arranged so as to eliminate the influence on the potential of the positive electrode).
  • the ground fault detection device 36 is configured so that the influence of the detection target solar cell string 12 caused by the grounding by the ground line 40 on the negative electrode potential is eliminated by the switch device 48 in the detection target solar cell string 12. Detect a ground fault.
  • the detection target solar cell string 12 is disconnected from the system by turning off (opening) the two switch devices 48 of the detection target solar cell string 12.
  • the switch devices 31 and 33 that are connected to the positive and negative electrodes of the solar cell string 12 to be detected and are driven by control from a control system (not shown) are turned on (closed).
  • the ground fault detection unit 36 is connected to the solar power generation system 100 when detecting a ground fault of the solar cell string 12 to be detected.
  • the two switch devices 48 connected to the positive and negative electrodes other than the detection target solar cell string 12 and driven by control from a control system (not shown) are turned on (closed) and driven by control from a control system (not shown).
  • the switch devices 31 and 33 are OFF (open).
  • Each switch device 102 and switches 402 and 404 are turned ON (closed).
  • ground fault detection device 36 and the ground fault detection method may be the same as those described in FIG. 4B.
  • the seventh embodiment it is possible to eliminate a blind spot where it is difficult to detect a ground fault while performing grounding for PID countermeasures.
  • both the positive electrode and the negative electrode of each solar cell string 12 are connected to the ground fault detection device 36.
  • one of the positive electrode or the negative electrode of each solar cell string 12 is connected to the ground fault detection device 36. It may be configured to connect to.
  • the internal configuration and ground fault detection method of the ground fault detection device 36 when the positive electrode of each solar cell string 12 is connected to the ground fault detection device 36 may be the same as the contents described in FIGS. 5B to 5D.
  • the internal configuration and ground fault detection method of the ground fault detection device 36 when the negative electrode of each solar cell string 12 is connected to the ground fault detection device 36 may be the same as the contents described in FIGS. 6B to 6D.
  • the embodiment has been described above with reference to specific examples. However, the present invention is not limited to these specific examples.
  • the failure detection method described above is an example, and is not limited to the failure detection method described above. Other fault detection methods such as ground faults may be used.
  • One embodiment of the present invention relates to a solar power generation system, and can be used for, for example, a solar power generation system in which a PID countermeasure is taken.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Photovoltaic Devices (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

Selon un mode de réalisation, la présente invention porte sur un système de génération d'énergie solaire qui est caractérisé en ce qu'il comprend: une unité de génération d'énergie comportant un ou plusieurs modules solaires qui utilisent la lumière du soleil pour générer de l'énergie électrique ; un dispositif de charge, électriquement isolé du côté unité de génération d'énergie ou de la masse, qui consomme ou convertit l'énergie électrique générée par l'unité de génération d'énergie ; une unité de mise à la masse qui met à la masse l'électrode positive ou l'électrode négative de l'unité de génération d'énergie ; une unité d'exclusion positionnée de manière à pouvoir exclure l'effet que la mise à la masse effectuée par l'unité de mise à la masse aurait sur le potentiel de masse de l'unité de production d'énergie ; une unité de détection de défaut de masse qui détecte des défauts de masse dans l'unité de génération d'énergie, l'effet que la mise à la masse effectuée par l'unité de mise à la masse aurait sur le potentiel de masse de l'unité de génération d'énergie étant exclu par l'unité d'exclusion, par réglage de son potentiel de masse à au moins deux potentiels différents.
PCT/JP2014/059198 2013-07-31 2014-03-28 Système de génération d'énergie solaire WO2015015835A1 (fr)

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US10323623B2 (en) 2016-10-25 2019-06-18 General Electric Company System and method for transporting or storing wind turbine tower sections
CN110785905A (zh) * 2017-06-23 2020-02-11 东芝三菱电机产业系统株式会社 电力转换装置的控制装置

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CN113489354B (zh) * 2021-05-27 2022-05-31 华为数字能源技术有限公司 一种光伏发电系统及变换电路
KR20230092115A (ko) * 2021-12-17 2023-06-26 주식회사 엘지에너지솔루션 에너지 저장 시스템 및 에너지 저장 시스템의 접지구조 제어 방법
KR102637544B1 (ko) * 2023-06-16 2024-02-16 박동철 태양광 발전 시스템의 태양광 dc 어레이 관리 장치 및 방법

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JP2013033827A (ja) * 2011-08-01 2013-02-14 Jx Nippon Oil & Energy Corp 地絡検出装置、地絡検出方法、太陽光発電システム、及び地絡検出プログラム

Cited By (4)

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Publication number Priority date Publication date Assignee Title
US10323623B2 (en) 2016-10-25 2019-06-18 General Electric Company System and method for transporting or storing wind turbine tower sections
CN110785905A (zh) * 2017-06-23 2020-02-11 东芝三菱电机产业系统株式会社 电力转换装置的控制装置
CN110785905B (zh) * 2017-06-23 2022-04-01 东芝三菱电机产业系统株式会社 电力转换装置的控制装置
CN109639233A (zh) * 2018-12-12 2019-04-16 深圳市禾望科技有限公司 电势诱导衰减装置及其控制方法

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