Fault positioning system of photovoltaic power station

Abstract

The invention discloses a fault positioning system of a photovoltaic power station, and relates to the technical field of integrated circuits, and the fault positioning system of the photovoltaic power station comprises a starting power supply VCC1, a detection power supply VCC2, resistors R0 and R7, a plurality of first automatic voltage division circuits, a plurality of multiplexers U, a plurality of traversal circuit units, a panel sensor, a support sensor and a short circuit positioning circuit. According to the method, the resistance value and the delay time of each detection node are collected, so that the loosening state of the screws of the photovoltaic module is accurately judged, the loosened photovoltaic module is positioned through the resistance value change, the number of the loosened screws in the photovoltaic module is obtained through the delay time change, and meanwhile, the number of the loosened screws in the photovoltaic module is calculated through a method of combining the MOS tube and the multiplexer. The topological design has the advantages of being simple in structure, convenient to operate, high in detection efficiency and the like, and is suitable for screw looseness detection of equipment such as a photovoltaic module and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits, and in particular to a fault location system for a photovoltaic power station. Background Art

[0002] In the field of circuit detection, traditional traversal detection methods often involve complex circuit layouts and a large number of detection points, which not only increases the difficulty of detection, but also reduces the detection efficiency. Therefore, developing a simple, efficient and reliable traversal detection topology design is of great significance for improving the performance of circuit detection and reducing costs.

[0003] At present, although the existing fault detection technology has made some progress, it still has some shortcomings. For example, a breakpoint detection device based on a bidirectional detection method has complex wiring and high cost, and the number of detections is limited, which is difficult to meet the needs of large-scale circuit detection.

[0004] Currently, no effective solution has been proposed for the problems in the related technologies. Summary of the invention

[0005] In view of the problems in the related art, the present invention proposes a fault location system for a photovoltaic power station to overcome the above technical problems existing in the existing related art.

[0006] To this end, the specific technical solution adopted by the present invention is as follows: A fault location system for a photovoltaic power station, the fault location system for the photovoltaic power station comprising a starting power supply VCC1, a detection power supply VCC2, resistors R0, R7, a plurality of first automatic voltage-dividing circuits, a plurality of multiplexers U, a plurality of traversal circuit units, a panel sensor, a bracket sensor and a short-circuit location circuit; wherein the detection power supply VCC2 is connected in series with the resistor R0, and a single-chip microcomputer detection point X is set, the single-chip microcomputer detection point X is connected to an ADC port of the single-chip microcomputer, the single-chip microcomputer detection point X is connected to Yin of a plurality of traversal circuit units, the first automatic voltage-dividing circuit comprises a resistor R1 and a capacitor C1, the resistor R1 and the capacitor C1 are connected in series and grounded, the first first automatic voltage-dividing circuit is connected to the starting power supply VCC1, and the first first automatic voltage-dividing circuit is connected to the starting power supply VCC2. VCC1, other first automatic voltage-dividing circuits are connected to S2 of the previous multiplexer U, and several first automatic voltage-dividing circuits are connected to VDD and D of the corresponding multiplexer U, and VDD and D of the multiplexer U corresponding to several first automatic voltage-dividing circuits are connected to S2 of the previous multiplexer U; SEL of several multiplexers U is connected between resistor R1 and capacitor C1 in the corresponding first automatic voltage-dividing circuit, S1 of multiplexer U is connected to Vin of the corresponding traversal circuit unit, and R7 is connected to S2 of the last multiplexer U; panel sensors and bracket sensors are used to identify the bolt status, and short-circuit positioning circuits are used to locate short-circuit problems of photovoltaic modules.

[0007] Furthermore, when the startup power supply VCC1 is powered on, the SEL terminal of the first automatic voltage divider circuit is at a low level, and as time goes by, the capacitor C1 is gradually fully charged, the impedance gradually increases, the impedance of the capacitor C1 approaches infinity, and the SEL terminal of the first automatic voltage divider circuit is at a high level.

[0008] Further, when the SEL terminal of the multiplexer U is at a low level, S1 is closed, and the input terminal D is connected to the output terminal S1; when the SEL terminal of the multiplexer U is at a high level, S2 is closed, and the input terminal D is connected to the output terminal S2.

[0009] Furthermore, the traversal circuit unit includes a plurality of detection modules P, a plurality of detection nodes G and a plurality of resistors R10; the detection modules P are all connected to the corresponding detection nodes G, and the last detection module P is connected to the corresponding resistor R10 and grounded.

[0010] Further, the detection module P includes a plurality of second automatic voltage-dividing circuits, a plurality of first main-stage multiplexers and a plurality of first secondary multiplexers; the second automatic voltage-dividing circuit is connected to the corresponding first main-stage multiplexer, the first main-stage multiplexer is connected to the corresponding first secondary multiplexer, the first secondary multiplexer is connected to the corresponding detection node G, and a second automatic voltage-dividing circuit is arranged between each first main-stage multiplexer and the next first main-stage multiplexer; wherein, when the detection module P is powered on, due to the second automatic voltage-dividing circuit, the instantaneous capacitance impedance is zero, the SEL end of the first main-stage multiplexer is at a low level, the input end D is connected to S1, as the capacitance is fully charged, the capacitance impedance is infinite, the SEL end is at a high level, and the input end D is connected to S2; the first secondary multiplexer, as the detection end, after the detection of the detection node G is completed, the SEL end of the first main-stage multiplexer becomes a high level, D is connected to S2, and S2 is connected to the first main-stage multiplexer in the next detection module P as a power supply.

[0011] Optionally, the detection node G includes a plurality of resistors R, a plurality of resistors r and a plurality of micro switches S; the resistors R, the resistors r and the micro switches S are in a one-to-one correspondence, and the detection node G is used to detect loose screws of photovoltaic modules; when the screw is in a tightened state, the micro switch S is in a disconnected state, and since the plurality of resistors R are connected in series and are not grounded, the detected resistance value is infinite; when the screw is loose, the micro switch S is closed, the resistor R is short-circuited, the resistor r is grounded, and the resistance value of the circuit equivalent resistance is detected; if a screw is loose, the equivalent resistance is an integer multiple of the resistor R, and the position of the loose screw is determined by dividing the equivalent resistance by R to obtain the quotient n, where n represents the nth screw that is loose; if the equivalent resistance is not an integer multiple of R, multiple screws are loose, and the position of the first loose screw is determined by dividing the equivalent resistance by R and adding one; if Rr If the equivalent resistance is less than half of the first loose screw, multiple adjacent screws are loose and need to be repaired. R r It represents the value modulo the equivalent resistance divided by the equivalent resistance of the first loose screw. R represents the equivalent resistance of the first loose screw in the circuit.

[0012] Optionally, the detection node G includes a plurality of second primary multiplexers, a plurality of second secondary multiplexers, a plurality of voltage divider resistors R, a plurality of capacitors C, a plurality of micro switches S, a plurality of detection resistors r and a plurality of resistors Rb; wherein the number of the second primary multiplexers, the second secondary multiplexers, the voltage divider resistors R, the detection resistors r and the resistors Rb is the same, the number of the capacitors C and the micro switches S is the same, and the number of the capacitors C is twice that of the second primary multiplexers; when all the screws are in a tightened state, the micro switches S are all disconnected, and the second primary multiplexers and the second secondary multiplexers are disconnected. The SEL terminal is at a high level, the circuit of the entire detection node G is in an open circuit state, and the detected resistance value is infinite; when the screw is loose, the micro switch S is closed, the SEL terminals of the second main-stage multiplexer and the second secondary multiplexer are at a low level, and then change back to a high level state, and at a low level, the input terminal D of the second main-stage multiplexer is connected to S1, the resistance value of the equivalent resistance of the circuit is detected, and the position of the loosened edge is obtained; if the delay time is the predetermined time, one screw in the loosened edge is loose, and if the delay time is twice the predetermined time, two screws in the loosened edge are loose.

[0013] Furthermore, the panel sensor includes a panel sensor housing, a cover is provided at the top of the panel sensor housing, a concave notch is provided in the middle of the cover, a rotating rod is provided inside the panel sensor housing, a flat blade is provided at the top of the rotating rod, a horizontal axis is provided in the middle of the rotating rod, a spring is provided between the horizontal axis and the inner wall of the panel sensor housing, a square notch is provided on one side of the horizontal axis and on the side wall of the panel sensor housing, a hexagonal prism is provided at the bottom of the rotating rod, a bottom plate is provided at the bottom end of the panel sensor housing, and a first circular notch is provided in the middle of the bottom plate; notches are provided inside both ends of the panel sensor housing, buckles are provided outside both ends of the panel sensor housing, long holes are provided in the buckle and at the notch, screws are inserted in the long hole and the notch, a nut and a gasket are sequentially sleeved on one end of the screw, and a slot is provided at the bottom end of the buckle.

[0014] Furthermore, the interior of the bracket sensor is sequentially provided with an inner ring, an outer ring, a micro switch and an extended shell, the inner ring is provided with a first threaded structure, the outer wall of the inner ring is provided with an outer ring, the inner ring is provided with an inner ring inside the outer ring, the outer side of the outer ring is provided with a second threaded structure, the bottom of the outer ring is provided with a second circular notch, the second circular notch is used to fix the micro switch, and the interior of the extended shell has a spiral structure.

[0015] Furthermore, the short circuit positioning circuit includes a photovoltaic panel, an NMOS tube Q and a multiplexer A; when the photovoltaic panel is not short-circuited, the voltage of the gate of the NMOS tube Q is greater than the voltage of the source, the source and the drain are turned on, and due to the presence of a diode at the source, the current at the photovoltaic panel is blocked and flows to the SEL end of the multiplexer A, and the SEL end of the multiplexer A is at a high level, the input end D of the multiplexer A is connected to S2, and the short circuit positioning circuit is in an open circuit; when the photovoltaic panel is short-circuited, the voltage of the gate of the NMOS tube Q is less than the voltage of the source, the source and the drain are not turned on, the SEL end of the multiplexer A is at a low level, the input end D of the multiplexer A is connected to S1, and the detected resistance value is calculated to obtain the position of the short circuit phenomenon.

[0016] The beneficial effects of the present invention are: (1) The present invention realizes an efficient and flexible detection mechanism, which accurately controls the selection state of the multiplexer U through the first automatic voltage divider circuit, so that the traversal circuit unit and its internal modules can be powered on in sequence and perform detailed detection. Each traversal unit includes multiple detection modules and detection nodes, and each detection module includes a second automatic voltage divider circuit, a first main multiplexer and a first secondary multiplexer, forming a complete and coordinated detection system. The single-chip microcomputer, as the core control unit, is responsible for collecting the resistance value and delay time of each detection node, so as to accurately determine the loose state of the screws of the photovoltaic module. The loose photovoltaic module is located by the change of resistance value, and the number of loose screws in the photovoltaic module is obtained by the change of delay time.

[0017] (2) The topological design of the present invention has the advantages of simple structure, convenient operation, and high detection efficiency. It is suitable for detecting loose screws in photovoltaic modules and other equipment, and provides an effective technical means for related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1This is a simplified schematic diagram of the circuit principle of a fault location system for a photovoltaic power station according to an embodiment of the present invention; Figure 2 It is a simplified schematic diagram of the circuit principle of a traversal circuit unit in a fault location system of a photovoltaic power station according to an embodiment of the present invention; Figure 3 It is a detailed schematic diagram of the circuit principle of a traversal circuit unit in a fault location system of a photovoltaic power station according to an embodiment of the present invention; Figure 4 It is a schematic diagram of a circuit principle for detecting the loosening state of a group of photovoltaic component screws in a fault location system of a photovoltaic power station according to an embodiment of the present invention; Figure 5 A circuit schematic diagram of a method for loosening multiple screws in a fault location system of a photovoltaic power station according to an embodiment of the present invention; Figure 6 It is a circuit principle diagram of a second method for locating multiple screws loose in a fault location system of a photovoltaic power station according to an embodiment of the present invention; Figure 7 is one of the simulation curve diagrams of the topology design of the fault location system of a photovoltaic power station according to an embodiment of the present invention; Figure 8 This is a second simulation curve diagram of a topology design of a fault location system for a photovoltaic power station according to an embodiment of the present invention; Fig. 9 It is a schematic diagram of the principle of a short-circuit locating circuit in a fault locating system of a photovoltaic power station according to an embodiment of the present invention; Fig.10 is a simulation curve diagram of a photovoltaic module short-circuit locating circuit of a fault locating system of a photovoltaic power station according to an embodiment of the present invention; Fig.11 is an overall schematic diagram of a panel sensor in a fault location system of a photovoltaic power station according to an embodiment of the present invention; Fig.12 It is a schematic bottom view of the whole panel sensor in a fault location system of a photovoltaic power station according to an embodiment of the present invention; Fig.13 is a schematic diagram of an overall cross-section of a panel sensor in a fault location system of a photovoltaic power station according to an embodiment of the present invention; Fig.14 is a schematic diagram of a panel sensor housing in a fault location system of a photovoltaic power station according to an embodiment of the present invention; Fig.15 It is a schematic diagram of a panel sensor buckle in a fault location system of a photovoltaic power station according to an embodiment of the present invention; Fig.16is a schematic diagram of a panel sensor cover in a fault location system of a photovoltaic power station according to an embodiment of the present invention; Fig.17 is a schematic diagram of a panel sensor rotating rod in a fault location system of a photovoltaic power station according to an embodiment of the present invention; Fig.18 is an overall schematic diagram of a bracket sensor in a fault location system of a photovoltaic power station according to an embodiment of the present invention; Fig.19 It is a schematic diagram of an inner ring of a bracket sensor in a fault location system of a photovoltaic power station according to an embodiment of the present invention; Fig. 20 is a schematic diagram of an outer ring of a bracket sensor in a fault location system of a photovoltaic power station according to an embodiment of the present invention; Fig.21 It is a schematic diagram of an extended shell of a bracket sensor in a fault location system of a photovoltaic power station according to an embodiment of the present invention.

[0020] In the figure: 1. Panel sensor housing; 10. Square notch; 11. Notch; 12. First circular notch; 13. Bottom plate; 2. Buckle; 20. Long hole; 21. Slot; 3. Cover; 30. Concave notch; 4. Rotating rod; 40. Slotted edge; 41. Horizontal axis; 42. Hexagonal prism; 5. Spring; 6. Screw; 60. Nut; 61. Gasket; 7. Bracket sensor; 71. Inner ring; 711. First thread structure; 72. Outer ring; 721. Second thread structure; 73. Micro switch; 74. Extension shell; 75. Outer ring; 76. Inner ring; 77. Second circular notch; 741. Spiral structure. DETAILED DESCRIPTION

[0021] To further illustrate each embodiment, the present invention provides drawings, which are part of the disclosure of the present invention and are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, ordinary technicians in the field should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0022] According to an embodiment of the present invention, a fault location system for a photovoltaic power station is provided to solve the problems of complex wiring and high cost of traditional circuit state detection methods. The present invention cleverly uses a multiplexer and an automatic voltage divider circuit to achieve rapid automatic detection of multiple circuit states. It aims to simplify the circuit structure, improve detection efficiency, and reduce manufacturing costs. The core of the present invention is to use a combination of an automatic voltage divider circuit and a multiplexer to achieve sequential connection between modules and resistance change detection of a single-chip microcomputer. In this way, the present invention not only simplifies the circuit layout, but also improves the accuracy and reliability of detection.

[0023] The present invention is further described with reference to the accompanying drawings and specific embodiments. Figure 1 As shown, according to the fault location system of the photovoltaic power station according to the embodiment of the present invention, the fault location system of the photovoltaic power station includes a starting power supply VCC1, a detection power supply VCC2, resistors R0, R7, a plurality of first automatic voltage dividing circuits, a plurality of multiplexers U, a plurality of traversal circuit units, a panel sensor, a bracket sensor and a short circuit location circuit; wherein, the detection power supply VCC2 is connected in series with the resistor R0, and a single-chip microcomputer detection point X is set, the single-chip microcomputer detection point X is connected to the ADC port of the single-chip microcomputer, the single-chip microcomputer detection point X is connected to the Yin of the plurality of traversal circuit units, the first automatic voltage dividing circuit includes a resistor R1 and a capacitor C1, the resistor R1 is connected in series with the capacitor C1 and is grounded, and the first first automatic voltage dividing circuit is connected Connect the startup power supply VCC1, other first automatic voltage-dividing circuits are connected to S2 of the previous multiplexer U, and several first automatic voltage-dividing circuits are connected to VDD and D of the corresponding multiplexer U, and VDD and D of the multiplexer U corresponding to several first automatic voltage-dividing circuits are connected to S2 of the previous multiplexer U; SEL of several multiplexers U is connected between resistor R1 and capacitor C1 in the corresponding first automatic voltage-dividing circuit, S1 of multiplexer U is connected to Vin of the corresponding traversal circuit unit, and R7 is connected to S2 of the last multiplexer U; panel sensors and bracket sensors are used to identify the bolt status, and short-circuit positioning circuits are used to locate short-circuit problems of photovoltaic modules.

[0024] Specifically, Figure 1As shown, the first first automatic voltage-dividing circuit is connected to the startup power supply VCC1, the power supply terminal VDD and the input terminal D of the multiplexer U1 are connected to the startup power supply VCC1, and GND is grounded, the SEL terminal of the multiplexer U1 is connected between the resistor R1 and the capacitor C1 in the first first automatic voltage-dividing circuit, the output terminal S1 of the multiplexer U1 is connected to the Vin of the first traversal circuit unit, the output terminal S2 of the multiplexer U1 is used as a power supply, and is connected to the VDD and D of the multiplexer U2 and the second first automatic voltage-dividing circuit, the traversal circuit units have two pins, Vin and Yin, and the Vin of the first traversal circuit unit is connected to the multiplexer U1 S1, Yin of the first traversal circuit unit is connected to the microcontroller detection point X. Similarly to the above, the remaining multiplexers U2 to U6 are connected in this way, except that S2 of the last multiplexer is connected to a resistor R7 and then grounded. The VDD, D and the automatic voltage divider circuit of the multiplexer are connected to S2 of the previous multiplexer, and the SEL end of the multiplexer is connected between the resistor and the capacitor in the automatic voltage divider circuit. The output end S1 of the multiplexer is connected to Vin of the traversal circuit unit. The output end S2 of the multiplexer is used as a power supply to connect VDD, D and the automatic voltage divider circuit of the next multiplexer.

[0025] The working principle of the circuit is as follows: when the first multiplexer U1 and the first automatic voltage divider circuit are connected to the power supply, due to the first automatic voltage divider circuit, the SEL terminal is first at a low level, the input terminal D and the output S1 are connected, the S1 terminal acts as the starting power supply of the first traversal circuit, and VCC2 acts as the output power supply of all traversal circuits. At this time, the first traversal circuit starts to operate until all detection nodes in the first traversal circuit unit are detected.

[0026] The SEL terminal of the multiplexer U1 becomes a high level, and the input terminal D is connected to S2. S2 serves as the startup power supply and output power supply of the multiplexer U2. Similarly, the multiplexer U2 is at a low level due to the automatic voltage divider circuit. At this time, the second traversal circuit unit starts to operate and starts to traverse the detection node G to which the second traversal circuit unit belongs until all detection nodes are detected and become a high level. Similar to the first multiplexer U1, when a traversal circuit unit detects all the detection nodes, the subsequent multiplexers will change from a low level to a high level due to the automatic voltage divider circuit, and the input terminal D switches from being connected to S1 to being connected to S2, starting the next multiplexer and starting to traverse and detect all detection nodes in the next traversal circuit unit at the same time, until the last traversal circuit unit is traversed and detected, and the last multiplexer becomes the input terminal D connected to S2, and S2 is connected to a resistor. In theory, this circuit can form an m*n topology.

[0027] The multiplexer U model is TMUX1119, which is a multiplexer with a 2:1 switching function. The multiplexer U is compatible with a variety of power supply voltages, including 1.2V, 1.8V, 2.5V, 3.3V and 5V, and its internal resistance is 2.5Ω.

[0028] In one embodiment, when the startup power supply VCC1 is powered on, the impedance of the capacitor C1 is initially very small, and the SEL terminal of the first automatic voltage-dividing circuit is at a low level. As time goes by, the capacitor C1 is gradually fully charged and the impedance gradually increases. Finally, the impedance of the capacitor C1 approaches infinity, and the SEL terminal of the first automatic voltage-dividing circuit is at a high level.

[0029] In one embodiment, VDD of the multiplexer U is connected to the startup power supply VCC1, GND is grounded, and the SEL terminal of the multiplexer controls the switch. When the SEL terminal of the multiplexer U is at a low level, S1 is closed, and the input terminal D is connected to the output terminal S1; When the SEL terminal of the multiplexer U is at a high level, S2 is closed, and the input terminal D and the output terminal S2 are connected.

[0030] like Figure 2-Figure 3 As shown, in one embodiment, the traversal circuit unit includes a number of detection modules P, a number of detection nodes G and a number of resistors R10; The detection modules P are all connected to the corresponding detection node G, and the last detection module P is connected to the corresponding resistor R10 and grounded.

[0031] Specifically, Figure 2-Figure 3 As shown, each traversal circuit unit includes multiple groups of detection modules P1 to P6 and multiple groups of detection nodes G1 to G6. Each detection module has Vin, Vout, Yin, Yout has four pins, among which pin Yin is the input terminal D of each first secondary multiplexer U in each detection module in each traversal unit, Yout is the output terminal S2 of each first main multiplexer U in each detection module in each traversal unit, Vin of the traversal circuit unit is the connection point with pin Vin of the detection module P1, and Yin of the traversal circuit unit is the connection point with Yin of all detection modules P1. The Vin of the detection module P1 is connected to the output terminal S1 of the multiplexer U1, the Vout of the detection module P1 is connected to the Vin of the detection module P2, the Yin of the detection module P1 is connected to the detection point X of the single-chip microcomputer, and the Yout of the detection module P1 is connected to the detection node G1. The connection method of the first detection module P1 is the same. The remaining detection modules P2 to P6 are connected in the above manner, except that the Vout of the last group of detection modules P6 must be connected to a resistor R7 and then grounded. The Vin of the detection module P is connected to the Vout of the previous module P, the Vout of the detection module P is connected to the Vin of the next module P, the Yin of the detection module P is connected to the detection point X of the single-chip microcomputer, and the Yout of the detection module P1 is connected to a detection node G.

[0032] The circuit working principle of the traversal circuit unit is as follows: when the power supply is connected to the traversal circuit unit Vin, that is, the detection module P1 is powered on, and at the same time, the single-chip microcomputer detection point X is connected to the Yin of the detection module P1 as the output power supply. Due to the automatic voltage-dividing circuit in the detection module P1, the Yin of the detection module P1 is first connected to Yout, and after detecting the first detection node G1 of the detection module P1, Yin becomes connected to Vout, and Vout is connected to the Vin of the next module, serving as the startup power supply of the next module. At this time, the Yin of the detection module P2 is also connected to the single-chip microcomputer detection point X, Yout is connected to the detection node G2, and Vout is connected to the Vin of the detection module P3. Similarly to the above, the subsequent modules P3 to P6 are connected in accordance with the connection method of the detection module P2, Vin is connected to the Vout of the previous group of modules, Vout is connected to the Vin of the next group of modules, Yin is connected to the single-chip microcomputer detection point X, and Yout is connected to the detection node G, until the detection of the detection node G of the last group of modules is completed, the automatic voltage-dividing circuit in the module becomes a high level, and Vout is connected to a resistor and then grounded.

[0033] In one embodiment, the detection module P includes a plurality of second automatic voltage dividing circuits, a plurality of first primary multiplexers, and a plurality of first secondary multiplexers; The second automatic voltage dividing circuit is connected to the corresponding first main-stage multiplexer, the first main-stage multiplexer is connected to the corresponding first secondary multiplexer, the first secondary multiplexer is connected to the corresponding detection node G, and the second automatic voltage dividing circuit is arranged between each first main-stage multiplexer and the next first main-stage multiplexer; Specifically, Vin of the detection module P corresponds to the intersection of VDD and D of the first main-stage multiplexer in the module and the second automatic voltage-dividing circuit, Vout of the detection module P corresponds to the output terminal S2 of the first main-stage multiplexer in the module, Yin of the detection module P corresponds to the input terminal D of the first secondary multiplexer in the module, and Yout of the detection module P corresponds to the output terminal S2 of the first secondary multiplexer in the module. The second automatic voltage-dividing circuit is connected to the S1 terminal of the multiplexer U1, the power supply terminal VDD and the input terminal D of the first main-stage multiplexer U11 are connected to the S1 terminal of the multiplexer U1, and GND is grounded, the SEL terminal of the first main-stage multiplexer U11 is connected between the resistor R10 and the capacitor C101 in the second automatic voltage-dividing circuit, and the output terminal S1 of the first main-stage multiplexer U101 is connected to the VDD and input terminal D of the first main-stage multiplexer U11 in the next group of modules, and the second automatic voltage-dividing circuit The output terminal S2 of the first main-stage multiplexer U11 is connected to the power supply terminal VDD of the first secondary multiplexer U101, the input terminal D of the first secondary multiplexer U101 is connected to the detection power supply VCC2, the power supply terminal VDD of the first secondary multiplexer U101 is connected to the output terminal S1 of the first main-stage multiplexer U1, the SEL terminal, S2 and GND of the first secondary multiplexer U101 are grounded, and the output terminal S1 of the first secondary multiplexer U101 is connected to a detection node G.

[0034] Among them, when the detection module P is powered on, due to the second automatic voltage-dividing circuit, the instantaneous capacitor impedance is zero, the SEL terminal of the first main-stage multiplexer in the module is at a low level, and the input terminal D is connected to S1. As the capacitor is fully charged, the capacitor impedance is infinite, the SEL terminal is at a high level, and the input terminal D is connected to S2; In order to avoid the delay time RC affecting the detection circuit, a secondary multiplexer needs to be added as the detection end. Similar to the first main multiplexer U11, to ensure that the first secondary multiplexer can work normally, the VDD of the first secondary multiplexer U101 is connected to S1 of the first main multiplexer U11, and GND is grounded. At the same time, in order to ensure that the SEL end of the first secondary multiplexer U101 is always at a low level, the SEL end is grounded. Therefore, the input end D of the first secondary multiplexer U101 is always connected to S1, S1 is connected to a detection node G, and S2 is grounded. Because the microcontroller needs to detect the change in the resistance value of the detection node G of the output end S1 of the first secondary multiplexer U101 through voltage detection, the input end D of the first secondary multiplexer U101 is connected to the microcontroller detection point X. Voltage detection, that is, the ADC port of the microcontroller is connected to the microcontroller detection point X. The ADC detects the voltage Ued, calculates the current through the formula I=(U-Ued) / R0, and then calculates the Red resistance through the formula Red=Ued / I.

[0035] After the detection of the detection node G is completed, the SEL terminal of the first main multiplexer becomes a high level, D and S2 are connected, and S2 is connected to the first main multiplexer in the next detection module P as a power supply.

[0036] like Figure 4-Figure 6 As shown, in one embodiment, method 1: each detection node G is a circuit for detecting a group of loose screws of photovoltaic components, and the detection node G includes a plurality of resistors R, a plurality of resistors r and a plurality of micro switches S; The resistor R, the resistor r and the micro switch S are in a one-to-one correspondence, and the detection node G is used to detect the looseness of the screws of the photovoltaic module; each micro switch, the resistor R and the resistor r corresponds to a screw, the micro switch has an input end, two output ends, and a total of three pins, the output end of the micro switch is connected to the left end of the resistor R, one output end of the micro switch is connected to the resistor r and then grounded, and the other output end of the micro switch is connected to the right end of the resistor R. Subsequent switches and resistors are connected in the above manner, and each resistor is connected in series with a resistor. A node Din is set at the front end of the first resistor R, and the node Din is connected to the pin Yout of the module, that is, S1 of the first secondary multiplexer.

[0037] The detection node G determines whether the screw is loose by detecting the change in resistance in the circuit. In this circuit, the resistance of resistor R and resistor r are the same. When the screw is in a tightened state, the micro switch S is in a disconnected state. Since several resistors R are connected in series and not grounded, the resistance value detected is infinite; When the screws of the photovoltaic module are loose, the micro switch S is closed, the resistor R is short-circuited, the resistor r is grounded, and the circuit equivalent resistance is detected. R ed resistance value; detect the voltage Ued through the ADC of the microcontroller, calculate the current through the formula I=(U-Ued) / R0, and then R ed =Ued / I formula is used to calculate R ed Resistance value.

[0038] Determine which screw is loose by the following method: If one screw is loose, the equivalent resistance is an integer multiple of the resistance R, and the position of the loose screw is determined by the quotient n obtained by dividing the equivalent resistance by R, where n indicates that the nth screw is loose; If the equivalent resistance is not R If the circuit is an integer multiple of the equivalent resistance, it means that multiple screws are loose, and the equivalent resistance is divided by R Another way to determine the position of the first loose screw is to divide the equivalent resistance Red by R Take the remainder R r ,like Rr In the interval (1 / 2R, R), according to the formula R ed2 =( R r × R ) / ( RR r ) is calculated, where R is the equivalent resistance of the first loose screw in the circuit, R ed2 is the equivalent resistance of the next loose screw circuit.

[0039] like R r If it is less than half of the equivalent resistance of the first loose screw, then multiple adjacent screws are loose and need to be repaired. The specific positions of the specific adjacent screws are calculated according to the above method.

[0040] Assumption 1: All resistors in the circuit have a resistance of 10kΩ. R ed 7.5kΩ, R ed no R There are multiple screws loose. R ed Divisibility R Add one more and judge that the screw at switch S1 is loose, and then take the remainder R r 7.5kΩ, R r In the (1 / 2R, R) interval, R is 10kΩ, then R ed2 After calculation, it is 3R. The same as above, R ed2 yes R Integer multiples of the second screw loose, indicating that only one screw is loose in the circuit. R ed2 Divide by R The quotient n is 3, which is then added to the first screw that was loosened before, and it is concluded that the screw of switch S4 is loose. After calculation, it can be concluded that the screws at S1 and S4 in Assumption 1 are loose.

[0041] Assumption 2: All resistors in the circuit have a value of 10kΩ. R ed 5kΩ, R ed no R There are multiple screws loose. R edDivide R and add 1 to determine that the screw at switch S1 is loose, and then take the remainder R r 5kΩ, R r If it is not in the (1 / 2R, R) interval, it means that multiple adjacent screws are loose. R is 10kΩ, calculated by the relevant formula R ed2 10kΩ, R ed2 yes R Integer multiples of, similarly, the second screw is loose and only one screw is loose. R ed2 Divide by R The quotient n is 1, which means that the screw of the first switch S in the second circuit is loose, that is, the screw of switch S2 is loose. After calculation, it can be concluded that the two adjacent screws at S1 and S2 in hypothesis 2 are loose, and repair is needed quickly.

[0042] In one embodiment, method 2: the detection node G includes a plurality of second main-stage multiplexers, a plurality of second secondary-stage multiplexers, a plurality of voltage-dividing resistors R, a plurality of capacitors C, a plurality of micro switches S, a plurality of detection resistors r and a plurality of resistors Rb; each detection node G is a circuit for detecting a group of loose screws of photovoltaic components.

[0043] The number of the second main-stage multiplexer, the second secondary-stage multiplexer, the voltage-dividing resistor R, the detection resistor r and the resistor Rb is the same, the number of the capacitor C and the micro switch S is the same, and the number of the capacitor C is twice that of the second main-stage multiplexer; Specifically, each micro switch and capacitor are connected in series, and each two sets of micro switches and capacitor series circuits are connected in parallel. A voltage divider resistor is connected on the left side of each parallel circuit and the right side is grounded. The left side of each voltage divider resistor is connected to the input terminal D and the power supply terminal VDD of the second secondary multiplexer. A large resistor is connected in series to the ground of S1 of each second secondary multiplexer, and GND is grounded. The output terminal S2 of the second secondary multiplexer is connected to the next second secondary multiplexer as a power supply. The input terminal D and the power supply terminal VDD of each second secondary multiplexer are connected to the input terminal D and the power supply terminal VDD of the previous second secondary multiplexer. Output terminal S2, a node Din is set at the connection point of the first second secondary multiplexer input terminal D and the power supply terminal VDD, and the node Din is connected to the pin Yout of the module. The SEL terminals of the second main-stage multiplexer and the second secondary multiplexer are connected between the voltage-dividing resistor and the parallel capacitor. The input terminal D of each second main-stage multiplexer is connected in series with a detection resistor to the output terminals S1 and S2 of the previous second main-stage multiplexer, GND is grounded, and VDD is connected to Din. The input terminal D of the first second main-stage multiplexer is connected in series with a detection resistor and then connected to the node Din.

[0044] This circuit determines which side is loose by detecting the change in resistance in the circuit, and then determines how many screws are loose based on the change in delay. In this circuit, the detection resistors R are the same. When all screws are in a tightened state, the micro switches S are all disconnected, and the SEL terminals of the second primary multiplexer and the second secondary multiplexer are at a high level. The circuit of the entire detection node G is in an open circuit state, and the detected resistance value is infinite; When the screw is loosened, the micro switch S is closed, and the SEL terminals of the second main multiplexer and the second secondary multiplexer are at a low level for a period of time and then return to a high level state. At the low level, the input terminal D of the second main multiplexer is connected to S1, and the resistance value of the equivalent resistance of the circuit is detected. The position of the loose edge can be obtained by the formula L = R ed / R Calculate which side is loose. Since two capacitors are connected in parallel, we can judge whether one screw or two screws are loose based on the change of the delay time RC. Red is the resistance value detected by the microcontroller, R is the resistance of each large series resistor, L is the calculated serial number, L =1, which means the first side is loose.

[0045] If the delay time is the preset time (i.e., the normal delay time), one screw on the loose side is loose. If the delay time is twice the preset time, two screws on the loose side are loose. In order to prevent the voltage from being reduced due to voltage division, the secondary multiplexer is used as the power supply terminal for the SEL terminal.

[0046] like Figure 7 As shown in the figure, taking 3*3 detection nodes as an example, the looseness of the screws of 9n photovoltaic modules is detected, and the simulation results are shown in the figure. By adjusting the resistance and capacitance of the automatic voltage divider circuit, the detection process time of all the detection node resistance values ​​in the three groups of traversal circuits is set to 0.9 seconds, the detection process of each group of traversal circuits is set to 0.3 seconds, and the detection time of each detection node is set to 100 milliseconds. The square wave value between each two nodes corresponds to the equivalent resistance of a group of photovoltaic modules when all the screws are loose. Because when the screws are not loose, the equivalent resistance of each group of photovoltaic module screws is infinite. According to this setting, assuming that the resistance is 10kΩ, if two adjacent screws are loose at the first detection node, and the two screws at S1 and S2 are loose, the first square wave value in the figure will become 5kΩ; if two screws are also loose at the third detection node, and the screws are loose at S1 and S3, the third square wave value in the figure will become 6.67kΩ; if one screw is loose at the fifth detection node, and the screw is loose at S2, the fifth square wave value in the figure will become 20kΩ; if three screws are also loose at the eighth detection node, and the screws are loose at S1, S2 and S3, the eighth square wave value in the figure will become 3.33kΩ; no screws are loose at other nodes, and the square wave values ​​are all infinite.

[0047] like Figure 8 As shown in the figure, taking 3*3 detection nodes as an example, the looseness of screws of 90 photovoltaic modules was detected, and the simulation results are shown in the figure. By adjusting the resistance and capacitance of the automatic voltage divider circuit, the detection process time of the resistance values ​​of all detection nodes in the three groups of traversal circuits is set to 1.98 seconds, and the detection process of each group of traversal circuits is set to 0.66 seconds. The detection time of each detection node is set to 220 milliseconds, and the delay time of the loose photovoltaic module in each detection node is set to 20 milliseconds. A total of 10 photovoltaic modules are detected in the detection node, with a total of 11 edges. The dual features of equivalent resistance change and delay time change are used to calculate which edge is loose and how many screws are loose. The square wave value between each two nodes in the figure corresponds to the equivalent resistance and delay time when one edge of a group of photovoltaic modules is loose.

[0048] According to this setting, assuming that all resistors are 1kΩ, the first edge of the first detection node is loose but only one screw is loose, the first square wave value in the figure will become 1kΩ, and the delay time will be 10ms; if the second edge of the first detection node is loose and two screws are loose, the second square wave value in the figure will become 2kΩ, and the delay time will be 20ms, which is twice as long as the loosening of one screw; if the fifth edge of the second detection node has two screws loose, the 16th square wave value will become 5kΩ, and the delay time will be 20ms; if the 11th edge of the 10th detection node has two screws loose, the 110th square wave value will become 11kΩ, and the delay time will be 20ms; none of the other nodes have any loose edges, and the square wave values ​​are all infinite.

[0049] like Figure 11-Figure 17 As shown, in one embodiment, the board surface sensor includes a board surface sensor housing 1, a cover 3 is provided at the top of the board surface sensor housing 1, a concave notch 30 is provided in the middle of the cover 3, a rotating rod 4 is provided inside the board surface sensor housing 1, a flat blade 40 is provided at the top of the rotating rod 4, a horizontal axis 41 is provided in the middle of the rotating rod 4, a spring 5 is provided between the horizontal axis 41 and the inner wall of the board surface sensor housing 1, a square notch 10 is provided on one side of the horizontal axis 41 and on the side wall of the board surface sensor housing 1, and the square notch 10 is used to place a wire, a hexagonal prism 42 is provided at the bottom of the rotating rod 4, and the board surface sensor housing 1 is provided with a plurality of hexagonal prisms. A bottom plate 13 is provided at the bottom end of the surface sensor housing 1, and a first circular notch 12 is provided in the middle of the bottom plate 13. The first circular notch 12 is used to accommodate the head of the detection bolt, and copper foil needs to be arranged on the top and bottom of the horizontal axis 41; recesses 11 are provided inside both ends of the plate surface sensor housing 1, and buckles 2 are provided outside both ends of the plate surface sensor housing 1. A long hole 20 is provided in the buckle 2 and located at the recess 11. Screws 6 are inserted in the long hole 20 and the recess 11. The recess 11 is used to place the screw 6. One end of the screw 6 is sequentially sleeved with a nut 60 and a gasket 61, and a slot 21 is provided at the bottom end of the buckle 2.

[0050] The principle of the panel sensor is as follows: fix the panel sensor housing 1 on the bolt, insert the hexagonal prism 42 at the bottom of the rotating rod 4 into the hexagonal notch at the top of the bolt, buckle the cover 3, and put the buckle 2 on the extended edge of the panel sensor housing 1. The screw 6 passes through the notch 11 of the extended edge and the long hole 20 of the buckle 2, and is tightened with a nut 60. At the same time, the length of the structure can be adjusted through the long hole 20 of the buckle 2. When the bolt is fully tightened, the horizontal axis 41 on the rotating rod 4 is offset from the bottom plate 13, which is equivalent to the switch being disconnected. At this time, the spring 5 is relaxed; when the bolt is loose, the horizontal axis 41 collides with the bottom plate 13, and the copper foil at the bottom of the horizontal axis 41 contacts the copper foil on the bottom plate 13, and the switch is closed. At this time, the spring 5 is tightened, and the spring 5 pulls the bolt back to the tightened state through the tension generated by the tightening.

[0051] like Figure 18-Figure 21As shown, in one embodiment, the interior of the bracket sensor 7 is sequentially provided with an inner ring 71, an outer ring 72, a micro switch 73 and an extension shell 74, the inner ring 71 is provided with a first thread structure 711, the inner ring 71 is tightened with a screw along the thread line, the outer wall of the inner ring 71 is provided with an outer ring 75, the inner ring 72 is provided with an inner ring 76, the outer side of the outer ring 72 is provided with a second thread structure 721, the bottom of the outer ring 72 is provided with a second circular notch 77, the second circular notch 77 is used to fix the micro switch 73, and the extension shell 74 has a spiral structure 741 inside.

[0052] The working principle of the bracket sensor is as follows: the inner ring 71 rotates along the thread line to fix the inner ring 71 on the bolt, a normally closed micro switch 73 is placed at the bottom of the outer ring 72, the inner ring 71 is inserted into the outer ring 72 to press against the micro switch 73, and the extension shell 74 is sleeved on the outside of the outer ring 72. When the bolt is fully tightened, the micro switch 73 is pressed by the bottom surface of the inner ring 71, and the micro switch 73 is disconnected; when the bolt is loosened, the nut at the bracket will be displaced under the deformation of the spring gasket, and the outer ring 72 will move outward, and the inner ring 76 protrusion will gradually reverse over the outer ring 75 protrusion of the inner ring 71, and the micro switch 73 will return to the closed state. At the same time, the loosening of the screw will cause the extension shell 74 to rotate along the thread structure toward the nut.

[0053] like Fig. 9 As shown, in one embodiment, the short circuit positioning circuit includes a photovoltaic panel (photovoltaic module), an NMOS tube Q and a multiplexer A; The short circuit positioning circuit also includes a plurality of second detection resistors r, a plurality of second voltage-dividing resistors R, a plurality of diodes D, and a power supply VCC. The cathode of each diode D is connected between the positive and negative electrodes of the photovoltaic module, the gate of each NMOS tube Q is connected to the positive electrode of the photovoltaic module, the drain of the NMOS tube Q is connected to the power supply VCC, the source of the NMOS tube Q and the anode of the diode are connected to the SEL end of the multiplexer A, the SEL end of the multiplexer A is connected to a voltage-dividing resistor and grounded, the output end S1 of the multiplexer A and GND are grounded, the power supply end VDD is connected to the power supply, the input end D of the multiplexer A is connected in series with a second detection resistor r, and then connected to the output end S2 of the previous multiplexer A, the input end D of the first multiplexer A is connected in series with a detection resistor, and a node Din is set at the front end, and the node Din can be connected to the power supply VCC or the pin Yout of the access module P.

[0054] When the photovoltaic panel is not short-circuited, the gate voltage of the NMOS tube Q is U G Greater than the source voltage U S, the source and drain are turned on. Due to the presence of a diode at the source, the current at the photovoltaic panel is blocked and flows to the SEL end of the multiplexer A. The SEL end of the multiplexer A is at a high level. The input end D of the multiplexer A is connected to S2, and the short-circuit positioning circuit is open; When the photovoltaic panel is short-circuited, the gate voltage of the NMOS tube Q U G Less than the source voltage U S , the source and drain are not conducting, the SEL terminal of the multiplexer A is at a low level, the input terminal D of the multiplexer A is connected to S1, and the detected resistance value is calculated to obtain the location of the short circuit phenomenon. Specifically, the location of the photovoltaic module with a short circuit is obtained by calculation using the formula L1=Red / r. Red is the detected resistance value, r is the resistance value of the second detection resistor, and L1 is the short circuit location number obtained by calculation.

[0055] like Fig.10 As shown in the figure, taking 3*3 detection nodes and 10 photovoltaic modules in each node as an example, the short circuit of 90 photovoltaic modules is located, and the simulation results are shown in the figure. By adjusting the resistance and capacitance of the automatic voltage divider circuit, the detection process time of all the detection node resistance values ​​in the three groups of traversal circuits is set to 0.9 seconds, the detection process of each group of traversal circuits is set to 0.3 seconds, and the detection time of each detection node is set to 100 milliseconds. A total of 10 photovoltaic module short circuit problems are detected in the detection node. Assuming that the detection resistor is 1kΩ, if there is no short circuit in the photovoltaic module in the first detection node, the positioning circuit is open, and the square wave value in the figure indicates infinite resistance; if there is a short circuit between the first photovoltaic module and the second photovoltaic module in the second detection node or between the second photovoltaic module and the third photovoltaic module, the square wave value will become 1kΩ, if there is a short circuit between the fourth photovoltaic module and the fifth photovoltaic module in the fifth detection node, the square wave value will become 3kΩ, if there is a short circuit between the ninth photovoltaic module and the tenth photovoltaic module in the seventh detection node, the square wave value will become 8kΩ, if there is a short circuit in the positive pole of the tenth photovoltaic module in the ninth detection node, the square wave value will become 9kΩ, and there is no short circuit problem in the photovoltaic module strings in the remaining detection nodes, and the square wave value is infinite.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A fault location system for a photovoltaic power station, characterized in that: The fault location system of the photovoltaic power station includes a starting power supply VCC1, a detection power supply VCC2, resistors R0, R7, a plurality of first automatic voltage-dividing circuits, a plurality of multiplexers U, a plurality of traversal circuit units, a panel sensor, a bracket sensor and a short-circuit location circuit; Wherein, the detection power supply VCC2 is connected in series with the resistor R0, and a single-chip microcomputer detection point X is set, the single-chip microcomputer detection point X is connected to Yin of several traversal circuit units, the first automatic voltage dividing circuit includes a resistor R1 and a capacitor C1, the resistor R1 is connected in series with the capacitor C1 and is grounded, the first first automatic voltage dividing circuit is connected to the start power supply VCC1, the other first automatic voltage dividing circuits are connected to S2 of the previous multiplexer U, and several first automatic voltage dividing circuits are connected to VDD and D of the corresponding multiplexer U; The SELs of some of the multiplexers U are connected between the resistor R1 and the capacitor C1 in the corresponding first automatic voltage divider circuit, the S1 of the multiplexer U is connected to the Vin of the corresponding traversal circuit unit, and the R7 is connected to the S2 of the last multiplexer U; The panel sensor and the bracket sensor are used to identify the bolt status, and the short-circuit locating circuit is used to locate the short-circuit problem of the photovoltaic module.

2. A photovoltaic power station fault location system according to claim 1, characterized in that: When the startup power supply VCC1 is powered on, the SEL end of the first automatic voltage-dividing circuit is at a low level, and as time goes by, the capacitor C1 is gradually fully charged, the impedance gradually increases, the impedance of the capacitor C1 approaches infinity, and the SEL end of the first automatic voltage-dividing circuit is at a high level.

3. A photovoltaic power station fault location system according to claim 2, characterized in that: When the SEL terminal of the multiplexer U is at a low level, S1 is closed, and the input terminal D and the output terminal S1 are connected; When the SEL terminal of the multiplexer U is at a high level, S2 is closed, and the input terminal D is connected to the output terminal S2.

4. A photovoltaic power station fault location system according to claim 3, characterized in that: The traversal circuit unit includes a plurality of detection modules P, a plurality of detection nodes G and a plurality of resistors R10; The detection modules P are all connected to the corresponding detection node G, and the last detection module P is connected to the corresponding resistor R10 and grounded.

5. A photovoltaic power station fault location system according to claim 4, characterized in that: The detection module P includes a plurality of second automatic voltage dividing circuits, a plurality of first primary multiplexers and a plurality of first secondary multiplexers; The second automatic voltage-dividing circuit is connected to the corresponding first main-stage multiplexer, the first main-stage multiplexer is connected to the corresponding first secondary multiplexer, the first secondary multiplexer is connected to the corresponding detection node G, and the second automatic voltage-dividing circuit is arranged between each first main-stage multiplexer and the next first main-stage multiplexer; Wherein, when the detection module P is powered on, due to the second automatic voltage-dividing circuit, the instantaneous capacitor impedance is zero, the SEL terminal of the first primary multiplexer is at a low level, and the input terminal D is connected to S1. As the capacitor is fully charged, the capacitor impedance is infinite, the SEL terminal is at a high level, and the input terminal D is connected to S2. The first secondary multiplexer serves as a detection terminal. After the detection of the detection node G is completed, the SEL terminal of the first main multiplexer becomes a high level, D and S2 are connected, and S2 serves as a power supply to connect the first main multiplexer in the next detection module P.

6. A photovoltaic power station fault location system according to claim 5, characterized in that: The detection node G includes a plurality of resistors R, a plurality of resistors r and a plurality of micro switches S; The resistor R, the resistor r and the micro switch S are in a one-to-one correspondence, and the detection node G is used to detect the loosening of the screws of the photovoltaic module; When the screw is in a tightened state, the micro switch S is in an open state. Since several resistors R are connected in series and not grounded, the resistance value detected is infinite. When the screw is loosened, the micro switch S is closed and the resistor R The circuit is short-circuited, the resistor r is grounded, and the resistance value of the circuit equivalent resistor is detected; If one screw is loose, the equivalent resistance is R The position of the loosened screw is divisible by the equivalent resistance R The obtained quotient n is used to determine, where n represents the nth screw that is loose; If the equivalent resistance is not R If the equivalent resistance is an integer multiple of R Another way to determine the location of the first loose screw; like R r If the equivalent resistance is less than half of the first loose screw, multiple adjacent screws are loose and need to be repaired. R r It represents the value obtained by dividing the equivalent resistance by the equivalent resistance of the first loosened screw. R Represents the equivalent resistance of the first loose screw in the circuit.

7. A photovoltaic power station fault location system according to claim 6, characterized in that: The detection node G includes a plurality of second primary multiplexers, a plurality of second secondary multiplexers, a plurality of voltage dividing resistors R, a plurality of capacitors C, a plurality of micro switches S, a plurality of detection resistors r and a plurality of resistors Rb; The second primary multiplexer, the second secondary multiplexer, the voltage divider resistor R, the detection resistor r and the resistor Rb are of the same number, the capacitor C and the micro switch S are of the same number, and the capacitor C is twice the number of the second primary multiplexer; When all the screws are in a tightened state, the micro switches S are all disconnected, the entire circuit of the detection node G is in an open circuit state, and the detected resistance value is infinite; When the screw is loosened, the micro switch S is closed, the SEL terminals of the second main multiplexer and the second secondary multiplexer are at a low level and then change back to a high level state, and at a low level, the input terminal D of the second main multiplexer is connected to S1, the resistance value of the equivalent resistance of the circuit is detected, and the position of the loose edge is obtained; If the delay time is the preset time, one screw of the loose side is loose, and if the delay time is twice the preset time, two screws of the loose side are loose.

8. A photovoltaic power station fault location system according to claim 7, characterized in that: The board surface sensor comprises a board surface sensor housing, a cover is arranged at the top end of the board surface sensor housing, a concave notch is arranged in the middle of the cover, a rotating rod is arranged inside the board surface sensor housing, a straight-edge is arranged at the top of the rotating rod, a horizontal axis is arranged in the middle of the rotating rod, a spring is arranged between the horizontal axis and the inner wall of the board surface sensor housing, a square notch is arranged on one side of the horizontal axis and on the side wall of the board surface sensor housing, a hexagonal prism is arranged at the bottom of the rotating rod, a bottom plate is arranged at the bottom end of the board surface sensor housing, and a first circular notch is arranged in the middle of the bottom plate; Recesses are provided at both ends of the panel sensor housing, and buckles are provided on the outside of both ends of the panel sensor housing. Long holes are provided in the buckles and at the recesses. Screws are inserted in the long holes and the recesses, and a nut and a gasket are sequentially sleeved on one end of the screw. A slot is provided at the bottom end of the buckle.

9. A photovoltaic power station fault location system according to claim 8, characterized in that: The bracket sensor includes a bracket sensor housing, an inner ring, an outer ring, a micro switch and an extension shell are sequentially arranged inside the bracket sensor housing, a first thread structure is arranged inside the inner ring, an outer ring is arranged on the outer side wall of the inner ring, an inner ring is arranged inside the outer ring, a second thread structure is arranged on the outer side of the outer ring, a second circular notch is arranged at the bottom of the outer ring, the second circular notch is used to fix the micro switch, and a spiral structure is arranged inside the extension shell.

10. A photovoltaic power station fault location system according to claim 9, characterized in that: The short circuit positioning circuit includes a photovoltaic panel, an NMOS tube Q and a multiplexer A; When the photovoltaic panel is not short-circuited, the voltage of the gate of the NMOS tube Q is greater than the voltage of the source, the source and the drain are turned on, and due to the presence of a diode at the source, the current at the photovoltaic panel is blocked and flows to the SEL end of the multiplexer A, and the SEL end of the multiplexer A is at a high level, the input end D of the multiplexer A is connected to S2, and the short-circuit locating circuit is in an open circuit; When a short circuit occurs in the photovoltaic panel, the voltage of the gate of the NMOS tube Q is less than the voltage of the source, the source and the drain are not conducting, the SEL terminal of the multiplexer A is at a low level, the input terminal D of the multiplexer A is connected to S1, and the detected resistance value is calculated to obtain the location of the short circuit phenomenon.

Images