Stray current detection method and system for photovoltaic power generation system

Abstract

The invention discloses a stray current detection method and system for a photovoltaic power generation system, and the method comprises the steps: obtaining the equivalent resistivity in the north-south direction and the equivalent resistivity in the east-west direction of a measurement point according to a first control signal and a second control signal, and determining a target measurement point according to the equivalent resistivity and the second equivalent resistivity; acquiring a first equivalent resistivity rho NS in the north-south direction, a second equivalent resistivity rho WE in the east-west direction, a first electric field FNS in the north-south direction, a second electric field FWE in the east-west direction, a first ground current density JNS in the north-south direction and a second ground current density JWE in the east-west direction of the target measuring point; and analyzing the photovoltaic power generation system according to the first equivalent resistivity rho NS, the second equivalent resistivity rho WE, the first electric field FNS, the second electric field FWE, the first ground current density JNS and the second ground current density JWE, and generating a maintenance signal of the photovoltaic power generation system according to an analysis result. And detection and treatment of the stray current of the photovoltaic system are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic power generation system detection, and in particular relates to a stray current detection method and system for a photovoltaic power generation system. Background Art

[0002] Due to factors such as sunlight and site conditions, many photovoltaic power stations operate in harsh mountainous and desert environments. During these projects, the metal frames, support structures, and combiner boxes of photovoltaic modules must all be grounded. As photovoltaic systems grow in size, age, or develop undetected DC grounding faults, DC leakage current inevitably increases. Therefore, it is imperative to monitor stray currents in photovoltaic power generation systems. Summary of the Invention

[0003] The present invention provides a stray current detection method and system for a photovoltaic power generation system, which are used to solve the technical problem of difficulty in detecting stray current of a large-scale photovoltaic power generation system on site.

[0004] In a first aspect, the present invention provides a stray current detection method for a photovoltaic power generation system, comprising:

[0005] Acquire a satellite clock signal, and generate a first control signal for local resistivity detection and a second control signal for local electric field monitoring according to the satellite clock signal;

[0006] Obtaining an equivalent resistivity in a north-south direction and an equivalent resistivity in an east-west direction of a measuring point according to the first control signal and the second control signal, and determining a target measuring point according to the equivalent resistivity and the second equivalent resistivity;

[0007] Get the first equivalent resistivity ρ in the north-south direction of the target measuring point NS , the second equivalent resistivity ρ in the east-west direction WE , the first electric field F in the north-south direction NS , the second electric field F in the east-west direction WE , the first ground current density J in the north-south direction NS and the second current density J in the east-west direction WE ;

[0008] According to the first equivalent resistivity ρ NS , the second equivalent resistivity ρ WE , the first electric field F NS The second electric field F WE , the first ground current density J NS And the second ground current density J WE The photovoltaic power generation system is analyzed, and a maintenance signal for the photovoltaic power generation system is generated according to the analysis result.

[0009] In a second aspect, the present application provides a stray current detection system for a photovoltaic power generation system, comprising:

[0010] A generation module configured to obtain a satellite clock signal, generate a first control signal for local resistivity detection and a second control signal for local electric field monitoring according to the satellite clock signal;

[0011] A determination module configured to obtain an equivalent resistivity in the north-south direction and an equivalent resistivity in the east-west direction of a measurement point according to the first control signal and the second control signal, and determine a target measurement point according to the equivalent resistivities;

[0012] An acquisition module configured to obtain a first equivalent resistivity in the north-south direction ρ NS , a second equivalent resistivity in the east-west direction ρ WE , a first electric field in the north-south direction F NS , a second electric field in the east-west direction F WE , a first ground current density in the north-south direction J NS , and a second ground current density in the east-west direction J WE of the target measurement point;

[0013] An analysis module configured to analyze the photovoltaic power generation system according to the first equivalent resistivity ρ NS , the second equivalent resistivity ρ WE , the first electric field F NS , the second electric field F WE , the first ground current density J NS , and the second ground current density J WE , and generate a maintenance signal of the photovoltaic power generation system according to the analysis result.

[0014] In a third aspect, an electronic device is provided, comprising at least one processor, and a memory connected to the at least one processor in communication, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the steps of the stray current detection method for a photovoltaic power generation system according to any one of the embodiments of the present application.

[0015] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein the program instructions are executed by a processor to enable the processor to perform the steps of the stray current detection method for a photovoltaic power generation system according to any one of the embodiments of the present application.

[0016] The stray current detection method and system for photovoltaic power generation systems of the present application implement long-term monitoring of the local geoelectric field and geocurrent density monitoring system, analyze the correlation between photovoltaic power generation and geocurrent density, and realize the detection and control of stray currents in photovoltaic systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 A flow chart of a stray current detection method for a photovoltaic power generation system provided by one embodiment of the present invention;

[0019] Figure 2 A schematic diagram of the arrangement of local resistivity monitoring sensors according to a specific embodiment of the present invention;

[0020] Figure 3 A structural block diagram of a stray current detection system for a photovoltaic power generation system provided by one embodiment of the present invention;

[0021] Figure 4 It is a structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] See also Figure 1 , which shows a flow chart of a stray current detection method for a photovoltaic power generation system of the present application.

[0024] like Figure 1 As shown, the photovoltaic power generation system analysis method specifically includes the following steps:

[0025] Step S101, acquiring a satellite clock signal, and generating a first control signal for local resistivity detection and a second control signal for local electric field monitoring according to the satellite clock signal;

[0026] Step S102: obtaining the equivalent resistivity of the measuring point in the north-south direction and the equivalent resistivity in the east-west direction according to the first control signal and the second control signal, and determining the target measuring point according to the equivalent resistivity and the second equivalent resistivity.

[0027] In this step, it is determined whether the difference between the equivalent resistivity and the equivalent resistivity of a certain measuring point is greater than a preset threshold; if it is not greater than the preset threshold, the certain measuring point is defined as a target measuring point; if it is greater than the preset threshold, it is continued to determine whether the difference between the equivalent resistivity and the equivalent resistivity of another measuring point is greater than the preset threshold, until the difference is no greater than the preset threshold.

[0028] Specifically, if the difference between the equivalent resistivity in the north-south direction and the equivalent resistivity in the east-west direction is greater than 200 Ω·m, it is considered that there is an underground anomaly, such as buried exposed metal, cables, or uneven rock mass. The measuring point needs to be relocated until the difference between the equivalent resistivity in the north-south direction and the equivalent resistivity in the east-west direction is less than 200 Ω·m.

[0029] Step S103: Obtain the first equivalent resistivity ρ of the target measuring point in the north-south direction NS , the second equivalent resistivity ρ in the east-west direction WE , the first electric field F in the north-south direction NS , the second electric field F in the east-west direction WE , the first ground current density J in the north-south direction NS and the second current density J in the east-west direction WE .

[0030] In this step, the first equivalent resistivity ρ in the north-south direction of the target measuring point is obtained by the local resistivity monitoring sensor. NS , the second equivalent resistivity ρ in the east-west direction WE ; The local resistivity monitoring sensor includes a voltage monitoring unit and a current excitation unit; the voltage monitoring unit is composed of metal electrodes driven into the ground 0.1m-0.3m, namely the north voltage electrode PN, the south voltage electrode PS, the west voltage electrode PW and the east voltage electrode PE, the distance between the north voltage electrode PN and the south voltage electrode PS is 0.5m-1.5m, and the distance between the west voltage electrode PW and the east voltage electrode PE is 0.5-1.5m; the current excitation unit is composed of metal electrodes driven into the ground 0.1m-0.3m, namely the north current electrode CN, the south current electrode CS, the west current electrode CW and the east current electrode CE, the distance between the north current electrode CN and the south current electrode CS is 1.5m-2.5m, and the distance between the west current electrode CW and the east current electrode CE is 1.5m-2.5m.

[0031] Specifically, the voltage monitoring unit consists of four metal electrodes driven 0.2 m into the ground: the north voltage electrode PN, the south voltage electrode PS, the west voltage electrode PW, and the east voltage electrode PE. The distance between PN and PS is 1 m, and the distance between PW and PE is also 1 m. The current excitation unit consists of four metal electrodes driven 0.2 m into the ground: the north current electrode CN, the south current electrode CS, the west current electrode CW, and the east current electrode CE. The distance between CN and CS is 2 m, and the distance between CW and CE is also 2 m.

[0032] It should be noted that the current excitation unit applies a voltage excitation of 20Hz-30Hz and an effective value of 5V-15V between the north current electrode CN and the south current electrode CS, and the first output I of the current excitation unit is obtained by monitoring. NS ;

[0033] Get the first potential difference V between the north voltage pole PN and the south voltage pole PS NS ;

[0034] According to the first output I NS and the first potential difference V NS Calculate the first equivalent resistivity ρ in the north-south direction NS , the expression is:

[0035]

[0036] The current excitation unit applies a voltage excitation of 20Hz-30Hz and an effective value of 5V-15V between the west current electrode CW and the east current electrode CE, and monitors the second output I WE ;

[0037] Monitor the second potential difference V between the west voltage pole PW and the east voltage pole PE WE ;

[0038] According to the second output I WE and the second potential difference V WE Calculate the second equivalent resistivity ρ in the east-west direction WE , the expression is:

[0039]

[0040] Furthermore, when the preset time of the satellite clock signal is reached every minute, the current excitation unit does not act, and the first potential difference V between the north voltage pole PN and the south voltage pole PS is NS Defined as the first electric field F in the north-south direction NS , and the second potential difference V between the west voltage electrode PW and the east voltage electrode PE WE .

[0041] Calculate the first ground current density J in the north-south directionNS and the eastward second ground current density J WE The expression of J is:

[0042]

[0043] wherein V NS is a first potential difference between the north voltage pole PN and the south voltage pole PS, V WE is a second potential difference between the west voltage pole PW and the east voltage pole PE.

[0044] In step S104, the photovoltaic power generation system is analyzed according to the first equivalent resistivity p NS , the second equivalent resistivity p WE , the first electric field F NS , the second electric field F WE , the first ground current density J NS and the second ground current density J WE , and a maintenance signal of the photovoltaic power generation system is generated according to an analysis result.

[0045] In this step, it is judged whether the average of the first equivalent resistivity p NS and the second equivalent resistivity p WE is greater than a first preset threshold value.

[0046] If the average is not greater than the first preset threshold value, it is determined that the photovoltaic power generation system has buried metal corrosion, otherwise it is determined that the photovoltaic power generation system does not have buried metal corrosion.

[0047] Specifically, the resistivity is rated according to Table 1.

[0048] Table 1: Resistivity Rating

[0049] <![CDATA[电阻率ρ NS and ρ WE Average value of]]> Rating Less than 100Ω·m Level I, buried metal corrosion is very likely to occur 100Ω·m (inclusive) to 1000Ω·m (exclusive) Level II, more prone to buried metal corrosion 1000Ω·m (inclusive) to 10000Ω·m (inclusive) Level III, not prone to buried metal corrosion >10000Ω·m (inclusive) Level VI, buried metal corrosion is unlikely to occur

[0050] It is judged whether the synthetic current density J is greater than a second preset threshold value, wherein the expression of the synthetic current density is:

[0051]

[0052] If the synthetic current density is greater than the second preset threshold value, it is determined that the photovoltaic power generation system has corrosion, otherwise it is determined that the photovoltaic power generation system does not have corrosion.

[0053] Specifically, the corrosion rate of the synthetic current density is rated according to Table 2, and a warning message is sent according to a result.

[0054] <![CDATA[合成电流密度(mAm 2 )]]> Corrosion Rate Rating ＜8.62 Mild corrosion 8.62 (inclusive) to 86.22 (exclusive) Moderate corrosion 86.22 (inclusive) to 862.22 (inclusive) Severe corrosion, severe corrosion warning issued ＞862.22 Extremely severe corrosion, issuing an extremely severe corrosion warning

[0055] Determine whether the combined earth electric field strength is greater than the step voltage threshold, wherein the expression for calculating the combined earth electric field strength is:

[0056]

[0057] The expression for calculating the step voltage threshold is:

[0058] U s =7.42+0.0159(ρ NS +ρ WE ),

[0059] If it is greater than the step voltage threshold, it is determined that the photovoltaic power generation system has a step voltage; otherwise, it is determined that the photovoltaic power generation system does not have a step voltage.

[0060] In a specific embodiment, a long-term monitoring system for local geoelectric field and geocurrent density is implemented to analyze the correlation between photovoltaic power generation and geocurrent density, and provide maintenance suggestions for the photovoltaic power generation system.

[0061] The local geoelectric field and geocurrent density monitoring system conducts long-term monitoring.

[0062] According to the long-term monitoring data of ground current density, the composite current density J has a deviation of more than 86.22 mA / m between day and night. 2 , it is believed that there is a strong correlation between photovoltaic power generation and ground current density.

[0063] If a strong correlation is found between photovoltaic power generation and ground current density, on-site maintenance recommendations will be given to check whether there are cracks in the photovoltaic panels, whether there are insulation defects in the cables, and whether there are leakage faults in the inverter.

[0064] In summary, the method of the present application, for large-scale photovoltaic power generation systems, builds a local geoelectric field and geocurrent density monitoring system unit with a satellite signal receiving unit, a local resistivity monitoring sensor, a geoelectric field monitoring sensor, a control unit, a data bus and a data processing and storage unit as basic units. It can be used for analysis and early warning of long-term monitoring data of the north-south equivalent resistivity ρNS, the east-west equivalent resistivity ρWE, the north-south electric field FNS, the east-west electric field FWE, the north-south geocurrent density JNS, and the east-west geocurrent density JWE at the head end of the photovoltaic support structure, the end of the photovoltaic support structure, and near the junction box. It can be used to analyze the correlation between photovoltaic power generation and geocurrent density, and provide maintenance suggestions for the photovoltaic power generation system. For photovoltaic power plants, inverters have a lifespan of 10 to 15 years, subject to the risk of component and insulation aging. PV modules also have a design lifespan of 10 to 15 years, subject to risks such as film aging and backsheet cracking. Metal supports can last for over 25 years, provided corrosion does not exceed standards. DC cables, with a design lifespan of 15 to 25 years, also face risks such as insulation aging and leakage current. Given the operational lifespan requirement of photovoltaic systems exceeding 25 years, there are no field-based methods for measuring stray current in large-scale photovoltaic systems. As photovoltaic systems age, component aging inevitably leads to stray current leakage, accelerating corrosion of buried metal structures. The proposed local geoelectric field and geocurrent density monitoring system provides a reference for detecting and controlling stray currents in photovoltaic systems.

[0065] In a specific embodiment, first, a local geoelectric field and geocurrent density monitoring system is built with a satellite signal receiving unit, a local resistivity monitoring sensor, a geoelectric field monitoring sensor, a control unit, a data bus, and a data processing and storage unit as basic units. Secondly, the local geoelectric field and geocurrent density monitoring basic unit is installed at the head end of the photovoltaic support structure, the end of the photovoltaic support structure, and near the junction box, and the longitude and latitude of the measuring point are recorded. The equivalent resistivity in the north-south direction, the equivalent resistivity in the east-west direction, the north-south electric field, the east-west electric field, the north-south geocurrent density, and the east-west geocurrent density of the measuring point are measured and obtained. The monitoring data is analyzed and warned, and the analysis and warning results are recorded. Finally, long-term monitoring of the local geoelectric field and geocurrent density monitoring system is implemented, the correlation between photovoltaic power generation and geocurrent density is analyzed, and maintenance suggestions for the photovoltaic power generation system are given.

[0066] See also Figure 3 , which shows a structural block diagram of a stray current detection system for a photovoltaic power generation system of the present application.

[0067] like Figure 3As shown, the stray current detection system 200 includes a generating module 210 , a determining module 220 , an acquiring module 230 and an analyzing module 240 .

[0068] The generating module 210 is configured to obtain a satellite clock signal and generate a first control signal for local resistivity detection and a second control signal for local electric field monitoring according to the satellite clock signal;

[0069] a determination module 220 configured to obtain an equivalent resistivity in a north-south direction and an equivalent resistivity in an east-west direction of a measuring point according to the first control signal and the second control signal, and determine a target measuring point according to the equivalent resistivity and the second equivalent resistivity;

[0070] The acquisition module 230 is configured to obtain the first equivalent resistivity ρ of the target measuring point in the north-south direction NS , the second equivalent resistivity ρ in the east-west direction WE , the first electric field F in the north-south direction NS , the second electric field F in the east-west direction WE , the first ground current density J in the north-south direction NS and the second current density J in the east-west direction WE ;

[0071] The analysis module 240 is configured to analyze the first equivalent resistivity ρ NS , the second equivalent resistivity ρ WE , the first electric field F NS The second electric field F WE , the first ground current density J NS And the second ground current density J WE The photovoltaic power generation system is analyzed, and a maintenance signal for the photovoltaic power generation system is generated according to the analysis result.

[0072] It should be understood that Figure 3 Modules and references documented in Figure 1 Therefore, the operations and features described above for the method and the corresponding technical effects also apply to Figure 3 The modules in it will not be described in detail here.

[0073] In other embodiments, embodiments of the present invention further provide a computer-readable storage medium having a computer program stored thereon, wherein when the program instructions are executed by a processor, the processor is caused to execute the stray current detection method for a photovoltaic power generation system in any of the above method embodiments;

[0074] As an embodiment, the computer-readable storage medium of the present invention stores computer-executable instructions, and the computer-executable instructions are configured as follows:

[0075] Acquire a satellite clock signal, and generate a first control signal for local resistivity detection and a second control signal for local electric field monitoring according to the satellite clock signal;

[0076] Obtaining an equivalent resistivity in a north-south direction and an equivalent resistivity in an east-west direction of a measuring point according to the first control signal and the second control signal, and determining a target measuring point according to the equivalent resistivity and the second equivalent resistivity;

[0077] Get the first equivalent resistivity ρ in the north-south direction of the target measuring point NS , the second equivalent resistivity ρ in the east-west direction WE , the first electric field F in the north-south direction NS , the second electric field F in the east-west direction WE , the first ground current density J in the north-south direction NS and the second current density J in the east-west direction WE ;

[0078] According to the first equivalent resistivity ρ NS , the second equivalent resistivity ρ WE , the first electric field F NS The second electric field F WE , the first ground current density J NS And the second ground current density J WE The photovoltaic power generation system is analyzed, and a maintenance signal for the photovoltaic power generation system is generated according to the analysis result.

[0079] The computer-readable storage medium may include a program storage area and a data storage area. The program storage area may store an operating system and application programs required for at least one function; the data storage area may store data generated based on the use of the stray current detection system for a photovoltaic power generation system. Furthermore, the computer-readable storage medium may include high-speed random access memory and may also include a memory device, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state memory device. In some embodiments, the computer-readable storage medium may optionally include a memory device remotely located relative to the processor, and such remote memory device may be connected to the stray current detection system for a photovoltaic power generation system via a network. Examples of such networks include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0080] Figure 4 Schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. Figure 4As shown, the device includes a processor 310 and a memory 320. The electronic device can also include an input device 330 and an output device 340. The processor 310, the memory 320, the input device 330 and the output device 340 can be connected by a bus or other means, Figure 4 The memory 320 is the computer readable storage medium described above. The processor 310 performs various functional applications and data processing of the server by running the non-volatile software programs, instructions and modules stored in the memory 320, that is, implements the stray current detection method for the photovoltaic power generation system according to the method embodiments described above. The input device 330 can receive input digital or character information, and generate key signal input related to user settings and function control of the stray current detection system for the photovoltaic power generation system. The output device 340 can include a display device such as a display screen.

[0081] The electronic device described above can perform the method provided by the embodiments of the present application, and has the corresponding functional modules and beneficial effects of performing the method. Technical details not described in detail in the present embodiment can be referred to the method provided by the embodiments of the present application.

[0082] As an implementation, the electronic device described above is applied to the stray current detection system for the photovoltaic power generation system, and is used for a client, including: at least one processor; and a memory in communication connection with the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to:

[0083] Obtain a satellite clock signal, generate a first control signal for local resistivity detection and a second control signal for local electric field monitoring according to the satellite clock signal;

[0084] Obtain the equivalent resistivity in the north-south direction and the equivalent resistivity in the east-west direction of the measurement point according to the first control signal and the second control signal, and determine the target measurement point according to the equivalent resistivity and the second equivalent resistivity;

[0085] Obtain the first equivalent resistivity p NS in the north-south direction, the second equivalent resistivity p WE in the east-west direction, the first electric field F NS in the north-south direction, the second electric field F WE in the east-west direction, the first ground current density J NS in the north-south direction, and the second ground current density J WE in the east-west direction of the target measurement point;

[0086] Determine the first equivalent resistivity p NS and the second equivalent resistivity p WE, the first electric field F NS The second electric field F WE , the first ground current density J NS And the second ground current density J WE The photovoltaic power generation system is analyzed, and a maintenance signal for the photovoltaic power generation system is generated according to the analysis result.

[0087] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus the necessary general hardware platform, or of course, by hardware. Based on this understanding, the essence of the above technical solution or the part that contributes to the existing technology can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods of each embodiment or certain parts of the embodiment.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A stray current detection method for a photovoltaic power generation system, characterized in that: include: Acquire a satellite clock signal, and generate a first control signal for local resistivity detection and a second control signal for local electric field monitoring according to the satellite clock signal; Obtaining an equivalent resistivity in a north-south direction and an equivalent resistivity in an east-west direction of a measuring point according to the first control signal and the second control signal, and determining a target measuring point according to the equivalent resistivity and the second equivalent resistivity; Get the first equivalent resistivity ρ in the north-south direction of the target measuring point NS , the second equivalent resistivity ρ in the east-west direction WE , the first electric field F in the north-south direction NS , the second electric field F in the east-west direction WE , the first ground current density J in the north-south direction NS and the second east-west current density J WE ; According to the first equivalent resistivity ρ NS , the second equivalent resistivity ρ WE , the first electric field F NS The second electric field F WE , the first ground current density J NS And the second ground current density J WE The photovoltaic power generation system is analyzed, and a maintenance signal for the photovoltaic power generation system is generated according to the analysis result.

2. A stray current detection method for a photovoltaic power generation system according to claim 1, characterized in that: Determining the target measuring point according to the equivalent resistivity and the second equivalent resistivity includes: Determine whether the difference between the equivalent resistivity and the equivalent resistivity of a certain measuring point is greater than a preset threshold; If it is not greater than a preset threshold, the certain measuring point is defined as a target measuring point; If it is greater than the preset threshold, continue to determine whether the difference between the equivalent resistivity of another measuring point and the equivalent resistivity is greater than the preset threshold, until the difference is no greater than the preset threshold.

3. The stray current detection method for a photovoltaic power generation system according to claim 1, characterized in that: in, The first equivalent resistivity ρ in the north-south direction of the target measuring point is obtained by a local resistivity monitoring sensor. NS , the second equivalent resistivity ρ in the east-west direction WE ; The local resistivity monitoring sensor includes a voltage monitoring unit and a current excitation unit; The voltage monitoring unit is composed of metal electrodes driven into the ground 0.1m-0.3m, namely the north voltage electrode PN, the south voltage electrode PS, the west voltage electrode PW and the east voltage electrode PE. The distance between the north voltage electrode PN and the south voltage electrode PS is 0.5m-1.5m, and the distance between the west voltage electrode PW and the east voltage electrode PE is 0.5-1.5m. The current excitation unit consists of metal electrodes driven into the ground 0.1m-0.3m, namely the north current electrode CN, the south current electrode CS, the west current electrode CW and the east current electrode CE. The distance between the north current electrode CN and the south current electrode CS is 1.5m-2.5m, and the distance between the west current electrode CW and the east current electrode CE is 1.5m-2.5m.

4. A stray current detection method for a photovoltaic power generation system according to claim 3, characterized in that: Get the first equivalent resistivity ρ in the north-south direction of the target measuring point NS , the second equivalent resistivity ρ in the east-west direction WE , specifically: The current excitation unit applies a voltage excitation of 20Hz-30Hz and an effective value of 5V-15V between the north current electrode CN and the south current electrode CS, and monitors the first output I of the current excitation unit. NS ; Get the first potential difference V between the north voltage pole PN and the south voltage pole PS NS ; According to the first output I NS and the first potential difference V NS Calculate the first equivalent resistivity ρ in the north-south direction NS , the expression is: The current excitation unit applies a voltage excitation of 20Hz-30Hz and an effective value of 5V-15V between the west current electrode CW and the east current electrode CE, and monitors the second output I WE ; Monitor the second potential difference V between the west voltage pole PW and the east voltage pole PE WE ; According to the second output I WE and the second potential difference V WE Calculate the second equivalent resistivity ρ in the east-west direction WE , the expression is:

5. The stray current detection method for a photovoltaic power generation system according to claim 3, characterized in that: Obtain the first electric field F in the north-south direction of the target measuring point NS , the second electric field F in the east-west direction WE , specifically: When the preset time of the satellite clock signal is reached every minute, the current excitation unit does not act, and the first potential difference V between the north voltage pole PN and the south voltage pole PS is NS Defined as the first electric field F in the north-south direction NS , and the second potential difference V between the west voltage electrode PW and the east voltage electrode PE WE .

6. The stray current detection method for a photovoltaic power generation system according to claim 1, characterized in that: Calculate the first ground current density J in the north-south direction NS and the second east-west current density J WE The expression is: Where V NS is the first potential difference between the north voltage pole PN and the south voltage pole PS, V WE is the second potential difference between the west voltage pole PW and the east voltage pole PE.

7. The stray current detection method for a photovoltaic power generation system according to claim 1, characterized in that: According to the first equivalent resistivity ρ NS , the second equivalent resistivity ρ WE , the first electric field F NS The second electric field F WE , the first ground current density J NS And the second ground current density J WE Analyzing the photovoltaic power generation system and generating a maintenance signal for the photovoltaic power generation system according to the analysis result includes: Determine the first equivalent resistivity ρ NS The second equivalent resistivity ρ WE whether the average value of is greater than a first preset threshold; If it is not greater than the first preset threshold, it is determined that buried metal corrosion occurs in the photovoltaic power generation system; otherwise, it is determined that buried metal corrosion does not occur in the photovoltaic power generation system; Determine whether the combined current density J is greater than a second preset threshold, wherein the expression for calculating the combined current density is: If the value is greater than a second preset threshold, it is determined that the photovoltaic power generation system is corroded; otherwise, it is determined that the photovoltaic power generation system is not corroded; Determine whether the combined earth electric field strength is greater than the step voltage threshold, wherein the expression for calculating the combined earth electric field strength is: The expression for calculating the step voltage threshold is: U S =7.42+0.0159(ρ NS +r WE ), If it is greater than the step voltage threshold, it is determined that the photovoltaic power generation system has a step voltage; otherwise, it is determined that the photovoltaic power generation system does not have a step voltage.

8. A stray current detection system for a photovoltaic power generation system, characterized in that: include: a generating module configured to obtain a satellite clock signal and generate a first control signal for local resistivity detection and a second control signal for local electric field monitoring according to the satellite clock signal; a determination module configured to obtain an equivalent resistivity in a north-south direction and an equivalent resistivity in an east-west direction of a measuring point according to the first control signal and the second control signal, and determine a target measuring point according to the equivalent resistivity and the second equivalent resistivity; An acquisition module configured to acquire the first equivalent resistivity ρ in the north-south direction of the target measuring point NS , the second equivalent resistivity ρ in the east-west direction WE , the first electric field F in the north-south direction NS , the second electric field F in the east-west direction WE , the first ground current density J in the north-south direction NS and the second east-west current density J WE ; An analysis module configured to analyze the first equivalent resistivity ρ NS , the second equivalent resistivity ρ WE , the first electric field F NS The second electric field F WE , the first ground current density J NS And the second ground current density J WE The photovoltaic power generation system is analyzed, and a maintenance signal for the photovoltaic power generation system is generated according to the analysis result.

9. An electronic device, characterized in that: include: At least one processor, and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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