Distributed photovoltaic power station cable fault positioning system and method

Abstract

The invention belongs to the technical field of circuit detection, and particularly relates to a distributed photovoltaic power station cable fault positioning system and method.Detection equipment is started, a carrier signal is sent to a cable network, electromagnetic interference characteristics are recorded synchronously, the frequency of the carrier signal is systematically adjusted to avoid recognized interference, and the fault positioning accuracy is improved. And repeating the steps until a non-interference working frequency band is found, then monitoring the signal transmission condition step by step along a cable path, and analyzing a signal attenuation mode to accurately position a potential fault point. According to the method, the problem of misjudgment caused by electromagnetic interference generated by the frequency converter is effectively solved, the accuracy and reliability of fault detection are remarkably improved, the maintenance cost and time are reduced, and the operation and maintenance efficiency of a photovoltaic power station is improved. The improvement has remarkable technical effect and practical value in a complex electromagnetic environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of circuit detection, and particularly relates to a cable fault location system and method for a distributed photovoltaic power station. Background Art

[0002] In a distributed photovoltaic power station, the accurate location of cable faults is a key issue. Existing cable fault detection methods usually rely on carrier signal transmission technology. Specifically, these methods send carrier signals with specific frequencies to the cable network and monitor the signal transmission conditions to identify potential fault points. However, devices such as inverters in photovoltaic power stations will generate significant electromagnetic interference (EMI), which will affect the carrier signals, resulting in signal attenuation or distortion, thus causing misjudgment problems.

[0003] General solutions of the prior art:

[0004] Carrier signal transmission method: By sending carrier signals and monitoring the changes on their transmission paths to identify areas where the signal strength decreases, and then locate the fault points.

[0005] Filtering technology: Using filters to reduce the influence of electromagnetic interference on carrier signals, but this method has limited effectiveness in a strong interference environment.

[0006] Frequency adjustment method: Trying to avoid the interference frequency band by adjusting the frequency of carrier signals, but due to the lack of a systematic frequency selection and verification mechanism, it is still difficult to completely avoid interference.

[0007] Although the above methods can help detect cable faults to a certain extent, in practical applications, especially in photovoltaic power stations with a large number of devices such as inverters, due to the existence of electromagnetic interference, misjudgment phenomena often occur. Specifically manifested as:

[0008] Misjudgment problem: Due to the influence of electromagnetic interference, the carrier signal may show abnormal fluctuations during transmission, causing the detection device to mistakenly think that there is a fault at this location, while there is actually no fault. Summary of the Invention

[0009] The purpose of the present invention is to provide a cable fault location system and method for a distributed photovoltaic power station, which can effectively eliminate interference in a complex electromagnetic environment, improve the accuracy of fault detection, reduce misjudgment phenomena, and thus improve the operation and maintenance efficiency and reliability of the photovoltaic power station, so as to solve the problems raised in the above background art.

[0010] To achieve the above purpose, on the one hand, the present invention proposes a cable fault location method for a distributed photovoltaic power station, including:

[0011] S1: Start the detection device and send a carrier signal to the cable network; S2: Based on the sent carrier signal, synchronously record the electromagnetic interference characteristics during the operation of the frequency converter; S3: According to the obtained electromagnetic interference characteristics, adjust the carrier signal frequency to avoid the identified interference; S4: Repeat steps S1 to S3 until a working frequency band without interference is found; S5: Gradually monitor the signal transmission situation within the working frequency band without interference along the cable path to obtain the monitoring results; S6: According to the monitoring results, analyze the signal attenuation pattern to locate potential fault points, and then confirm the fault location by comparing normal and abnormal signal patterns.

[0012] Preferably, the starting the detection device and sending a carrier signal to the cable network includes:

[0013] Record the intensity and frequency value of the initial carrier signal;

[0014] Measure the signal intensity after a period of time during the operation of the frequency converter and calculate the signal attenuation;

[0015] Adjust the gain setting of the receiving device according to the obtained attenuation to compensate for the signal loss caused by attenuation, so that the received signal intensity is close to the initial value;

[0016] Continuously monitor the change of the adjusted signal intensity, compare and analyze the real-time data with the original data, and if abnormal fluctuations are found, mark this section of the cable for inspection.

[0017] Preferably, the synchronously recording the electromagnetic interference characteristics during the operation of the frequency converter based on the sent carrier signal includes:

[0018] Collect the electromagnetic interference signal intensity and frequency distribution during the operation of the frequency converter, and calculate the energy density of the interference signal according to the obtained signal intensity and frequency distribution;

[0019] Use the energy density to determine the main frequency band range of the interference signal, based on the determined main frequency band range, adjust the working frequency band of the detection device to avoid the main interference frequency band, ensure the separation of the detection signal and the interference signal, and calculate the new signal intensity through the adjusted frequency band;

[0020] Monitor the signal transmission situation in the new frequency band, record the signal intensity change and frequency stability, and confirm whether there are new interference or signal attenuation problems; if abnormalities are found, re-select a new working frequency band.

[0021] Preferably, the adjusting the carrier signal frequency to avoid the identified interference according to the obtained electromagnetic interference characteristics includes:

[0022] Determine the main interference frequency band to be avoided and record its frequency range;

[0023] Select a new operating frequency band, ensuring that it is not within the interference frequency band range. According to the selected new operating frequency band, reconfigure the transmission and reception parameters of the detection device so that the frequency of the transmitted carrier signal is adjusted to the new operating frequency band;

[0024] Monitor the signal transmission on the adjusted operating frequency band, record the signal strength change and frequency stability, and confirm whether there are new interference or signal attenuation problems; if abnormalities are found, re-select a new operating frequency band.

[0025] Preferably, repeating steps S1 to S3 until a working frequency band without interference is found includes:

[0026] Initialize a counter to record the number of times of attempting to adjust the frequency band;

[0027] Based on the selected new operating frequency band and signal strength, conduct a complete detection cycle, including transmitting a carrier signal, recording electromagnetic interference characteristics, adjusting the carrier signal frequency, and monitoring the signal transmission on the new frequency band;

[0028] According to the monitoring results, calculate the interference index for the current frequency band; if the interference index is less than the preset threshold, confirm that this frequency band is the working frequency band without interference; if the interference index is greater than or equal to the preset threshold, increase the value of the counter and return to re-select a new operating frequency band until a working frequency band without interference that meets the conditions is found.

[0029] Preferably, gradually monitoring the signal transmission within the working frequency band without interference along the cable path to obtain the monitoring results includes:

[0030] Select the starting point of the cable path as the monitoring starting point and record the coordinate position and initial signal strength at this point;

[0031] Conduct a signal strength measurement at a fixed interval along the cable path, and record the position and corresponding signal strength of each measurement point;

[0032] Based on the obtained signal attenuation and the positions of each measurement point, draw a curve graph of signal strength changing with the path to find the area where the signal strength significantly decreases;

[0033] Scan the area where the signal strength significantly decreases that is identified, reduce the interval distance, re-measure and record the signal strength change; by comparing the new measurement data, confirm whether there is a fault point; if so, mark the specific position and corresponding signal strength of the fault point.

[0034] Preferably, analyzing the signal attenuation pattern according to the monitoring results to locate potential fault points includes:

[0035] Calculate the average signal attenuation rate of each section of the cable based on the position of each measurement point recorded and the corresponding signal strength;

[0036] Based on the calculated average signal attenuation rate, identify the signal attenuation abnormal regions, and mark the starting and ending points of these regions. Within the identified abnormal regions, further divide the regions into multiple small sections, and re-measure the signal strength of each section, and calculate the local signal attenuation rate of each section;

[0037] Based on the calculated local signal attenuation rate, determine the point with the most severe signal attenuation, record the specific coordinates of this point and the corresponding signal strength. If there are multiple points with severe attenuation, mark all the suspected fault points in sequence.

[0038] Preferably, the confirmation of the fault location by comparing the normal and abnormal signal patterns includes:

[0039] Based on the determined suspected fault points and their corresponding signal strengths, collect the signal data of the normal regions around these points;

[0040] According to the collected signal data of the normal regions, calculate the average signal strength and standard deviation in the normal signal pattern;

[0041] Use the obtained normal signal pattern parameters to compare the signal strength of the fault points; if the deviation between the signal strength of the fault point and the average signal strength exceeds the preset coefficient multiplied by the standard deviation, confirm that there is a significant signal abnormality at this point; repeat the verification process for all marked suspected fault points;

[0042] For each confirmed fault point, record its detailed information, generate a final fault report, and list all the confirmed fault points and their related information.

[0043] Preferably, it further includes: marking all the confirmed fault locations and generating a maintenance report.

[0044] On the other hand, the present invention proposes a cable fault location system for a distributed photovoltaic power station, including:

[0045] An initialization and signal sending module, used to start the detection device and send a carrier signal to the cable network;

[0046] An electromagnetic interference characteristic recording module, used to synchronously record the electromagnetic interference characteristics during the operation of the frequency converter based on the sent carrier signal;

[0047] A frequency adjustment and interference avoidance module, used to adjust the carrier signal frequency to avoid the identified interference according to the obtained electromagnetic interference characteristics;

[0048] A non-interference frequency band search module, used to repeat steps S1 to S3 until a working frequency band without interference is found;

[0049] A path monitoring and signal transmission analysis module, which is used to gradually monitor the signal transmission situation within the working frequency band without interference influence along the cable path and obtain the monitoring results;

[0050] A fault point location and confirmation module, which is used to analyze the signal attenuation mode to locate potential fault points according to the monitoring results, and then confirm the fault location by comparing the normal and abnormal signal modes;

[0051] A report generation module, which is used to mark all the confirmed fault locations and generate a maintenance report.

[0052] The technical effects and advantages of the present invention: A distributed photovoltaic power station cable fault location system and method proposed by the present invention have the following advantages compared with the prior art:

[0053] The present invention starts the detection device and sends a carrier signal to the cable network, synchronously records the electromagnetic interference characteristics, systematically adjusts the carrier signal frequency to avoid the identified interference, and repeats the above steps until a working frequency band without interference is found. Subsequently, it gradually monitors the signal transmission situation along the cable path, analyzes the signal attenuation mode to accurately locate potential fault points. This method effectively solves the misjudgment problem caused by electromagnetic interference generated by frequency converters, significantly improves the accuracy and reliability of fault detection, reduces the maintenance cost and time, and improves the operation and maintenance efficiency of the photovoltaic power station. This improvement has significant technical effects and practical value in a complex electromagnetic environment. Description of the Drawings

[0054] Figure 1 It is a flowchart of the distributed photovoltaic power station cable fault location method of the present invention;

[0055] Figure 2 It is a block diagram of the distributed photovoltaic power station cable fault location system of the present invention. Detailed Embodiments

[0056] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0057] The present invention provides a distributed photovoltaic power station cable fault location method as Figure 1 shown, including the following steps:

[0058] S1: Start the detection device and send a carrier signal to the cable network; specifically, it includes the following steps:

[0059] Record the intensity and frequency values of the initial carrier signal, denoted as I0 and F0; this step ensures a reliable reference point in subsequent steps for accurately evaluating signal changes.

[0060] Based on the obtained I0 and F0 values, measure the signal intensity It after time t during the operation of the frequency converter, and calculate the signal attenuation D using the formula D = (It - I0) / t; this step helps identify the attenuation degree of the signal during transmission, thereby determining whether there are potential problems.

[0061] Principle of formula application:

[0062] The formula D = (It - I0) / t calculates the average attenuation rate of the signal within time t. Here, It is the signal intensity after time t, I0 is the initial signal intensity, and t is the time interval. This formula is used to measure the attenuation of the signal over time.

[0063] According to the obtained attenuation D, adjust the gain setting G of the receiving device to compensate for signal loss caused by attenuation, so that the received signal intensity is close to the initial value I0, where G = I0 / (It - D*t). This formula compensates for signal attenuation by adjusting the gain to restore the received signal intensity to close to the initial value; this step ensures the stability and consistency of signal quality and improves the accuracy of detection.

[0064] Continuously monitor the change in the adjusted signal intensity, compare and analyze the real-time data with the original data I0 and F0. If abnormal fluctuations are found, mark this section of the cable for detailed inspection, which helps quickly locate potential fault points and improve maintenance efficiency.

[0065] Suppose in a distributed photovoltaic power station, it is necessary to detect faults in the cable network. The following are the detailed steps and technical effect descriptions:

[0066] Step 1: Record the intensity and frequency values of the initial carrier signal:

[0067] Operation: Use the detection device to send a carrier signal to the cable network and record the initial signal intensity I0 and frequency F0.

[0068] Data: I0 = 10V, F0 = 5MHz.

[0069] Technical effect: Provide a reliable reference value for subsequent signal attenuation calculation and adjustment.

[0070] Step 2: Measure the signal intensity after time t and calculate the signal attenuation:

[0071] Operation: During the operation of the frequency converter, after selecting a time interval t, measure the signal intensity It obtained.

[0072] Data: t = 10 seconds, It = 8V.

[0073] Formula: D=(It - I0) / t;

[0074] Calculation: D=(8 - 10) / 10=-0.2V / s;

[0075] Technical effect: Quantify the attenuation degree of the signal during transmission and identify potential problems.

[0076] Step 3: Adjust the gain setting of the receiving device:

[0077] Operation: According to the obtained attenuation amount D, adjust the gain setting G of the receiving device to compensate for the signal loss caused by attenuation.

[0078] Formula: G = I0 / (It - D*t);

[0079] Calculation: G = 10 / (8 - (-0.2*10)) = 10 / (8 + 2) = 10 / 10 = 1;

[0080] Technical effect: By adjusting the gain setting, make the received signal intensity close to the initial value and improve the detection accuracy.

[0081] Step 4: Continuously monitor the change of the adjusted signal intensity:

[0082] Operation: Continuously monitor the change of the adjusted signal intensity and compare and analyze the real-time data with the original data.

[0083] Data: The signal intensity is suddenly monitored to drop to 6V in real time.

[0084] Technical effect: Timely detect abnormal fluctuations in the signal, mark this section of the cable for detailed inspection, and quickly locate potential fault points.

[0085] Suppose in a distributed photovoltaic power station, the following steps are executed:

[0086] Record the intensity and frequency values of the initial carrier signal:

[0087] Use the detection device to send a carrier signal to the cable network and record the initial signal intensity I0 = 10V and frequency F0 = 5MHz.

[0088] Measure the signal intensity after time t and calculate the signal attenuation amount:

[0089] During the operation of the frequency converter, after selecting a time interval t = 10 seconds, measure the signal intensity It = 8V obtained.

[0090] Calculate the signal attenuation D using the formula D = (It - I0) / t: D = (8 - 10) / 10 = -0.2 V / s;

[0091] This indicates that the signal attenuates by 0.2 V per second.

[0092] Adjust the gain setting of the receiving device:

[0093] Based on the calculated attenuation D = -0.2 V / s, adjust the gain setting G of the receiving device: G = 10 / (8 - (-0.2*10)) = 10 / (8 + 2) = 10 / 10 = 1;

[0094] Set the gain of the receiving device to 1 to compensate for signal attenuation and make the received signal strength close to the initial value of 10 V.

[0095] Continuously monitor the change in the adjusted signal strength:

[0096] Continuously monitor the change in the adjusted signal strength and compare and analyze the real-time data with the original data I0 = 10 V and F0 = 5 MHz.

[0097] If abnormal fluctuations in the signal strength are detected (for example, suddenly dropping to 6 V), mark the section of the cable for detailed inspection to further confirm whether there is a fault.

[0098] S2: Based on the transmitted carrier signal, synchronously record the electromagnetic interference characteristics during the operation of the frequency converter; specifically, it includes the following steps:

[0099] Collect the electromagnetic interference signal strength Ei and frequency distribution Fd during the operation of the frequency converter; obtain detailed information about the electromagnetic interference to provide basic data for subsequent calculations and analyses.

[0100] According to the obtained Ei and Fd, calculate the energy density Ed of the interference signal using the formula Ed = Ei^2 * Fd; the energy density Ed reflects the strength of the interference signal within a specific frequency range and helps identify the main interference frequency bands.

[0101] Using the obtained energy density Ed, determine the main frequency band range Bm of the interference signal, where Bm is the frequency band with the highest energy density; identify the interference frequency band that has the greatest impact on the detected signal to facilitate subsequent adjustment of the working frequency band of the detection device to avoid these interferences.

[0102] Based on the determined main frequency band range Bm, adjust the operating frequency band of the detection device to avoid the main interference frequency band, ensure the separation of the detection signal from the interference signal, calculate the new signal strength Ea through the adjusted frequency band range Ba, using the formula Ea = I0 / (1 + Ed / Ba), where I0 is the initial carrier signal strength. By adjusting the operating frequency band, avoid the influence of the interference signal and ensure the stability and accuracy of the detection signal.

[0103] Embodiment

[0104] Suppose in a distributed photovoltaic power station, it is necessary to detect cable network faults and handle electromagnetic interference problems:

[0105] Collect the electromagnetic interference signal strength Ei and frequency distribution Fd during the operation of the frequency converter:

[0106] Use the detection device to synchronously record the electromagnetic interference signal strength Ei = 5V / m and frequency distribution Fd = 1MHz generated during the operation of the frequency converter.

[0107] Technical effect: Obtain detailed information on electromagnetic interference and provide basic data for subsequent calculations and analyses.

[0108] Calculate the energy density Ed of the interference signal:

[0109] Based on the collected electromagnetic interference signal strength Ei and frequency distribution Fd, calculate the energy density Ed = 25V^2 / m^2·MHz of the interference signal;

[0110] This indicates that at the 1MHz frequency band, the energy density of the interference signal is 25V^2 / m^2·MHz.

[0111] Technical effect: The energy density Ed reflects the intensity of the interference signal within a specific frequency range and helps identify the main interference frequency band.

[0112] Determine the main frequency band range Bm of the interference signal:

[0113] By comparing the energy densities Ed of different frequency bands, it is found that Bm = 1MHz is the frequency band with the highest energy density, i.e., the main interference frequency band.

[0114] Technical effect: Identify the interference frequency band that has the greatest impact on the detection signal, facilitating subsequent adjustment of the operating frequency band of the detection device to avoid these interferences.

[0115] Adjust the operating frequency band of the detection device and calculate the new signal strength Ea:

[0116] According to the main interference frequency band Bm = 1MHz, select a new operating frequency band Ba = 2MHz (avoiding the main interference frequency band).

[0117] Calculate the new signal strength Ea using the formula Ea = I0 / (1 + Ed / Ba): Ea = 10 / 13.5 ≈ 0.74V;

[0118] Set the operating frequency band of the detection device to 2MHz to make the new signal strength close to 0.74V, thereby avoiding the main interference frequency band and ensuring the separation of the detection signal and the interference signal.

[0119] Technical effect: By adjusting the operating frequency band, the influence of the interference signal is avoided, and the stability and accuracy of the detection signal are ensured.

[0120] S3: According to the obtained electromagnetic interference characteristics, adjust the carrier signal frequency to avoid the identified interference; specifically include the following steps:

[0121] Determine the main interference frequency band Bm to be avoided and record its frequency range from F1 to F2; clarify the interference frequency band range to be avoided, providing a basis for selecting a new operating frequency band later.

[0122] Based on the determined frequency range F1 and F2, select a new operating frequency band Fn, ensuring that Fn is not within the range of F1 to F2 and satisfies Fn = (F1 + F2) / 2 + k*(F2 - F1), where k is an integer greater than 1; by selecting a new operating frequency band not within the interference frequency band range, the influence of the interference signal is avoided, and the stability and accuracy of the detection signal are ensured.

[0123] According to the selected new operating frequency band Fn, reconfigure the transmission and reception parameters of the detection device so that the frequency of the transmitted carrier signal is adjusted to Fn, and at the same time calculate the adjusted signal strength In, using the formula In = I0*(Fn / F0), where I0 and F0 are the initial signal strength and frequency respectively; by reconfiguring the device parameters, the frequency of the carrier signal is adjusted to the new operating frequency band, ensuring that the signal strength is close to the initial value and improving the detection accuracy.

[0124] Monitor the signal transmission situation on the adjusted operating frequency band Fn, record the signal strength change ΔI and frequency stability ΔF in the new frequency band, and confirm whether there are new interference or signal attenuation problems by comparing ΔI and ΔF with the initial values. If any abnormality is found, return to reselect a new operating frequency band. By monitoring the signal strength and frequency stability, new interference or signal attenuation problems can be discovered and processed in a timely manner, ensuring the accuracy and reliability of the detection process.

[0125] Suppose in a distributed photovoltaic power station, it is necessary to detect cable network faults and handle electromagnetic interference problems:

[0126] Determine the main interference frequency band Bm to be avoided and record its frequency range from F1 to F2:

[0127] According to the main interference frequency bands identified in the previous steps, record its frequency range as F1 = 1 MHz to F2 = 2 MHz.

[0128] Technical effect: Clearly define the range of interference frequency bands to be avoided, providing a basis for selecting a new working frequency band subsequently.

[0129] Select a new working frequency band Fn:

[0130] Use the formula Fn = (F1 + F2) / 2 + k*(F2 - F1) to calculate the new frequency band:

[0131] Fn = (1 + 2) / 2 + k*(2 - 1) = 1.5 + k*1; Fn = (1 + 2) / 2 + k*(2 - 1) = 1.5 + k*1;

[0132] Assume k = 2, then:

[0133] Fn = 1.5 + 2*1 = 3.5 MHz; Fn = 1.5 + 2*1 = 3.5 MHz;

[0134] Technical effect: By selecting a new working frequency band outside the interference frequency band range, avoid the influence of interference signals, and ensure the stability and accuracy of the detection signal.

[0135] Reconfigure the transmission and reception parameters of the detection device, and calculate the adjusted signal strength In:

[0136] According to the new working frequency band Fn, reconfigure the transmission and reception parameters of the detection device, and use the formula In = I0*(Fn / F0) to calculate the new signal strength: In = 10*(3.5 / 5) = 10*0.7 = 7 V;

[0137] Technical effect: By reconfiguring the device parameters, adjust the carrier signal frequency to the new working frequency band, ensure that the signal strength is close to the initial value, and improve the detection accuracy.

[0138] Monitor the signal transmission situation on the adjusted working frequency band Fn:

[0139] Continuously monitor the signal transmission situation on the adjusted working frequency band Fn, and record the signal strength change ΔI and frequency stability ΔF:

[0140] Assume that ΔI = 0.5 V (change relative to the initial value) and ΔF = 0.1 MHz (change relative to the initial frequency) are monitored.

[0141] Technical effect: By monitoring the signal strength and frequency stability, promptly discover and handle new interference or signal attenuation problems, and ensure the accuracy and reliability of the detection process.

[0142] S4: Repeat steps S1 to S3 until a working frequency band without interference is found; The fixture includes the following steps:

[0143] Initialize a counter n = 1 to record the number of times of attempting to adjust the frequency band; Track the frequency bands that have been attempted through the counter to ensure that each newly selected frequency band does not overlap with the previously attempted frequency bands, avoiding duplicate work.

[0144] Based on the selected new working frequency band Fn and signal strength In, conduct a complete detection cycle, including transmitting a carrier signal, recording the electromagnetic interference characteristics, adjusting the carrier signal frequency, and monitoring the signal transmission situation on the new frequency band; Through the complete detection cycle, verify whether the new frequency band is interfered, ensuring the stability and accuracy of the detection signal.

[0145] According to the monitoring results, calculate the interference index Ji of the current frequency band, using the formula Ji = ΔI / In + ΔF / Fn, where ΔI and ΔF are the changes in signal strength and frequency stability respectively. If Ji is less than the preset threshold T, confirm that this frequency band is a working frequency band without interference; By calculating the interference index Ji, evaluate the interference situation of the current frequency band to ensure finding a suitable working frequency band without interference.

[0146] If Ji is greater than or equal to T, increase the value of the counter n (n = n + 1), and reselect a new working frequency band Fn+1, ensuring that each selected frequency band does not overlap with the previously attempted frequency bands until a working frequency band without interference that meets the conditions is found. By cyclically adjusting the frequency band, gradually exclude the interference frequency bands, and finally find a working frequency band without interference, ensuring the stability and accuracy of the detection signal.

[0147] Suppose in a distributed photovoltaic power station, it is necessary to detect faults in the cable network and handle electromagnetic interference problems:

[0148] Initialize a counter n = 1:

[0149] Initialize the counter n = 1 to record the number of times of attempting to adjust the frequency band.

[0150] Technical effect: Track the frequency bands that have been attempted through the counter to ensure that each newly selected frequency band does not overlap with the previously attempted frequency bands, avoiding duplicate work.

[0151] Based on the selected new working frequency band Fn and signal strength In, conduct a complete detection cycle:

[0152] Suppose the selected new working frequency band Fn = 3.5 MHz and the signal strength In = 7 V.

[0153] Perform a complete detection cycle, including transmitting a carrier signal, recording the electromagnetic interference characteristics, adjusting the carrier signal frequency, and monitoring the signal transmission on the new frequency band.

[0154] Technical effect: Through the complete detection cycle, verify whether the new frequency band is interfered, and ensure the stability and accuracy of the detection signal.

[0155] According to the monitoring results, calculate the interference index Ji under the current frequency band:

[0156] Assume that the monitored signal strength change ΔI = 0.5V and the frequency stability change ΔF = 0.1MHz, then:

[0157] Ji = ΔI / In + ΔF / Fn = 0.5 / 7 + 0.1 / 3.5 ≈ 0.0714 + 0.0286 = 0.1;

[0158] Assume the preset threshold T = 0.05, then Ji > T.

[0159] Technical effect: By calculating the interference index Ji, evaluate the interference situation of the current frequency band, and ensure to find a suitable interference-free working frequency band.

[0160] If Ji is greater than or equal to T, then increase the value of the counter n and reselect the new working frequency band Fn+1:

[0161] Because Ji = 0.1 > T = 0.05, so increase the value of the counter n (n = n + 1 = 2).

[0162] Reselect the new working frequency band Fn+1:

[0163] Fn+1 = (F1 + F2) / 2 + k*(F2 - F1)

[0164] Assume k = 3, then:

[0165] Fn+1 = 1.5 + 3*1 = 4.5 MHz;

[0166] Reconfigure the transmission and reception parameters of the detection device and calculate the new signal strength In+1:

[0167] In+1 = I0*(Fn+1 / F0) = 10*(4.5 / 5) = 9 V;

[0168] Perform the complete detection cycle again and calculate the new interference index Ji+1:

[0169] Ji+1 = ΔI / In+1 + ΔF / Fn+1;

[0170] Assume the new monitoring results are ΔI = 0.3V and ΔF = 0.05MHz, then:

[0171] Ji+1 = 0.3 / 9 + 0.05 / 4.5 ≈ 0.0333 + 0.0111 = 0.0444;

[0172] Since Ji+1 < T = 0.05, it is confirmed that this frequency band is an interference-free operating frequency band.

[0173] Technical effect: By cyclically adjusting the frequency band, gradually excluding the interference frequency band, and finally finding an interference-free operating frequency band, the stability and accuracy of the detected signal are ensured.

[0174] S5: Gradually monitor the signal transmission in the interference-free operating frequency band along the cable path to obtain the monitoring results; specifically, it includes the following steps:

[0175] Select the starting point of the cable path as the monitoring starting point, and record the coordinate position P0 and the initial signal intensity I0 at this point; provide a reliable reference value for subsequent signal attenuation calculation and analysis.

[0176] Based on the starting point information, perform a signal intensity measurement every fixed distance d along the cable path, and record the position Pi and the corresponding signal intensity Ii of each measurement point. Use the formula Di = (Ii - I0) / i to calculate the signal attenuation Di from the starting point to the i-th measurement point; by gradually measuring the signal intensity and calculating the attenuation, identify the possible problem areas during signal transmission.

[0177] According to the obtained signal attenuation Di and the positions Pi of each measurement point, draw a curve graph of the signal intensity changing with the path, and find the area Rm where the signal intensity drops significantly. The definition of Rm is the continuous interval where the signal attenuation Di exceeds the preset threshold Td; by drawing the curve graph, visually identify the area where the signal intensity drops significantly for further detailed inspection.

[0178] For the identified area Rm where the signal intensity drops significantly, conduct a more detailed scan, reduce the interval distance to d / 2, re-measure and record the signal intensity change ΔIi. By comparing ΔIi with the previous measurement data, confirm whether there is a fault point. If so, mark the specific position Pf and the corresponding signal intensity If of the fault point. Through more detailed scanning and re-measurement, accurately identify and locate potential fault points to improve the detection accuracy.

[0179] Suppose in a distributed photovoltaic power station, it is necessary to detect faults in the cable network:

[0180] Select the starting point of the cable path as the monitoring starting point, and record the coordinate position P0 and the initial signal intensity I0:

[0181] Select the starting point of the cable path as the monitoring starting point, and record the coordinate position P0=(0,0) meters and the initial signal strength I0 = 10V of this point.

[0182] Technical effect: Provide a reliable reference value for subsequent signal attenuation calculation and analysis.

[0183] Based on the starting point information, perform a signal strength measurement every fixed distance d along the cable path:

[0184] Assume the fixed distance d = 10 meters, perform a signal strength measurement every 10 meters along the cable path, and record the position Pi and the corresponding signal strength Ii of each measurement point.

[0185] Calculate the signal attenuation Di: Di=(Ii−I0) / i;

[0186] For example, for the first measurement point P1=(10,0) and I1 = 9.5V, then:

[0187] D1=(9.5−10) / 1 = -0.5V;

[0188] Based on the obtained signal attenuation Di and the positions Pi of each measurement point, draw a curve graph of the signal strength changing with the path:

[0189] Based on the obtained signal attenuation Di and the positions Pi of each measurement point, draw a curve graph of the signal strength changing with the path, and find the region Rm where the signal strength significantly drops.

[0190] Assume the preset threshold Td = -0.3V. If Di on a certain path continuously drops below -0.3V, then this section of the path is marked as Rm.

[0191] Technical effect: By drawing the curve graph, visually identify the region where the signal strength significantly drops, which is convenient for further detailed inspection.

[0192] For the identified region Rm where the signal strength significantly drops, conduct a more detailed scan:

[0193] For the identified region Rm where the signal strength significantly drops, conduct a more detailed scan, reduce the interval distance to d / 2 = 5 meters, and re-measure and record the signal strength change ΔIi.

[0194] Calculate the signal strength change ΔIi: ΔIi = Ii_new−Ii_old. For example, at a certain new measurement point Ii_new = 8.5V, and the corresponding previous point Ii_old = 9.0V, then: ΔIi = 8.5−9.0 = -0.5V;

[0195] By comparing ΔIi with previous measurement data, confirm whether there is a fault point. If so, mark the specific location Pf of the fault point and the corresponding signal strength If.

[0196] Technical effect: By more meticulous scanning and re-measurement, accurately identify and locate potential fault points, improving the detection accuracy.

[0197] S6: According to the monitoring results, analyze the signal attenuation pattern to locate potential fault points, and then confirm the fault location by comparing normal and abnormal signal patterns.

[0198] Analyze the signal attenuation pattern to locate potential fault points, specifically including the following steps:

[0199] Based on the position Pi and the corresponding signal strength Ii of each recorded measurement point, calculate the average signal attenuation rate Ra of each section of the cable. Use the formula Ra = (Ii - I0) / (Pi - P0), where I0 and P0 are the signal strength and position of the starting point respectively; by calculating the average signal attenuation rate Ra, quantify the signal attenuation of each section of the cable and identify the regions with abnormal signal attenuation.

[0200] According to the calculated average signal attenuation rate Ra, identify the regions with abnormal signal attenuation Rm, defined as the continuous intervals where the signal attenuation rate exceeds the preset threshold Ta. Mark the starting point Ps and the ending point Pe of these regions; by identifying the regions with abnormal signal attenuation, narrow the search range of the fault point for further detailed inspection.

[0201] Within the identified abnormal region Rm, further divide this region into multiple small sections, each with a length of d / 2, and re-measure the signal strength Ij of each section. Calculate the local signal attenuation rate Rl of each section, using the formula Rl = (Ij - I(j - 1)) / (d / 2), where Ij is the signal strength of the jth section; by more meticulous measurement and calculation of the local signal attenuation rate Rl, accurately identify the point with the most severe signal attenuation and improve the accuracy of fault location.

[0202] Based on the calculated local signal attenuation rate Rl, determine the point Pf with the most severe signal attenuation, that is, the position with the largest Rl value. Record the specific coordinates of this point and the corresponding signal strength If. If there are multiple points with severe attenuation, mark all suspicious fault points in sequence. By determining the point with the most severe signal attenuation, accurately locate potential fault points and ensure the accuracy and reliability of the detection results.

[0203] Suppose in a distributed photovoltaic power station, it is necessary to detect faults in the cable network:

[0204] Based on the position Pi and the corresponding signal strength Ii of each recorded measurement point, calculate the average signal attenuation rate Ra of each section of the cable:

[0205] Assume the starting point P0 = (0, 0) m and the initial signal strength I0 = 10 V.

[0206] For the measurement point P1 = (10, 0) m and the signal strength I1 = 9.5 V, then:

[0207] Ra1 = (I1 - I0) / (P1 - P0) = (9.5 - 10) / (10 - 0) = -0.05 V / m;

[0208] For the measurement point P2 = (20, 0) m and the signal strength I2 = 9.0 V, then:

[0209] Ra2 = (I2 - I0) / (P2 - P0) = (9.0 - 10) / (20 - 0) = -0.05 V / m;

[0210] Technical effect: By calculating the average signal attenuation rate Ra, the signal attenuation of each section of the cable is quantified, and the area with abnormal signal attenuation is identified.

[0211] Based on the calculated average signal attenuation rate Ra, identify the area with abnormal signal attenuation Rm:

[0212] Assume the preset threshold Ta = -0.04 V / m. If the Ra on a certain path is continuously lower than -0.04 V / m, then this section of the path is marked as Rm.

[0213] For example, the Ra from P1 to P2 is -0.05 V / m, which is lower than the preset threshold Ta = -0.04 V / m. Therefore, this section of the path is marked as Rm.

[0214] Mark the starting point of this area Ps = (10, 0) m and the ending point Pe = (20, 0) m.

[0215] Technical effect: By identifying the area with abnormal signal attenuation, the search range for the fault point is narrowed, which is convenient for further detailed inspection.

[0216] Within the identified abnormal area Rm, further divide this area into multiple small sections, each with a length of d / 2, and re-measure the signal strength Ij of each section:

[0217] Assume the original interval d = 10 m, which is now reduced to d / 2 = 5 m. Re-measure the signal strength Ij and calculate the local signal attenuation rate Rl of each section.

[0218] For example, between Ps = (10, 0) m and the midpoint (15, 0) m, the signal strengths are I1 = 9.5 V and I2 = 9.2 V respectively. Then: Rl1 = (I2 - I1) / (d / 2) = (9.2 - 9.5) / 5 = -0.06 V / m;

[0219] Between the midpoint (15, 0) m and Pe = (20, 0) m, the signal strengths are I2 = 9.2 V and I3 = 9.0 V respectively. Then:

[0220] Rl2 = (I3 - I2) / (d / 2) = (9.0 - 9.2) / 5 = -0.04 V / m;

[0221] Technical effect: By measuring and calculating the local signal attenuation rate Rl more precisely, the point with the most severe signal attenuation can be accurately identified, improving the accuracy of fault location.

[0222] Based on the calculated local signal attenuation rate Rl, determine the point Pf with the most severe signal attenuation:

[0223] The calculated local signal attenuation rates are Rl1 = -0.06 V / m and Rl2 = -0.04 V / m, where Rl1 is the largest. Therefore, the point Pf with the most severe signal attenuation is located at (15, 0) m.

[0224] Record the specific coordinates of this point Pf = (15, 0) m and the corresponding signal strength If = 9.2 V.

[0225] If there are multiple points with severe attenuation, mark all suspicious fault points in sequence.

[0226] Technical effect: By determining the point with the most severe signal attenuation, the potential fault point can be accurately located, ensuring the accuracy and reliability of the detection results.

[0227] Confirm the fault location by comparing the normal and abnormal signal patterns, specifically including the following steps:

[0228] Based on the determined suspicious fault point Pf and its corresponding signal strength If, collect the signal data of the normal area around this point, including the signal strength In and the position Pn. Ensure that the selected normal area is far enough from the fault point to avoid interference;

[0229] According to the collected signal data of the normal area, calculate the average signal strength In_avg and the standard deviation σn in the normal signal pattern. Use the formulas In_avg = (ΣIn) / N and σn = sqrt(Σ(In - In_avg)^2 / N), where N is the number of data points in the normal area;

[0230] Using the obtained normal signal pattern parameters In_avg and σn, compare the signal strength If of the fault point Pf. If |If - In_avg| > k * σn (k is a preset coefficient, usually greater than 1), then confirm that there is a significant signal abnormality at this point;

[0231] Repeat the verification for all marked suspicious fault points. For each confirmed fault point, record its detailed information, including the coordinates Pf, signal intensity If, the deviation value ΔI = |If - In_avg| from the normal signal pattern, and the basis for confirming it as a fault point (i.e., ΔI > k * σn). Generate a final fault report listing all confirmed fault points and their relevant information.

[0232] In a preferred embodiment, the cable fault location method for a distributed photovoltaic power station further includes: marking all confirmed fault locations and generating a maintenance report; specifically including the following steps:

[0233] Based on all the confirmed fault point information, including the coordinates Pf, signal intensity If, and the deviation value ΔI from the normal signal pattern, establish a detailed fault point list. Each entry contains the coordinates, signal intensity, and deviation value of the fault point; by establishing a detailed fault point list, clear fault point information is provided for subsequent classification and processing.

[0234] According to the fault point list, classify and mark each fault point. The marking types can include severe (ΔI > 2 * σn), medium (σn < ΔI ≤ 2 * σn), and minor (ΔI ≤ σn), where σn is the standard deviation of the normal signal pattern; by classifying and marking the fault points, it helps maintenance personnel quickly identify the severity of the faults and formulate corresponding maintenance measures.

[0235] For the fault points of each marking type, generate detailed description information, including the specific location Pf, signal intensity If, deviation value ΔI, and marking type of the fault point. At the same time, calculate the total number Ns of the fault points of each marking type, using the formula Ns = Σ(1), where the summation range is the number of fault points of the corresponding marking type; by generating detailed description information and statistical results, comprehensive fault point information is provided for subsequent maintenance personnel to refer to and execute.

[0236] Summarize the detailed description information and statistical results of all fault points to generate a final maintenance report. This report should include a distribution map of the fault points, a quantity statistics of each marking type, the specific information of each fault point, and recommended maintenance measures. Ensure that the report format is clear for subsequent maintenance personnel to refer to and execute.

[0237] Suppose in a distributed photovoltaic power station, it is necessary to detect the cable network for faults and generate a maintenance report:

[0238] Suppose the data:

[0239] The starting point P0 = (0, 0) m, and the initial signal intensity I0 = 10 V.

[0240] The standard deviation σn of the normal signal pattern = 0.5 V.

[0241] Fault point information:

[0242] Fault point 1: Pf1 = (15,0) m, If1 = 9.2 V, ΔI1 = 0.8 V;

[0243] Fault point 2: Pf2 = (30,0) m, If2 = 8.5 V, ΔI2 = 1.5 V;

[0244] Fault point 3: Pf3 = (45,0) m, If3 = 7.0 V, ΔI3 = 3.0 V;

[0245] Step 1: Establish a detailed list of fault points:

[0246] The list is as follows:

[0247] Serial number Coordinate Pf (m) Signal intensity If (V) Deviation value ΔI (V) 1 (15,0) 9.2 0.8 2 (30,0) 8.5 1.5 3 (45,0) 7.0 3.0

[0248] Step 2: Classify and label each fault point:

[0249] Classify according to the deviation value ΔI and the standard deviation σn = 0.5 V:

[0250] Fault point 1: ΔI1 = 0.8 V, belonging to minor (ΔI ≤ σn);

[0251] Fault point 2: ΔI2 = 1.5 V, belonging to medium (σn < ΔI ≤ 2*σn);

[0252] Fault point 3: ΔI3 = 3.0 V, belonging to severe (ΔI > 2*σn);

[0253] Step 3: Generate detailed description information and calculate the total number of fault points:

[0254] Generate detailed description information:

[0255] Serial number Coordinate Pf (m) Signal intensity If (V) Deviation value ΔI (V) Marking type 1 (15,0) 9.2 0.8 Slight 2 (30,0) 8.5 1.5 Medium 3 (45,0) 7.0 3.0 Severe

[0256] Calculate the total number of fault points for each label type:

[0257] Minor: Ns_minor = 1;

[0258] Medium: Ns_medium = 1;

[0259] Severe: Ns_severe = 1;

[0260] Step 4: Generate the final maintenance report:

[0261] The content of the maintenance report is as follows:

[0262] Maintenance report:

[0263] I. Quantity statistics of each label type:

[0264] Marking type Quantity Slight 1 Medium 1 Severe 1

[0265] II. Specific Information of Each Fault Point

[0266] Serial number Coordinate Pf (m) Signal intensity If (V) Deviation value ΔI (V) Marking type 1 (15,0) 9.2 0.8 Slight 2 (30,0) 8.5 1.5 Medium 3 (45,0) 7.0 3.0 Severe

[0267] III. Suggested Maintenance Measures

[0268] 1. For minor fault points (such as at (15,0) meters), it is recommended to conduct regular monitoring to ensure the signal strength remains stable.

[0269] 2. For medium fault points (such as at (30,0) meters), it is recommended to perform local repair or replace the relevant cable section.

[0270] 3. For severe fault points (such as at (45,0) meters), it is recommended to immediately carry out emergency repair to avoid further damage.

[0271] Through the above steps, this method can effectively identify and locate fault points in the cable path, generate a clear maintenance report, and improve the accuracy and efficiency of cable fault detection and maintenance. This improvement has significant technical effects and practical value in a complex electromagnetic environment.

[0272] On the other hand, the present invention proposes a distributed photovoltaic power station cable fault location system, including:

[0273] Initialization and signal sending module, used to start the detection device and send carrier signals to the cable network;

[0274] Electromagnetic interference characteristic recording module, used to synchronously record electromagnetic interference characteristics during the operation of the frequency converter based on the sent carrier signals;

[0275] Frequency adjustment and interference avoidance module, used to adjust the carrier signal frequency to avoid the identified interference according to the obtained electromagnetic interference characteristics;

[0276] Interference-free frequency band search module, used to repeat steps S1 to S3 until an interference-free operating frequency band is found;

[0277] Path monitoring and signal transmission analysis module, used to gradually monitor the signal transmission situation within the interference-free operating frequency band along the cable path to obtain monitoring results;

[0278] Fault point location and confirmation module, used to analyze the signal attenuation pattern to locate potential fault points according to the monitoring results, and then confirm the fault location by comparing normal and abnormal signal patterns;

[0279] Report generation module, used to mark all the confirmed fault locations and generate a maintenance report.

[0280] In addition, when the above-mentioned modules are executed, they are also used to implement other steps of the above-mentioned method for cable fault location in a distributed photovoltaic power station, which will not be elaborated one by one here.

[0281] In summary, the present invention starts a detection device and sends a carrier signal to the cable network, synchronously records the electromagnetic interference characteristics, systematically adjusts the carrier signal frequency to avoid the identified interference, and repeats the above steps until a non-interfering working frequency band is found. Subsequently, the signal transmission situation is gradually monitored along the cable path, and the signal attenuation mode is analyzed to accurately locate potential fault points.

[0282] This method effectively solves the problem of misjudgment caused by electromagnetic interference generated by frequency converters, significantly improves the accuracy and reliability of fault detection, reduces maintenance costs and time, and improves the operation and maintenance efficiency of photovoltaic power stations. This improvement has significant technical effects and practical value in a complex electromagnetic environment.

[0283] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for cable fault location in a distributed photovoltaic power station, characterized in that, Including: S1: Start the detection device and send a carrier signal to the cable network; S2: Based on the sent carrier signal, synchronously record the electromagnetic interference characteristics during the operation of the frequency converter; S3: According to the obtained electromagnetic interference characteristics, adjust the carrier signal frequency to avoid the identified interference; S4: Repeat steps S1 to S3 until a working frequency band without interference is found; S5: Gradually monitor the signal transmission situation within the working frequency band without interference along the cable path to obtain the monitoring results; S6: According to the monitoring results, analyze the signal attenuation mode to locate potential fault points, and then confirm the fault location by comparing normal and abnormal signal modes.

2. The cable fault location method for a distributed photovoltaic power station according to claim 1, characterized in that: The starting the detection device and sending a carrier signal to the cable network includes: Record the intensity and frequency value of the initial carrier signal; Measure the signal intensity after a period of time during the operation of the frequency converter and calculate the signal attenuation; Adjust the gain setting of the receiving device according to the obtained attenuation to compensate for the signal loss caused by attenuation, so that the received signal intensity is close to the initial value; Continuously monitor the change of the adjusted signal intensity, compare and analyze the real-time data with the original data. If abnormal fluctuations are found, mark this section of the cable for inspection.

3. A method for cable fault location in a distributed photovoltaic power station according to claim 2, characterized in that: The synchronously recording the electromagnetic interference characteristics during the operation of the frequency converter based on the sent carrier signal includes: Collect the electromagnetic interference signal intensity and frequency distribution during the operation of the frequency converter. According to the obtained signal intensity and frequency distribution, calculate the energy density of the interference signal; Use the energy density to determine the main frequency band range of the interference signal. Based on the determined main frequency band range, adjust the working frequency band of the detection device to avoid the main interference frequency band, ensure the separation of the detection signal and the interference signal, and calculate the new signal intensity through the adjusted frequency band; Monitor the signal transmission situation in the new frequency band, record the signal intensity change and frequency stability, and confirm whether there are new interference or signal attenuation problems; if abnormalities are found, re-select a new working frequency band.

4. A cable fault location method for a distributed photovoltaic power station according to claim 3, characterized in that: The adjusting the carrier signal frequency to avoid the identified interference according to the obtained electromagnetic interference characteristics includes: Determine the main interference frequency band to be avoided and record its frequency range; Select a new working frequency band to ensure that it is not within the interference frequency band range. According to the selected new working frequency band, reconfigure the sending and receiving parameters of the detection device so that the frequency of the sent carrier signal is adjusted to the new working frequency band; Monitor the signal transmission situation on the adjusted working frequency band, record the signal intensity change and frequency stability, and confirm whether there are new interference or signal attenuation problems; if abnormalities are found, re-select a new working frequency band.

5. A method for cable fault location in a distributed photovoltaic power station according to claim 4, characterized in that: The repeating steps S1 to S3 until a working frequency band without interference is found includes: Initialize a counter to record the number of times of attempting to adjust the frequency band; Based on the selected new working frequency band and signal intensity, perform a complete detection cycle, including sending a carrier signal, recording electromagnetic interference characteristics, adjusting the carrier signal frequency, and monitoring the signal transmission situation on the new frequency band; According to the monitoring results, calculate the interference index for the current frequency band; if the interference index is less than the preset threshold, confirm that this frequency band is an interference-free operating frequency band; if the interference index is greater than or equal to the preset threshold, increase the value of the counter and return to re-select a new operating frequency band until an interference-free operating frequency band that meets the conditions is found.

6. A method for cable fault location in a distributed photovoltaic power station according to claim 5, characterized in that: The step-by-step monitoring of the signal transmission in the interference-free operating frequency band along the cable path to obtain the monitoring results includes: Select the starting point of the cable path as the monitoring starting point, and record the coordinate position and initial signal strength of this point; Perform a signal strength measurement every fixed distance along the cable path, and record the position of each measurement point and the corresponding signal strength; According to the obtained signal attenuation amount and the positions of each measurement point, draw a curve graph of the signal strength changing with the path, and find the area where the signal strength significantly decreases; Scan the identified area where the signal strength significantly decreases, reduce the interval distance, re-measure and record the signal strength change; by comparing the new measurement data, confirm whether there is a fault point; if so, mark the specific position of the fault point and the corresponding signal strength.

7. A method for cable fault location in a distributed photovoltaic power station according to claim 6, characterized in that: The analysis of the signal attenuation pattern based on the monitoring results to locate potential fault points includes: Based on the recorded position of each measurement point and the corresponding signal strength, calculate the average signal attenuation rate of each section of the cable; According to the calculated average signal attenuation rate, identify the signal attenuation abnormal areas, and mark the starting point and ending point of these areas. Within the identified abnormal areas, further divide this area into multiple small sections, and re-measure the signal strength of each section and calculate the local signal attenuation rate of each section; Based on the calculated local signal attenuation rate, determine the point with the most serious signal attenuation, record the specific coordinates and the corresponding signal strength of this point. If there are multiple points with serious attenuation, mark all the suspicious fault points in sequence.

8. A method for cable fault location in a distributed photovoltaic power station according to claim 7, characterized in that: The confirmation of the fault position by comparing the normal and abnormal signal patterns includes: Based on the determined suspicious fault points and their corresponding signal strengths, collect the signal data of the normal area around this point; According to the collected signal data of the normal area, calculate the average signal strength and standard deviation in the normal signal pattern; Use the obtained normal signal pattern parameters to compare the signal strength of the fault point; if the deviation between the signal strength of the fault point and the average signal strength exceeds the preset coefficient multiplied by the standard deviation, confirm that there is a significant signal abnormality at this point; repeat the verification process for all marked suspicious fault points; For each confirmed fault point, record its detailed information, generate a final fault report, and list all the confirmed fault points and their related information.

9. A method for cable fault location in a distributed photovoltaic power station according to claim 1, characterized in that: It also includes: Mark all the confirmed fault positions and generate a maintenance report.

10. A distributed photovoltaic power station cable fault location system for implementing the method according to any one of claims 1-9, characterized in that, It includes: An initialization and signal transmission module, which is used to start the detection device and send a carrier signal to the cable network; An electromagnetic interference characteristic recording module, which is used to synchronously record the electromagnetic interference characteristics during the operation of the frequency converter based on the sent carrier signal; A frequency adjustment and interference avoidance module, which is used to adjust the frequency of the carrier signal to avoid the identified interference according to the obtained electromagnetic interference characteristics; A interference-free frequency band search module, which is used to repeat steps S1 to S3 until an interference-free operating frequency band is found; A path monitoring and signal transmission analysis module, which is used to gradually monitor the signal transmission situation within the interference-free operating frequency band along the cable path to obtain monitoring results; A fault point location and confirmation module, which is used to analyze the signal attenuation mode to locate potential fault points according to the monitoring results, and then confirm the fault location by comparing normal and abnormal signal modes; A report generation module, which is used to mark all the confirmed fault locations and generate a maintenance report.

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