Fault distance measurement and fault positioning system for distributed power line

Abstract

The invention, which belongs to the technical field of fault detection, discloses a fault distance measurement and fault positioning system for a distributed power line, comprising a line signal state analysis module, a line signal adjustment module, a line communication interference determination module and a line fault distance measurement and positioning result output module. According to the method, the accuracy of the input signal is judged by analyzing the characteristics of the abnormal signal, so that the signal is adjusted, the accuracy of the input signal of the ranging and positioning system is improved, the problem that the accuracy of the input signal is neglected in the prior art is effectively solved, the system can accurately and quickly carry out ranging and positioning on a fault, and the working efficiency is improved. Losses caused by wrong positioning faults are reduced, and power supply reliability and stability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fault detection, and particularly to a fault distance measurement and fault location system for a distributed power line. Background Art

[0002] The power line system is an important infrastructure in modern society, and its safe and stable operation is directly related to industrial production, commercial activities and residents' lives. However, the power line may malfunction due to some reasons during operation, making the power line unable to work properly. Therefore, the power line fault distance measurement and location technology is a key means to ensure the safe operation of the power grid. Its core goal is to quickly and accurately measure the fault distance and locate the fault point, which is crucial for shortening the power outage time and improving the power supply reliability.

[0003] For example, the invention patent with the publication number: CN103389441B discloses a fault detection and location system for a power line, including: fault detection terminals installed on the transmission line or at the outlets of the main line and each branch line of the distribution line, a communication terminal for receiving the data transmitted by the fault detection terminals, and a system master station for receiving the data uploaded by the communication terminal and analyzing to obtain the specific location of the fault point; the aforementioned fault detection terminal includes the following units: an electromagnetic field induction unit, a current and voltage detection unit, a GPS signal acquisition unit, a high-precision clock unit, a power supply unit, a data storage unit, a local communication unit, a status display unit and a main processing unit. The beneficial effects of the present invention are: it can not only quickly and accurately locate the fault points of medium-voltage distribution lines and high-voltage transmission lines, but also the fault detection terminal has a simple structure, low power consumption and convenient installation, which can effectively reduce the engineering construction difficulty and cost.

[0004] For example, the invention patent with the publication number: CN103901324B discloses a combined ranging method for a distribution network hybrid line based on single-end fault information. Step 1: Decompose the high-frequency traveling wave components of the fault current signal and the fault voltage signal of the hybrid line; Step 2: Offline measure the wave velocity of the traveling wave propagating in the overhead line and the cable; Step 3: Use the correlation coefficient analysis method for preliminary fault distance measurement; Step 4: Use the wave head combination method for final fault distance measurement; Step 5: Verify the fault distance measurement result. The present invention only uses the fault information measured at one end of the line, can effectively extract the initial wave head and various reflected wave heads of the traveling wave during the fault, and can be applied to the occasions without double-end traveling wave ranging to achieve accurate fault distance measurement, supplementing the deficiencies of the existing distribution network hybrid line fault distance measurement. On the basis of realizing fault distance measurement by current traveling waves, the present invention comprehensively considers the results of voltage traveling wave ranging to improve the reliability and accuracy of ranging discrimination.

[0005] However, in the process of implementing the technical solution of the present invention in the embodiments of the present invention, it is found that the above technology has at least the following technical problems: Currently, most of the fault ranging and fault location methods for power lines focus on analyzing the ranging and location signal results for fault location, but ignore the accuracy of the input signals. The traditional ranging and location technology uses a band-pass filter to extract specific frequency bands for the traveling wave signal, and then analyzes the specific frequency bands and outputs the fault location as an accurate signal. However, if the key traveling wave frequency happens to be at the filter cut-off edge, the signal will be affected by the cut-off edge frequency at this time, resulting in signal distortion, so that the obtained data may have errors. If the fault location is analyzed and output based on such error data, it may lead to incorrect fault location, thus affecting the accuracy of the ranging and location system judgment and the power supply stability of the power line. Summary of the Invention

[0006] The embodiments of the present invention provide a fault ranging and fault location system for a distributed power line, which solves the problem of ignoring the accuracy of the input signal in the prior art and achieves the effect of improving the accuracy of the input signal of the ranging and location system.

[0007] The embodiments of the present invention provide a fault ranging and fault location system for a distributed power line, including the following steps: a line signal state analysis module, which receives abnormal signals of the power line, records the power line as the target monitoring line, collects signal state characterization parameters of the target monitoring line, analyzes signal state characterization factors of the target monitoring line, and thus determines the first execution strategy of the target monitoring line.

[0008] A line signal adjustment module, when the first execution strategy of the target monitoring line is to execute the first filter adjustment, completes the first filter adjustment based on the signal state characterization factors of the target monitoring line and analyzes the first adjustment effect label of the target monitoring line.

[0009] A line communication interference judgment module, when the first adjustment effect label of the target monitoring line is effective adjustment, analyzes the communication interference introduction information, and when the communication interference introduction information is confirmed to introduce communication interference, analyzes the communication interference index of the target monitoring line, and thus determines the second execution strategy of the target monitoring line.

[0010] A line fault ranging and location result output module, which receives the execution fault confirmation signal, continuously monitors the target monitoring line, obtains the fault confirmation data of the target monitoring line, and performs fault ranging and fault location on the target monitoring line.

[0011] Furthermore, the analysis of the signal state characterization factors of the target monitoring line is specifically as follows: Collect the signal state characterization parameters of the target monitoring line, including the main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation of the target monitoring line signal.

[0012] Analyze the signal state characterization factors of the target monitoring line based on the signal state characterization parameters of the target monitoring line.

[0013] The signal state characterization factor of the target monitoring line is a quantitative characterization of the combined influence degree of the main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation of the target monitoring line signal on the signal state of the target detection line. The specific analysis process is as follows: Compare the main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation of the collected target monitoring line signal with the corresponding reference values respectively, and then perform a coupling process on each comparison result combined with the corresponding metric factor to obtain the signal state characterization factor of the target monitoring line.

[0014] Furthermore, determine the first execution strategy of the target monitoring line. The specific analysis process is as follows: Extract the preset signal state characterization factor threshold in the database.

[0015] If the signal state characterization factor of the target monitoring line is less than or equal to the signal state characterization factor threshold of the monitoring line, then record the first execution strategy of the target monitoring line as outputting an execution fault confirmation signal.

[0016] If the signal state characterization factor of the target monitoring line is greater than the signal state characterization factor threshold of the monitoring line, then record the first execution strategy of the target monitoring line as performing the first adjustment of the filter.

[0017] Performing the first adjustment of the filter is to increase the bandwidth of the filter.

[0018] Furthermore, complete the first adjustment of the filter based on the signal state characterization factor of the target monitoring line. The specific analysis process is as follows: Subtract the signal state characterization factor threshold of the monitoring line from the signal state characterization factor of the target monitoring line to obtain the signal state characterization deviation factor.

[0019] Extract the bandwidth increment values corresponding to each signal state characterization deviation factor interval stored in the database, and map and extract the bandwidth increment value corresponding to the interval where the signal state characterization deviation factor is located, denoted as the filter bandwidth increment value.

[0020] Obtain the current filter bandwidth, denoted as the first filter bandwidth.

[0021] Complete the first adjustment of the filter based on the first filter bandwidth and the filter bandwidth increment value.

[0022] Further, analyze the first adjustment effect label of the target monitoring line. The specific analysis process is as follows: After the first adjustment of the filter, re-acquire the signal state characterization factor of the target monitoring line, denoted as the first signal state characterization factor.

[0023] If the first signal state characterization factor is still greater than the signal state characterization factor threshold, then mark the first adjustment effect label of the target monitoring line at this time as ineffective adjustment and send a warning message.

[0024] If the first signal state characterization factor is less than or equal to the signal state characterization factor threshold, then mark the first adjustment effect label of the target monitoring line at this time as effective adjustment.

[0025] Further, analyze the communication interference introduction information. The specific analysis process is as follows: When the first adjustment effect label of the target monitoring line is effective adjustment, collect the harmonic distortion rate of the target monitoring line signal.

[0026] Extract the preset harmonic distortion rate threshold in the database.

[0027] If the harmonic distortion rate of the target monitoring line signal is less than or equal to the harmonic distortion rate threshold, then mark the communication interference introduction information as no communication interference introduced and output an execution fault confirmation signal.

[0028] If the harmonic distortion rate of the target monitoring line signal is greater than the harmonic distortion rate threshold, then mark the communication interference introduction information as communication interference confirmed.

[0029] Further, analyze the communication interference index of the target monitoring line. The specific analysis process is as follows: After the communication interference introduction information is marked as communication interference confirmed, collect the communication interference parameters of the target monitoring line, including the signal-to-noise ratio, signal quality value, and harmonic distortion rate of the signal.

[0030] Analyze the communication interference index of the target monitoring line based on the communication interference parameters of the target monitoring line.

[0031] The communication interference index of the target monitoring line is a quantitative representation of the influence degree of the signal-to-noise ratio, signal quality value, and harmonic distortion rate of the signal on the communication interference state of the target monitoring line. The specific analysis process is as follows: Compare the collected signal-to-noise ratio, signal quality value, and harmonic distortion rate of the signal with the corresponding reference values respectively, and perform coupling processing on the comparison results combined with the corresponding metric factors, so as to obtain the communication interference index of the target monitoring line.

[0032] Further, determine the second execution strategy of the target monitoring line. The specific analysis process is as follows: Extract the preset communication interference index threshold in the database.

[0033] If the communication interference index of the target monitoring line is greater than the communication interference index threshold, record the second execution strategy of the target monitoring line as performing the second adjustment of the filter.

[0034] If the communication interference index of the target monitoring line is less than or equal to the communication interference index threshold, record the second execution strategy of the target monitoring line as performing spectrum purification.

[0035] Furthermore, perform the second adjustment of the filter, and the specific analysis process is as follows: Subtract the communication interference index threshold from the communication interference index of the target monitoring line to obtain the communication interference deviation index.

[0036] Extract the filter bandwidth reduction ratio based on the communication interference deviation index.

[0037] Obtain the filter bandwidth increment value.

[0038] Analyze the filter bandwidth reduction value based on the filter bandwidth increment value and the filter bandwidth reduction ratio.

[0039] Obtain the current filter bandwidth, denoted as the second filter bandwidth.

[0040] Perform the second adjustment of the filter according to the second filter bandwidth and the filter bandwidth reduction value.

[0041] Judge the effect of the second adjustment of the filter, and thus determine the third execution strategy of the target monitoring line.

[0042] Furthermore, after performing the second adjustment of the filter, re-obtain the communication interference index of the target monitoring line, denoted as the first communication interference index.

[0043] Re-collect the harmonic distortion rate of the target monitoring line, denoted as the first harmonic distortion rate.

[0044] If the first harmonic distortion rate is less than or equal to the harmonic distortion rate threshold, record the third execution strategy of the target monitoring line as outputting an execution fault confirmation signal.

[0045] If the first harmonic distortion rate is greater than the harmonic distortion rate threshold and the first communication interference index is greater than the communication interference index threshold, record the third execution strategy of the target monitoring line as outputting a warning signal.

[0046] If the first harmonic distortion rate is greater than the harmonic distortion rate threshold and the first communication interference index is less than or equal to the communication interference index threshold, record the third execution strategy of the target monitoring line as performing spectrum purification.

[0047] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: 1. A fault distance measurement and fault location system for a distributed power line provided by the present invention analyzes the characteristics of abnormal signals to judge the accuracy of the input signals, thereby adjusting the signals, and further improving the accuracy of the input signals of the distance measurement and location system. It effectively solves the problem of ignoring the accuracy of input signals in the current technology, enables the system to accurately and quickly measure and locate faults, reduces the losses caused by incorrect fault location, and improves the power supply reliability and stability.

[0048] 2. By dynamically adjusting the filter bandwidth, for signals with distortion, the operation of broadening the filter bandwidth is performed. By supplementing the filter bandwidth to change the actual value of the bandwidth, the frequency of the signal is not at the edge of the cut-off frequency of the filter. The broadened bandwidth can accommodate the frequency of the signal, and further realizes the adjustment of the distorted signal, improves the accuracy of the signal, and enables the system to accurately measure and locate faults.

[0049] 3. The present invention dynamically regulates communication interference, thereby reducing the influence of communication interference existing in the signals. By judging and adjusting the degree of communication interference, the degree of communication interference is reduced to a controllable range that does not affect the signal accuracy, and further improves the accuracy of the input signals of the distance measurement and location system, ensures the reliability of fault distance measurement and location, reduces the losses caused by incorrect fault location, and improves the power supply reliability and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a schematic structural diagram of a fault distance measurement and fault location system for a distributed power line provided by an embodiment of the present invention.

[0051] Figure 2 It is a flowchart of signal state analysis based on signal state characterization provided by an embodiment of the present invention.

[0052] Figure 3 It is a flowchart of judging the introduction of signal communication interference based on the signal harmonic distortion rate provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0053] 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. 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.

[0054] Such as Figure 1As shown in the figure, it is a schematic structural diagram of a fault ranging and fault location system for a distributed power line provided by an embodiment of the present invention, including: a line signal state analysis module, which receives abnormal signals of the power line, designates the power line as the target monitoring line, collects signal state characterization parameters of the target monitoring line, analyzes signal state characterization factors of the target monitoring line, and thereby determines the first execution strategy of the target monitoring line.

[0055] It should be added that the sudden change of the line current is monitored in real time, and when the sudden change value of the current in any one or more phases of the distributed power line is greater than the threshold value, an abnormal signal of the power line is generated.

[0056] It should also be added that the threshold value is a value preset in the database.

[0057] Furthermore, the signal state characterization factors of the target monitoring line are analyzed, and the specific analysis process is as follows: Collect signal state characterization parameters of the target monitoring line, including the main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation of the target monitoring line signal.

[0058] It should be noted that the signal state characterization parameters are obtained by collecting and analyzing the signals of the target monitoring line. In a specific embodiment, they can be directly obtained through fast Fourier transform analysis.

[0059] It should be noted that the main frequency energy ratio refers to the proportion of the main frequency component in the total energy of the filtered signal. The energy ratio refers to the ratio of the energy of the filtered signal to the full-band energy, where the full-band energy refers to the energy of the original unfiltered signal, and the energy of the filtered signal refers to the energy of the signal after passing through the filter. The main frequency position offset refers to the relative difference between the center frequency of the main frequency and the center frequency of the filter.

[0060] It should be added that when the energy ratio decreases, the energy of the filtered signal decreases or the full-band energy increases, indicating that the signal frequency is at the edge of the filter band at this time, causing signal energy loss, thereby resulting in a synchronous decrease in the main frequency energy ratio. At this time, due to the energy decrease, the main frequency position offset becomes larger and the main frequency is farther from the center, indicating that the signal frequency is at the edge of the filter band at this time. At this time, the change in the bandwidth will cause the bandwidth standard deviation to change.

[0061] Analyze the signal state characterization factors of the target monitoring line based on the signal state characterization parameters of the target monitoring line.

[0062] The signal state characterization factor of the target monitoring line is a quantitative characterization of the combined influence of the main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation of the target monitoring line signal on the signal state of the target detection line. The specific analysis process is as follows: Compare the main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation of the collected target monitoring line signal with the corresponding reference values respectively, and then perform coupling processing on each comparison result with the corresponding measurement factor to obtain the signal state characterization factor of the target monitoring line.

[0063] It should be noted that the reference main frequency energy ratio, reference energy ratio, reference main frequency position offset, and reference bandwidth standard deviation stored in the database are extracted.

[0064] Extract the measurement factors of the main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation preset in the database.

[0065] It should be supplemented that the value ranges of the measurement factors of the main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation of the signal are all between 0 and 1, and the sum of the measurement factors of the main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation is 1. When using, the preset values can be directly extracted from the database. The specific extraction method is as follows: Construct a one-to-one mapping set between the main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation of the signal and the corresponding main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation of the signal. When using, input the obtained main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation of the signal into the corresponding mapping set respectively to extract the main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation of the signal.

[0066] In the specific implementation process, the signal state characterization factor is specifically represented as follows: , where A is the signal state characterization factor, is the main frequency energy ratio of the signal, is the energy ratio of the signal, is the main frequency position offset of the signal, P is the bandwidth standard deviation of the signal, is the reference main frequency energy ratio of the signal, is the reference energy ratio of the signal, is the reference main frequency position offset of the signal, is the reference bandwidth standard deviation of the signal, is the measurement factor of the main frequency energy ratio of the signal, is the measurement factor of the energy ratio of the signal, is a measurement factor for the offset of the main frequency position of the signal, and is a measurement factor for the standard deviation of the signal bandwidth.

[0067] Furthermore, the first execution strategy for the target monitoring line is determined, and the specific analysis process is as follows: Extract the preset signal state characterization factor threshold in the database.

[0068] If the signal state characterization factor of the target monitoring line is less than or equal to the signal state characterization factor threshold of the monitoring line, then record the first execution strategy of the target monitoring line as outputting an execution fault confirmation signal.

[0069] It should be noted that if the signal state characterization factor of the target monitoring line is less than or equal to the signal state characterization factor threshold of the monitoring line, it indicates that the signal frequency is not at the edge of the filter cut-off frequency and the signal is not distorted. Therefore, it is determined that there is no signal frequency attenuation caused by the filter frequency setting, and an execution fault confirmation signal can be directly output.

[0070] If the signal state characterization factor of the target monitoring line is greater than the signal state characterization factor threshold of the monitoring line, then record the first execution strategy of the target monitoring line as performing the first filter adjustment.

[0071] It should be noted that if the signal state characterization factor of the target monitoring line is greater than the signal state characterization factor threshold of the monitoring line, it indicates that the signal frequency is exactly at the edge of the filter cut-off frequency at this time, which will cause signal distortion. Therefore, it is determined that there is signal frequency attenuation caused by the filter frequency setting, and the first filter adjustment needs to be performed.

[0072] Performing the first filter adjustment is to perform a bandwidth augmentation of the filter.

[0073] The line signal adjustment module, when the first execution strategy of the target monitoring line is to perform the first filter adjustment, completes the first filter adjustment based on the signal state characterization factor of the target monitoring line and analyzes the first adjustment effect label of the target monitoring line.

[0074] Furthermore, completing the first filter adjustment based on the signal state characterization factor of the target monitoring line, the specific analysis process is as follows: Subtract the signal state characterization factor threshold of the monitoring line from the signal state characterization factor of the target monitoring line to obtain the signal state characterization deviation factor.

[0075] Extract the bandwidth augmentation values corresponding to each signal state characterization deviation factor interval stored in the database, and map and extract the bandwidth augmentation value corresponding to the interval where the signal state characterization deviation factor is located, which is denoted as the filter bandwidth augmentation value.

[0076] It should be understood that the larger the signal state characterization deviation factor is, the more serious the deviation between the current output state of the filter and the ideal stable state is. In order to obtain a stable state and reduce the influence of interference, a larger bandwidth of the supplementary signal frequency is required to reduce the deviation value, so that the filter frequency can output in a more stable state.

[0077] Obtain the current filter bandwidth, denoted as the first filter bandwidth.

[0078] Complete the first adjustment of the filter based on the first filter bandwidth and the filter bandwidth increment value.

[0079] It should be noted that the current filter bandwidth value obtained from the system program log is the first filter bandwidth, and the first adjustment of the filter is completed in combination with the filter bandwidth increment value.

[0080] In a specific embodiment, if the first filter bandwidth is L0 and the extracted bandwidth increment value is L1, then the adjusted filter bandwidth is L0 + L1.

[0081] It should be understood that if the first filter bandwidth after adjustment based on the extracted bandwidth increment value is greater than the maximum bandwidth allowed for the filter output, the filter will operate at the maximum bandwidth allowed for the filter output.

[0082] Furthermore, analyze the first adjustment effect label of the target monitoring line. The specific analysis process is as follows: After completing the first adjustment of the filter, re-obtain the signal state characterization factor of the target monitoring line, denoted as the first signal state characterization factor.

[0083] If the first signal state characterization factor is still greater than the signal state characterization factor threshold, then mark the first adjustment effect label of the target monitoring line at this time as ineffective adjustment and send a warning message.

[0084] It should be noted that if the first signal state characterization factor is still greater than the signal state characterization factor threshold, it means that the bandwidth adjustment of the filter at this time has not achieved the desired effect. Therefore, it is judged that the first adjustment effect of the filter at this time is ineffective adjustment.

[0085] If the first signal state characterization factor is less than or equal to the signal state characterization factor threshold, then mark the first adjustment effect label of the target monitoring line at this time as effective adjustment.

[0086] It should be noted that if the first signal state characterization factor is less than or equal to the signal state characterization factor threshold, it means that the bandwidth adjustment of the filter at this time has achieved the desired effect and can alleviate the influence brought by signal distortion. Therefore, it is judged that the first adjustment effect of the filter at this time is effective adjustment.

[0087] By dynamically adjusting the filter bandwidth, an operation of widening the filter bandwidth is performed on the distorted signal. By supplementing the filter bandwidth, the actual value of the bandwidth is changed, so that the frequency of the signal does not lie on the edge of the cut-off frequency of the filter. The widened bandwidth can accommodate the frequency of the signal, thereby realizing the adjustment of the distorted signal, improving the accuracy of the signal, and enabling the system to accurately measure and locate faults.

[0088] The line communication interference judgment module analyzes the communication interference introduction information when the first adjustment effect label of the target monitoring line is effective adjustment, and analyzes the communication interference index of the target monitoring line when the communication interference introduction information is confirmed to introduce communication interference, thereby determining the second execution strategy of the target monitoring line.

[0089] Furthermore, the analysis of the communication interference introduction information is as follows: When the first adjustment effect label of the target monitoring line is effective adjustment, the harmonic distortion rate of the signal of the target monitoring line is collected.

[0090] It should be noted that the harmonic distortion rate of the signal is a parameter measuring the degree of signal waveform distortion, quantifying the pollution ratio of the harmonic components in the signal to the original signal, representing the percentage of the sum of all harmonic energies in the fundamental wave energy. The larger the value, the more serious the signal distortion.

[0091] The preset harmonic distortion rate threshold in the database is extracted.

[0092] If the harmonic distortion rate of the signal of the target monitoring line is less than or equal to the harmonic distortion rate threshold, the communication interference introduction information is recorded as no communication interference introduced, and an execution fault confirmation signal is output.

[0093] It should be understood that if the harmonic distortion rate of the signal of the target monitoring line is less than or equal to the harmonic distortion rate threshold, it means that the adjusted signal is a stable and accurate signal at this time, and no interference is introduced. Therefore, the communication interference introduction information is recorded as no communication interference introduced, and the signal is determined as a feasible signal and an execution fault confirmation signal is output.

[0094] If the harmonic distortion rate of the signal of the target monitoring line is greater than the harmonic distortion rate threshold, the communication interference introduction information is recorded as confirmed to introduce communication interference.

[0095] It should be understood that if the harmonic distortion rate of the signal of the target monitoring line is greater than the harmonic distortion rate threshold, it means that the signal is still not an accurate signal after adjustment, proving that interference is introduced. Therefore, the communication interference introduction information is recorded as confirmed to introduce communication interference.

[0096] Furthermore, the analysis of the communication interference index of the target monitoring line is as follows: After recording the information of communication interference introduction as confirmation of communication interference introduction, collect the communication interference parameters of the target monitoring line, including the signal-to-noise ratio, signal quality value, and harmonic distortion rate of the signal.

[0097] It should be noted that the communication interference parameters are obtained by collecting and analyzing the signals of the target monitoring line. In a specific embodiment, they can be directly obtained through fast Fourier transform analysis.

[0098] It should be noted that the signal-to-noise ratio in the signal is the ratio of signal power to noise power. The signal error rate is used as the numerical result of the signal quality value, and the harmonic distortion rate of the signal refers to the percentage of the total harmonic energy relative to the fundamental wave energy.

[0099] It should be added that when the harmonic distortion rate of the signal is too large, it indicates that the signal waveform is distorted, which will cause the signal quality to deteriorate, resulting in a decrease in the signal quality value. When the signal waveform is distorted and the signal quality value decreases, the signal power will change, causing the signal-to-noise ratio to be abnormal. There is a correlation among the three, and when any one parameter changes, it will drive the changes of the other two parameters.

[0100] Analyze the communication interference parameters of the target monitoring line to obtain the communication interference index of the target monitoring line.

[0101] The communication interference index of the target monitoring line is a quantitative representation of the influence degree of the signal-to-noise ratio, signal quality value, and harmonic distortion rate of the signal on the communication interference state of the target monitoring line. The specific analysis process is as follows: Compare the collected signal-to-noise ratio, signal quality value, and harmonic distortion rate of the signal with the corresponding reference values respectively, and perform coupling processing on the results of the comparison processing combined with the corresponding measurement factors, so as to obtain the communication interference index of the target monitoring line.

[0102] Extract the reference values of the signal-to-noise ratio, harmonic distortion rate of the signal, and reference value of the signal quality value stored in the database.

[0103] Extract the measurement factors of the signal-to-noise ratio, signal quality value, and harmonic distortion rate of the signal preset in the database.

[0104] It should be noted that the measurement factors of the signal-to-noise ratio, the measurement factor of the signal quality value, and the measurement factor of the harmonic distortion rate of the signal all have a value range between 0 and 1, and the sum of the measurement factor of the signal-to-noise ratio, the measurement factor of the signal quality value, and the measurement factor of the harmonic distortion rate of the signal is 1. When in use, the preset values can be directly extracted from the database. The specific extraction method is as follows: A one-to-one mapping set is constructed for the signal-to-noise ratio, the signal quality value, and the harmonic distortion rate of the signal with the corresponding signal-to-noise ratio, signal quality value, and harmonic distortion rate of the signal. When in use, the obtained signal-to-noise ratio, signal quality value, and harmonic distortion rate of the signal are respectively input into the corresponding mapping set, so as to extract the signal-to-noise ratio, signal quality value, and harmonic distortion rate of the signal.

[0105] In the specific implementation process, the communication interference index is specifically represented as follows: , where B is the communication interference index, is the signal-to-noise ratio, is the signal-to-noise ratio reference value, is the signal quality value, is the signal harmonic distortion rate, is the reference value of the signal quality value, is the reference value of the signal harmonic distortion rate, is the measurement factor of the signal-to-noise ratio, is the measurement factor of the signal quality value, is the measurement factor of the signal harmonic distortion rate.

[0106] Furthermore, to determine the second execution strategy for the target monitoring line, the specific analysis process is as follows: Extract the preset communication interference index threshold in the database.

[0107] If the communication interference index of the target monitoring line is greater than the communication interference index threshold, record the second execution strategy of the target monitoring line as executing the second adjustment of the filter.

[0108] It should be noted that if the communication interference index of the target monitoring line is greater than the communication interference index threshold, it indicates that the communication interference degree is large and the signal error is large at this time. It may be due to an incorrect adjustment degree of the first filter. In order to reduce the communication interference degree, the second execution strategy is determined to be executing the second adjustment of the filter.

[0109] If the communication interference index of the target monitoring line is less than or equal to the communication interference index threshold, record the second execution strategy of the target monitoring line as performing spectrum purification.

[0110] It should be noted that if the communication interference index of the target monitoring line is less than or equal to the communication interference index threshold, it indicates that the communication interference level is relatively small at this time, but it may still affect the accuracy of the collected signal. To further reduce the communication interference, the second execution strategy is determined to be spectrum purification.

[0111] It should be supplemented that spectrum purification is a method of removing or suppressing the identified interference frequency points or frequency bands in the spectrum without changing the overall bandwidth of the filter. In a specific embodiment, it can be achieved by embedding a dynamic Notch Filter.

[0112] Furthermore, perform the second adjustment of the filter. The specific analysis process is as follows: Subtract the communication interference index threshold from the communication interference index of the target monitoring line to obtain the communication interference deviation index.

[0113] Based on the communication interference deviation index, extract the filter bandwidth reduction ratio. The specific extraction process is as follows: Extract the bandwidth reduction ratio corresponding to each communication interference deviation index interval stored in the database, and map and extract the bandwidth reduction ratio corresponding to the interval where the communication interference deviation index is located, denoted as the filter bandwidth reduction ratio.

[0114] It should be supplemented that the larger the communication interference deviation index, the greater the communication interference of the current signal, indicating that there is an error in the bandwidth augmentation of the filter. To obtain an accurate signal and reduce the impact of interference, it is necessary to adjust the bandwidth augmentation value of the filter to reduce the degree of communication interference and enable the signal to be accurately output.

[0115] Obtain the filter bandwidth augmentation value from the system program log.

[0116] Analyze the filter bandwidth reduction value based on the filter bandwidth augmentation value and the filter bandwidth reduction ratio.

[0117] It should be noted that in a specific embodiment, if the current filter bandwidth augmentation value is , and the extracted filter bandwidth reduction ratio is , then the adjusted filter bandwidth reduction value is .

[0118] Obtain the current filter bandwidth, denoted as the second filter bandwidth.

[0119] Execute the second adjustment of the filter according to the second filter bandwidth and the filter bandwidth reduction value.

[0120] It should be understood that in a specific embodiment, if the second filter bandwidth is , and the filter bandwidth reduction value is , then the adjusted filter bandwidth value is 。

[0121] Determine the second adjustment effect of the filter, and thus determine the third execution strategy of the target monitoring line.

[0122] Furthermore, to determine the third execution strategy of the target monitoring line, the specific analysis process is as follows: After performing the second adjustment of the filter, re-obtain the communication interference index of the target monitoring line, denoted as the first communication interference index.

[0123] Re-collect the harmonic distortion rate of the target monitoring line, denoted as the first harmonic distortion rate.

[0124] If the first harmonic distortion rate is less than or equal to the harmonic distortion rate threshold, then record the third execution strategy of the target monitoring line as outputting an execution fault confirmation signal.

[0125] It should be noted that if the first harmonic distortion rate is less than or equal to the harmonic distortion rate threshold, it means that at this time, through adjustment, the interference degree of the signal is not only reduced but also reduced to a level that does not affect the accuracy of the signal. The signal output at this time can be used as accurate data for subsequent analysis and positioning. Therefore, it is determined that the third execution strategy is to output an execution fault confirmation signal.

[0126] If the first harmonic distortion rate is greater than the harmonic distortion rate threshold and the first communication interference index is greater than the communication interference index threshold, then record the third execution strategy of the target monitoring line as outputting a warning signal.

[0127] It should be noted that if the first harmonic distortion rate is greater than the harmonic distortion rate threshold and the first communication interference index is greater than the communication interference index threshold, it means that at this time, through adjustment, the interference degree of the signal has not been reduced and still belongs to a large degree of interference. Therefore, it is determined that the third execution strategy is to output a warning signal.

[0128] If the first harmonic distortion rate is greater than the harmonic distortion rate threshold and the first communication interference index is less than or equal to the communication interference index threshold, then record the third execution strategy of the target monitoring line as performing spectrum purification.

[0129] It should be noted that if the first harmonic distortion rate is greater than the harmonic distortion rate threshold and the first communication interference index is less than or equal to the communication interference index threshold, it means that at this time, through adjustment, the interference degree of the signal has indeed been reduced, but the reduction degree is not enough and there is still a certain degree of interference. Therefore, it is determined that the third execution strategy is to perform spectrum purification.

[0130] Through the dynamic regulation of communication interference, the present invention reduces the influence of communication interference existing in the signal. By determining and adjusting the degree of communication interference, the degree of communication interference is reduced to a controllable range that does not affect the signal accuracy, thereby improving the accuracy of the input signal of the ranging and positioning system, ensuring the reliability of fault ranging and positioning, reducing the losses caused by incorrect fault positioning, and improving the power supply reliability and stability.

[0131] The line fault ranging and positioning result output module receives the execution fault confirmation signal, activates the fault positioning function, and performs fault ranging and fault positioning on the target monitoring line.

[0132] It should be added that after activating the fault positioning function, the specific fault type of the line is discriminated. Specifically: according to zero voltage, zero current, phase current, and the operation of protection elements, the actual fault type of the line is judged. The actual fault types of the line include A-phase ground fault (AN), B-phase ground fault (BN), C-phase ground fault (CN), AB-phase ground fault (ABN), BC-phase ground fault (BCN), CA-phase ground fault (CAN), ABC-phase ground fault (ABCN), AB-phase interphase fault (AB), BC-phase interphase fault (BC), CA-phase interphase fault (CA), and ABC-phase interphase fault (ABC).

[0133] Synchronously record the sampling data of the first 8 cycles before the fault, and continuously record the sampling data of the 8 cycles after the fault at the same time. Use the Fourier algorithm to calculate the voltage and current vectors before and after the fault.

[0134] Determine the corresponding ranging calculation formula according to the wave sampling data combined with the fault type.

[0135] It should be added that the ranging calculation formulas corresponding to each fault type are stored in the database.

[0136] In a specific embodiment, if it is a ground fault, first calculate the grounding coefficient K to ensure the accurate detection of the ground fault by compensating the influence of zero-sequence current on the measured impedance. Subsequently, use the ground fault calculation formula to calculate the impedance and obtain the resistance and reactance values, which are specifically expressed as: , Among them, is the fault voltage of phase A, is the fault current of phase A, is the current of phase A before the fault, K is the grounding coefficient, is the ground fault current, calculated from the phase current, is the current before the ground fault.

[0137] It should be added that the specific representation method of the grounding coefficient is: , Among them, is the zero-sequence line impedance, and

[0138] is the positive-sequence line impedance. , where is the ground fault current, is the phase current of phase A, is the phase current of phase B, is the phase current of phase C.

[0139] In another specific embodiment, if it is an interphase fault, its specific representation method is: , where is the voltage to ground of phase A, is the voltage to ground of phase B, is the current of phase A, is the current of phase B, is the load current before the fault.

[0140] It should also be added that one reactance value can be obtained from the data per cycle, and finally a total of 8 groups of reactance values are obtained. The 8 groups of reactance values are screened. First, the rationality of the reactance is judged. The specific process is as follows: Calculate the maximum reactance value according to the longest length of the line. If the calculated reactance result is greater than this value, the calculated reactance result of this group is discarded.

[0141] Then, its directionality is judged. The specific process is as follows: If 5 groups or more meet the same direction, that is, all positive or all negative, the reactance values that meet the conditions are selected for use.

[0142] It should be noted that the number of acquisition cycles before and after the above wave sampling data and the limited number of groups that meet the directionality judgment adjustment can be specifically limited according to the specific situation in other embodiments. This embodiment is only an example and no special limitation is made thereto.

[0143] Next, the reactance values will be sorted, and the reactance values smaller than the preset reactance boundary value in the database will be screened out, that is, the deviated calculation results will be discarded, and the finally retained data will be used as the final reactance data.

[0144] According to the reactance value, the fault distance is calculated, that is, the ratio result of the reactance value to the unit reactance is used as the numerical result of the fault distance, and the fault location measurement ends.

[0145] Such as Figure 2As shown in the figure, it is a flowchart for signal state analysis based on signal state characterization provided by an embodiment of the present invention. Signal state characterization parameters of a target detection line are collected, and then signal state characterization factors are analyzed. The signal state characterization factors are compared with a threshold. If it is less than or equal to the signal state characterization factor threshold, a fault confirmation signal is output. If it is greater than the signal state characterization factor threshold, the first adjustment of the filter is performed.

[0146] As Figure 3 shown in the figure, it is a flowchart for judging the introduction of signal communication interference based on the signal harmonic distortion rate provided by an embodiment of the present invention. The signal harmonic distortion rate of a target detection line is collected, and the harmonic distortion rate of the signal is compared with a threshold. If it is greater than the harmonic distortion rate threshold, it is confirmed that communication interference is introduced, and the communication interference index is analyzed. If it is less than or equal to the harmonic distortion rate threshold, no communication interference is introduced, and a fault confirmation signal is output.

[0147] A fault ranging and fault location system for a distributed power line provided by the present invention judges the accuracy of an input signal by analyzing the characteristics of an abnormal signal, thereby adjusting the signal, and further improves the accuracy of the input signal of the ranging and positioning system, effectively solving the problem of ignoring the accuracy of the input signal in the current technology, enabling the system to accurately and quickly range and locate faults, reducing losses caused by incorrect fault location, and improving power supply reliability and stability.

[0148] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0149] The present invention is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 this flow Figure 1 or multiple flows and / or blocks

[0150] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to work in a particular manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction device that implements the function specified in one or more processes and / or blocks Figure 1 in one or more processes and / or blocks Figure 1 specified in the block or blocks.

[0151] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, such that a series of operation steps are performed on the computer or other programmable apparatus to produce a computer-implemented process, so that the instructions executed on the computer or other programmable apparatus provide steps for implementing the function specified in one or more processes and / or blocks Figure 1 in one or more processes and / or blocks Figure 1 specified in the block or blocks.

[0152] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made by those skilled in the art once they learn of the basic inventive concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0153] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A fault distance measurement and fault location system for a distributed power line, characterized in that, Including: A line signal status analysis module, which receives abnormal signals of a power line, designates the power line as a target monitoring line, collects signal status characterization parameters of the target monitoring line, analyzes signal status characterization factors of the target monitoring line, and thereby determines a first execution strategy for the target monitoring line; A line signal adjustment module, when the first execution strategy of the target monitoring line is to execute the first adjustment of the filter, based on the signal status characterization factors of the target monitoring line, completes the first adjustment of the filter and analyzes the first adjustment effect label of the target monitoring line; A line communication interference judgment module, when the first adjustment effect label of the target monitoring line is effective adjustment, analyzes communication interference introduction information, and when the communication interference introduction information is confirmed to introduce communication interference, analyzes the communication interference index of the target monitoring line, and thereby determines a second execution strategy for the target monitoring line; A line fault ranging and positioning result output module, which receives an execution fault confirmation signal, continuously monitors the target monitoring line, obtains fault confirmation data of the target monitoring line, and performs fault ranging and fault positioning on the target monitoring line.

2. The fault distance measurement and fault location system for a distributed power line according to claim 1, characterized in that: The specific analysis process of analyzing the signal status characterization factors of the target monitoring line is as follows: Collect signal status characterization parameters of the target monitoring line, including the main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation of the target monitoring line signal; Analyze the signal status characterization factors of the target monitoring line based on the signal status characterization parameters of the target monitoring line; The signal status characterization factors of the target monitoring line are a quantitative characterization of the combined influence degree of the main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation of the target monitoring line signal on the signal status of the target detection line. The specific analysis process is as follows: Compare the main frequency energy ratio, energy ratio, main frequency position offset, and bandwidth standard deviation of the collected target monitoring line signal with the corresponding reference values respectively, and then perform coupling processing on each comparison result combined with the corresponding metric factor to obtain the signal status characterization factors of the target monitoring line.

3. The fault location and fault ranging system for a distributed power line according to claim 2, wherein: The specific analysis process of determining the first execution strategy of the target monitoring line is as follows: Extract the preset signal status characterization factor threshold in the database; If the signal status characterization factor of the target monitoring line is less than or equal to the signal status characterization factor threshold of the monitoring line, record the first execution strategy of the target monitoring line as outputting an execution fault confirmation signal; If the signal status characterization factor of the target monitoring line is greater than the signal status characterization factor threshold of the monitoring line, record the first execution strategy of the target monitoring line as executing the first adjustment of the filter; The execution of the first adjustment of the filter is to execute the bandwidth augmentation of the filter.

4. The fault distance measurement and fault location system for a distributed power line according to claim 3, characterized in that: The specific analysis process of completing the first adjustment of the filter based on the signal status characterization factors of the target monitoring line is as follows: Subtract the signal status characterization factor threshold of the monitoring line from the signal status characterization factor of the target monitoring line to obtain a signal status characterization deviation factor; Extract the bandwidth augmentation values corresponding to each signal status characterization deviation factor interval stored in the database, and map and extract the bandwidth augmentation value corresponding to the interval where the signal status characterization deviation factor is located, denoted as the filter bandwidth augmentation value; Obtain the current filter bandwidth, denoted as the first filter bandwidth; Complete the first adjustment of the filter based on the first filter bandwidth and the filter bandwidth increment value.

5. The fault distance measurement and fault location system for a distributed power line according to claim 1, characterized in that: Analyze the first adjustment effect label of the target monitoring line. The specific analysis process is as follows: After completing the first adjustment of the filter, re-obtain the signal state characterization factor of the target monitoring line, denoted as the first signal state characterization factor; If the first signal state characterization factor is still greater than the signal state characterization factor threshold, then record the first adjustment effect label of the target monitoring line at this time as ineffective adjustment and send a warning message; If the first signal state characterization factor is less than or equal to the signal state characterization factor threshold, then record the first adjustment effect label of the target monitoring line at this time as effective adjustment.

6. The fault distance measurement and fault location system for a distributed power line according to claim 1, characterized in that: Analyze the communication interference introduction information. The specific analysis process is as follows: When the first adjustment effect label of the target monitoring line is effective adjustment, collect the harmonic distortion rate of the signal of the target monitoring line; Extract the preset harmonic distortion rate threshold in the database; If the harmonic distortion rate of the signal of the target monitoring line is less than or equal to the harmonic distortion rate threshold, then record the communication interference introduction information as no communication interference introduced and output an execution fault confirmation signal; If the harmonic distortion rate of the signal of the target monitoring line is greater than the harmonic distortion rate threshold, then record the communication interference introduction information as communication interference confirmed to be introduced.

7. The fault distance measurement and fault location system for a distributed power line according to claim 1, characterized in that: Analyze the communication interference index of the target monitoring line. The specific analysis process is as follows: After the communication interference introduction information is recorded as communication interference confirmed to be introduced, collect the communication interference parameters of the target monitoring line, including the signal-to-noise ratio, signal quality value, and harmonic distortion rate of the signal; Analyze the communication interference index of the target monitoring line based on the communication interference parameters of the target monitoring line; The communication interference index of the target monitoring line is a quantitative representation of the influence degree of the signal-to-noise ratio, signal quality value, and harmonic distortion rate of the signal on the communication interference state of the target monitoring line. The specific analysis process is: compare the collected signal-to-noise ratio, signal quality value, and harmonic distortion rate of the signal with the corresponding reference values respectively, and perform coupling processing on the comparison results combined with the corresponding measurement factors, so as to obtain the communication interference index of the target monitoring line.

8. The fault distance measurement and fault location system for a distributed power line according to claim 7, characterized in that: Determine the second execution strategy of the target monitoring line. The specific analysis process is as follows: Extract the preset communication interference index threshold in the database; If the communication interference index of the target monitoring line is greater than the communication interference index threshold, then record the second execution strategy of the target monitoring line as performing the second adjustment of the filter; If the communication interference index of the target monitoring line is less than or equal to the communication interference index threshold, record the second execution strategy of the target monitoring line as performing spectrum purification.

9. The fault distance measurement and fault location system for a distributed power line according to claim 8, characterized in that: Perform the second adjustment of the filter. The specific analysis process is as follows: Subtract the communication interference index threshold from the communication interference index of the target monitoring line to obtain the communication interference deviation index; Extract the filter bandwidth reduction ratio based on the communication interference deviation index; Obtain the filter bandwidth increment value; Analyze the filter bandwidth reduction value based on the filter bandwidth increment value and the filter bandwidth reduction ratio; Obtain the current filter bandwidth, denoted as the second filter bandwidth; Perform the second adjustment of the filter according to the second filter bandwidth and the filter bandwidth reduction value; Determine the effect of the second adjustment of the filter, thereby determining the third execution strategy of the target monitoring line.

10. The fault distance measurement and fault location system for a distributed power line according to claim 9, wherein: The specific analysis process for determining the third execution strategy of the target monitoring line is as follows: After performing the second adjustment of the filter, re-acquire the communication interference index of the target monitoring line, denoted as the first communication interference index; Re-collect the harmonic distortion rate of the target monitoring line, denoted as the first harmonic distortion rate; If the first harmonic distortion rate is less than or equal to the harmonic distortion rate threshold, record the third execution strategy of the target monitoring line as outputting an execution fault confirmation signal; If the first harmonic distortion rate is greater than the harmonic distortion rate threshold and the first communication interference index is greater than the communication interference index threshold, record the third execution strategy of the target monitoring line as outputting a warning signal; If the first harmonic distortion rate is greater than the harmonic distortion rate threshold and the first communication interference index is less than or equal to the communication interference index threshold, record the third execution strategy of the target monitoring line as performing spectrum purification.

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