A fault distance measurement and fault location system for distributed power lines

Abstract

The present invention discloses a fault ranging and fault location system for distributed power lines, belonging to the field of fault detection technology. The system comprises a line signal state analysis module, a line signal adjustment module, a line communication interference determination module, and a line fault ranging and location result output module. The present invention analyzes the characteristics of abnormal signals to determine the accuracy of input signals, thereby adjusting the signals and thereby improving the accuracy of the input signals of the ranging and location system. This effectively solves the problem of neglecting the accuracy of input signals in current technologies, enabling the system to accurately and quickly measure and locate faults, reducing losses caused by incorrectly located faults, and improving power supply reliability and stability.

Description

Technical Field

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

[0002] Power transmission systems are crucial infrastructure in modern society, and their safe and stable operation is directly related to industrial production, commercial activities, and even residents' lives. However, power lines can fail during operation for various reasons, causing them to malfunction. Therefore, power line fault location and locating technology is a key means of ensuring the safe operation of power grids. Its core goal is to quickly and accurately locate faults, which is crucial for shortening outages and improving power supply reliability.

[0003] For example, the invention patent with the announcement number: CN103389441B announces a fault detection and positioning system for power lines, including: a fault detection terminal installed on the transmission line or installed at the main line outlet and each branch line outlet of the distribution line, a communication terminal that receives data transmitted by the fault detection terminal, and a system main station that receives the data uploaded by the communication terminal and analyzes the specific location of the fault point; the aforementioned fault detection terminal includes the following units: 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 benefits of the present invention are that it can not only realize the rapid and accurate positioning of 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 is easy to install, which can effectively reduce the difficulty and cost of engineering construction.

[0004] For example, the invention patent with the announcement number: CN103901324B discloses a combined distance measurement method for hybrid lines in a distribution network based on single-ended fault information. The method includes the following steps: Step 1: Decomposing the high-frequency traveling wave components of the hybrid line fault current signal and the fault voltage signal; Step 2: Offline measurement of the wave velocity of the traveling wave propagating in overhead lines and cables; Step 3: Preliminary fault distance measurement using the correlation coefficient analysis method; Step 4: Final fault distance measurement using the wave head combination method; Step 5: Verification of the fault distance measurement results. The present invention only uses the fault information measured at one end of the line and can effectively extract the initial wave head and various reflected wave heads of the traveling wave at the time of the fault. It can be applied to situations where dual-end traveling wave distance measurement is not available to achieve accurate fault distance measurement, thus supplementing the shortcomings of existing hybrid line fault distance measurement in distribution networks. Based on the fault distance measurement achieved by current traveling waves, the present invention comprehensively considers the voltage traveling wave distance measurement results to improve the reliability and accuracy of distance measurement.

[0005] However, in the process of implementing the technical solutions of the embodiments of the present invention, the present invention found that the above technology has at least the following technical problems:

[0006] Current fault ranging and fault location methods for power lines mostly focus on analyzing the ranging and positioning signal results to locate the fault, but ignore the accuracy of the input signal. Traditional ranging and positioning technology uses a bandpass filter to extract a specific frequency band from the traveling wave signal, and then analyzes the specific frequency band and outputs it as an accurate signal for fault location. However, if the critical traveling wave frequency is exactly at the cutoff edge of the filter, the signal will be affected by the cutoff edge frequency, resulting in signal distortion, which may cause errors in the obtained data. If this erroneous data is analyzed and output as the fault location, it may lead to fault location errors, thereby affecting the accuracy of the ranging and positioning system's judgment and the power supply stability of the power line. Summary of the Invention

[0007] The embodiment of the present invention solves the problem of neglecting the accuracy of input signals in the prior art by providing a fault ranging and fault locating system for distributed power lines, thereby achieving the effect of improving the accuracy of input signals of the ranging and locating system.

[0008] An embodiment of the present invention provides a fault ranging and fault location system for distributed power lines, comprising the following steps: a line signal state analysis module receives an abnormal signal of a power line, records the power line as a target monitoring line, collects signal state characterization parameters of the target monitoring line, analyzes the signal state characterization factor of the target monitoring line, and thereby determines a first execution strategy for the target monitoring line.

[0009] The line signal adjustment module completes the first filter adjustment based on the signal state characterization factor of the target monitoring line when the first execution strategy of the target monitoring line is to perform the first filter adjustment, and analyzes the first adjustment effect label of the target monitoring line.

[0010] 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 have introduced communication interference, thereby determining the second execution strategy of the target monitoring line.

[0011] The line fault distance measurement and location result output module 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 distance measurement and fault location on the target monitoring line.

[0012] Furthermore, the signal status characterization factors of the target monitoring line are analyzed. The specific analysis process is as follows:

[0013] The signal status characterization parameters of the target monitoring line are collected, including the main frequency energy proportion, energy ratio, main frequency position offset and bandwidth standard deviation of the target monitoring line signal.

[0014] The signal state characterization factor of the target monitoring line is analyzed based on the signal state characterization parameters of the target monitoring line.

[0015] The signal state characterization factor of the target monitoring line is a quantitative representation of the degree of influence of the main frequency energy proportion, 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: the main frequency energy proportion, energy ratio, main frequency position offset and bandwidth standard deviation of the collected target monitoring line signal are compared with the corresponding reference values ​​respectively, and then the comparison processing results are coupled with the corresponding measurement factors to obtain the signal state characterization factor of the target monitoring line.

[0016] Furthermore, the first execution strategy of the target monitoring line is determined. The specific analysis process is as follows:

[0017] Extract the signal state characterization factor threshold preset in the database.

[0018] 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, the first execution strategy of the target monitoring line is recorded as outputting an execution fault confirmation signal.

[0019] If the signal state characterization factor of the target monitoring line is greater than the signal state characterization factor threshold of the monitoring line, the first execution strategy of the target monitoring line is recorded as executing the first filter adjustment.

[0020] The first adjustment of the filter is to perform bandwidth augmentation of the filter.

[0021] Furthermore, the first filter adjustment is completed based on the signal state characterization factor of the target monitoring line. The specific analysis process is as follows:

[0022] The signal state characterization factor of the target monitoring line is subtracted from the signal state characterization factor threshold of the monitoring line to obtain the signal state characterization deviation factor.

[0023] The bandwidth supplement value corresponding to each signal state characterization deviation factor interval stored in the database is extracted, and the bandwidth supplement value corresponding to the interval where the signal state characterization deviation factor is located is mapped and recorded as the filter bandwidth supplement value.

[0024] Get the current filter bandwidth, recorded as the first filter bandwidth.

[0025] A first filter adjustment is performed based on the first filter bandwidth and the filter bandwidth increment value.

[0026] Furthermore, the first adjustment effect label of the target monitoring line is analyzed. The specific analysis process is as follows:

[0027] After the first adjustment of the filter is completed, the signal state characterization factor of the target monitoring line is reacquired and recorded as the first signal state characterization factor.

[0028] If the first signal state characterization factor is still greater than the signal state characterization factor threshold, the first adjustment effect label of the target monitoring line at this time is recorded as invalid adjustment, and an early warning message is sent.

[0029] If the first signal state characterization factor is less than or equal to the signal state characterization factor threshold, the first adjustment effect label of the target monitoring line at this time is recorded as effective adjustment.

[0030] Furthermore, the information introduced by communication interference is analyzed. The specific analysis process is as follows:

[0031] When the first adjustment effect label of the target monitoring line is effective adjustment, the harmonic distortion rate of the target monitoring line signal is collected.

[0032] Extract the preset harmonic distortion rate threshold value in the database.

[0033] If the harmonic distortion rate of the target monitoring line signal is less than or equal to the harmonic distortion rate threshold, the communication interference introduction information is recorded as no communication interference is introduced, and an execution fault confirmation signal is output.

[0034] If the harmonic distortion rate of the target monitoring line signal is greater than the harmonic distortion rate threshold, the communication interference introduction information is recorded as confirmation of the introduction of communication interference.

[0035] Furthermore, the communication interference index of the target monitoring line is analyzed. The specific analysis process is as follows:

[0036] After the communication interference introduction information is recorded as confirmation of the introduction of communication interference, communication interference parameters of the target monitoring line are collected, including the signal-to-noise ratio, signal quality value, and harmonic distortion rate of the signal.

[0037] The communication interference index of the target monitoring line is obtained based on the communication interference parameter analysis of the target monitoring line.

[0038] The communication interference index of the target monitoring line is a quantitative expression of the degree of influence 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: the signal-to-noise ratio, signal quality value and harmonic distortion rate of the collected signal are compared with the corresponding reference values ​​respectively, and the comparison results are coupled with the corresponding measurement factors to obtain the communication interference index of the target monitoring line.

[0039] Furthermore, the second execution strategy of the target monitoring line is determined. The specific analysis process is as follows:

[0040] Extract the communication interference index threshold preset in the database.

[0041] If the communication interference index of the target monitoring line is greater than the communication interference index threshold, the second execution strategy of the target monitoring line is recorded as executing the second filter adjustment.

[0042] If the communication interference index of the target monitoring line is less than or equal to the communication interference index threshold, the second execution strategy of the target monitoring line is recorded as performing spectrum cleanup.

[0043] Furthermore, the second filter adjustment is performed, and the specific analysis process is as follows:

[0044] The communication interference deviation index is obtained by subtracting the communication interference index threshold from the communication interference index of the target monitoring line.

[0045] Extract the filter bandwidth reduction ratio based on the communication interference deviation index.

[0046] Gets the filter bandwidth increment value.

[0047] Analyze the filter bandwidth reduction value based on the filter bandwidth increase value and the filter bandwidth reduction ratio.

[0048] Get the current filter bandwidth, recorded as the second filter bandwidth.

[0049] A second filter adjustment is performed based on the second filter bandwidth and the filter bandwidth reduction value.

[0050] A second adjustment effect of the filter is determined, thereby determining a third execution strategy for the target monitoring line.

[0051] Furthermore, after performing the second adjustment of the filter, the communication interference index of the target monitoring line is reacquired and recorded as the first communication interference index.

[0052] The harmonic distortion rate of the target monitoring line is collected again and recorded as the first harmonic distortion rate.

[0053] If the first harmonic distortion rate is less than or equal to the harmonic distortion rate threshold, the third execution strategy of the target monitoring line is recorded as outputting an execution fault confirmation signal.

[0054] 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, the third execution strategy of the target monitoring line is recorded as outputting a warning signal.

[0055] 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, the third execution strategy of the target monitoring line is recorded as performing spectrum cleanup.

[0056] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0057] 1. The present invention provides a fault ranging and fault location system for distributed power lines. By analyzing the characteristics of abnormal signals to determine the accuracy of input signals, the system adjusts the signals, thereby improving the accuracy of input signals of the ranging and location system. This effectively solves the problem of neglecting the accuracy of input signals in current technologies, enables the system to accurately and quickly measure distance to and locate faults, reduces losses caused by incorrect fault location, and improves power supply reliability and stability.

[0058] 2. By dynamically adjusting the filter bandwidth, the filter bandwidth is relaxed for distorted signals. By increasing the filter bandwidth, the actual bandwidth value is changed so that the frequency of the signal is not at the edge of the cutoff frequency of the filter. The relaxed bandwidth can accommodate the frequency of the signal, thereby achieving the adjustment of the distorted signal and improving the accuracy of the signal, so that the system can accurately measure the distance and locate the fault.

[0059] 3. The present invention reduces the impact of communication interference in the signal by dynamically regulating the communication interference. By determining and adjusting the degree of communication interference, the communication interference level is reduced to a controllable range that does not affect the accuracy of the signal, 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 positioning of faults, and improving power supply reliability and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 A schematic structural diagram of a fault distance measurement and fault location system for distributed power lines provided by an embodiment of the present invention.

[0061] Figure 2 This is a flowchart of performing signal state analysis based on signal state representation provided by an embodiment of the present invention.

[0062] Figure 3 A flowchart of determining whether communication interference is introduced based on signal harmonic distortion rate is provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0063] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only 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 ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0064] like Figure 1 As shown, a schematic diagram of the structure of a fault ranging and fault location system for distributed power lines provided by an embodiment of the present invention includes: a line signal state analysis module, which receives an abnormal signal of the power line, records the power line as a target monitoring line, collects signal state characterization parameters of the target monitoring line, analyzes the signal state characterization factor of the target monitoring line, and thereby determines the first execution strategy of the target monitoring line.

[0065] It should be added that the line current mutation is monitored in real time, and when the mutation value of any phase or multi-phase current of the distributed power line is greater than the threshold value, a power line abnormal signal is generated.

[0066] It should also be added that the threshold value is a value pre-set in the database.

[0067] Furthermore, the signal status characterization factors of the target monitoring line are analyzed. The specific analysis process is as follows:

[0068] The signal status characterization parameters of the target monitoring line are collected, including the main frequency energy proportion, energy ratio, main frequency position offset and bandwidth standard deviation of the target monitoring line signal.

[0069] It should be noted that the signal state characterization parameter is obtained by collecting and analyzing the signal of the target monitoring line. In a specific embodiment, it can be directly obtained through fast Fourier transform analysis.

[0070] It should be noted that the dominant frequency energy fraction refers to the proportion of the dominant frequency component in the total energy of the filtered signal. The energy ratio refers to the ratio of the filtered signal energy to the full-band energy, where the full-band energy refers to the energy of the original unfiltered signal and the filtered signal energy refers to the energy of the signal after passing through the filter. The dominant frequency offset refers to the relative difference between the dominant frequency center frequency and the filter center frequency.

[0071] It's important to note that when the energy ratio decreases, the filtered signal energy decreases or the full-band energy increases, indicating that the signal frequency is at the edge of the filter band, resulting in signal energy loss and a simultaneous decrease in the dominant frequency energy ratio. This energy decrease also increases the dominant frequency position offset, moving it further from the center, indicating that the signal frequency is at the edge of the filter band. The bandwidth is changing, causing the bandwidth standard deviation to change.

[0072] The signal state characterization factor of the target monitoring line is analyzed based on the signal state characterization parameters of the target monitoring line.

[0073] The signal state characterization factor of the target monitoring line is a quantitative representation of the degree of influence of the main frequency energy proportion, 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: the main frequency energy proportion, energy ratio, main frequency position offset and bandwidth standard deviation of the collected target monitoring line signal are compared with the corresponding reference values ​​respectively, and then the comparison processing results are coupled with the corresponding measurement factors to obtain the signal state characterization factor of the target monitoring line.

[0074] It should be noted that the reference main frequency energy proportion, reference energy ratio, reference main frequency position offset and reference bandwidth standard deviation stored in the database are extracted.

[0075] Extract the measurement factors of the main frequency energy proportion, energy ratio, main frequency position offset and bandwidth standard deviation preset in the database.

[0076] It should be noted that the measurement factor of the signal's main frequency energy ratio, the measurement factor of the energy ratio, the measurement factor of the main frequency position offset and the measurement factor of the bandwidth standard deviation all have value ranges between 0 and 1, and the sum of the measurement factor of the main frequency energy ratio, the measurement factor of the energy ratio, the measurement factor of the main frequency position offset and the measurement factor of the bandwidth standard deviation is 1. When used, the pre-set value 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's main frequency energy ratio, energy ratio, main frequency position offset and bandwidth standard deviation with the corresponding signal's main frequency energy ratio, energy ratio, main frequency position offset and bandwidth standard deviation. When used, the obtained signal's main frequency energy ratio, energy ratio, main frequency position offset and bandwidth standard deviation are respectively input into the corresponding mapping set, thereby extracting the signal's main frequency energy ratio, energy ratio, main frequency position offset and bandwidth standard deviation.

[0077] In the specific implementation process, the signal state characterization factor is specifically expressed as follows:

[0078] ,

[0079] Among them, A is the signal state characterization factor, is the energy ratio of the main frequency of the signal, is the signal energy ratio, is the signal main frequency position offset, P is the signal bandwidth standard deviation, is the reference signal main frequency energy ratio, is the reference signal energy ratio, is the reference signal main frequency position offset, is the reference signal bandwidth standard deviation, It is a measure of the energy ratio of the main frequency of the signal. is a measure of the signal energy ratio, is the measurement factor of the signal's main frequency position offset, is a measure of the standard deviation of the signal bandwidth.

[0080] Furthermore, the first execution strategy of the target monitoring line is determined. The specific analysis process is as follows:

[0081] Extract the signal state characterization factor threshold preset in the database.

[0082] 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, the first execution strategy of the target monitoring line is recorded as outputting an execution fault confirmation signal.

[0083] 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 means that the signal frequency is not at the edge of the filter cutoff frequency and the signal is not distorted. Therefore, it is determined that there is no signal frequency weakening caused by the filter frequency setting, and the fault confirmation signal can be directly output.

[0084] If the signal state characterization factor of the target monitoring line is greater than the signal state characterization factor threshold of the monitoring line, the first execution strategy of the target monitoring line is recorded as executing the first filter adjustment.

[0085] 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 means that the signal frequency is at the edge of the filter cutoff frequency, which will cause signal distortion. Therefore, it is determined that the signal frequency is weakened due to the filter frequency setting, and the first filter adjustment needs to be performed.

[0086] The first adjustment of the filter is to perform bandwidth augmentation of the filter.

[0087] The line signal adjustment module completes the first filter adjustment based on the signal state characterization factor of the target monitoring line when the first execution strategy of the target monitoring line is to perform the first filter adjustment, and analyzes the first adjustment effect label of the target monitoring line.

[0088] Furthermore, the first filter adjustment is completed based on the signal state characterization factor of the target monitoring line. The specific analysis process is as follows:

[0089] The signal state characterization factor of the target monitoring line is subtracted from the signal state characterization factor threshold of the monitoring line to obtain the signal state characterization deviation factor.

[0090] The bandwidth supplement value corresponding to each signal state characterization deviation factor interval stored in the database is extracted, and the bandwidth supplement value corresponding to the interval where the signal state characterization deviation factor is located is mapped and recorded as the filter bandwidth supplement value.

[0091] It should be understood that the larger the signal state characterization deviation factor, the more serious the deviation between the current output state of the filter and the ideal stable state. In order to obtain a stable state and reduce the impact of interference, it is necessary to increase the bandwidth of the signal frequency to a greater extent to reduce the deviation value, so that the filter frequency can be output in a more stable state.

[0092] Get the current filter bandwidth, recorded as the first filter bandwidth.

[0093] A first filter adjustment is performed based on the first filter bandwidth and the filter bandwidth increment value.

[0094] It should be noted that the current filter bandwidth value obtained in the system program log is the first filter bandwidth, and the first filter adjustment is completed in combination with the filter bandwidth supplement value.

[0095] In a specific embodiment, if the first filter bandwidth is L0 and the extracted bandwidth supplement value is L1, then the adjusted filter bandwidth is L0+L1.

[0096] It should be understood that if the bandwidth of the first filter adjusted based on the extracted bandwidth supplement value is greater than the maximum bandwidth allowed to be output by the filter, the filter will operate with the maximum bandwidth allowed to be output by the filter.

[0097] Furthermore, the first adjustment effect label of the target monitoring line is analyzed. The specific analysis process is as follows:

[0098] After the first adjustment of the filter is completed, the signal state characterization factor of the target monitoring line is reacquired and recorded as the first signal state characterization factor.

[0099] If the first signal state characterization factor is still greater than the signal state characterization factor threshold, the first adjustment effect label of the target monitoring line at this time is recorded as invalid adjustment, and an early warning message is sent.

[0100] 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, so it is judged that the first adjustment effect of the filter at this time is invalid adjustment.

[0101] If the first signal state characterization factor is less than or equal to the signal state characterization factor threshold, the first adjustment effect label of the target monitoring line at this time is recorded as effective adjustment.

[0102] 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 has achieved the desired effect and can alleviate the impact of signal distortion. Therefore, it is judged that the first adjustment effect of the filter is effective adjustment.

[0103] By dynamically adjusting the filter bandwidth, the filter bandwidth is relaxed for distorted signals. By increasing the filter bandwidth, the actual bandwidth value is changed so that the frequency of the signal is not at the edge of the cutoff frequency of the filter. The relaxed bandwidth can accommodate the frequency of the signal, thereby achieving the adjustment of the distorted signal and improving the accuracy of the signal, so that the system can accurately measure the distance and locate the fault.

[0104] 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 have introduced communication interference, thereby determining the second execution strategy of the target monitoring line.

[0105] Furthermore, the information introduced by communication interference is analyzed. The specific analysis process is as follows:

[0106] When the first adjustment effect label of the target monitoring line is effective adjustment, the harmonic distortion rate of the target monitoring line signal is collected.

[0107] It should be noted that the harmonic distortion rate of a signal is a parameter that measures the degree of distortion of the signal waveform. It quantifies the proportion of contamination of the original signal by the harmonic components in the signal and represents the percentage of the sum of all harmonic energies to the fundamental wave energy. The larger the value, the more severe the signal distortion.

[0108] Extract the preset harmonic distortion rate threshold value in the database.

[0109] If the harmonic distortion rate of the target monitoring line signal is less than or equal to the harmonic distortion rate threshold, the communication interference introduction information is recorded as no communication interference is introduced, and an execution fault confirmation signal is output.

[0110] It should be understood that if the harmonic distortion rate of the target monitoring line signal is less than or equal to the harmonic distortion rate threshold, it means that the adjusted signal is a stable and accurate signal and no interference is introduced. Therefore, the information of communication interference introduction is recorded as no communication interference is introduced, and the signal is judged as a feasible signal to output and execute the fault confirmation signal.

[0111] If the harmonic distortion rate of the target monitoring line signal is greater than the harmonic distortion rate threshold, the communication interference introduction information is recorded as confirmation of the introduction of communication interference.

[0112] It should be understood that if the harmonic distortion rate of the target monitoring line signal is greater than the harmonic distortion rate threshold, it means that it is still not an accurate signal after signal adjustment, which proves that interference has been introduced. Therefore, the communication interference introduction information is recorded as confirmation of the introduction of communication interference.

[0113] Furthermore, the communication interference index of the target monitoring line is analyzed. The specific analysis process is as follows:

[0114] After the communication interference introduction information is recorded as confirmation of the introduction of communication interference, communication interference parameters of the target monitoring line are collected, including the signal-to-noise ratio, signal quality value, and harmonic distortion rate of the signal.

[0115] It should be noted that the communication interference parameter is obtained by collecting and analyzing the signal of the target monitoring line. In a specific embodiment, it can be directly obtained through fast Fourier transform analysis.

[0116] It should be noted that the signal-to-noise ratio (SNR) is the ratio of signal power to noise power. The bit error rate (BER) is the numerical value of signal quality, while the harmonic distortion (HDR) of a signal refers to the percentage of total harmonic energy relative to the fundamental energy.

[0117] It should be added that when the harmonic distortion rate of the signal is too large, it means that the signal waveform is distorted, which will cause the signal quality to deteriorate and reduce 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 become abnormal. There is a correlation between the three, and when any parameter changes, it will lead to changes in the other two parameters.

[0118] The communication interference index of the target monitoring line is obtained based on the communication interference parameter analysis of the target monitoring line.

[0119] The communication interference index of the target monitoring line is a quantitative expression of the degree of influence 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: the signal-to-noise ratio, signal quality value and harmonic distortion rate of the collected signal are compared with the corresponding reference values ​​respectively, and the comparison results are coupled with the corresponding measurement factors to obtain the communication interference index of the target monitoring line.

[0120] Extract the reference value of the signal-to-noise ratio, the reference value of the signal harmonic distortion rate, and the reference value of the signal quality value stored in the database.

[0121] Extract the signal-to-noise ratio measurement factor, the signal quality value measurement factor, and the signal harmonic distortion rate measurement factor preset in the database.

[0122] It should be noted that the measurement factor of the signal-to-noise ratio, the measurement factor of the signal quality value and the measurement factor of the signal harmonic distortion rate all range from 0 to 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 signal harmonic distortion rate is 1. When used, the pre-set value 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, signal quality value and harmonic distortion rate of the signal and the corresponding signal-to-noise ratio, signal quality value and harmonic distortion rate of the signal. When used, the obtained signal-to-noise ratio, signal quality value and harmonic distortion rate of the signal are respectively input into the corresponding mapping set, thereby extracting the signal-to-noise ratio, signal quality value and harmonic distortion rate of the signal.

[0123] In the specific implementation process, the communication interference index is specifically expressed as follows:

[0124] ,

[0125] Among them, B is the communication interference index, is the signal-to-noise ratio, is the reference value of the signal-to-noise ratio, 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 a measure of the signal-to-noise ratio, is a measure of the signal quality value, It is a measure of the harmonic distortion rate of the signal.

[0126] Furthermore, the second execution strategy of the target monitoring line is determined. The specific analysis process is as follows:

[0127] Extract the communication interference index threshold preset in the database.

[0128] If the communication interference index of the target monitoring line is greater than the communication interference index threshold, the second execution strategy of the target monitoring line is recorded as executing the second filter adjustment.

[0129] It should be noted that if the communication interference index of the target monitoring line is greater than the communication interference index threshold, it means that the degree of communication interference is large and the signal error is large. This may be due to an error in the first adjustment degree of the filter. In order to reduce the degree of communication interference, the second execution strategy is determined to be to execute the second adjustment of the filter.

[0130] If the communication interference index of the target monitoring line is less than or equal to the communication interference index threshold, the second execution strategy of the target monitoring line is recorded as performing spectrum cleanup.

[0131] 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 means that the degree of communication interference is relatively small at this time, but it may still affect the accuracy of the collected signal. In order to further reduce communication interference, the second execution strategy is determined to perform spectrum purification.

[0132] It should be noted that spectrum cleanup is a method of removing or suppressing identified interfering frequency points or bands in the spectrum without changing the overall bandwidth of the filter. In a specific embodiment, this can be achieved by embedding a dynamic Notch Filter.

[0133] Furthermore, the second filter adjustment is performed, and the specific analysis process is as follows:

[0134] The communication interference deviation index is obtained by subtracting the communication interference index threshold from the communication interference index of the target monitoring line.

[0135] The filter bandwidth reduction ratio is extracted based on the communication interference deviation index. The specific extraction process is as follows:

[0136] The bandwidth reduction ratio corresponding to each communication interference deviation index interval stored in the database is extracted, and the bandwidth reduction ratio corresponding to the interval in which the communication interference deviation index is located is mapped and extracted, and recorded as the filter bandwidth reduction ratio.

[0137] It should be added that the larger the communication interference deviation index is, the greater the communication interference of the current signal is, indicating that the bandwidth supplement of the filter is incorrect. In order to obtain an accurate signal and reduce the impact of interference, it is necessary to adjust the bandwidth supplement value of the filter to reduce the degree of communication interference and ensure accurate signal output.

[0138] Get the filter bandwidth increment value from the system program log.

[0139] Analyze the filter bandwidth reduction value based on the filter bandwidth increase value and the filter bandwidth reduction ratio.

[0140] It should be noted that, in a specific embodiment, if the current filter bandwidth supplement value is , the extracted filter bandwidth reduction ratio is , then the adjusted filter bandwidth reduction value is .

[0141] Get the current filter bandwidth, recorded as the second filter bandwidth.

[0142] A second filter adjustment is performed based on the second filter bandwidth and the filter bandwidth reduction value.

[0143] It should be understood that in one embodiment, if the second filter bandwidth is , the filter bandwidth reduction value is , then the adjusted filter bandwidth is .

[0144] A second adjustment effect of the filter is determined, thereby determining a third execution strategy for the target monitoring line.

[0145] Furthermore, the third execution strategy of the target monitoring line is determined. The specific analysis process is as follows:

[0146] After performing the second filter adjustment, the communication interference index of the target monitoring line is reacquired and recorded as the first communication interference index.

[0147] The harmonic distortion rate of the target monitoring line is collected again and recorded as the first harmonic distortion rate.

[0148] If the first harmonic distortion rate is less than or equal to the harmonic distortion rate threshold, the third execution strategy of the target monitoring line is recorded as outputting an execution fault confirmation signal.

[0149] 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 the signal has not only reduced the interference level through adjustment, but also reduced the interference level to a level that does not affect the accuracy of the signal. The output signal at this time can be used as accurate data for subsequent analysis and positioning. Therefore, the third execution strategy is determined to be the output execution fault confirmation signal.

[0150] 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, the third execution strategy of the target monitoring line is recorded as outputting a warning signal.

[0151] 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 the signal has not been adjusted to reduce the interference level and still belongs to a large degree of interference. Therefore, the third execution strategy is determined to output a warning signal.

[0152] 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, the third execution strategy of the target monitoring line is recorded as performing spectrum cleanup.

[0153] 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 the signal has indeed reduced the interference level through adjustment, but the degree of reduction is not enough and there is still a certain degree of interference. Therefore, the third execution strategy is determined to be spectrum purification.

[0154] The present invention reduces the impact of communication interference in signals by dynamically regulating communication interference. By determining and adjusting the degree of communication interference, the communication interference level is reduced to a controllable range that does not affect 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 losses caused by incorrect positioning of faults, and improving power supply reliability and stability.

[0155] The line fault distance measurement and location result output module receives the fault confirmation signal, starts the fault location function, and performs fault distance measurement and fault location on the target monitoring line.

[0156] It should be noted that after the fault location function is started, the specific fault type of the line is determined. Specifically, the actual fault type of the line is determined based on zero voltage, zero current, phase current and the action of protection elements. 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-to-phase fault (AB), BC phase-to-phase fault (BC), CA phase-to-phase fault (CA) and ABC phase-to-phase fault (ABC).

[0157] The 8-cycle sampling data before the fault is recorded synchronously, and the 8-cycle sampling data after the fault is recorded continuously at the same time, and the voltage and current vectors before and after the fault are calculated using the Fourier algorithm.

[0158] The corresponding distance calculation formula is determined based on the wave sampling data and the fault type.

[0159] It should be added that the database stores distance calculation formulas corresponding to various fault types.

[0160] In one specific embodiment, if a ground fault occurs, the grounding coefficient K is first calculated to ensure accurate detection of the ground fault by compensating for the effect of zero-sequence current on the measured impedance. Subsequently, the impedance is calculated using the ground fault calculation formula to obtain the resistance and reactance values, which are specifically expressed as:

[0161] ,

[0162] in, is the phase A fault voltage, is the phase A fault current, is the current before the fault of phase A, K is the grounding coefficient, is the ground fault current, calculated from the phase currents, is the current before the ground fault.

[0163] It should be added that the specific expression method of grounding coefficient is:

[0164] ,

[0165] in, is the zero-sequence line impedance, is the positive sequence line impedance.

[0166] The specific expression method of ground fault current is:

[0167] ,

[0168] in, 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.

[0169] In another specific embodiment, if it is a phase-to-phase fault, the specific representation method is:

[0170] ,

[0171] in, is the voltage of A relative to ground, is the voltage of B relative to ground, is the phase A current, is the B phase current, is the pre-fault load current.

[0172] It should also be added that a reactance value can be obtained for each cycle of data, and ultimately 8 groups of reactance values ​​are obtained. These 8 groups of reactance values ​​are screened and processed to determine the rationality of the reactance. The specific process is: the maximum reactance value is calculated based on the longest length of the line. If the calculated reactance result is greater than this value, the reactance result of this group is discarded.

[0173] Then judge its directionality. The specific process is: if 5 groups or more meet the same direction, that is, the same positive or negative, take the reactance value that meets the conditions for use.

[0174] It should be noted that the number of acquisition cycles before and after the wave sampling data and the limited number of groups that meet the directionality judgment adjustment can be specifically limited according to specific circumstances in other embodiments. This embodiment is only an example and does not impose any special limitations on this.

[0175] Next, the reactance values ​​will be sorted, and the reactance values ​​that are less than the preset reactance limit value in the database will be screened out, that is, the deviated calculation results will be discarded, and the last retained data will be used as the reactance data for final use.

[0176] According to the reactance value, the fault distance is calculated, that is, the ratio of the reactance value to the unit reactance is used as the numerical result of the fault distance, and the fault distance measurement is completed.

[0177] like Figure 2 As shown, it is a flowchart of signal state analysis based on signal state characterization provided by an embodiment of the present invention, which collects signal state characterization parameters of the target detection line, analyzes the signal state characterization factor, compares the signal state characterization factor with the threshold, and outputs a fault confirmation signal if it is less than or equal to the signal state characterization factor threshold; and executes the first filter adjustment if it is greater than the signal state characterization factor threshold.

[0178] like Figure 3 As shown, 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. The signal harmonic distortion rate of the target detection line is collected, and the harmonic distortion rate of the signal is compared with the threshold. If it is greater than the harmonic distortion rate threshold, it is confirmed that communication interference has been introduced. The communication interference index is analyzed. If it is less than or equal to the harmonic distortion rate threshold, communication interference has not been introduced, and an execution fault confirmation signal is output.

[0179] The present invention provides a fault ranging and fault location system for distributed power lines. The system analyzes the characteristics of abnormal signals to determine the accuracy of input signals, thereby adjusting the signals and improving the accuracy of input signals of the ranging and location system. This effectively solves the problem of neglecting the accuracy of input signals in current technologies, enables the system to accurately and quickly measure distance and locate faults, reduces losses caused by incorrectly located faults, and improves power supply reliability and stability.

[0180] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0181] The present invention is described with reference to 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 process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0182] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0183] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0184] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0185] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A fault distance measurement and fault location system for distributed power lines, characterized in that: include: a line signal state analysis module, which receives an abnormal power line signal, records the power line as a target monitoring line, collects signal state characterization parameters of the target monitoring line, analyzes the signal state characterization factors of the target monitoring line, and thereby determines a first execution strategy for the target monitoring line; a line signal adjustment module, which, when the first execution strategy of the target monitoring line is to perform the first filter adjustment, performs 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; a line communication interference judgment module, which 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 indicates that communication interference has been confirmed, thereby determining the second execution strategy of the target monitoring line; The line fault distance measurement and location result output module 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 distance measurement and fault location on the target monitoring line; Collect the signal status characterization parameters of the target monitoring line, including the main frequency energy proportion, energy ratio, main frequency position offset and bandwidth standard deviation of the target monitoring line signal; Analyze the signal state characterization factor of the target monitoring line based on the signal state characterization parameter of the target monitoring line; The signal state characterization factor of the target monitoring line is a quantitative characterization of the degree of influence of the main frequency energy proportion, 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: the main frequency energy proportion, energy ratio, main frequency position offset and bandwidth standard deviation of the collected target monitoring line signal are respectively compared with the corresponding reference values, and then the comparison results are coupled with the corresponding measurement factors to obtain the signal state characterization factor of the target monitoring line; When the first adjustment effect label of the target monitoring line is effective adjustment, collecting the harmonic distortion rate of the target monitoring line signal; Extracting the preset harmonic distortion rate threshold value in the database; If the harmonic distortion rate of the target monitoring line signal is less than or equal to the harmonic distortion rate threshold, the communication interference introduction information is recorded as no communication interference is introduced, and a fault confirmation signal is output; If the harmonic distortion rate of the target monitoring line signal is greater than the harmonic distortion rate threshold, the communication interference introduction information is recorded as confirmation of the introduction of communication interference; After the communication interference introduction information is recorded as confirmation of the introduction of communication interference, the communication interference parameters of the target monitoring line are collected, including the signal-to-noise ratio, signal quality value and harmonic distortion rate of the signal; The communication interference index of the target monitoring line is obtained based on the communication interference parameter analysis of the target monitoring line; The communication interference index of the target monitoring line is a quantitative representation of the degree of influence 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: the signal-to-noise ratio, signal quality value and harmonic distortion rate of the collected signal are compared with the corresponding reference values ​​respectively, and the results of the comparison are coupled with the corresponding measurement factors to obtain the communication interference index of the target monitoring line.

2. A fault distance measurement and fault location system for distributed power lines according to claim 1, characterized in that: The first execution strategy for determining the target monitoring line is specifically analyzed as follows: Extracting the signal state characterization factor threshold preset in the database; 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, the first execution strategy of the target monitoring line is recorded as outputting an execution fault confirmation signal; If the signal state characterization factor of the target monitoring line is greater than the signal state characterization factor threshold of the monitoring line, the first execution strategy of the target monitoring line is recorded as the first adjustment of the execution filter; The first adjustment of the filter is to increase the bandwidth of the filter.

3. A fault distance measurement and fault location system for distributed power lines according to claim 2, characterized in that: The first filter adjustment is completed based on the signal state characterization factor of the target monitoring line. The specific analysis process is as follows: The signal state characterization factor of the target monitoring line is subtracted from the signal state characterization factor threshold of the monitoring line to obtain a signal state characterization deviation factor; Extracting the bandwidth supplement value corresponding to each signal state characterization deviation factor interval stored in the database, and mapping the extracted bandwidth supplement value corresponding to the interval where the signal state characterization deviation factor is located, and recording it as the filter bandwidth supplement value; Get the current filter bandwidth, recorded as the first filter bandwidth; A first filter adjustment is performed based on the first filter bandwidth and the filter bandwidth increment value.

4. A fault distance measurement and fault location system for distributed power lines according to claim 1, characterized in that: The first adjustment effect label of the target monitoring line is analyzed, and the specific analysis process is as follows: After completing the first adjustment of the filter, the signal state characterization factor of the target monitoring line is re-obtained and recorded as the first signal state characterization factor; If the first signal state characterization factor is still greater than the signal state characterization factor threshold, the first adjustment effect label of the target monitoring line at this time is recorded as invalid adjustment, and a warning message is sent; If the first signal state characterization factor is less than or equal to the signal state characterization factor threshold, the first adjustment effect label of the target monitoring line at this time is recorded as effective adjustment.

5. The fault distance measurement and fault location system for distributed power lines according to claim 1, characterized in that: The specific analysis process of the second execution strategy for determining the target monitoring line is as follows: Extracting a preset communication interference index threshold value in a database; If the communication interference index of the target monitoring line is greater than the communication interference index threshold, the second execution strategy of the target monitoring line is recorded as executing the second filter adjustment; If the communication interference index of the target monitoring line is less than or equal to the communication interference index threshold, the second execution strategy of the target monitoring line is recorded as performing spectrum cleanup.

6. A fault distance measurement and fault location system for distributed power lines according to claim 5, characterized in that: The second adjustment of the filter is performed, and the specific analysis process is as follows: The communication interference deviation index is obtained by subtracting the communication interference index threshold from the communication interference index of the target monitoring line; Extract the filter bandwidth reduction ratio based on the communication interference deviation index; Get the filter bandwidth supplement value; Analyze the filter bandwidth reduction value based on the filter bandwidth supplement value and the filter bandwidth reduction ratio; Get the current filter bandwidth, record it as the second filter bandwidth; performing a second filter adjustment based on the second filter bandwidth and the filter bandwidth reduction value; A second adjustment effect of the filter is determined, thereby determining a third execution strategy for the target monitoring line.

7. A fault distance measurement and fault location system for distributed power lines according to claim 6, characterized in that: The specific analysis process of the third execution strategy for determining the target monitoring line is as follows: After performing the second filter adjustment, the communication interference index of the target monitoring line is reacquired and recorded as the first communication interference index; Re-collect the harmonic distortion rate of the target monitoring line and record it as the first harmonic distortion rate; If the first harmonic distortion rate is less than or equal to the harmonic distortion rate threshold, the third execution strategy of the target monitoring line is recorded 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, the third execution strategy of the target monitoring line is recorded 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, the third execution strategy of the target monitoring line is recorded as performing spectrum cleanup.

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