Double-end traveling wave distance measurement method and device for coping with time synchronization loss and storage medium

Abstract

The invention discloses a double-end traveling wave distance measurement method and device for coping with time synchronization loss and a storage medium, and the method comprises the steps: calibrating and storing the inherent phase offset of power frequency voltages at two ends of a line in advance when time synchronization is normal; when a fault occurs after the time synchronization signal is lost, through identifying a power frequency voltage zero crossing point before the fault and combining with the phase offset, or carrying out cross-correlation calculation on a power frequency waveform before the fault at one end and a waveform at the other end, realizing accurate alignment of recording data at the two ends on a time axis, so as to establish a relative synchronization time reference; then, accurately identifying the arrival time of the wave heads of the initial traveling waves at the two ends by using a wavelet transform modulus maximum method; and finally, based on the aligned time reference, calculating the time difference of the traveling wave arriving at the two ends, thereby realizing accurate fault positioning independent of a satellite time synchronization signal. The device and the storage medium are used for implementing the method. According to the method, the robustness and the usability of the power distribution network traveling wave fault positioning system under the time synchronization abnormal working condition are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of two-end traveling wave ranging methods, specifically a two-end traveling wave ranging method, device, and storage medium for addressing time loss during ranging. Background Technology

[0002] In the field of fault location in power distribution networks, traveling wave ranging is one of the most commonly used methods, mainly divided into single-end ranging and double-end ranging. Due to the complexity of power distribution network lines and the large number of branches, it is difficult to locate fault reflection waves, making single-end ranging difficult to apply. Double-end ranging, on the other hand, only requires utilizing the initial traveling wave of the fault and the time difference between the arrival times of the initial traveling wave at both ends to determine the fault location. This method is simple to implement and is therefore widely used.

[0003] The core of existing two-end ranging technology lies in obtaining the time it takes for the fault traveling wave to reach both ends. The two-end devices use BeiDou / GPS for time synchronization. However, in actual power distribution network environments, satellite positioning may experience poor signal or even signal loss due to weather, ambient temperature and humidity, leading to the loss of time synchronization between the two ends.

[0004] In cases of satellite signal loss, the conventional method is to maintain time synchronization using historical crystal oscillator counting. However, crystal oscillators inherently have errors, and these accumulated errors increase over time. Some methods record historical crystal oscillator data and statistically analyze the historical error distribution to assess future crystal oscillator errors and reduce accumulated errors. However, this method can only maintain time synchronization for a very short period and cannot solve the problem of bilateral ranging failure after satellite signal loss. Therefore, a method is needed to address time synchronization loss and ensure the reliability of bilateral new wave ranging. Summary of the Invention This invention provides a method, device, and storage medium for two-end traveling wave ranging under time synchronization loss, in order to solve the problem that the reliability of two-end traveling wave ranging cannot be guaranteed when the satellite time synchronization signal is lost in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A two-terminal traveling wave ranging method to address time loss is described below:

[0007] Determining the traveling wave sampling device at both ends of the distribution network , Is the time synchronization normal? The traveling wave sampling device , Time synchronization is performed based on the PPS second pulse signal of the GPS or BeiDou positioning system;

[0008] When the time synchronization is normal, based on the traveling wave sampling device , Each from the arrival time of the pps second pulse signal The power frequency phase offset calibration value was calculated from the initial sampling traveling wave data and multiple zero-crossing moments. ;

[0009] When the time synchronization signal is lost, causing abnormal time synchronization, based on the traveling wave sampling device , The waveform data, including transient traveling waves and power frequency, recorded independently by each timer, are used to obtain the traveling wave sampling device using a similarity search window method. , Number of sampling points corresponding to the time difference between the trigger times of the sampled signal amplitude exceeding the limit ;

[0010] Then, the traveling wave sampling device , The arrival time of the local traveling wave front is identified from the independently recorded waveform data to obtain the traveling wave sampling device. The local sampling point number of the arrival time of the traveling wave front in the recorded waveform data. Traveling wave sampling device The local sampling point number of the arrival time of the traveling wave front in the recorded waveform data. ;

[0011] Finally, based on the power frequency phase offset calibration value Number of sampling points Local sampling point number Local sampling point number The distance from the fault location to any one of the two-ended traveling wave sampling devices is calculated and located. .

[0012] Furthermore, when the timing is normal, based on the traveling wave sampling device , Each from the arrival time of the pps second pulse signal The traveling wave data at the beginning of sampling and multiple zero-crossing moments are used to obtain multiple phase deviations. The average of these phase deviations is then taken to obtain the power frequency phase offset calibration value. .

[0013] Furthermore, from the arrival time of the pps second pulse signal Initially, in the traveling wave sampling device Find the first zero-crossing moment in the sampled traveling wave data. and in traveling wave sampling device Find the first zero-crossing moment in the sampled traveling wave data. Combined with traveling wave sampling device At the arrival time of the pps second pulse signal The obtained sample values Traveling wave sampling device At the arrival time of the pps second pulse signal The obtained sample values Make a judgment when At that time, the first phase deviation ;when At that time, the first phase deviation ;

[0014] And so on, starting from the (n-1)th zero-crossing time... Start at traveling wave sampling device Find the nth zero-crossing moment in the sampled traveling wave data. And the zero-crossing time from the (n-1)th zero-crossing time Start at traveling wave sampling device Find the nth zero-crossing moment in the sampled traveling wave data. Combined with traveling wave sampling device At the (n-1)th zero crossing moment The obtained sample values Traveling wave sampling device At the (n-1)th zero crossing moment The obtained sample values Make a judgment when At that time, the nth phase deviation ;when At that time, the nth phase deviation ;

[0015] The average value of each phase deviation is taken to obtain the power frequency phase offset calibration value. .

[0016] Furthermore, when the time synchronization signal is lost, causing abnormal time synchronization, a traveling wave sampling device is used. , Sampling point at the time of over-limit triggering of either one As the center point of the similarity search window, and based on the sampling point at the time of the limit violation trigger. Centered on the sampling point The size of the similarity search window is determined from the waveform data recorded by the corresponding traveling wave sampling device;

[0017] Furthermore, using a traveling wave sampling device , The sampling point at the time of the over-limit trigger of the other one. As a reference point, based on the reference point At the reference point The search range of the center point of the similarity search window is obtained from the waveform data recorded by the corresponding traveling wave sampling device.

[0018] Center the similarity search window at the reference point. The search range within the waveform data recorded by the corresponding traveling wave sampling device is moved step by step over time to obtain the reference point within the search range at each time step. The corresponding traveling wave sampling device recorded waveform data, and the center search window and reference points within the search range of each time step were calculated. The cross-correlation coefficient of the waveform data recorded by the corresponding traveling wave sampling device;

[0019] Take the index corresponding to the maximum value of the cross-correlation coefficients at each time step. This is a traveling wave sampling device. , The number of sampling points corresponding to the time difference between the trigger times when the amplitude of the sampled signal exceeds the limit.

[0020] Furthermore, the sampling points at the time of triggering the limit Centered on the sampling point The corresponding traveling wave sampling device extracts both forward and backward segments of the waveform data. Zhou Bo, as the size of the similarity search window.

[0021] Furthermore, the center point of the similarity search window is at the reference point. The search range size in the waveform data recorded by the corresponding traveling wave sampling device is ,in Traveling wave sampling device , The sampling rate.

[0022] Furthermore, the wavelet transform modulus maxima method is used to analyze the double-ended traveling wave sampling device. , The arrival time of the local traveling wave front is identified from the waveform data recorded by each individual during independent timing.

[0023] Furthermore, the wavelet function db5 is used to sample the independent timing traveling wave sampling device. , The recorded wave data are subjected to discrete wavelet transform to obtain the traveling wave sampling device. , The corresponding detail coefficients at each scale Where j is the decomposition scale and k is the sampling point number; then the traveling wave sampling device is calculated. , The corresponding third-scale modulus and find a point modulus Greater than its two adjacent points -1 and The modulus of +1, at this point That is, the arrival time of the wavefront of the corresponding traveling wave sampling device, thus obtaining the traveling wave sampling device. The local sampling point number of the arrival time of the traveling wave front in the recorded waveform data. Traveling wave sampling device The local sampling point number of the arrival time of the traveling wave front in the recorded waveform data. .

[0024] Furthermore, based on the power frequency phase offset calibration value Number of sampling points Local sampling point number Local sampling point number The calculation shows that the traveling wave front reaches the double-ended traveling wave sampling device. , Time difference As shown in the following formula:

[0025]

[0026] Based on time difference The distance from the fault point to one of the traveling wave sampling devices was located. As shown in the following formula:

[0027]

[0028] In the formula: c represents the speed of light. L represents the traveling wave sampling device. , The distance between them; Traveling wave sampling device , The sampling rate.

[0029] An electronic device includes a processor and a memory, wherein program instructions in the memory are read and executed by the processor to perform the above-described method for two-end traveling wave ranging under time-loss conditions.

[0030] A storage medium storing program instructions, which, when read and executed, perform the aforementioned method for dual-end traveling wave ranging under conditions of time-of-flight loss.

[0031] Compared with the prior art, the advantages of the present invention are:

[0032] In this invention, when the satellite synchronization signal fails, a relative synchronization time reference is constructed by precisely aligning the pre-calibrated double-ended power frequency phase offset with the power frequency component of the fault recording data. This allows for high-precision double-ended traveling wave fault location without relying on absolute clock synchronization, significantly improving the robustness and availability of the power distribution network fault location system under extreme conditions. Attached Figure Description

[0033] Figure 1 This is a flowchart of the method according to an embodiment of the present invention.

[0034] Figure 2 This is a schematic diagram of power frequency signal phase deviation calibration in an embodiment of the present invention.

[0035] Figure 3 This is a schematic diagram of waveform data alignment in an embodiment of the present invention. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0037] like Figure 1 As shown, this embodiment discloses a two-end traveling wave ranging method to address time-loss conditions. The frequency of the power frequency voltage and current in the distribution network is assumed to be 50Hz, and the traveling wave sampling devices at both ends of the distribution network are respectively... , Traveling wave sampling device , Each device is communicatively connected to the ranging data processing unit. Traveling wave sampling device. , Time synchronization is performed using GPS or BeiDou positioning systems; traveling wave sampling device. , The sampling rates are all =10MHz, traveling wave sampling device , The distance between them was set to 5 km. Furthermore, a traveling wave sampling device was used. , During sampling, waveform data from at least the previous cycle starting from the current sampling time are retained. The method process in this embodiment is as follows:

[0038] Step 1: When the traveling wave sampling device , When both receive PPS (pulse per second) signals from GPS or BeiDou positioning systems, the traveling wave sampling device... , The first message is sent to the ranging data processing device. When the ranging data processing device receives the message from the traveling wave sampling device... , Upon receiving the first message, the ranging data processing device determines the traveling wave sampling device. , The timing is normal.

[0039] Dual-end traveling wave sampling device , When the time synchronization is normal, it is achieved by the traveling wave sampling device. , Time synchronization is performed based on the received pps second pulse signal, and is achieved by a traveling wave sampling device. , From the same pps second pulse signal arrival time They began sampling traveling wave data separately, with the sampled waveform data being at time [time value missing]. Two cycles are taken from both the front and back, and a traveling wave sampling device is installed. , At the arrival time of the pps second pulse signal The obtained sample values ​​are respectively , Traveling wave sampling device , Each from the arrival time of the pps second pulse signal The traveling wave data that begins to be sampled is transmitted to the ranging data processing device.

[0040] like Figure 2 As shown, a dual-end traveling wave sampling device , When the time synchronization is normal, the distance measurement data processing device records the arrival time of the pps second pulse signal. Initially, in the traveling wave sampling device Find the first zero-crossing moment in the sampled traveling wave data. and in traveling wave sampling device Find the first zero-crossing moment in the sampled traveling wave data. The ranging data processing device is combined with a traveling wave sampling device. At the arrival time of the pps second pulse signal The obtained sample values Traveling wave sampling device At the arrival time of the pps second pulse signal The obtained sample values Make a judgment and pass through the first zero-crossing point based on the judgment result. , The traveling wave sampling device caused by the line parameters was calculated. At the first zero-crossing moment relative to the traveling wave sampling device First phase deviation Specifically, the ranging data processing device will process the sampled values. Multiply by sample value ,when At that time, the first phase deviation ;when At that time, the first phase deviation .

[0041] Then, the ranging data processing device starts from the first zero-crossing moment. Start at traveling wave sampling device Find the second zero-crossing moment in the sampled traveling wave data. And from the first zero-crossing moment Start at traveling wave sampling device Find the second zero-crossing moment in the sampled traveling wave data. The ranging data processing device is combined with a traveling wave sampling device. At the first zero crossing moment The obtained sample values Traveling wave sampling device At the first zero crossing moment The obtained sample values Make a judgment, and based on the judgment result, proceed through the second zero-crossing point. , The traveling wave sampling device caused by the line parameters was calculated. At the second zero-crossing time relative to the traveling wave sampling device The second phase deviation Specifically, the ranging data processing device will process the sampled values. Multiply by sample value ,when At that time, the second phase deviation ;when At that time, the second phase deviation .

[0042] And so on, the ranging data processing device crosses zero at the (n-1)th zero-crossing time. Start at traveling wave sampling device Find the nth zero-crossing moment in the sampled traveling wave data. And the zero-crossing time from the (n-1)th zero-crossing time Start at traveling wave sampling device Find the nth zero-crossing moment in the sampled traveling wave data. The ranging data processing device is combined with a traveling wave sampling device. At the (n-1)th zero crossing moment The obtained sample values Traveling wave sampling device At the (n-1)th zero crossing moment The obtained sample values Make a judgment, and based on the judgment result, proceed through the nth zero-crossing point. , The traveling wave sampling device caused by the line parameters was calculated. At the nth zero-crossing time relative to the traveling wave sampling device The nth phase deviation Specifically, the ranging data processing device will process the sampled values. Multiply by sample value ,when At that time, the nth phase deviation ;when At that time, the nth phase deviation .

[0043] Finally, the ranging data processing device averages the total n phase deviations to calculate the power frequency phase offset calibration value. In this embodiment, the ranging data processing device calculates the phase deviation a total of n=5 times and takes the average value to obtain the power frequency phase offset calibration value. As shown in the following formula:

[0044] .

[0045] Step 2: When the ranging data processing device does not receive data from the traveling wave sampling device , When at least one of them sends the first message, the ranging data processing device determines that the time synchronization signal is lost or the time synchronization is abnormal, and assumes that the traveling wave sampling device is not working. , Each device enters an independent timing state. During independent timing, the traveling wave sampling device... , Each traveling wave sampling device separately records waveform data containing transient traveling waves and power frequency signals. The waveform data range of each traveling wave sampling device is two cycles before and after the moment when the transient traveling wave signal exceeds the threshold. , The recorded waveform data is transmitted to the ranging data processing device. When the transient traveling wave signal exceeds the threshold, the ranging data processing device determines that a fault has occurred.

[0046] like Figure 3 As shown, when the timing is abnormal, the dual-end traveling wave sampling device , The independent timing and ranging data processing device uses a similarity search window method to obtain the traveling wave sampling device. , Number of sampling points corresponding to the time difference between the trigger times of the sampled signal amplitude exceeding the limit This enables the implementation of a traveling wave sampling device. , Data alignment. The specific process is as follows:

[0047] Because traveling waves have a short propagation distance in power distribution networks, traveling wave sampling devices... The detected fault start time and traveling wave sampling device The absolute time difference between the fault initiation time and the fault initiation time will not exceed 1ms, that is... One cycle length. Therefore, the ranging data processing device is in the traveling wave sampling device. In the recorded waveform data, the traveling wave sampling device Sampling points at the local limit trigger time As the center point of the similarity search window, and in the traveling wave sampling device In the recorded waveform data, the sampling points at the time of the over-limit trigger are used. Cut off both forward and backward from the center. The size of the similarity search window is determined by the frequency band. In this embodiment, the size of the similarity search window is the size of the traveling wave sampling device. Sampling points obtained from the recorded waveform data The scope of the center is The waveform.

[0048] Furthermore, the ranging data processing device is integrated with the traveling wave sampling device. In the recorded waveform data, the traveling wave sampling device The sampling point at the local time of the limit exceedance trigger is used as the reference point, denoted as... Therefore, the ranging data processing device obtains the center point of the similarity search window in the traveling wave sampling device. The search range size in the waveform data is In this embodiment, the center point of the similarity search window is determined in the traveling wave sampling device. The search range size in the waveform data is .

[0049] The ranging data processing device places the center point of the similarity search window on the traveling wave sampling device. The search range within the recorded waveform data is moved step by step over time to obtain the traveling wave sampling device within the search range of each time step. The recorded waveform data is used to calculate the center search window and the traveling wave sampling device within the search range of each time step. The cross-correlation coefficient of the waveform data is calculated using the following formula:

[0050] ,

[0051] ,

[0052] .

[0053] In the above formula: For time step interval, ; for The recorded waveform data The values ​​of each sampling point; For the first in the search window The values ​​of each sampling point; Let be the cross-correlation number at the k-th time step.

[0054] The ranging data processing device then calculates the cross-correlation coefficients from time step 0 to time step 20000. Then, the ranging data processing device takes the index corresponding to the maximum value of the cross-correlation coefficients at each time step. This is a traveling wave sampling device. , The number of sampling points corresponding to the time difference between the trigger times of the sampled signal amplitude exceeding the limit is shown in the following formula:

[0055] .

[0056] It should be noted that although this embodiment is based on a traveling wave sampling device The center and size of the similarity search window are determined by the sampling points of the waveform data at the time of the over-limit trigger, and based on the traveling wave sampling device. The sampling point at the local over-limit trigger moment is used as a reference point to determine the center point of the similarity search window in the traveling wave sampling device. The search range size in the waveform data is determined, but the determination of the center and size of the central search window and the search range size in this invention is not limited to this. Based on a traveling wave sampling device... The center and size of the similarity search window are determined by the sampling points of the waveform data at the time of the over-limit trigger, based on the traveling wave sampling device. The sampling point at the local over-limit trigger moment is used as a reference point to determine the center point of the similarity search window in the traveling wave sampling device. The technical solution for determining the search range size in the waveform data should also be considered to fall within the protection scope of this invention.

[0057] Step 3: When the time synchronization is abnormal, the ranging data processing device uses the wavelet transform modulus maxima method to process the double-ended traveling wave sampling device. , The arrival time of the local traveling wavefront is identified from the waveform data recorded independently during timing. This method utilizes the amplification effect of wavelet transform on signal singularities at multiple scales, which can effectively identify the traveling wavefront and suppress noise interference.

[0058] Specifically, the wavelet function used in this embodiment is db5. db5 has good tight support and vanishing moment, effectively capturing the steep leading edge of transient traveling waves and achieving a good balance in the time and frequency domains. In this embodiment, the decomposition scale of the db5 wavelet function is selected as the third layer. The detail coefficients of the third layer contain the main high-frequency components of the traveling wavefront, resulting in a high signal-to-noise ratio.

[0059] The ranging data processing device uses the db5 wavelet function to sample the independent timing traveling wave sampling device. , The recorded wave data are subjected to discrete wavelet transform to obtain the traveling wave sampling device. , The corresponding detail coefficients at each scale Where j is the decomposition scale and k is the sampling point number. Then, the ranging data processing device calculates the value of the traveling wave sampling device. , The corresponding third-scale modulus and find a point modulus Greater than its two adjacent points -1 and The modulus of +1, at this point This refers to the arrival time of the wavefront of the corresponding traveling wave sampling device.

[0060] Using the above method, the ranging data processing device identifies the traveling wave sampling device. , The arrival time of the traveling wavefront in the waveform data recorded independently by each device. Thus, a traveling wave sampling device is obtained. The local sampling point number of the arrival time of the traveling wave front in the recorded waveform data. Traveling wave sampling device The local sampling point number of the arrival time of the traveling wave front in the recorded waveform data. .

[0061] Step 4: The ranging data processing device calibrates the power frequency phase offset value obtained in Step 1. and the traveling wave sampling device obtained in step 2. , Number of sampling points corresponding to the time difference between the trigger times of the sampled signal amplitude exceeding the limit and the traveling wave sampling device obtained in step 3. , The local sampling point sequence number of the corresponding wavefront arrival time. , The calculation shows that the traveling wave front reaches the double-ended traveling wave sampling device. , Time difference As shown in the following formula:

[0062]

[0063] The final ranging data processing device is based on time difference The distance between the fault point and the reference point was determined. Corresponding traveling wave sampling device distance As shown in the following formula:

[0064]

[0065] In the formula: c represents the speed of light. L represents the traveling wave sampling device. , The distance between them, in this embodiment, is L=5km; Traveling wave sampling device , The sampling rate, in this embodiment =10MHz.

[0066] This embodiment also discloses an electronic device, which serves as a ranging data processing device. The device includes a processor and a memory, the memory storing program instructions, including a data acquisition module and a data calculation module. The data acquisition module is used to acquire data from a traveling wave sampling device. , The messages and data sent.

[0067] The data calculation module is used to calculate the power frequency phase offset calibration value. and traveling wave sampling device and Number of sampling points corresponding to the time difference between the trigger times of the sampled signal amplitude exceeding the limit and traveling wave sampling device and The local sampling point sequence number of the corresponding wavefront arrival time. , And finally, the distance from the fault point to the traveling wave sampling device was calculated and located. distance .

[0068] Therefore, when the program instructions in the memory are read and run by the processor, steps 1-4 of the above-mentioned two-end traveling wave ranging method for handling time loss are executed.

[0069] This embodiment also discloses a storage medium storing program instructions, which are read and executed by any device to perform steps 1-4 of the above-described method for the two-end traveling wave ranging under time-loss conditions.

[0070] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. These embodiments are merely descriptions of preferred embodiments and are not intended to limit the scope or concept of the invention. The specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. Such combinations, as long as they do not violate the spirit of the present invention, should also be considered as part of this disclosure. To avoid unnecessary repetition, the present invention will not further describe the various possible combinations.

[0071] This invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this invention and without departing from the design idea of ​​this invention, all modifications and improvements made by those skilled in the art to the technical solutions of this invention should fall within the protection scope of this invention. The technical content for which protection is sought in this invention has been fully described in the claims.

Claims

1. A method for two-terminal traveling wave ranging under time loss, characterized in that, The process is as follows: Determining the traveling wave sampling device at both ends of the distribution network , Is the time synchronization normal? The traveling wave sampling device , Time synchronization is performed based on the PPS second pulse signal of the positioning system; When the time synchronization is normal, based on the traveling wave sampling device , Each from the arrival time of the pps second pulse signal The power frequency phase offset calibration value was calculated from the initial sampling traveling wave data and multiple zero-crossing moments. ; When the time synchronization signal is lost, causing abnormal time synchronization, based on the traveling wave sampling device , The waveform data, including transient traveling waves and power frequencies, recorded independently at different times, are used to obtain the traveling wave sampling device using a similarity search window method. , Number of sampling points corresponding to the time difference between the trigger times of the sampled signal amplitude exceeding the limit ; Then, the traveling wave sampling device , The arrival time of the local traveling wave front is identified from the independently recorded waveform data to obtain the traveling wave sampling device. The local sampling point number of the arrival time of the traveling wave front in the recorded waveform data. Traveling wave sampling device The local sampling point number of the arrival time of the traveling wave front in the recorded waveform data. ; Finally, based on the power frequency phase offset calibration value Number of sampling points Local sampling point serial number Local sampling point serial number The distance from the fault location to any one of the two-ended traveling wave sampling devices is calculated and located. .

2. The method for dual-end traveling wave ranging under time loss as described in claim 1, characterized in that, When the time synchronization is normal, based on the traveling wave sampling device , Each from the arrival time of the pps second pulse signal The traveling wave data at the beginning of sampling and multiple zero-crossing moments are used to obtain multiple phase deviations. The average of these phase deviations is then taken to obtain the power frequency phase offset calibration value. .

3. The method for dual-end traveling wave ranging under time loss as described in claim 2, characterized in that, From the arrival time of the pps second pulse signal Initially, in the traveling wave sampling device Find the first zero-crossing moment in the sampled traveling wave data. and in traveling wave sampling device Find the first zero-crossing moment in the sampled traveling wave data. Combined with traveling wave sampling device At the arrival time of the pps second pulse signal The obtained sample values Traveling wave sampling device At the arrival time of the pps second pulse signal The obtained sample values Make a judgment when At that time, the first phase deviation ;when At that time, the first phase deviation ; And so on, starting from the (n-1)th zero-crossing time... Start at traveling wave sampling device Find the nth zero-crossing moment in the sampled traveling wave data. And the zero-crossing time from the (n-1)th zero-crossing time Start at traveling wave sampling device Find the nth zero-crossing moment in the sampled traveling wave data. Combined with traveling wave sampling device At the (n-1)th zero crossing moment The obtained sample values Traveling wave sampling device At the (n-1)th zero crossing moment The obtained sample values Make a judgment when At that time, the nth phase deviation ;when At that time, the nth phase deviation ; The average value of each phase deviation is taken to obtain the power frequency phase offset calibration value. .

4. The method for dual-end traveling wave ranging under time loss as described in claim 1, characterized in that, When the time synchronization signal is lost, causing abnormal time synchronization, a traveling wave sampling device is used. , Sampling point at the time of over-limit triggering of either one As the center point of the similarity search window, and based on the sampling point at the time of the limit violation trigger. Centered on the sampling point The size of the similarity search window is determined from the waveform data recorded by the corresponding traveling wave sampling device; Furthermore, using a traveling wave sampling device , The sampling point at the time of the over-limit trigger of the other one. As a reference point, based on the reference point At the reference point The search range of the center point of the similarity search window is obtained from the waveform data recorded by the corresponding traveling wave sampling device. Center the similarity search window at the reference point. The search range within the waveform data recorded by the corresponding traveling wave sampling device is moved step by step over time to obtain the reference point within the search range at each time step. The corresponding traveling wave sampling device recorded waveform data, and the center search window and reference points within the search range of each time step were calculated. The cross-correlation coefficient of the waveform data recorded by the corresponding traveling wave sampling device; Take the index corresponding to the maximum value of the cross-correlation coefficients at each time step. This is a traveling wave sampling device. , The number of sampling points corresponding to the time difference between the trigger times when the amplitude of the sampled signal exceeds the limit.

5. The method for dual-end traveling wave ranging under time loss as described in claim 4, characterized in that, Sampling points at the time of exceeding the limit trigger Centered on the sampling point The corresponding traveling wave sampling device extracts both forward and backward segments of the waveform data. Zhou Bo, as the size of the similarity search window.

6. The method for dual-end traveling wave ranging under time loss according to claim 4, characterized in that, The center point of the similarity search window is at the reference point. The search range size in the waveform data recorded by the corresponding traveling wave sampling device is ,in Traveling wave sampling device , The sampling rate.

7. The method for dual-end traveling wave ranging under time loss as described in claim 1, characterized in that, The wavelet transform modulus maxima method is used to analyze the double-ended traveling wave sampling device. , The arrival time of the local traveling wavefront is identified from the waveform data recorded by each individual during independent timing. The wavelet function db5 is used to sample the independent timing traveling wave device. , The recorded wave data are subjected to discrete wavelet transform to obtain the traveling wave sampling device. , The corresponding detail coefficients at each scale Where j is the decomposition scale and k is the sampling point number; then the traveling wave sampling device is calculated. , The corresponding third-scale modulus and find a point modulus Greater than its two adjacent points -1 and The modulus of +1, at this point That is, the arrival time of the wavefront of the corresponding traveling wave sampling device, thus obtaining the traveling wave sampling device. The local sampling point number of the arrival time of the traveling wave front in the recorded waveform data. Traveling wave sampling device The local sampling point number of the arrival time of the traveling wave front in the recorded waveform data. .

8. A method for determining the distance between two traveling waves under time loss according to any one of claims 1-7, characterized in that, Based on power frequency phase offset calibration value Number of sampling points Local sampling point serial number Local sampling point serial number The calculation shows that the traveling wave front reaches the double-ended traveling wave sampling device. , Time difference As shown in the following formula: Based on time difference The distance from the fault point to one of the traveling wave sampling devices was located. As shown in the following formula: In the formula: c represents the speed of light. L represents the traveling wave sampling device. , The distance between them; Traveling wave sampling device , The sampling rate.

9. An electronic device comprising a processor and a memory, characterized in that, The program instructions in the memory are read and executed by the processor to perform a dual-end traveling wave ranging method for handling time loss as described in any one of claims 1-8.

10. A storage medium storing program instructions, characterized in that, When the program instructions are read and executed, a dual-end traveling wave ranging method for handling time loss as described in any one of claims 1-8 is performed.

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