Current traveling wave synchronization positioning method with GPS lock loss fault tolerance

Abstract

This invention relates to the field of online monitoring and location technology for cable faults, specifically a current traveling wave synchronous location method with GPS loss-of-lock fault tolerance. Measurement terminals are set up at at least two measurement ends of the cable line, using a temperature-controlled crystal oscillator as the local clock source and establishing a unified time reference using global navigation satellite system time information. When a cable fault generates a current traveling wave, the traveling wave signal is triggered and the corresponding local clock count value is recorded, forming a time stamp of the traveling wave arrival time. When the satellite time signal is unavailable, the arrival time of the traveling wave is continuously calculated based on the most recent valid time reference and the local clock count relationship, achieving synchronous failure fault-tolerant timing. After filtering the traveling wave waveform, the waveform data and time stamp are uploaded to the location processing platform, and cable fault location is achieved through traveling wave time difference calculation.

Description

Technical Field

[0001] This invention relates to the field of online monitoring and location technology for cable faults, specifically a current traveling wave synchronous location method with GPS loss-of-lock fault tolerance. Background Technology

[0002] With the continuous expansion of power system scale and the increasing density of power cable laying in urban distribution networks, cable insulation faults caused by transient disturbances such as lightning overvoltage and switching overvoltage are gradually increasing. These faults are characterized by their sudden onset and rapid propagation. If the fault location cannot be accurately and promptly identified, it will delay maintenance and repair, affecting power supply reliability and grid safety. Therefore, rapid online monitoring and precise location technology for power cable faults has become an important research direction in power system operation and maintenance.

[0003] Among existing cable fault location technologies, methods based on the traveling wave principle are widely used in medium and high voltage cable lines because they can directly utilize transient fault signals and are insensitive to changes in line parameters. These methods acquire voltage or current traveling wave signals generated by the fault and calculate the fault location based on the propagation time of the traveling wave in the cable. Depending on the measurement method, traveling wave location methods are generally divided into single-ended traveling wave location methods and double-ended traveling wave location methods.

[0004] Single-ended traveling wave (TW) positioning methods estimate fault distance by analyzing the time difference of the reflected TW signals, simplifying equipment deployment. However, in long-distance cables or lines with branches, joints, or other structural features, TW propagation attenuates significantly, and multiple reflected signals easily overlap, making effective reflection wave identification difficult and limiting positioning accuracy. Dual-ended TW positioning methods achieve positioning by synchronously acquiring TW signals from both ends, requiring high time synchronization accuracy. Existing synchronization methods are susceptible to clock drift or external interference in complex operating environments, resulting in insufficient positioning stability.

[0005] In view of this, the present invention provides a current traveling wave synchronous positioning method with GPS loss-of-lock fault tolerance. Summary of the Invention

[0006] The purpose of this invention is to provide a current traveling wave synchronous positioning method with GPS loss-of-lock fault tolerance, aiming to solve the problems of existing current traveling wave positioning technology being highly dependent on time synchronization accuracy and having insufficient synchronization stability in complex operating environments, which easily leads to a decrease in fault positioning accuracy.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] In a first aspect, the present invention provides a current traveling wave synchronous positioning method with GPS loss-of-lock fault tolerance, comprising the following steps:

[0009] S1. Establish a time reference by setting up measurement terminals at at least two measurement ends of the cable line. Each measurement terminal uses a temperature-controlled crystal oscillator as a local clock source and receives time information provided by the global satellite navigation system to establish a time reference of the second level or above for traveling wave positioning.

[0010] S2. Mark the traveling wave trigger and time. When a cable fault generates a current traveling wave, the measurement terminal calculates the statistical amplitude characteristics of the collected current signal and compares the statistical amplitude characteristics with a preset threshold. When the trigger condition is met, the local clock count value corresponding to the trigger time is latched to form a time marker of the arrival time of the traveling wave.

[0011] S3. Timing synchronization failure fault tolerance: When the time signal of the global satellite navigation system is unavailable, the measurement terminal uses the most recent valid second-level time reference as a reference, determines the number of counts corresponding to a unit second based on the local clock count statistics within multiple adjacent whole-second cycles, and uses the number of counts to continuously calculate the subsequent traveling wave triggering time.

[0012] S4. Upload waveform processing and data. Perform frequency domain filtering on the triggered traveling wave waveform to reduce low-frequency interference components, and upload the filtered traveling wave waveform data and corresponding time stamp information to the positioning processing platform.

[0013] S5. Location Time Difference Calculation and Fault: Under the constraint of the time marker, the location processing platform performs alignment analysis on the traveling wave waveforms from different measurement terminals, determines the relative time offset between the waveforms, and calculates the arrival time difference of the traveling wave based on the relative time offset, thereby realizing cable fault location.

[0014] As a preferred embodiment of the present invention, the measuring terminal parses the serial port time information output by the Global Navigation Satellite System (GNSS) module and uses it as a time reference at the second level or higher; the rising edge of the second pulse signal output by the GNSS module is used as the starting mark of the whole second; between two adjacent second pulse signals, the clock count value of the local temperature-controlled crystal oscillator is counted to obtain the crystal oscillator clock count value within adjacent whole second periods. This establishes a local clock counting relationship for sub-second timing.

[0015] In a preferred embodiment of the present invention, in the traveling wave triggering and time-marking step, the statistical amplitude characteristic is the root mean square value of the acquired current signal within a preset time window. The preset threshold is based on the multiple relationship of the root mean square value. Sure.

[0016] As a preferred embodiment of the present invention, when the statistical amplitude characteristic meets the triggering condition, the measuring terminal latches the local clock count value corresponding to the triggering time. The count value is used as the basis for determining the time information below the second level.

[0017] As a preferred embodiment of the present invention, in the synchronization failure fault-tolerant timing step, the most recent valid second pulse signal is used as the starting reference for a time of less than a second, based on a preset duration before the loss of lock. The average local clock count is used as the number of counts per second for sub-second time scale calculations.

[0018] As a preferred technical solution of the present invention, during periods when time information from the global satellite navigation system is unavailable, the measurement terminal accumulates the local clock count value in whole-second cycles based on the number of local clocks corresponding to the unit second, so as to form a continuous time estimation result.

[0019] As a preferred embodiment of the present invention, the cutoff frequency of the high-pass filter is set to 200kHz to retain the high-frequency components of the rising edge of the traveling wave and remove low-frequency interference.

[0020] As a preferred embodiment of the present invention, in the time difference calculation and fault location steps, the location processing platform performs correlation analysis on the traveling wave waveforms from different measurement terminals under the constraint of time stamps, and selects the time difference at the point of maximum correlation. Adding the difference in timestamps between the two terminals' trigger times, which serves as the time difference for the fault traveling wave to reach the two terminals, the distance from the fault point to one of the measurement terminals can be calculated according to the following relationship:

[0021] ;

[0022] in: The crystal oscillator clock count is used to determine the trigger time of terminal 1; The crystal oscillator clock count is used to determine the trigger time of terminal 2; For terminal 1, count the crystal oscillator clock every second; For terminal 2, count the crystal oscillator clock every second; The velocity of the traveling wave current in the cable; This indicates the distance between the two terminals.

[0023] As a preferred embodiment of the present invention, interference discrimination is performed before positioning calculation: positioning is performed only when the absolute value of the difference between the timestamps of the two terminals is less than the time it takes for the traveling wave to pass through the entire line; otherwise, it is determined to be an interference signal.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] This invention introduces a temperature-controlled crystal oscillator calibrated with GPS time information as a unified time reference for dual-end measurement terminals. This achieves high-precision time synchronization during normal satellite signal reception and maintains continuous timekeeping capability in the event of short-term GPS signal failure, relying on the stable timing characteristics of the temperature-controlled crystal oscillator. This effectively avoids the problem of inaccurate traveling wave arrival time markings caused by clock drift or synchronization interruptions, significantly improving the system's synchronization stability and positioning reliability in complex operating environments. Simultaneously, this invention performs high-pass filtering on the acquired current traveling wave signal after the traveling wave is triggered, suppressing low-frequency components with high energy content but limited contribution to positioning, highlighting the high-frequency, rapidly changing components reflecting the characteristics of the traveling wave arrival time. This makes subsequent time difference calculations based on waveform similarity or time alignment insensitive to noise and interference, thereby reducing time deviations introduced by low-frequency components and improving the accuracy and consistency of fault location results. Attached Figure Description

[0026] Figure 1 This is a flowchart of the present invention.

[0027] Figure 2 This is a fault traveling current waveform diagram captured by two terminals in an embodiment of the present invention.

[0028] Figure 3 This is a waveform diagram of the filtered fault traveling current captured by two terminals in an embodiment of the present invention.

[0029] Figure 4 This is the cross-correlation calculation curve of the original fault traveling wave signal in the embodiment of this invention.

[0030] Figure 5 This is the cross-correlation curve of the fault traveling wave signal after filtering in an embodiment of the present invention.

[0031] Figure 6 This is the error statistics result of the frequency distribution of time difference in multiple tests in the embodiments of the present invention;

[0032] Figure 7 This is the error statistics result of the probability distribution of time difference in multiple trials in the embodiments of this invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be noted that the terms "vertical," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0036] Example 1

[0037] Reference Figure 1 This embodiment provides a current traveling wave synchronous positioning method with GPS loss-of-lock fault tolerance, including the following steps:

[0038] S1. Establish a time reference by setting up measurement terminals at at least two measurement ends of the cable line. Each measurement terminal uses a temperature-controlled crystal oscillator as a local clock source and receives time information provided by the global satellite navigation system to establish a time reference of the second level or above for traveling wave positioning.

[0039] Specifically, the measurement terminal uses a temperature-controlled crystal oscillator (OCXO) as a local high-stability clock source to parse the serial port time information output by the GPS module, using this serial port time information as a time reference at the second level and above. Simultaneously, the rising edge of the second pulse signal (1PPS) output by the GPS module is used as the starting mark for the integer second. Between two adjacent second pulse signals, the clock count value of the temperature-controlled crystal oscillator is statistically analyzed to obtain the crystal oscillator clock count value within adjacent integer second periods. This establishes a local clock counting relationship for sub-second timing. While ensuring second-level time consistency, the measurement terminal constructs a sub-second time scale based on local crystal oscillator counting, providing a unified time reference for accurate time marking of subsequent traveling wave trigger moments.

[0040] S2. Mark the traveling wave trigger and time. When a cable fault generates a current traveling wave, the measurement terminal calculates the statistical amplitude characteristics of the collected current signal and compares the statistical amplitude characteristics with a preset threshold. When the trigger condition is met, the local clock count value corresponding to the trigger time is latched to form a time marker of the arrival time of the traveling wave.

[0041] Specifically, in step S2, the traveling wave signal is captured and acquired, and the measurement terminal calculates the root mean square value of the real-time acquired current signal. And set the trigger threshold according to the multiple relationship of the root mean square value. When the root mean square value exceeds the trigger threshold, a traveling wave trigger is determined, and the isothermal crystal clock count value at the corresponding trigger time is recorded. Simultaneously, the measuring terminal stores the data prior to the triggering time. microseconds until trigger time Raw traveling wave waveform data within the microsecond range is used for subsequent waveform processing and positioning calculations.

[0042] The time information below the second level corresponding to the trigger moment is determined by the relationship between the local clock count value and the crystal oscillator count corresponding to a unit second, and its representation is as follows:

[0043] ;

[0044] in, This represents the thermostatic crystal oscillator count value within adjacent whole-second cycles. To avoid false triggering caused by noise or non-fault disturbances, the trigger threshold multiple is... Settings can be configured according to actual operating conditions; to obtain complete fault traveling wave characteristics, and The configuration can be adjusted based on the sampling rate and cable length.

[0045] To further explain, in step S2, in order to avoid accidental triggering, It can be set to 5-10 to obtain the complete fault traveling wave waveform. , It can be set to 100 or 300.

[0046] S3. Timing synchronization failure fault tolerance: When the time signal of the global satellite navigation system is unavailable, the measurement terminal uses the most recent valid second-level time reference as a reference, determines the number of counts corresponding to a unit second based on the local clock count statistics within multiple adjacent whole-second cycles, and uses the number of counts to continuously calculate the subsequent traveling wave triggering time.

[0047] Specifically, step S3, GPS failure fault tolerance processing, involves using the most recently parsed serial port time information as a time base above the second level during the GPS signal loss period, and using the most recently valid second pulse as a time base below the second level, based on the previous... Average crystal oscillator count per minute As a measure of one second, sub-second time scales are calculated, and second-level and minute-level timing data are accumulated according to the number of whole second cycles.

[0048] Based on this, the count values ​​of the isothermal crystal oscillator within multiple adjacent whole-second cycles before the failure are statistically analyzed to determine the number of local clock counters corresponding to a unit second. Using the count value as a time measure, the sub-second time scale is calculated for the traveling wave triggering time generated during the failure period. The measurement terminal updates the local clock count value according to the count value corresponding to the unit second in whole-second cycles, thereby forming continuous time estimation results at the second level and above, so as to ensure the continuity and consistency of time marking during the failure of the satellite time signal.

[0049] To further explain, in step S3, due to the inherent stability of the temperature-controlled crystal oscillator, It can be set to 5, and considering the loss of system reliability when the overall error is too large, it can keep time for about 1 hour in the case of GPS lock failure, ensuring an accuracy within 100ns. Since the temperature-controlled crystal oscillator has high frequency stability, the measurement terminal can maintain acceptable timing accuracy within a preset time range in the fault-tolerant timing state of synchronization failure, so as to meet the time consistency requirements of traveling wave positioning.

[0050] S4. Upload waveform processing and data. Perform frequency domain filtering on the triggered traveling wave waveform to reduce low-frequency interference components, and upload the filtered traveling wave waveform data and corresponding time stamp information to the positioning processing platform.

[0051] Specifically, the measurement terminal performs frequency domain filtering on the traveling wave trigger waveform determined in step S3. This frequency domain filtering is a high-pass filter, used to suppress low-frequency components in the traveling wave signal that contribute little to the arrival time determination, while retaining the rapidly changing portions reflecting the arrival characteristics of the traveling wave. Simultaneously, based on the time stamp results determined in steps S2 and S3, the measurement terminal confirms the absolute timestamp of the corresponding traveling wave waveform and uploads the filtered traveling wave waveform data along with the corresponding timestamp information to the positioning processing platform.

[0052] To further explain, in step S4, high-pass filtering... It can be set to 200 to retain the high-frequency components of the rising edge in the traveling wave fault current signal and remove the low-frequency components to improve positioning accuracy. The cutoff frequency of the high-pass filter can be configured according to the cable type, sampling frequency and noise distribution characteristics to adapt to the traveling wave signal processing needs in different application scenarios.

[0053] S5. Location Time Difference Calculation and Fault: Under the constraint of the time marker, the location processing platform performs alignment analysis on the traveling wave waveforms from different measurement terminals, determines the relative time offset between the waveforms, and calculates the arrival time difference of the traveling wave based on the relative time offset, thereby realizing cable fault location.

[0054] Specifically, based on the uploaded traveling wave waveform data, the positioning processing platform performs correlation analysis on the traveling wave waveforms of different measurement terminals within the time window of the corresponding time mark to determine the alignment position between the waveforms, and combines the time offset corresponding to the alignment position with the time mark difference of each measurement terminal to obtain the time difference between the traveling wave arriving at the two measurement terminals.

[0055] Based on the aforementioned time difference, correlation calculations are performed on the waveform data uploaded by the two terminals, and the time difference at which the correlation is maximized is determined. Adding the difference in timestamps between the two terminals' trigger times, which serves as the time difference for the fault traveling wave to reach the two terminals, the distance from the fault point to one of the measurement terminals can be calculated according to the following relationship:

[0056] ;

[0057] in: The crystal oscillator clock count is used to determine the trigger time of terminal 1; The crystal oscillator clock count is used to determine the trigger time of terminal 2; For terminal 1, count the crystal oscillator clock every second; For terminal 2, count the crystal oscillator clock every second; The velocity of the traveling wave current in the cable; This indicates the distance between the two terminals.

[0058] To further clarify, the location processing platform will only perform the aforementioned fault location calculation when both measurement terminals successfully upload the corresponding traveling wave waveform data and time stamp information, and the time stamp difference is within a preset consistency range; if the consistency condition is not met, the corresponding data will be determined not to be used for fault location processing.

[0059] Specifically, the preset consistency range is determined based on the propagation speed of the traveling wave in the cable, and is used to reflect the time scale corresponding to the propagation of the traveling wave between the measurement ends, preferably... .

[0060] Reference Figure 2 The fault traveling wave current waveforms captured by the two terminals show that the original traveling wave signal exhibits obvious transient characteristics when the fault occurs. Its waveform contains a relatively steep rising edge and a relatively gentle falling edge, while also being superimposed with a certain amplitude of low-frequency components.

[0061] Reference Figure 3 The filtered fault traveling wave current waveforms captured by the two terminals show that, compared with the original waveforms, the low-frequency components in the traveling wave signal are effectively weakened after high-pass filtering, the rising edge characteristics of the waveform are more prominent, and the overall trend of change is steeper, which is beneficial for subsequent time alignment analysis based on waveform similarity.

[0062] Reference Figure 4 The cross-correlation curve of the original fault traveling wave signal is shown in the figure. It can be seen that the cross-correlation curve of the original signal is relatively flat overall, the peak position is not concentrated, and the time position corresponding to the peak has a certain uncertainty, which can easily introduce a large time deviation.

[0063] Reference Figure 5 The cross-correlation curve of the filtered fault traveling wave signal is compared to... Figure 4 It can be clearly seen that the cross-correlation curve of the traveling wave signal after filtering has a sharper peak and a clearer and more stable peak position, which makes the time offset calculated by cross-correlation more predictable.

[0064] Reference Figure 6-7 The statistical results of positioning time error obtained from multiple experiments under the same experimental conditions show that the positioning time error distribution is relatively concentrated in multiple repeated experiments, and the overall error remains within a small range, indicating that the method of the present invention has good time consistency and positioning stability in practical applications.

[0065] Based on relevant time information, the performance of the original fault traveling wave signal and the traveling wave signal after high-pass filtering in cross-correlation analysis and positioning calculation was compared. Table 1 shows that, under the same experimental conditions, when performing cross-correlation calculation based on the original traveling wave signal, the time deviation corresponding to the cross-correlation peak is relatively large, leading to a deviation of the overall positioning time deviation from the experimentally set true value. High-pass filtering reduces the error by 131 ns compared to direct filtering, demonstrating the necessity of high-pass filtering.

[0066] Table 1: Comparison of Time Alignment and Positioning Data Before and After Traveling Wave Signal Filtering

[0067]

[0068] In contrast, after high-pass filtering of the traveling wave signal, the time deviation corresponding to the cross-correlation peak is significantly reduced. The comprehensive positioning time result of the filtered signal is closer to the true time difference set in the experiment, indicating that high-pass filtering helps to weaken the interference of low-frequency components on cross-correlation calculation and improve the stability and consistency of traveling wave time alignment results.

[0069] Furthermore, by comparing the combined positioning time deviation between the original signal and the filtered signal, it can be observed that the positioning time deviation after filtering is significantly reduced compared to the unfiltered case, verifying the necessity and rationality of introducing high-pass filtering as a preprocessing step for traveling wave waveforms in the method of this invention.

[0070] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A current-traveling-wave synchronous positioning method with GPS loss-of-lock fault tolerance, characterized in that: Includes the following steps: S1. Establish a time reference by setting up measurement terminals at at least two measurement ends of the cable line. Each measurement terminal uses a temperature-controlled crystal oscillator as a local clock source and receives time information provided by the global satellite navigation system to establish a time reference of the second level or above for traveling wave positioning. S2. Mark the traveling wave trigger and time. When a cable fault generates a current traveling wave, the measurement terminal calculates the statistical amplitude characteristics of the collected current signal and compares the statistical amplitude characteristics with a preset threshold. When the trigger condition is met, the local clock count value corresponding to the trigger time is latched to form a time marker of the arrival time of the traveling wave. S3. Timing synchronization failure fault tolerance: When the time signal of the global satellite navigation system is unavailable, the measurement terminal uses the most recent valid second-level time reference as a reference, determines the number of counts corresponding to a unit second based on the local clock count statistics within multiple adjacent whole-second cycles, and uses the number of counts to continuously calculate the subsequent traveling wave triggering time. S4. Upload waveform processing and data. Perform frequency domain filtering on the triggered traveling wave waveform to reduce low-frequency interference components, and upload the filtered traveling wave waveform data and corresponding time stamp information to the positioning processing platform. S5. Location Time Difference Calculation and Fault: Under the constraint of the time marker, the location processing platform performs alignment analysis on the traveling wave waveforms from different measurement terminals, determines the relative time offset between the waveforms, and calculates the arrival time difference of the traveling wave based on the relative time offset, thereby realizing cable fault location.

2. The current traveling wave synchronous positioning method with GPS loss-of-lock fault tolerance according to claim 1, characterized in that: The measurement terminal analyzes the serial port time information output by the global navigation satellite system module and uses it as a time reference at the second level and above; the rising edge of the second pulse signal output by the global navigation satellite system module is used as the starting mark of the whole second. Between two adjacent second pulse signals, the clock count value of the local temperature-controlled crystal oscillator is counted to obtain the crystal oscillator clock count value within adjacent integer second periods. This establishes a local clock counting relationship for sub-second timing.

3. The current traveling wave synchronous positioning method with GPS loss-of-lock fault tolerance according to claim 2, characterized in that: In the traveling wave triggering and time-marking step, the statistical amplitude characteristic is the root mean square value of the acquired current signal within a preset time window. The preset threshold is based on the multiple relationship of the root mean square value. Sure.

4. The current traveling wave synchronous positioning method with GPS loss-of-lock fault tolerance according to claim 3, characterized in that: When the statistical amplitude characteristic meets the triggering condition, the measurement terminal latches the local clock count value at the corresponding triggering time. The count value is used as the basis for determining the time information below the second level.

5. A current traveling wave synchronous positioning method with GPS loss-of-lock fault tolerance as described in claim 2, characterized in that: In the synchronization failure fault-tolerant timing step, the most recent valid second pulse signal is used as the starting reference for a time interval of less than a second, based on a preset duration before the loss of lock. The average local clock count is used as the number of counts per second for sub-second time scale calculations.

6. The current traveling wave synchronous positioning method with GPS loss-of-lock fault tolerance according to claim 5, characterized in that: During periods when global satellite navigation system time information is unavailable, the measurement terminal accumulates the local clock count value in whole-second cycles based on the number of local clocks corresponding to the unit of second, in order to form a continuous time estimation result.

7. The current traveling wave synchronous positioning method with GPS loss-of-lock fault tolerance according to claim 1, characterized in that: The cutoff frequency of the high-pass filter is set to 200kHz to retain the high-frequency components of the rising edge of the traveling wave and remove low-frequency interference.

8. The current traveling wave synchronous positioning method with GPS loss-of-lock fault tolerance according to claim 1, characterized in that: In the time difference calculation and fault location steps, the location processing platform performs correlation analysis on traveling wave waveforms from different measurement terminals under the constraint of time stamps, and identifies the time difference at the point of maximum correlation. Adding the difference in timestamps between the two terminals' trigger times, which serves as the time difference for the fault traveling wave to reach the two terminals, the distance from the fault point to one of the measurement terminals can be calculated according to the following relationship: ； in: The crystal oscillator clock count is used to determine the trigger time of terminal 1; The crystal oscillator clock count is used to determine the trigger time of terminal 2; For terminal 1, count the crystal oscillator clock every second; For terminal 2, count the crystal oscillator clock every second; The velocity of the traveling wave current in the cable; This indicates the distance between the two terminals.

9. A current traveling wave synchronous positioning method with GPS loss-of-lock fault tolerance according to claim 1, characterized in that: Before positioning calculation, interference detection is performed: positioning is only performed when the absolute value of the difference between the timestamps of the two terminals is less than the time it takes for the traveling wave to pass through the entire line; otherwise, it is judged as an interference signal.

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