A low-power time synchronization method suitable for traveling wave positioning

Abstract

The present invention relates to a low-power time synchronization method suitable for traveling wave positioning, which is specifically as follows: first, in a traveling wave positioning device, no time synchronization operation is usually performed; a global crystal oscillator counter is maintained in the device, and when a fault is detected, a fault recording is performed and the crystal oscillator count value of the traveling wave data head is recorded; after the fault recording is completed, the device performs the first time synchronization and records the time value and crystal oscillator count value after the first synchronization; the device delays for a period of time to perform the second time synchronization and records the time value and crystal oscillator count value after the second synchronization; the time value of the first data of the traveling wave data and the actual sampling interval of the traveling wave data are calculated based on the above recorded data. Finally, accurate fault positioning is completed according to the conventional wave head arrival time method. The present invention reduces the frequency of time synchronization, thereby reducing the power consumption of the system; the method is also highly adaptable and easy to implement, and is suitable for various traveling wave positioning devices.

Description

Technical Field

[0001] The present invention belongs to the technical field of power systems, and in particular relates to a low-power time synchronization method suitable for traveling wave positioning. Background Art

[0002] In power systems, fault detection and location in distribution lines are crucial for ensuring power supply reliability and system stability. Traveling wave positioning technology relies on the near-speed of light, measuring the propagation time of traveling waves to determine the location of faults or targets. However, this high-precision positioning requires extremely high time synchronization accuracy, typically reaching 0.1 microseconds.

[0003] To meet this precision requirement, existing systems must perform regular time synchronization operations at intervals of seconds to ensure accurate positioning data. Due to installation requirements, traveling wave positioning devices are often powered only by electric field or solar energy. However, frequent time synchronization operations significantly increase system power consumption, significantly limiting the practicality of traveling wave positioning and limiting the system's reliability and stability. This high power consumption is particularly problematic in remote or outdoor areas with limited energy supply.

[0004] To address this challenge, this paper proposes a low-power time synchronization method that aims to significantly reduce system power consumption while maintaining high-precision time synchronization. The core concept of this method is to avoid any time synchronization operations during non-fault periods, thereby reducing energy consumption during normal system operation. Time synchronization is initiated only after a fault is detected and fault recording is complete, ensuring the accuracy of fault data. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and propose a low-power time synchronization method suitable for traveling wave positioning, aiming to solve the challenge of reducing system power consumption while maintaining high-precision time synchronization. In the traveling wave positioning system, since the speed of the traveling wave is close to the speed of light, the requirement for time synchronization accuracy is extremely high (reaching 0.1 microseconds). In order to meet this accuracy requirement, the existing technology has to perform time synchronization operations frequently, resulting in a contradiction between limited energy supply of the device and excessive power consumption of the system. In response to this problem, the present invention proposes an optimized time synchronization strategy, which greatly reduces the frequency of time synchronization while ensuring the accuracy of time synchronization, thereby significantly reducing system power consumption.

[0006] The advantage of the low-power time synchronization method of the present invention is that it only starts time synchronization after a fault occurs and the recording is completed, which significantly reduces the frequency of time synchronization and thus reduces the power consumption of the system; at the same time, the data obtained through multiple time synchronizations are used to accurately calculate the timestamp of the traveling wave data through the linear least squares method, avoiding timing errors caused by crystal oscillator deviations due to temperature changes, etc., thereby ensuring the accuracy of time synchronization; finally, the actual sampling interval of the traveling wave data is also sent to the traveling wave positioning master station, so that the traveling wave positioning master station can resample through cubic spline oversampling interpolation and unify the traveling wave waveforms of each device to the same target sampling rate, thereby completing a more accurate time difference calculation and ensuring the accuracy of traveling wave positioning. In addition, this method is also highly adaptable and easy to implement, and is suitable for various traveling wave positioning devices.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows: a low-power time synchronization method suitable for traveling wave positioning, the method comprising the following steps:

[0008] Step 1: In the traveling wave positioning device, no time synchronization operation is usually performed to reduce system power consumption;

[0009] Step 2: A global crystal oscillator counter is maintained in the device, and the resolution of the global crystal oscillator counter is not less than 10ns;

[0010] Step 3: When a fault is detected, perform fault recording and record the crystal oscillator count value corresponding to the first data of the traveling wave data;

[0011] Step 4: After completing the fault recording, the device shall perform time synchronization at least twice and record the time value and crystal oscillator count value after each synchronization; the time interval between each two adjacent synchronizations shall be determined according to the travel time deviation of the crystal oscillator, and the empirical value shall be greater than 5 minutes so that the travel time deviation per unit time in the device can be accurately calculated.

[0012] Step 5: Based on the recorded count value of the first data of the traveling wave, the moment of each time synchronization and the crystal oscillator count value, the linear least squares method is used to predict the change trend of the crystal oscillator count value, and the moment of the first data of the traveling wave and the actual sampling interval of the traveling wave data are calculated; (1) Assuming that the number of time synchronizations is N, the moment value and crystal oscillator count value recorded at the i-th synchronization are t[i] and c[i] respectively;

[0013] (2) Calculate the fitting coefficients m and n according to the linear least squares method,

[0014]

[0015]

[0016] n=t_avg-m×c_avg,

[0017] Among them, t_avg is the average value at the time, c_avg is the average value of the crystal oscillator count, m, n

[0018] is the fitting coefficient of the time series relationship between the crystal oscillator count value and the timestamp,

[0019] (3) Calculate the first data moment of the traveling wave:

[0020] t_waveStart=c_waveStart×m+n,

[0021] Where c_waveStart is the crystal oscillator count value of the traveling wave head

[0022] (4) The fitting coefficient m is taken as the actual sampling interval.

[0023] Step 6: Synchronously send the traveling wave waveform data, the first data time of the traveling wave and the actual sampling interval of the device to the traveling wave positioning master station;

[0024] Step 7: After receiving the traveling wave waveform data, the first data time of the traveling wave, and the sampling interval of the traveling wave waveform, the traveling wave positioning master station first uses cubic spline oversampling interpolation on the traveling wave data; then resamples it according to the target sampling rate to obtain the traveling wave waveform data for final positioning;

[0025] The target frequency of the cubic spline oversampling is not less than 100 MHz, and the process is as follows:

[0026] 1) Construct a cubic spline: For every four consecutive data points of the original data, construct a cubic spline polynomial S, ensuring that the spline is continuous at the data points and continuous in the second-order derivative. The i-th data point is represented by (x i ,y i ),

[0027] 2)S i (x) = a i +b i (xx i )+c i (xx i ) 2 +d i (xx i ) 3 ,

[0028] The coefficient is calculated as follows:

[0029] h=x i+1 -x i ,

[0030] a i =y i ,

[0031]

[0032] Where h is the difference between adjacent data points, a i 、b i 、c i d i are the coefficients of the cubic spline polynomial respectively;

[0033] 3) Determine the interpolation sampling point locations based on the target oversampling frequency, which are located between the original data points.

[0034] 4) For the new sampling point x between the i-th and i+3 original data points, use the cubic spline polynomial S to calculate the interpolation

[0035] z(x)=a i +b i (xx i )+c i (xx i ) 2 +d i (xx i ) 3 ,

[0036] Where z is the data after oversampling interpolation, x is the position of the new sampling point, and a i 、b i 、c i d i are the coefficients of the cubic spline polynomial respectively;

[0037] 5) Combine all calculated interpolation points z(x) into new oversampled data.

[0038] Step 8: The traveling wave positioning master station uses the conventional wave head arrival time method to complete accurate fault location based on the resampled traveling wave waveform data.

[0039] An electronic device comprises a memory, a processor and a computer program stored in the memory and runnable on the processor, wherein when the processor executes the program, the method for low-power time synchronization suitable for traveling wave positioning is implemented.

[0040] Compared with the prior art, the present invention has the following significant advantages:

[0041] 1. This solution significantly reduces system power consumption: Compared to the frequent timed synchronization of traditional devices, this solution does not perform any time synchronization operations during non-fault periods, significantly reducing the system's energy consumption during normal operation. This design allows the traveling wave positioning device to operate in a low-power state most of the time, and only initiates the time synchronization process after a fault is detected and the fault recording is completed. This strategy effectively balances the need for time synchronization and system power consumption, making the entire system more energy-efficient.

[0042] 2. This solution maintains high-precision time synchronization: Although the frequency of time synchronization is reduced, the present invention uses data acquired through multiple time synchronizations and the linear least squares method to accurately calculate the current crystal oscillator period, thereby ensuring the accuracy of time synchronization. This strategy not only avoids crystal oscillator deviations caused by temperature changes, but also ensures the accuracy of traveling wave positioning by accurately calculating the first data moment of the traveling wave and the actual sampling interval.

[0043] 3. This solution improves fault location accuracy: The present invention also sends the actual sampling interval to the traveling wave positioning master station. The traveling wave positioning master station reconstructs the traveling wave waveform through cubic spline oversampling interpolation, and then resamples it into traveling wave data at the target sampling rate according to the target sampling rate. This solves the error caused by crystal oscillator deviation between different traveling wave positioning devices and improves the fault location accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0046] The following descriptions of the embodiments refer to the accompanying drawings to illustrate specific embodiments in which the present invention may be implemented.

[0047] Example: Figure 1 A low-power time synchronization method suitable for traveling wave positioning is shown, and the method includes the following steps:

[0048] (1) In the traveling wave positioning device, no time synchronization operation is usually performed to reduce system power consumption;

[0049] (2) A global crystal oscillator counter is maintained in the device, and the resolution of the global crystal oscillator counter is not less than 10ns;

[0050] (3) When a fault is detected, perform fault recording and record the crystal oscillator count value corresponding to the first data of the traveling wave data;

[0051] (4) After completing the fault recording, the device shall perform time synchronization for no less than 2 times and record the time value and crystal oscillator count value after each synchronization; the time interval between each two adjacent synchronizations shall be determined according to the travel time deviation of the crystal oscillator, and the empirical value shall be greater than 5 minutes, so that the travel time deviation per unit time in the device can be accurately calculated.

[0052] (5) Based on the recorded count value of the first data of the traveling wave, the moment of each time synchronization and the crystal oscillator count value, the linear least squares method is used to predict the change trend of the crystal oscillator count value, and the moment of the first data of the traveling wave and the actual sampling interval of the traveling wave data are calculated; assuming that the number of time synchronizations is N, the moment value and crystal oscillator count value recorded for the i-th synchronization are t[i] and c[i] respectively;

[0053] The fitting coefficients m and n are calculated according to the linear least squares method.

[0054]

[0055] n=t_avg-m×c_avg,

[0056] Among them, t_avg is the average value at the moment, c_avg is the average value of the crystal oscillator count, m and n are the time series relationship fitting coefficients of the crystal oscillator count value and the timestamp,

[0057] Calculate the first data moment of the traveling wave:

[0058] t_waveStart=c_waveStart×m+n,

[0059] Where c_waveStart is the crystal oscillator count value of the traveling wave head

[0060] Let the fitting coefficient m be the actual sampling interval.

[0061] (6) The traveling wave waveform data, the first data moment of the traveling wave and the actual sampling interval of the device are synchronously sent to the traveling wave positioning main station; (7) After the traveling wave positioning main station receives the traveling wave waveform data, the first data moment of the traveling wave and the sampling interval of the traveling wave waveform, it first uses cubic spline oversampling interpolation to interpolate the traveling wave data, and then resamples it according to the target sampling rate (not less than 10MHz) to obtain the traveling wave waveform data for final positioning.

[0062] The target frequency of the cubic spline oversampling is not less than 100 MHz, and the process is as follows:

[0063] Construct a cubic spline: For every four consecutive data points of the original data, construct a cubic spline polynomial S, ensuring that the spline is continuous at the data points and continuous in the second-order derivative. The i-th data point is represented by (x i ,y i ),

[0064] S i (x) = a i +b i (xx i )+c i (xx i ) 2 +d i (xx i ) 3 ,

[0065] The coefficient is calculated as follows:

[0066] h=x i+1 -x i ,

[0067] a i =y i ,

[0068]

[0069]

[0070] Where h is the difference between adjacent data points, a i 、b i 、c i d i are the coefficients of the cubic spline polynomial respectively;

[0071] The interpolation sampling points are determined based on the target oversampling frequency, and these points are located between the original data points.

[0072] For the new sampling point X between the i-th and i+3 original data points, use the cubic spline polynomial S to calculate the interpolation

[0073] z(x)=a i +b i (xx i )+c i (xx i ) 2 +d i (xx i ) 3 ,

[0074] Where z is the data after oversampling interpolation, x is the position of the new sampling point, and a i 、b i 、ci d i are the coefficients of the cubic spline polynomial respectively;

[0075] Combine all calculated interpolation points z(x) into new oversampled data.

[0076] (8) The traveling wave positioning master station uses the conventional wave head arrival time method to complete accurate fault positioning based on the resampled traveling wave waveform data.

[0077] The technical means disclosed in the solution of the present invention are not limited to the technical means disclosed in the above-mentioned embodiment, but also include technical solutions composed of any combination of the above technical features.

Claims

1. A low-power time synchronization method suitable for traveling wave positioning, characterized in that: The method comprises the following steps: Step 1: In the traveling wave positioning device, no time synchronization operation is usually performed to reduce system power consumption. Step 2: Maintain a global crystal oscillator counter in the device. Step 3: When a fault is detected, perform fault recording and record the crystal oscillator count value corresponding to the first data of the traveling wave data. Step 4: After completing the fault recording, the device performs time synchronization at least twice and records the time value and crystal oscillator count value after each synchronization; Step 5: Based on the recorded traveling wave first data count value, the time of each time synchronization and the crystal oscillator count value, the linear least squares method is used to predict the change trend of the crystal oscillator count value, and the time of the first data of the traveling wave and the actual sampling interval of the traveling wave data are calculated. Step 6: Synchronously send the traveling wave waveform data, the first data time of the traveling wave and the actual sampling interval of the device to the traveling wave positioning master station. Step 7: The traveling wave positioning master station first uses cubic spline oversampling interpolation to the traveling wave data according to each traveling wave waveform moment and the actual sampling interval of the traveling wave data, and then resamples it according to the target sampling rate to obtain the traveling wave waveform data for final positioning. Step 8: The traveling wave positioning master station uses the conventional wave head arrival time method to accurately locate the fault based on the resampled traveling wave waveform data. The resolution of the global crystal oscillator counter is not less than 10ns to ensure the accuracy of time synchronization; After completing the fault recording, the device shall be synchronized at least twice; the time interval between each two adjacent synchronizations shall be determined according to the travel time deviation of the crystal oscillator, and the empirical value shall be greater than 5 minutes, so that the travel time deviation per unit time in the device can be accurately calculated; The method of calculating the time of the traveling wave head and the actual sampling interval of the traveling wave data by the linear least squares method is: (1) Assuming that the number of time synchronizations is N, the time value and crystal oscillator count value recorded in the i-th synchronization are t[i] and c[i] respectively; (2) Calculate the fitting coefficients m and n according to the linear least squares method, n=t_avg-m×c_avg Among them, t_avg is the average value at the moment, c_avg is the average value of the crystal oscillator count, m and n are the time series relationship fitting coefficients of the crystal oscillator count value and the timestamp, (3) Calculate the first data moment of the traveling wave: t_waveStart=c_waveStart×m+n Where c_waveStart is the crystal oscillator count value of the traveling wave head (4) Taking the fitting coefficient m as the actual sampling interval; After receiving the traveling wave waveform data, the first data moment of the traveling wave, and the sampling interval of the traveling wave waveform, the traveling wave positioning master station first uses cubic spline oversampling interpolation on the traveling wave data, and then resamples according to the target sampling rate; And use the reconstructed traveling wave data to locate the fault. The target frequency of the cubic spline oversampling is not less than 100 MHz, and the process is as follows: 1) Construct a cubic spline: For every four consecutive data points of the original data, construct a cubic spline polynomial S, ensuring that the spline is continuous at the data points and continuous in the second-order derivative. The i-th data point is represented by (x i ,y i ), 2)S i (x)=a i +b i (x-x i )+c i (x-x i ) 2 +d i (x-x i ) 3 The coefficient is calculated as follows: h=x i+1 -x i to i =and i Where h is the difference between adjacent data points, a i 、b i 、c i d i Three samples were The coefficients of the polynomials; 3) Determine the interpolation sampling point locations based on the target oversampling frequency, which are located between the original data points. 4) For the new sampling point x between the i-th and i+3 original data points, use the cubic spline polynomial S to calculate the interpolation z(x)=a i +b i (x-x i )+c i (x-x i ) 2 +d i (x-x i ) 3 Where z is the data after oversampling interpolation, x is the position of the new sampling point, and a i 、b i 、c i d i are the coefficients of the cubic spline polynomial respectively; 5) Combine all calculated interpolation points z(x) into new oversampled data.

2. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the low-power time synchronization method applicable to traveling wave positioning as described in claim 1 is implemented.

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