Power transmission line double-end traveling wave fault positioning method and device independent of satellite time synchronization

Abstract

The invention discloses a power transmission line double-end traveling wave fault positioning method and device independent of satellite time synchronization. The method comprises the steps that when it is determined that a power transmission line breaks down, fault initial traveling waves are acquired, and a first power frequency traveling wave phasor corresponding to a first fault detection device and a second power frequency traveling wave phasor corresponding to a second fault detection device are determined; determining an additional phase angle difference between the first power frequency traveling wave phasor and the second power frequency traveling wave phasor, the additional phase angle difference being used for representing clock asynchronism between the first fault detection device and the second fault detection device; the phase angle difference of the power frequency traveling wave phasor caused by the time difference of the fault initial traveling waves is detected by the first fault detection device and the second fault detection device; and determining the fault occurrence position of the power transmission line according to the additional phase angle difference, the line length of the power transmission line between the first fault detection device and the second fault detection device and the wave velocity of the traveling wave. According to the invention, accurate positioning of the fault occurrence position in the power transmission line can be realized without satellite time synchronization.

Description

Technical Field

[0001] The present application belongs to the technical field of relay protection for electric power systems, and in particular, relates to a method and device for locating double-end traveling wave faults in power transmission lines that do not rely on satellite timing. Background Art

[0002] Fault location is an important part of modern power system operation. Accurate fault location is an effective means to accelerate the recovery of transmission line faults and reduce power outage time. Traveling wave positioning has the characteristics of high accuracy, fast response, and no influence from system parameters. It is an important way to achieve high-precision fault location.

[0003] In order to improve the accuracy of fault location, in related technologies, two-terminal ranging is usually used to locate the fault location of the transmission line. Two-terminal ranging sets measurement devices at both ends of the transmission line, and completes the ranging by calculating the time difference between the initial fault wave reaching the two ends of the transmission line. However, the implementation of the two-terminal traveling wave ranging solution requires strict time synchronization at both ends of the transmission line. Currently, satellite timing is usually used to achieve time synchronization at both ends of the transmission line.

[0004] In the scheme of locating faults on transmission lines using the dual-end ranging method, satellite signals need to be obtained. This method requires additional antennas and hardware, which increases the cost of fault location and is not available in substations that are not equipped with satellite timing systems. In addition, there are stability issues with satellite signals. In extreme weather, electromagnetic interference, antenna damage, human attacks and other scenarios, satellite timing may cause timing errors and signal loss, which affects the reliability of the traveling wave ranging system and reduces the accuracy of transmission line fault location. Summary of the invention

[0005] The embodiments of the present application provide a method and device for locating double-end traveling wave faults in a power transmission line without relying on satellite timing, which can accurately locate the location of a fault in a power transmission line without the need for satellite timing.

[0006] In a first aspect, an embodiment of the present application provides a method for locating a two-end traveling wave fault in a power transmission line that does not rely on satellite timing, the method comprising: when determining that a fault occurs in the transmission line, obtaining an initial traveling wave of the fault, wherein the initial traveling wave of the fault is a traveling wave transmitted in the transmission line when the fault occurs in the transmission line; determining a first power frequency traveling wave phasor corresponding to the initial traveling wave of the fault detected by a first fault detection device, and a second power frequency traveling wave phasor corresponding to the initial traveling wave of the fault detected by a second fault detection device, wherein the first fault detection device and the second fault detection device are respectively located at two ends of the transmission line. end; determining an additional phase angle difference between the first power frequency traveling wave phasor and the second power frequency traveling wave phasor, wherein the additional phase angle difference is used to characterize the phase angle difference between the first power frequency traveling wave phasor and the second power frequency traveling wave phasor caused by the clock asynchronism between the first fault detection device and the second fault detection device, and the time difference between the first fault detection device and the second fault detection device in detecting the initial traveling wave of the fault; determining the fault location of the transmission line according to the additional phase angle difference, the line length of the transmission line between the first fault detection device and the second fault detection device, and the wave speed of the traveling wave transmitted in the transmission line.

[0007] In the second aspect, an embodiment of the present application provides a two-end traveling wave fault locating device for a transmission line that does not rely on satellite timing, and the device includes: an initial traveling wave acquisition module, which is used to acquire the fault initial traveling wave when it is determined that a fault occurs in the transmission line, wherein the fault initial traveling wave is a traveling wave transmitted in the transmission line when a fault occurs in the transmission line; a phasor determination module, which is used to determine the first power frequency traveling wave phasor corresponding to the fault initial traveling wave detected by the first fault detection device, and the second power frequency traveling wave phasor corresponding to the fault initial traveling wave detected by the second fault detection device, wherein the first fault detection device and the second fault detection device are respectively located at the transmission line. two ends; a phase angle determination module, used to determine the additional phase angle difference between the first power frequency traveling wave phasor and the second power frequency traveling wave phasor, wherein the additional phase angle difference is used to characterize the phase angle difference between the first power frequency traveling wave phasor and the second power frequency traveling wave phasor caused by the clock asynchronism between the first fault detection device and the second fault detection device, and the time difference between the first fault detection device and the second fault detection device in detecting the initial traveling wave of the fault; a fault location module, used to determine the fault location of the transmission line according to the additional phase angle difference, the line length of the transmission line between the first fault detection device and the second fault detection device, and the wave speed of the traveling wave transmitted in the transmission line.

[0008] In a third aspect, an embodiment of the present application provides an electronic device comprising: a processor and a memory storing computer program instructions; when the processor executes the computer program instructions, the method for locating two-end traveling wave faults in a transmission line that does not rely on satellite timing as described in the first aspect is implemented.

[0009] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium having computer program instructions stored thereon. When the computer program instructions are executed by a processor, the method for locating two-end traveling wave faults in a transmission line that does not rely on satellite timing as described in the first aspect is implemented.

[0010] In a fifth aspect, an embodiment of the present application provides a computer program product. When the instructions in the computer program product are executed by a processor of an electronic device, the electronic device executes the two-end traveling wave fault location method for transmission lines that does not rely on satellite timing as described in the first aspect.

[0011] It can be seen from the above content that when the scheme provided by the present application is used to locate the fault of the transmission line, the fault location of the transmission line is located according to the initial fault traveling wave detected by the fault detection devices at both ends of the transmission line and the power frequency traveling wave phasor before the fault, and the additional phase angle difference of the power frequency traveling wave phasor can reflect the detection time difference of the initial fault traveling wave caused by the asynchronous clock of the fault detection devices at both ends of the transmission line. Therefore, in the present application, when locating the fault of the transmission line, it is only necessary to determine the phase angle difference of the power frequency traveling wave phasor detected by the two fault detection devices, without the need to synchronize the clocks of the two fault detection devices, eliminating the dependence of the fault location of the transmission line on satellite timing, solving the problem of poor transmission line fault location accuracy caused by satellite timing in the related art, thereby improving the fault location accuracy of the transmission line. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solution of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0013] Figure 1 It is a flowchart of a method for locating a double-terminal traveling wave fault on a power transmission line that does not rely on satellite timing, provided by an embodiment of the present application;

[0014] Figure 2 is a schematic diagram of a double-terminal traveling wave fault location measurement provided by an embodiment of the present application;

[0015] Figure 3 It is a schematic diagram of the clock representation relationship of a double-terminal traveling wave ranging system provided by an embodiment of the present application;

[0016] Figure 4 is a schematic diagram of a double-terminal traveling wave fault location measurement provided by an embodiment of the present application;

[0017] Figure 5This is a diagram of an electromagnetic transient simulation model of an AC power transmission system provided by an embodiment of the present application;

[0018] Figure 6 is a schematic diagram of a frequency-variable parameter model tower structure provided by an embodiment of the present application;

[0019] Figure 7 is a waveform diagram of a traveling wave without time pre-synchronization provided by an embodiment of the present application;

[0020] Figure 8 is a waveform diagram of a traveling wave after time pre-synchronization provided by an embodiment of the present application;

[0021] Fig. 9 is a distribution diagram of positioning result errors in all simulation examples provided in one embodiment of the present application;

[0022] Fig.10 is a distance measurement error distribution diagram under different sampling frequencies provided by an embodiment of the present application;

[0023] Fig.11 is a schematic structural diagram of a transmission line double-end traveling wave fault location device that does not rely on satellite timing provided by another embodiment of the present application;

[0024] Fig.12 It is a structural diagram of an electronic device provided in yet another embodiment of the present application. DETAILED DESCRIPTION

[0025] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0026] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0027] For ease of understanding, before explaining the solution provided in the present application, the background of the solution provided in the present application is first explained.

[0028] At present, the fault location of the transmission line can be achieved by traveling wave fault ranging. The traveling wave fault ranging method mainly includes single-end ranging method and double-end ranging method. The single-end ranging method uses a measuring device located on one side of the transmission line to locate the fault location on the transmission line. It has the advantages of not relying on communication and low investment cost, but it needs to detect the reflected wave head of the fault point on the transmission line. It is easily interfered in the presence of adjacent short lines and near-end faults, and the accuracy is not high. In the double-end ranging method, it is necessary to set measuring devices at both ends of the transmission line to locate the fault location on the transmission line by calculating the time difference between the initial traveling wave of the fault and the two ends of the transmission line. This method only needs to detect the wave head of the initial traveling wave of the fault, and does not need to identify the reflected wave head of the fault point. However, the double-end ranging method needs to ensure that the measuring devices at both ends of the transmission line have strict time synchronization. At present, the clock of the measuring device is usually synchronized by satellite time synchronization, for example, using the Beidou satellite system or GPS (Global Positioning System).

[0029] However, in practical applications, on the one hand, obtaining satellite signals requires additional antennas and hardware, which increases the cost of fault location, and cannot be applied to substations that are not equipped with satellite timing systems. On the other hand, satellite signals have stability issues. In scenarios such as extreme weather, electromagnetic interference, antenna damage, and human attacks, satellite timing may have timing errors, signal loss, and other problems, thus affecting the reliability of the traveling wave ranging system.

[0030] To solve the above problems, in related technologies, the fault location of power transmission lines is usually achieved under the assumption that the communication delay is stable and estimable. However, the actual delay estimation accuracy is usually affected by multiple factors such as communication conditions and hardware processing speed, which in turn affects the accuracy of two-terminal ranging. In addition, this solution also has certain requirements for hardware, which increases the system complexity and equipment development costs.

[0031] In addition, in the related art, dual-end ranging can also be achieved based on the synchronization of the zero-crossing time of the voltage sampling waveform at both ends, but the detection of the zero-crossing moment is susceptible to interference such as hardware zero drift and noise. In addition, in the related art, it can be assumed that the second wave head after the initial wave head comes from the reflection of the fault point or the opposite end busbar reflection, so that the fault location of the transmission line can be determined, but when there are adjacent lines, the above assumption does not hold, resulting in the failure of the above solution.

[0032] Based on the above-mentioned related technologies, it can be known that in the related technologies, the research on two-end traveling wave ranging usually only focuses on the propagation law of the high-frequency initial traveling wave and its reflected wave after the fault occurs, but pays less attention to the propagation characteristics of the steady-state power frequency traveling wave before the fault. In fact, the traveling waves along the transmission line have broadband characteristics, and the steady-state power frequency traveling waves before the fault also satisfy the traveling wave propagation law. Based on this, this application is based on the fault traveling wave theory, comprehensively utilizing the arrival time of the initial traveling wave of the fault and the power frequency traveling wave phasor before the fault, and proposes a two-end traveling wave fault location method for the transmission line that does not rely on satellite synchronization.

[0033] The following is an introduction to the transmission line double-end traveling wave fault location method that does not rely on satellite timing provided in an embodiment of the present application.

[0034] Figure 1 The figure shows a schematic flow chart of a method for locating a two-terminal traveling wave fault in a power transmission line that does not rely on satellite timing according to an embodiment of the present application. Figure 1 As shown, the method comprises the following steps:

[0035] Step S101: when it is determined that a fault occurs on the power transmission line, an initial traveling wave of the fault is obtained.

[0036] Step S102, determining a first power frequency traveling wave phasor corresponding to the initial fault traveling wave detected by the first fault detection device, and a second power frequency traveling wave phasor corresponding to the initial fault traveling wave detected by the second fault detection device.

[0037] It should be noted that in the process of transmitting electric energy through transmission lines, electric energy propagates in the form of electromagnetic waves. Traveling waves are a transmission state of plane waves on transmission lines, whose amplitude changes exponentially along the propagation direction, and whose phase changes linearly along the transmission line. A phasor is a vector used in electronic engineering to represent the magnitude and phase of a sinusoidal quantity. A phasor consists of the effective value and initial phase of a sinusoidal voltage. The modulus of a complex number represents the maximum value of the voltage, and its argument represents the initial phase of the voltage.

[0038] In addition, it should be noted that in the embodiment of the present application, the first fault detection device and the second fault detection device are respectively located at the two ends of the transmission line, and the initial fault traveling wave is the traveling wave transmitted in the transmission line when the transmission line fails. That is, the present application adopts a double-end traveling wave ranging method to realize the fault location of the transmission line.

[0039] It is worth noting that regardless of whether the transmission line is faulty or not, traveling waves will be transmitted in the transmission line, but the traveling waves transmitted by the faulty transmission line are different from the industrial frequency traveling waves transmitted by the non-faulty transmission line. Therefore, in the embodiment of the present application, the fault detection devices deployed at both ends of the transmission line can determine whether a fault has occurred in the transmission line by detecting the characteristics of the industrial frequency traveling waves, wherein, after the transmission line fails, the traveling wave detected for the first time by the fault detection device is the fault initial traveling wave.

[0040] Step S103, determining an additional phase angle difference between the first power frequency traveling wave phasor and the second power frequency traveling wave phasor.

[0041] In step S103, the additional phase angle difference is used to characterize the phase angle difference between the first power frequency traveling wave phasor and the second power frequency traveling wave phasor caused by the clock asynchronism between the first fault detection device and the second fault detection device, and the time difference between the first fault detection device and the second fault detection device in detecting the initial fault traveling wave.

[0042] It should be noted that, since the additional phase angle difference can reflect time, after determining the additional phase angle difference, the relative time difference of the initial fault traveling waves detected by the fault detection devices at both ends of the transmission line can be determined based on the additional phase angle difference, and then the fault location of the transmission line can be determined based on the relative time difference.

[0043] As an example, after the fault detection devices at both ends of the transmission line detect the power frequency traveling wave phasor corresponding to the initial traveling wave of the fault, the relationship between the phase angles of the two power frequency traveling wave phasors can be determined based on the power frequency traveling wave phasors at both ends of the transmission line, and then the additional phase angle difference between the two power frequency traveling wave phasors can be obtained.

[0044] Step S104, determining the fault location of the transmission line according to the additional phase angle difference, the line length of the transmission line between the first fault detection device and the second fault detection device, and the wave speed of the traveling wave transmitted in the transmission line.

[0045] In step S104, after the additional phase angle difference is determined, the fault location of the transmission line can be determined according to formula (1):

[0046]

[0047] In formula (1), d is the distance between the fault location of the transmission line and the first fault detection device; l is the line length of the transmission line between the first fault detection device and the second fault detection device; is the additional phase angle difference; v is the transmission speed of the traveling wave in the transmission line, that is, the wave speed mentioned above; T is the power frequency period.

[0048] It can be seen from formula (1) that, through the method provided in the embodiment of the present application, it is only necessary to determine the additional phase angle difference of the power frequency traveling wave phasor at both ends of the transmission line and the length and wave speed of the transmission line to determine the fault location of the transmission line without the need for satellite timing, thereby eliminating the dependence of the fault location of the transmission line on satellite timing and solving the problem of poor transmission line fault location accuracy caused by satellite timing in the related art.

[0049] Based on the scheme defined by the above steps S101 to S104, it can be known that when the scheme provided by the present application is used to locate the fault of the transmission line, the fault location of the transmission line is located according to the initial fault traveling wave detected by the fault detection devices at both ends of the transmission line and the power frequency traveling wave phasor before the fault, and the additional phase angle difference of the power frequency traveling wave phasor can reflect the detection time difference of the initial fault traveling wave caused by the asynchronous clock of the fault detection devices at both ends of the transmission line. Therefore, in the present application, when locating the fault of the transmission line, it is only necessary to determine the phase angle difference of the power frequency traveling wave phasor detected by the two fault detection devices, without the need to synchronize the clocks of the two fault detection devices, thereby eliminating the dependence of the fault location of the transmission line on satellite timing, solving the problem of poor transmission line fault location accuracy caused by satellite timing in the related art, thereby improving the fault location accuracy of the transmission line.

[0050] The following is a detailed explanation of each step of the method provided in the embodiments of the present application.

[0051] First, the fault traveling wave theory is the basis of the double-terminal traveling wave fault location technology. Figure 2In the principle diagram of the double-terminal traveling wave fault location shown in the figure, at the moment of the fault between the transmission lines MN, the initial fault traveling wave is generated at the fault point F and propagates to both sides of the transmission line at the wave speed. Figure 2 In the embodiment of the present invention, M and N correspond to the first fault detection position where the first fault detection device is located and the second fault detection position where the second fault detection device is located, d is the distance between the fault point F and the fault detection position M, l is the length of the transmission line between MN, t M and t N They respectively represent the local time when the initial fault traveling wave is detected at the M end and the local time when the initial fault traveling wave is detected at the N segment.

[0052] The main idea of ​​traditional two-terminal traveling wave fault location is to calculate the time difference between the fault detection devices at M and N capturing the initial traveling wave of the fault in absolute time. The fault location of the transmission line can be determined by formula (2):

[0053]

[0054] In formula (2), l is the length of the transmission line, v is the propagation speed of the traveling wave in the transmission line; and They respectively represent the absolute time when the fault detection devices at locations M and N capture the initial fault traveling wave.

[0055] In the absence of satellite synchronization to provide absolute time, the local clocks of the fault detection devices at both ends of M and N are no longer equal. It can be expressed by formula (3):

[0056]

[0057] In formula (3), The local time when the fault detection devices at both ends of M and N capture the initial traveling wave of the fault; are the errors between the local time and the absolute time of the fault detection devices at both ends M and N respectively; is the relative time difference between the local times of the fault detection devices at both ends of M and N, as shown in Figure 3 As shown. Among them, Figure 3 The clock relationship of the double-ended traveling wave ranging system is shown in Figure 3 In the figure, M Clock is the local clock of the fault detection device at the M end, N Clock is the local clock of the fault detection device at the N end, and GPS Clock is the satellite synchronization clock.

[0058] If the relative time difference of the local clocks of the fault detection devices at both ends of the transmission line can be obtained The time difference between the fault location and the two ends of M and N can be obtained Thus, the fault location of the transmission line is achieved. The implementation of the two-end traveling wave fault location method for the transmission line that does not rely on satellite timing provided in the embodiment of the present application mainly includes two stages, namely the pre-synchronization stage and the fault location stage. In the pre-synchronization stage, the time when the fault detection device at both ends M and N detects the initial traveling wave of the fault is mainly used as the time reference to achieve time pre-synchronization; and in the fault location stage, on the basis of time pre-synchronization, the fault detection devices at both ends respectively calculate the local power frequency traveling wave phasor, and then calculate the additional phase angle difference of the power frequency traveling wave phasor of the fault detection device at both ends, and locate the fault of the transmission line according to the additional phase angle difference.

[0059] Specifically, in the pre-synchronization stage, the first detection time and the second detection time are pre-synchronized, wherein the first detection time is the local time when the first fault detection device detects the initial fault traveling wave, and the second detection time is the local time when the second fault detection device detects the initial fault traveling wave.

[0060] As an example, assuming that the time when the fault detection devices at both ends of M and N detect the initial fault wave is the same absolute time, the local clocks of the fault detection devices at both ends are pre-synchronized by using formula (4), that is:

[0061]

[0062] In fact, due to the propagation delay in the transmission line, the absolute time for the initial fault traveling wave to reach both ends of M and N is not necessarily equal.

[0063] Obviously, after the time pre-synchronization process, the absolute time difference of the fault traveling wave reaching both ends is equal to the relative error of the clocks at both ends, that is:

[0064]

[0065] From formula (5), we can see that the time difference between the local clocks of the fault detection devices at both ends of the transmission line and the time difference between the fault detection devices at both ends capturing the fault traveling wave are both reflected in middle.

[0066] After completing the time pre-synchronization, the fault location stage begins. By calculating the power frequency traveling wave phasor before the fault, the phase angle difference of the power frequency traveling wave phasor captured by the fault detection devices at both ends is used to solve the fault location problem. Thus, the absolute time difference between the initial fault wave reaching both ends is obtained. The corresponding principle diagram of double-end traveling wave fault location is as follows: Figure 4 As shown, in Figure 4 In, t W Represents a time window.

[0067] Specifically, after obtaining the initial fault traveling wave captured by the fault detection devices at both ends and the power frequency traveling wave phasor before the fault, the first forward traveling wave phasor and the first reverse traveling wave phasor corresponding to the first fault detection position are determined from the first power frequency traveling wave phasor, and the second forward traveling wave phasor and the second reverse traveling wave phasor corresponding to the second fault detection position are determined from the second power frequency traveling wave phasor; then, according to the phase angle relationship between the first forward traveling wave phasor and the second forward traveling wave phasor, and the phase angle relationship between the first reverse traveling wave phasor and the second reverse traveling wave phasor, a phase angle equation is constructed; finally, the phase angle equation is solved to obtain the additional phase angle difference.

[0068] In the process of constructing the phase angle equation, first, a first phasor relationship between the first forward wave phasor and the second forward wave phasor is constructed, and a second phasor relationship between the first reverse wave phasor and the second reverse wave phasor is constructed; then, based on the first phasor relationship, the first phase angle relationship between the first forward wave phasor and the second forward wave phasor is determined, and based on the second phasor relationship, the second phase angle relationship between the second reverse wave phasor and the second reverse wave phasor is determined; finally, the phase angle equation is constructed based on the first phase angle relationship and the second phase angle relationship.

[0069] As an example, according to the distributed parameter line model of the transmission line, the electrical quantity in the transmission line has the inherent characteristic of propagating along the line. When the line resistance and the ground conductivity are ignored, during the period when the transmission line is not faulty, the propagation characteristics of the current direction traveling wave at both ends of the transmission line are shown in formula (6):

[0070]

[0071] In formula (6), i f and i r They represent the instantaneous values ​​of the forward and reverse current waves respectively; τ is the transmission delay required for the traveling wave to propagate from the M end to the N end of the line, satisfying

[0072] Due to the existence of the traveling wave transmission delay τ, when the fault detection devices at both ends of the line calculate the power frequency fundamental wave phasor at the same absolute time, the obtained phasor will have a phase angle difference, as shown in formula (7):

[0073]

[0074] In formula (7), I f and I r Respectively represent the power frequency fundamental wave phasors of the forward and reverse current waves; t global The satellite timing provides the absolute time for the fault detection devices at both ends of M and N; f (0,t global ) represents the fault detection device at the M end at the absolute time tglobal , with a time window [t global -t W ,t global ]Calculate the power frequency fundamental wave phasor of the current forward wave; t W is the time window length of Fourier transform. In the embodiment of the present application, t W is one power frequency cycle; is the phase angle difference of the phase quantities at both ends of M and N due to the transmission delay of the power frequency traveling wave. Since it follows the natural law of traveling wave propagation along the line, in the embodiment of the present application, It is called the natural phase angle difference and satisfies the relationship shown in formula (8):

[0075]

[0076] In formula (8), T is the power frequency period.

[0077] After time pre-synchronization, the local clocks of the fault detection devices at both ends of the transmission line still have time errors. This time error will cause an additional error in the angle between the power frequency traveling wave phases obtained by the fault detection device at both ends of M and N. That is, an additional phase angle difference, which satisfies the relationship shown in formula (9):

[0078]

[0079] Formula (9) shows that after completing time pre-synchronization, the time error caused by fault traveling wave transmission is Additional phase angle difference with the traveling wave phase in the power frequency direction The additional phase angle difference can be solved by using the phase angle relationship of the power frequency traveling wave phasor calculated locally by the fault detection device at both ends of M and N, and then the absolute time difference of the initial traveling wave of the fault reaching the two places can be obtained.

[0080] Combining the above formulas (7), (8) and (9), it can be determined that when the clocks of the fault detection devices at both ends of M and N are not synchronized, the power frequency phasor relationship between both ends of M and N satisfies formula (10):

[0081]

[0082] In formula (10), I f (0,t local,M ) is the first forward wave phasor, I f (l,t local,N ) is the second forward wave phasor, I r (0,t local,M ) is the first reverse wave phasor, I r (l,t local,N) is the second reverse traveling wave phasor, is the natural phase angle difference, is the additional phase angle difference. The natural phase angle difference is the difference between the phase angle of the power frequency traveling wave detected at the first fault detection position and the phase angle of the power frequency traveling wave detected at the second fault detection position when the two-end clock of the transmission line is synchronized. is the first phasor relationship mentioned above, is the second phasor relationship mentioned above.

[0083] After obtaining the first phasor relationship and the second vector relationship, the phase angle relationship can be constructed, as shown in formula (11):

[0084]

[0085] In formula (11), is the phase angle corresponding to the first forward wave phasor, is the phase angle corresponding to the second forward wave phasor, is the phase angle corresponding to the first reverse traveling wave phasor, is the phase angle corresponding to the second reverse traveling wave phasor, is the natural phase angle difference, The natural phase angle difference is an additional phase angle difference, which is the difference between the phase angle of the power frequency traveling wave detected at the first fault detection position and the phase angle of the power frequency traveling wave detected at the second fault detection position when the double-end clocks of the transmission line are synchronized.

[0086] After obtaining the phase angle equation shown in formula (11), the additional phase angle difference can be obtained by calculating the sum of the two equations: Additional phase difference Satisfies formula (12):

[0087]

[0088] Furthermore, in order to obtain the additional phase difference Afterwards, the fault location of the transmission line can be determined based on the additional phase angle difference, the line length of the transmission line between the first fault detection device and the second fault detection device, and the wave speed of the traveling wave transmitted in the transmission line.

[0089] Specifically, first, the relative time difference between the first fault detection device and the second fault detection device for detecting the initial traveling wave of the fault is determined based on the additional phase angle difference; then, the distance difference between the first distance and the second distance is determined based on the relative time difference and the wave speed; then, the distance between the fault location and the first fault detection device and / or the second fault detection device is determined based on the distance difference and the line length; finally, the fault location of the transmission line is determined based on the distance. The first distance is the target distance between the first fault detection device and the fault location, and the second distance is the target distance between the second fault detection device and the fault location.

[0090] It should be noted that, in the process of determining the relative time difference between the initial fault traveling wave detected by the first fault detection device and the second fault detection device according to the additional phase angle difference, the transmission delay of the power frequency traveling wave from the first fault detection device to the second fault detection device before the transmission line fault occurs is obtained, and the relationship between the natural phase angle difference and the transmission delay is determined to obtain the correlation relationship, that is, formula (8); then, the time difference corresponding to the additional phase angle difference is determined according to the correlation relationship to obtain the relative time difference value, that is, after determining the additional phase angle difference, the relative time difference value can be determined by formula (9)

[0091] After determining the relative time difference Then, the fault location of the transmission line can be determined by combining formulas (2), (5), and (9), as shown in formula (13):

[0092]

[0093] In formula (12), Substituting the expression into formula (13), we can obtain the target expression of the fault location of the transmission line, as shown in formula (14):

[0094]

[0095] It can be seen from formula (14) that the fault location obtained by the fault location method provided in the embodiment of the present application is only related to factors such as the line length, wave speed, and the angle of the local power frequency traveling wave phasor of the fault detection device at both ends of MN. In principle, it eliminates the dependence on the absolute time of satellite synchronization, and does not rely on factors such as communication delay, fault type, system structure, etc., thereby improving the reliability of the traveling wave ranging system.

[0096] In terms of the calculation process, the embodiment of the present application first performs phase mode transformation on the three-phase sampling values, uses the wavelet transform modulus maximum method to complete the detection and time calibration of the initial traveling wave of the line mode fault, and then uses the solution provided by the embodiment of the present application to realize the fault location of the transmission line. The calculation process may include the following steps:

[0097] Step S1, signal preprocessing. In this step, the two-terminal three-phase voltage and current secondary side sampling signals are collected, and the collected signals are subjected to phase-mode transformation;

[0098] Step S2, detecting the initial traveling wave of the fault. In this step, the wavelet transform modulus maximum algorithm is performed on the double-ended line mode current signal to obtain the arrival time of the initial traveling wave of the fault;

[0099] Step S3, time pre-synchronization. Specifically, as shown in formula (4), it is assumed that the time when the initial fault traveling wave reaches both ends of M and N is the same absolute time;

[0100] Step S4, power frequency phasor calculation. In this step, based on the detection time of the initial fault traveling wave, the phasor calculation of the two-terminal power frequency current direction traveling wave is performed respectively;

[0101] Step S5, calculating the fault position. According to formula (12), the additional phase angle difference is estimated using the phase angle of the two-terminal power frequency current direction traveling wave phasor, and it is substituted into formula (12) to complete the calculation of the fault position.

[0102] In order to verify the effectiveness of the solution provided by this application, in the embodiment of this application, a 500kV AC transmission system simulation model was established in the PSCAD / EMTDC simulation software, and the performance of the solution provided by this application under different fault conditions and noise interference was verified through a large number of simulation examples. The simulation results show that without satellite time synchronization, the fault location result of the solution provided by this application can still reach the accuracy level of the current advanced dual-end traveling wave ranging.

[0103] The simulation experiment is introduced as follows:

[0104] In order to verify the performance of the solution provided by this application, this application built the following in PSCAD / EMTDC software: Figure 5 The electromagnetic transient simulation model of the 500kV / 50Hz AC transmission system shown in the figure completes the data processing and analysis process in Python software.

[0105] The simulation parameter settings of the AC transmission system are shown in Table 1. In addition, the unit length positive sequence series impedance Z of the transmission line L1 =0.00909+j0.2730Ω / km, positive sequence shunt admittance per unit length of the transmission line Y L1 =0+j1.300e-6S / km, the zero-sequence series impedance per unit length of the transmission line Z L0 =0.244+j0.919Ω / km, zero-sequence shunt admittance per unit length of the transmission line Y L0 =0+j3.100e-6S / km.

[0106] The AC overhead transmission line adopts the frequency-variable parameter model tower structure as follows Figure 6 As shown, the system sampling frequency is set to 1MHz. Figure 6 In the figure, G1 and G2 represent two parallel lightning conductors, and C1, C2, and C3 represent three-phase conductors. In order to fully verify the engineering practicability of the proposed scheme, the voltage and current transformers in the simulation model of this simulation experiment adopt the simulation model that considers the transmission characteristics of CVT (Continuously Variable Transmission) and CT (Current Transformer).

[0107] Table 1 AC transmission system parameters

[0108]

[0109]

[0110] In order to fully evaluate the performance of the solution provided in this application, in the simulation experiment, different fault locations, fault types, transition resistances, fault initial angle conditions and other fault conditions were set between the lines MN of the simulation system, and a total of 1904 groups of simulation examples were performed. The detailed settings of the faults are shown in Table 2.

[0111] Table 2 Simulation fault settings

[0112] parameter Value setting Number of groups Fault location (km) 20,30,40,…,170,180 17 Fault type AG,AB,ABG,ABC 4 Transition resistance(Ω) 0.01,10,100,300 4 Fault initial angle (°) 10,30,60,90,120,150,170 7 total 1904

[0113] The performance of the solution provided in this application is analyzed through specific examples below.

[0114] Figure 7 and Figure 8 The analysis diagram of the solution provided by the present application is shown in the case of a 5 ms time synchronization error, and the fault setting parameters are: a single-phase grounding fault with a fault location of 20 km, a transition resistance of 0.01 Ω, and a fault initial angle of 90°.

[0115] like Figure 7 The waveform diagram of the traveling wave without time pre-synchronization is shown in Figure 7 The original data contains a 5 ms double-end synchronization error, where L1 is the instantaneous value of the current traveling wave on the M side, L2 is the traveling wave before time pre-synchronization, and L3 is the actual traveling wave at the absolute time of satellite synchronization.

[0116] like Figure 8 The waveform of the traveling wave after time pre-synchronization is shown in the figure. The time pre-synchronization is performed based on the arrival time of the initial traveling wave of the fault, and the fundamental phasor of the steady-state traveling wave of the power frequency before the fault is calculated to complete the fault location. The additional phase angle difference calculated is The distance measurement result is d=20.0725km, with a relative error of 0.3625%.

[0117] For different fault locations, Table 3 shows the double-terminal traveling wave fault location results of the solution provided in the present application at different fault locations under the conditions of transition resistance 0Ω, single-phase grounding fault and fault initial phase angle 90°.

[0118] Table 3 Test results

[0119]

[0120] It can be seen from the simulation results in Table 3 that, under different fault locations between the transmission lines MN, there is a linear relationship between the additional phase angle difference and the fault location.

[0121] For different transition resistances, Table 4 shows the two-terminal traveling wave fault location results of the solution provided in the present application under the condition of a single-phase grounding fault and a fault initial phase angle of 90° with different transition resistances.

[0122] Table 4 Comparison of positioning results of different transition resistances

[0123]

[0124] It can be seen from the simulation results shown in Table 4 that the solution provided in the present application still maintains a good performance level under the condition of 300Ω transition resistance.

[0125] For different fault types, Table 5 shows the double-terminal traveling wave fault location results of different fault types in the solution provided by the present application when the transition resistance is 300Ω and the initial fault phase angle is 90°.

[0126] Table 5 Comparison of location results of different fault types

[0127]

[0128] It can be seen from the simulation results shown in Table 5 that the solution provided in the present application correctly identifies different fault types and maintains a good performance level.

[0129] For different fault initial phase angles, Table 6 shows the double-terminal traveling wave fault location results of the solution provided in this application at different fault initial phase angles under the conditions of transition resistance 300Ω and single-phase grounding fault.

[0130] Table 6 Comparison of location results of different fault initial phase angles

[0131]

[0132]

[0133] It can be seen from the simulation results shown in Table 6 that the solution provided in this application has good performance under different fault initial angles.

[0134] For the overall error distribution, Fig. 9 The figure shows the distribution of positioning result errors of the solution provided by this application in all simulation examples. Fig. 9 It can be seen that the maximum positioning error of the solution provided in this application under different fault conditions such as fault location, fault type, transition resistance and fault initial angle is less than 0.3km, and the relative error is less than 0.2%, which is basically consistent with the performance of the current advanced dual-end traveling wave positioning solution.

[0135] For different sampling frequencies, in order to explore the impact of sampling frequencies on the solution provided by this application, comparative experiments were carried out at different sampling frequencies. Fig.10 The distribution of ranging errors at different sampling frequencies is shown. Fig.10 It can be seen that the solution provided by this application can maintain good accuracy at different sampling frequencies. The higher the sampling frequency, the higher the accuracy of the solution provided by this application. Since the calibration accuracy of the fault travel wave arrival time is significantly restricted, when the sampling frequency is 50kHz, the maximum positioning error reaches 2.5km.

[0136] From the analysis of the above simulation experiments, it can be seen that in response to the dependence of traditional methods on the absolute time of satellite synchronization, this application proposes a two-end traveling wave fault location method that does not rely on satellite synchronization based on the initial arrival time of the fault traveling wave and the power frequency traveling wave phasor before the fault. This method eliminates the dependence of two-end traveling wave fault location on the absolute time of satellite synchronization through two-step calculations of time pre-synchronization and additional phase angle difference solution. A large number of simulation examples show that, under the premise of not relying on the absolute time of satellite synchronization, the solution provided by this application maintains good performance under different fault locations, fault types, transition resistances, and fault initial angles.

[0137] The present application also provides a transmission line double-end traveling wave fault location device that does not rely on satellite timing, such as Fig.11 As shown, the device 1100 includes: an initial traveling wave acquisition module 1101 , a phase determination module 1102 , a phase angle determination module 1103 and a fault location module 1104 .

[0138] The initial traveling wave acquisition module 1101 is used to acquire the initial traveling wave of the fault when it is determined that the transmission line has a fault, wherein the initial traveling wave of the fault is a traveling wave transmitted in the transmission line when the transmission line has a fault;

[0139] The phasor determination module 1102 is used to obtain, when it is determined that a fault occurs in the transmission line, a first power frequency traveling wave phasor corresponding to the initial fault traveling wave detected by the first fault detection device, and a second power frequency traveling wave phasor corresponding to the initial fault traveling wave detected by the second fault detection device, wherein the first fault detection device and the second fault detection device are respectively located at two ends of the transmission line;

[0140] The phase angle determination module 1103 is used to determine an additional phase angle difference between the first power frequency traveling wave phasor and the second power frequency traveling wave phasor, wherein the additional phase angle difference is used to characterize the phase angle difference between the first power frequency traveling wave phasor and the second power frequency traveling wave phasor caused by the clock asynchronism between the first fault detection device and the second fault detection device, and the time difference between the first fault detection device and the second fault detection device in detecting the initial traveling wave of the fault;

[0141] The fault location module 1104 is used to determine the fault location of the transmission line according to the additional phase angle difference, the line length of the transmission line between the first fault detection device and the second fault detection device, and the wave speed of the traveling wave transmitted in the transmission line.

[0142] In one example, the phase angle determination module includes: a first phasor determination module, an equation construction module, and an equation solving module. The first phasor determination module is used to determine the first forward wave phasor and the first reverse wave phasor corresponding to the first fault detection position where the first fault detection device is located from the first power frequency traveling wave phasor, and determine the second forward wave phasor and the second reverse wave phasor corresponding to the second fault detection position where the second fault detection device is located from the second power frequency traveling wave phasor; the equation construction module is used to construct the phase angle equation according to the phase angle relationship between the first forward wave phasor and the second forward wave phasor, and the phase angle relationship between the first reverse wave phasor and the second reverse wave phasor; the equation solving module is used to solve the phase angle equation to obtain the additional phase angle difference.

[0143] In one example, the equation construction module includes: a phasor relationship construction module, a phase angle relationship construction module, and an equation construction submodule. The phasor relationship construction module is used to construct a first phasor relationship between the first forward wave phasor and the second forward wave phasor, and to construct a second phasor relationship between the first reverse wave phasor and the second reverse wave phasor; the phase angle relationship construction module is used to determine the first phase angle relationship between the first forward wave phasor and the second forward wave phasor based on the first phasor relationship, and to determine the second phase angle relationship between the second reverse wave phasor and the second reverse wave phasor based on the second phasor relationship; the equation construction submodule is used to construct a phase angle equation based on the first phase angle relationship and the second phase angle relationship.

[0144] In one example, the phasor relationship building module is specifically used to build the first phasor relationship through the following formula:

[0145]

[0146] The second phasor relationship is constructed by the following formula:

[0147]

[0148] Among them, I f (0,t local,M ) is the first forward wave phasor, I f (l,t local,N ) is the second forward wave phasor, I r (0,t local,M ) is the first reverse wave phasor, I r (l,t local,N ) is the second reverse traveling wave phasor, is the natural phase angle difference, The natural phase angle difference is an additional phase angle difference, which is the difference between the phase angle of the power frequency traveling wave detected at the first fault detection position and the phase angle of the power frequency traveling wave detected at the second fault detection position when the double-end clocks of the transmission line are synchronized.

[0149] In one example, the equation building submodule is specifically used to build the phase angle equation through the following formula:

[0150]

[0151] in, is the phase angle corresponding to the first forward wave phasor, is the phase angle corresponding to the second forward wave phasor, is the phase angle corresponding to the first reverse traveling wave phasor, is the phase angle corresponding to the second reverse traveling wave phasor, is the natural phase angle difference, The natural phase angle difference is an additional phase angle difference, which is the difference between the phase angle of the power frequency traveling wave detected at the first fault detection position and the phase angle of the power frequency traveling wave detected at the second fault detection position when the double-end clocks of the transmission line are synchronized.

[0152] In one example, the fault location module includes: a time difference determination module, a first distance determination module, a second distance determination module and a fault location determination module. The time difference determination module is used to determine the relative time difference between the first fault detection device and the second fault detection device for detecting the initial traveling wave of the fault according to the additional phase angle difference; the first distance determination module is used to determine the distance difference between the first distance and the second distance based on the relative time difference and the wave speed, wherein the first distance is the distance between the first fault detection device and the fault location, and the second distance is the distance between the second fault detection device and the fault location; the second distance determination module is used to determine the target distance between the fault location and the first fault detection device and / or the second fault detection device based on the distance difference and the line length; the fault location determination module is used to determine the fault location of the transmission line according to the target distance.

[0153] In one example, the time difference determination module is specifically used to obtain the transmission delay of the traveling wave from the first fault detection device to the second fault detection device before the transmission line fails; determine the relationship between the natural phase angle difference and the transmission delay to obtain a correlation relationship; determine the time difference corresponding to the additional phase angle difference based on the correlation relationship to obtain a relative time difference value.

[0154] In one example, a two-end traveling wave fault location device for a power transmission line that does not rely on satellite timing also includes: a pre-synchronization module, used to pre-synchronize a first detection time and a second detection time, wherein the first detection time is the local time when the first fault detection device detects the initial traveling wave of the fault, and the second detection time is the local time when the second fault detection device detects the initial traveling wave of the fault.

[0155] The transmission line double-end traveling wave fault location device that does not rely on satellite timing provided in the embodiment of the present application can implement each process implemented in the aforementioned method embodiment, and will not be described again here to avoid repetition.

[0156] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0157] Fig.12 A schematic diagram of the hardware structure of an electronic device provided in an embodiment of the present application is shown.

[0158] The electronic device 1200 may include a processor 1201 and a memory 1202 storing computer program instructions.

[0159] Specifically, the processor 1201 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0160] The memory 1202 may include a large capacity memory for data or instructions. By way of example and not limitation, the memory 1202 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive or a combination of two or more of these. In appropriate cases, the memory 1202 may include a removable or non-removable (or fixed) medium. In appropriate cases, the memory 1202 may be inside or outside the integrated gateway disaster recovery device. In a specific embodiment, the memory 1202 is a non-volatile solid-state memory.

[0161] The memory may include read-only memory (ROM), random access memory (RAM), magnetic disk storage media devices, optical storage media devices, flash memory devices, electrical, optical or other physical / tangible memory storage devices. Thus, typically, the memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to an aspect of the present disclosure.

[0162] The processor 1201 reads and executes the computer program instructions stored in the memory 1202 to implement any one of the transmission line double-end traveling wave fault location methods that do not rely on satellite timing in the above embodiments.

[0163] In one example, the electronic device may further include a communication interface 1203 and a bus 1210. Fig.12 As shown, the processor 1201, the memory 1202, and the communication interface 1203 are connected via a bus 1210 and communicate with each other.

[0164] The communication interface 1203 is mainly used to implement communication between various modules, devices, units and / or equipment in the embodiments of the present application.

[0165] Bus 1210 includes hardware, software or both, and the parts of electronic equipment are coupled to each other.For example, but not limitation, bus may include accelerated graphics port (AGP) or other graphics bus, enhanced industrial standard architecture (EISA) bus, front side bus (FSB), hypertransport (HT) interconnection, industrial standard architecture (ISA) bus, infinite bandwidth interconnection, low pin count (LPC) bus, memory bus, micro channel architecture (MCA) bus, peripheral component interconnection (PCI) bus, PCI-Express (PCI-X) bus, serial advanced technology attachment (SATA) bus, video electronics standard association local (VLB) bus or other suitable bus or two or more of these combinations. In appropriate cases, bus 1210 may include one or more buses. Although the present application embodiment describes and shows a specific bus, the application considers any suitable bus or interconnection.

[0166] In addition, in combination with the transmission line double-end traveling wave fault location method that does not rely on satellite timing in the above embodiments, the embodiment of the present application can provide a computer-readable storage medium for implementation. The computer-readable storage medium stores computer program instructions; when the computer program instructions are executed by the processor, any of the transmission line double-end traveling wave fault location methods that do not rely on satellite timing in the above embodiments is implemented.

[0167] In addition, in combination with the transmission line double-end traveling wave fault location method that does not rely on satellite timing in the above embodiments, the embodiments of the present application can provide a computer program product for implementation. When the instructions in the computer program product are executed by the processor of the electronic device, the electronic device executes and implements any of the transmission line double-end traveling wave fault location methods that do not rely on satellite timing in the above embodiments.

[0168] It should be clear that the present application is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present application is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present application.

[0169] The functional modules shown in the above-described block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present application are programs or code segments that are used to perform the required tasks. Programs or code segments can be stored in machine-readable media, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier wave. "Machine-readable media" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0170] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be performed simultaneously.

[0171] The above describes various aspects of the present disclosure with reference to the flowchart and / or block diagram of the transmission line double-end traveling wave fault location method and device that does not rely on satellite synchronization according to the embodiment of the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine so that these instructions executed by the processor of the computer or other programmable data processing device enable the implementation of the functions / actions specified in one or more boxes of the flowchart and / or block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field programmable logic circuit. It can also be understood that each box in the block diagram and / or flowchart and the combination of boxes in the block diagram and / or flowchart can also be implemented by dedicated hardware that performs the specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0172] The above is only a specific implementation of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the protection scope of the present application is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the protection scope of this application.

Claims

1. A method for locating faults at two ends of a transmission line without relying on satellite timing, characterized in that: include: When it is determined that a fault occurs in the transmission line, obtaining a fault initial traveling wave, wherein the fault initial traveling wave is a traveling wave transmitted in the transmission line when the fault occurs in the transmission line; Determine a first power frequency traveling wave phasor corresponding to the initial fault traveling wave detected by a first fault detection device, and a second power frequency traveling wave phasor corresponding to the initial fault traveling wave detected by a second fault detection device, wherein the first fault detection device and the second fault detection device are respectively located at two ends of the transmission line; Determine an additional phase angle difference between the first power frequency traveling wave phasor and the second power frequency traveling wave phasor, wherein the additional phase angle difference is used to characterize the phase angle difference between the first power frequency traveling wave phasor and the second power frequency traveling wave phasor caused by the clock asynchronism between the first fault detection device and the second fault detection device, and the time difference between the first fault detection device and the second fault detection device in detecting the initial traveling wave of the fault; The fault location of the transmission line is determined according to the additional phase angle difference, the line length of the transmission line between the first fault detection device and the second fault detection device, and the wave speed of the traveling wave transmitted in the transmission line.

2. The method according to claim 1, characterized in that Determining an additional phase angle difference between the first power frequency traveling wave phasor and the second power frequency traveling wave phasor comprises: Determine a first forward-traveling wave phasor and a first reverse-traveling wave phasor corresponding to a first fault detection position where the first fault detection device is located from the first power-frequency traveling wave phasor, and determine a second forward-traveling wave phasor and a second reverse-traveling wave phasor corresponding to a second fault detection position where the second fault detection device is located from the second power-frequency traveling wave phasor; Constructing a phase angle equation according to a phase angle relationship between the first forward-traveling wave phasor and the second forward-traveling wave phasor, and a phase angle relationship between the first reverse-traveling wave phasor and the second reverse-traveling wave phasor; The phase angle equation is solved to obtain the additional phase angle difference.

3. The method according to claim 2, characterized in that According to the phase angle relationship between the first forward-traveling wave phasor and the second forward-traveling wave phasor, and the phase angle relationship between the first reverse-traveling wave phasor and the second reverse-traveling wave phasor, a phase angle equation is constructed, including: Constructing a first phasor relationship between the first forward-traveling wave phasor and the second forward-traveling wave phasor, and constructing a second phasor relationship between the first reverse-traveling wave phasor and the second reverse-traveling wave phasor; Determine a first phase angle relationship between the first forward-traveling wave phasor and the second forward-traveling wave phasor based on the first phasor relationship, and determine a second phase angle relationship between the second reverse-traveling wave phasor and the second reverse-traveling wave phasor based on the second phasor relationship; The phase angle equation is constructed based on the first phase angle relationship and the second phase angle relationship.

4. The method according to claim 3, characterized in that Constructing a first phasor relationship between the first forward-traveling wave phasor and the second forward-traveling wave phasor, and constructing a second phasor relationship between the first reverse-traveling wave phasor and the second reverse-traveling wave phasor, comprising: The first phasor relationship is constructed by the following formula: The second phasor relationship is constructed by the following formula: Among them, I f (0,t local,M ) is the first forward wave phasor, I f (l,t local,N ) is the second forward wave phasor, I r (0,t local,M ) is the first reverse traveling wave phasor, I r (l,t local,N ) is the second reverse traveling wave phasor, is the natural phase angle difference, The additional phase angle difference, the natural phase angle difference is the difference between the phase angle of the power frequency traveling wave detected at the first fault detection position and the phase angle of the power frequency traveling wave detected at the second fault detection position when the double-end clock of the transmission line is synchronized.

5. The method according to claim 3, characterized in that: Constructing the phase angle equation based on the first phase angle relationship and the second phase angle relationship includes: The phase angle equation is constructed by the following formula: in, is the phase angle corresponding to the first forward wave phasor, is the phase angle corresponding to the second forward wave phasor, is the phase angle corresponding to the first reverse traveling wave phasor, is the phase angle corresponding to the second reverse traveling wave phasor, is the natural phase angle difference, The additional phase angle difference, the natural phase angle difference is the difference between the phase angle of the power frequency traveling wave detected at the first fault detection position and the phase angle of the power frequency traveling wave detected at the second fault detection position when the double-end clock of the transmission line is synchronized.

6. The method according to claim 4 or 5, characterized in that: Determining the fault location of the transmission line according to the additional phase angle difference, the line length of the transmission line between the first fault detection device and the second fault detection device, and the wave speed of the traveling wave transmitted in the transmission line, comprises: Determine the relative time difference between the first fault detection device and the second fault detection device detecting the initial traveling wave of the fault according to the additional phase angle difference; Determine a distance difference between a first distance and a second distance based on the relative time difference and the wave speed, wherein the first distance is the distance between the first fault detection device and the fault occurrence location, and the second distance is the distance between the second fault detection device and the fault occurrence location; Determine a target distance between the fault occurrence location and the first fault detection device and / or the second fault detection device based on the distance difference and the line length; The fault location of the power transmission line is determined according to the target distance.

7. The method according to claim 6, characterized in that Determining the relative time difference between the first fault detection device and the second fault detection device detecting the initial traveling wave of the fault according to the additional phase angle difference includes: Acquire a transmission delay of a power frequency traveling wave from the first fault detection device to the second fault detection device before a fault occurs in the power transmission line; Determine the relationship between the natural phase angle difference and the transmission delay to obtain a correlation relationship; The time difference corresponding to the additional phase angle difference is determined according to the association relationship to obtain the relative time difference value.

8. The method according to claim 1, characterized in that Before determining the first power frequency traveling wave phasor corresponding to the initial fault traveling wave detected by the first fault detection device and the second power frequency traveling wave phasor corresponding to the initial fault traveling wave detected by the second fault detection device, the method further includes: The first detection time and the second detection time are pre-synchronized, wherein the first detection time is the local time when the first fault detection device detects the initial fault traveling wave, and the second detection time is the local time when the second fault detection device detects the initial fault traveling wave.

9. A transmission line double-end traveling wave fault location device that does not rely on satellite timing, characterized in that: include: An initial traveling wave acquisition module is used to acquire an initial traveling wave of the fault when it is determined that a fault occurs in the transmission line, wherein the initial traveling wave of the fault is a traveling wave transmitted in the transmission line when a fault occurs in the transmission line; a phasor determination module, used to determine a first power frequency traveling wave phasor corresponding to the initial traveling wave of the fault detected by the first fault detection device, and a second power frequency traveling wave phasor corresponding to the initial traveling wave of the fault detected by the second fault detection device, wherein the first fault detection device and the second fault detection device are respectively located at two ends of the transmission line; a phase angle determination module, used to determine an additional phase angle difference between the first power frequency traveling wave phasor and the second power frequency traveling wave phasor, wherein the additional phase angle difference is used to characterize the phase angle difference between the first power frequency traveling wave phasor and the second power frequency traveling wave phasor caused by the clock asynchronism between the first fault detection device and the second fault detection device, and the time difference between the first fault detection device and the second fault detection device in detecting the initial traveling wave of the fault; A fault locating module is used to determine the fault location of the transmission line according to the additional phase angle difference, the line length of the transmission line between the first fault detection device and the second fault detection device, and the wave speed of the traveling wave transmitted in the transmission line.

10. An electronic device, characterized in that: The electronic device comprises: a processor and a memory storing computer program instructions; When the processor executes the computer program instructions, the method for locating double-end traveling wave faults in a power transmission line without relying on satellite pairs as described in any one of claims 1 to 7 is implemented.

11. A computer-readable storage medium, characterized in that: Computer program instructions are stored on a computer-readable storage medium, and when the computer program instructions are executed by a processor, a method for locating two-terminal traveling wave faults in a power transmission line that does not rely on satellite timing as described in any one of claims 1 to 7 is implemented.

12. A computer program product, characterized in that When the instructions in the computer program product are executed by a processor of an electronic device, the electronic device executes the transmission line double-end traveling wave fault location method that does not rely on satellite timing as described in any one of claims 1 to 7.

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