Fault distance determination method, apparatus, and computer-readable storage medium

Abstract

The application relates to the electric power technical field and provides a fault distance determination method and device and a computer readable storage medium, the method comprises the following steps: acquiring the line length of each sub-line of a plurality of sub-lines of a power transmission line and the line type of each sub-line; the line type comprises a cable line or an overhead line; monitoring the zero sequence voltage or the zero sequence current, the phase current and the current traveling wave of the power transmission line through a traveling wave detection device located at the head end of the power transmission line; determining whether the power transmission line has a fault according to the zero sequence voltage or the zero sequence current and the phase current; in the case that the power transmission line has a fault, determining a preliminary fault length according to the current traveling wave and the line type of a first line; the first line is a sub-line where the traveling wave detection device is located; and determining the target fault length of the fault point from the traveling wave detection device and the target line type of the sub-line where the fault point is located according to the preliminary fault length, the line length of each sub-line and the line type of each sub-line. The accuracy of fault position determination can be improved.

Description

Technical Field

[0001] This application relates to the field of power technology, and in particular to a method, apparatus and computer-readable storage medium for determining fault distance. Background Technology

[0002] Currently, overhead lines and cables are widely used in power transmission lines to balance construction economy and operational reliability, and this has gradually become the mainstream technology for the transmission systems of wind power, photovoltaic and other new energy power plants, as well as for the capacity expansion and upgrading of urban distribution networks. However, this hybrid topology, consisting of overhead conductors and power cables connected by intermediate joints, faces a significant challenge in accurately locating faults during operation. The main reason for this is the fundamental difference in electrical parameters between the two media: the wave impedance of overhead lines is usually significantly higher than that of cables, while the propagation speed of traveling waves in cable insulation is generally only 1 / 2 to 1 / 3 of that of overhead lines. This discontinuity in parameters causes complex reflection and refraction phenomena of traveling waves at the connection points, and the wave velocity of fault traveling waves is not constant when propagating in the hybrid line, but varies segmentally depending on the type of section they pass through.

[0003] Traditional single-ended traveling wave ranging methods are based on the theory of uniform transmission lines. Their core principle is to calculate the fault distance by measuring the time difference between the initial traveling wave pulse at the fault location and the reflected wave pulse from the fault point or discontinuity, combined with a preset constant wave velocity. However, when applied to overhead-cable hybrid lines, the propagation delay of the traveling wave along the hybrid path is completely different from that in a single-medium line. Multiple reflected signals, such as fault point reflections, intermediate joint reflections, and busbar reflections, intertwine in the time domain, resulting in complex waveform characteristics that make it difficult for the ranging device to accurately identify the true fault point reflection. If the reflection from the impedance discontinuity at the cable-overhead line connection is mistakenly identified as a fault reflection, or if a single wave velocity is still used for calculation, significant ranging errors will be directly introduced, potentially even causing the ranging function to fail, resulting in low accuracy in fault location determination. Summary of the Invention

[0004] This application provides a method, apparatus, and computer-readable storage medium for determining fault distance, which can improve the accuracy of fault location determination.

[0005] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, a method for determining fault distance is provided, comprising: acquiring the line length and line type of each of multiple sub-lines of a transmission line; the line type includes cable or overhead line; monitoring the zero-sequence voltage or zero-sequence current, phase current, and current traveling wave of the transmission line using a traveling wave detection device located at the beginning of the transmission line; determining whether a fault has occurred in the transmission line based on the zero-sequence voltage or zero-sequence current and phase current; determining the preliminary fault length based on the current traveling wave and the line type of a first line in the event of a fault in the transmission line; the first line being the sub-line where the traveling wave detection device is located; and determining the target fault length from the fault point to the traveling wave detection device and the target line type of the sub-line where the fault point is located based on the preliminary fault length, the line length of each sub-line, and the line type of each sub-line.

[0006] By first calculating the initial fault length based on the first line where the traveling wave detection device is located and whose line type is known, and then combining the specific lengths and types of all sub-lines (including cables and overhead lines) in the transmission line for equivalent conversion and precise positioning, this method effectively overcomes the positioning error caused by the traditional traveling wave ranging method in mixed lines (cable-overhead lines) where the time difference is directly converted into a single fixed wave velocity due to the wave velocity differences of different line types. This method realizes a progressive ranging from initial coarse positioning to precise calibration based on the actual line structure, significantly improving the accuracy of fault distance determination in complex line structures containing cables and overhead lines with different wave velocity characteristics.

[0007] In conjunction with the first aspect, in some embodiments of the first aspect, determining whether a transmission line has experienced a fault based on zero-sequence voltage or zero-sequence current and phase current includes: determining whether a transmission line has experienced a fault when the zero-sequence voltage or zero-sequence current is greater than a preset threshold and / or the phase current is greater than a preset current threshold; and determining that the transmission line has not experienced a fault when the zero-sequence voltage or zero-sequence current is less than or equal to a preset threshold and the phase current is less than or equal to a preset current threshold.

[0008] In conjunction with the first aspect, in some embodiments of the first aspect, the current traveling wave includes an initial traveling wave front and a reflected traveling wave front. In the event of a fault in the transmission line, determining the preliminary fault length based on the current traveling wave and the first line includes: determining the time difference between the moment when the traveling wave detection device detects the initial traveling wave front and the moment when the traveling wave detection device detects the reflected traveling wave front; taking half of the product of the time difference and the first traveling wave velocity as the preliminary fault length; the first traveling wave velocity is the propagation speed of the traveling wave in a line of the first line type; the line type of the first line is the first line type.

[0009] In conjunction with the first aspect, in certain embodiments of the first aspect, determining the target fault length of the fault point from the traveling wave detection device and the target line type of the sub-line where the fault point is located, based on the preliminary fault length, the line length of each sub-line, and the line type of each sub-line, includes: obtaining the equivalent line length of a second sub-line among multiple sub-lines; the line type of the second sub-line is a second line type, which is different from the first line type, and the line type of the first line is the first line type; determining the equivalent transmission line length of the transmission line based on the line length of the third sub-line and the equivalent line length of the second sub-line; the line type of the third line is the first line type, and the third sub-line includes the first sub-line; determining the target sub-line where the fault point is located based on the equivalent transmission line length of the transmission line and the preliminary fault length; determining a first distance between the fault point and the target endpoint of the target sub-line based on the line type of the target sub-line; the target endpoint is the endpoint of the target sub-line that is close to the traveling wave detection device; using the first distance and the second distance as the target fault length, and using the line type of the target sub-line as the target line type; the second distance is the sum of the line lengths of the sub-lines between the target sub-line and the traveling wave detection device.

[0010] In conjunction with the first aspect, in some embodiments of the first aspect, obtaining the equivalent line length of a second sub-line among a plurality of sub-lines includes: obtaining a first traveling wave velocity and a second traveling wave velocity; the first traveling wave velocity is the propagation speed of a traveling wave in a line of a first line type, and the second traveling wave velocity is the propagation speed of a traveling wave in a line of a second line type; and multiplying a target ratio by the line length of the second sub-line as the equivalent line length of the second sub-line; the target ratio is the ratio of the first traveling wave velocity to the second traveling wave velocity.

[0011] In conjunction with the first aspect, in some embodiments of the first aspect, determining the target sub-line where the fault point is located based on the equivalent transmission line of the transmission line and the initial fault length includes: determining the fault point in the equivalent transmission line of the transmission line at a distance equal to the initial fault length from the traveling wave detection device; and designating the sub-line where the fault point is located as the target sub-line.

[0012] In conjunction with the first aspect, in certain embodiments of the first aspect, determining the first distance between the fault point and the target endpoint of the target sub-line based on the line type of the target sub-line includes: using the difference between the preliminary fault length and the third distance as a fourth distance; the third distance is the sum of the line length of the third sub-line between the traveling wave detection device and the target sub-line and the equivalent line length of the second sub-line; using the ratio of the fourth distance to the target ratio as the first distance; the target ratio is the ratio of the first traveling wave velocity to the second traveling wave velocity; the first traveling wave velocity is the propagation speed of the traveling wave in a line of the first line type, and the second traveling wave velocity is the propagation speed of the traveling wave in a line of the second line type.

[0013] Secondly, a fault distance determination device is provided for implementing the fault distance determination method of the first aspect described above. This fault distance determination device includes modules, units, or means corresponding to the above method. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the above functions.

[0014] In conjunction with the second aspect, in some embodiments of the second aspect, the apparatus includes: an acquisition module and a processing module; the acquisition module is used to acquire the line length and line type of each of a plurality of sub-lines of a transmission line; the line type includes cable or overhead line; the processing module is used to monitor the zero-sequence voltage or zero-sequence current, phase current and current traveling wave of the transmission line through a traveling wave detection device located at the beginning of the transmission line; the processing module is used to determine whether a fault has occurred in the transmission line based on the zero-sequence voltage or zero-sequence current and phase current; the processing module is used to determine the preliminary fault length based on the current traveling wave and the line type of a first line in the event of a fault in the transmission line; the first line is the sub-line where the traveling wave detection device is located; the processing module is used to determine the target fault length from the fault point to the traveling wave detection device and the target line type of the sub-line where the fault point is located based on the preliminary fault length, the line length of each sub-line and the line type of each sub-line.

[0015] In conjunction with the second aspect, in some embodiments of the second aspect, the processing module is used to determine whether a transmission line has experienced a fault based on the zero-sequence voltage or zero-sequence current and the phase current, including: determining whether a transmission line has experienced a fault when the zero-sequence voltage or zero-sequence current is greater than a preset threshold and / or the phase current is greater than a preset current threshold; and determining that the transmission line has not experienced a fault when the zero-sequence voltage or zero-sequence current is less than or equal to a preset threshold and the phase current is less than or equal to a preset current threshold.

[0016] In conjunction with the second aspect, in some embodiments of the second aspect, the current traveling wave includes an initial traveling wave front and a reflected traveling wave front. In the event of a fault in the transmission line, the processing module is used to determine the preliminary fault length based on the current traveling wave and the first line, including: determining the time difference between the moment when the traveling wave detection device detects the initial traveling wave front and the moment when the traveling wave detection device detects the reflected traveling wave front; taking half of the product of the time difference and the first traveling wave velocity as the preliminary fault length; the first traveling wave velocity is the propagation speed of the traveling wave in a line of the first line type; the line type of the first line is the first line type.

[0017] In conjunction with the second aspect, in some embodiments of the second aspect, the processing module is configured to determine the target fault length of the fault point from the traveling wave detection device and the target line type of the sub-line where the fault point is located, based on the preliminary fault length, the line length of each sub-line, and the line type of each sub-line, including: obtaining the equivalent line length of the second sub-line among multiple sub-lines; the line type of the second sub-line is a second line type, which is different from the first line type, and the line type of the first line is the first line type; determining the equivalent transmission line length of the transmission line based on the line length of the third sub-line and the equivalent line length of the second sub-line; the line type of the third line is the first line type, and the third sub-line includes the first sub-line; determining the target sub-line where the fault point is located based on the equivalent transmission line length of the transmission line and the preliminary fault length; determining a first distance between the fault point and the target endpoint of the target sub-line based on the line type of the target sub-line; the target endpoint is the endpoint of the target sub-line that is close to the traveling wave detection device; using the first distance and the second distance as the target fault length, and using the line type of the target sub-line as the target line type; the second distance is the sum of the line lengths of the sub-lines between the target sub-line and the traveling wave detection device.

[0018] In conjunction with the second aspect, in some embodiments of the second aspect, a processing module is used to obtain the equivalent line length of a second sub-line among multiple sub-lines, including: obtaining a first traveling wave velocity and a second traveling wave velocity; the first traveling wave velocity is the propagation speed of a traveling wave in a line of a first line type, and the second traveling wave velocity is the propagation speed of a traveling wave in a line of a second line type; and multiplying a target ratio by the line length of the second sub-line as the equivalent line length of the second sub-line; the target ratio is the ratio of the first traveling wave velocity to the second traveling wave velocity.

[0019] In conjunction with the second aspect, in some embodiments of the second aspect, the processing module is used to determine the target sub-line where the fault point is located based on the equivalent transmission line of the transmission line and the initial fault length, including: determining the fault point in the equivalent transmission line of the transmission line at a distance equal to the initial fault length from the traveling wave detection device; and designating the sub-line where the fault point is located as the target sub-line.

[0020] In conjunction with the second aspect, in some embodiments of the second aspect, the processing module is configured to determine a first distance between the fault point and the target endpoint of the target sub-line based on the line type of the target sub-line, including: using the difference between the preliminary fault length and the third distance as a fourth distance; the third distance is the sum of the line length of the third sub-line between the traveling wave detection device and the target sub-line and the equivalent line length of the second sub-line; using the ratio of the fourth distance to the target ratio as the first distance; the target ratio is the ratio of the first traveling wave velocity to the second traveling wave velocity; the first traveling wave velocity is the propagation speed of the traveling wave in the line of the first line type, and the second traveling wave velocity is the propagation speed of the traveling wave in the line of the second line type.

[0021] Thirdly, a fault distance determination apparatus is provided, comprising: at least one processor and a memory for storing processor-executable instructions; wherein the processor is configured to execute instructions to implement the method provided by the first aspect and any possible implementation thereof.

[0022] Fourthly, a computer-readable storage medium is provided, wherein when instructions in the computer-readable storage medium are executed by a processor of a fault distance determination device, the fault distance determination device is enabled to perform the method provided by the first aspect and any possible implementation thereof.

[0023] Fifthly, a computer program product containing instructions is provided that, when run on a computer, enables the computer to perform the methods provided in the first aspect and any possible implementation thereof.

[0024] The technical effects of any one of the second to fifth aspects can be found in the technical effects of the different embodiments of the first aspect described above, and will not be repeated here. Attached Figure Description

[0025] Figure 1 This application provides a schematic diagram of the architecture of a fault distance determination system; Figure 2 A flowchart illustrating a fault distance determination method provided in this application; Figure 3 A flowchart illustrating another method for determining fault distance provided in this application; Figure 4 A flowchart illustrating another method for determining fault distance provided in this application; Figure 5 A flowchart illustrating another method for determining fault distance provided in this application; Figure 6 This application provides a schematic diagram of the structure of a fault distance determination device; Figure 7A schematic diagram of another fault distance determination device provided in this application. Detailed Implementation

[0026] In the description of this application, unless otherwise stated, "multiple" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0027] Furthermore, to facilitate a clear description of the technical solutions in the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish identical or similar items with substantially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and the terms "first" and "second" are not necessarily different.

[0028] In this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being better or more advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner to facilitate understanding.

[0029] It is understood that the term "embodiment" used throughout the specification means that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, various embodiments throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It is understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0030] It is understood that in this application, "when," "if," and "if" all refer to the corresponding processing that will be carried out under certain objective circumstances, and are not limited to a specific time, nor do they require that there must be a judgment action when implemented, nor do they imply any other limitations.

[0031] It is understood that some optional features in the embodiments of this application can be implemented independently in certain scenarios without relying on other features, such as the current solution on which they are based, to solve the corresponding technical problems and achieve the corresponding effects. Alternatively, they can be combined with other features as needed in certain scenarios. Correspondingly, the apparatus given in the embodiments of this application can also implement these features or functions, which will not be elaborated here.

[0032] In this application, unless otherwise specified, the same or similar parts between the various embodiments can be referred to each other. In the various embodiments and implementation methods of the various embodiments in this application, unless otherwise specified or logically conflicting, the terminology and / or descriptions between different embodiments and between the implementation methods of the various embodiments are consistent and can be mutually referenced. The technical features in different embodiments and between the implementation methods of the various embodiments can be combined according to their inherent logical relationships to form new embodiments, implementation methods, implementation methods, or implementation approaches. The following embodiments of this application do not constitute a limitation on the scope of protection of this application.

[0033] Figure 1 This is a schematic diagram of the architecture of a fault distance determination system provided in this application. The technical solutions of the embodiments of this application can be applied to... Figure 1 The fault distance determination system shown is as follows: Figure 1 As shown, the fault distance determination system 10 includes a fault distance determination device 11 and an electronic device 12.

[0034] The fault distance determination device 11 is directly or indirectly connected to the electronic device 12. This connection can be wired or wireless, and this application embodiment does not limit this.

[0035] The fault distance determination device 11 and the electronic device 12 can exchange data.

[0036] It should be noted that the fault distance determination device 11 and the electronic device 12 can be independent devices or integrated into the same device; this application does not make any specific limitation in this regard.

[0037] When the fault distance determination device 11 and the electronic device 12 are integrated into the same device, the communication method between the fault distance determination device 11 and the electronic device 12 is the same as the communication method between internal modules of the device. In this case, the communication process between the two is the same as the communication process between the fault distance determination device 11 and the electronic device 12 when they are independent of each other.

[0038] In the following embodiments provided in this application, the fault distance determination device 11 and the electronic device 12 are described as being set up independently of each other.

[0039] In practical applications, the fault distance determination method provided in this application embodiment can be applied to the fault distance determination device 11, or to the devices included in the fault distance determination device 11.

[0040] The fault distance determination method provided in this application embodiment will be described below with reference to the accompanying drawings, taking the application of the fault distance determination method to the fault distance determination device 11 as an example.

[0041] Figure 2 A flowchart illustrating a fault distance determination method provided in this application is shown below. Figure 2 As shown, the method includes the following steps: S201, The fault distance determination device obtains the line length and line type of each sub-line among multiple sub-lines of the transmission line.

[0042] The line types include cable lines or overhead lines.

[0043] Cables are conductors wrapped in insulating material and sheathed, typically buried underground, underwater, or installed in conduits. They offer excellent insulation and protection, resisting moisture, corrosion, and mechanical damage, making them suitable for use in confined spaces or complex environments such as cities and factories.

[0044] Overhead lines are exposed or insulated conductors erected on open-air poles or towers, relying on air insulation and supporting structures to transmit electricity. They are simple in structure, inexpensive, easy to install and maintain, and are commonly used for long-distance power transmission and in rural areas.

[0045] The propagation speed of traveling waves differs significantly between cables and overhead lines. In overhead lines, the propagation speed of traveling waves approaches the speed of light (typically 95%–99% of the speed of light, approximately 2.8 × 10⁻⁶). 8 ~2.95×10 8 The speed of a traveling wave in a cable is approximately 1 m / s because the conductor is surrounded by air, which has a relative permittivity close to 1. In contrast, the traveling wave speed in a cable is typically about 1 / 2 to 2 / 3 the speed of light (approximately 1.5 × 10⁻⁶ m / s). 8 ~2.0×10 8 The speed of electromagnetic waves is slowed down by the fact that the cable conductor is tightly wrapped by an insulation layer (such as cross-linked polyethylene or oil-impregnated paper). These insulation materials have a relatively high permittivity (usually 2 to 4), which significantly increases the capacitance of the line and reduces the inductance, thereby slowing down the propagation speed of electromagnetic waves.

[0046] As one possible implementation method, combined with Figure 1The fault distance determination device receives a message from an electronic device, which includes the line length and line type of each of the multiple sub-lines of the transmission line. The fault distance determination device obtains the line length and line type of each of the multiple sub-lines of the transmission line from the message.

[0047] S202, The fault distance determination device monitors the zero-sequence voltage or zero-sequence current, phase current and current traveling wave of the transmission line through a traveling wave detection device located at the beginning of the transmission line.

[0048] Traveling wave (TW) detection devices are precision monitoring equipment used in power systems. Their core function is to capture and record transient voltage or current traveling wave signals that propagate at near the speed of light, generated by events such as lightning strikes, short circuits, or switching operations on transmission lines (including cables and overhead lines). Through high-frequency sampling (up to the megahertz level) and sensitive sensors, the device acquires the amplitude, polarity, and timing characteristics of the wavefront within an extremely short time (microseconds) of the wave's arrival at the measurement point. Based on the fixed propagation speed of the traveling wave on a specific line, the device can accurately determine the fault location (i.e., traveling wave ranging) by calculating the time difference of wavefront arrival at different monitoring points, or analyze the traveling wave waveform characteristics to achieve fault type identification and line status monitoring. It is a key technological equipment for modern smart grids to achieve rapid fault isolation and improve power supply reliability.

[0049] Phase current can be any one of the three phase currents.

[0050] S203. The fault distance determination device determines whether a fault has occurred in the transmission line based on the zero-sequence voltage or zero-sequence current and phase current.

[0051] As one possible implementation, the fault distance determination device determines whether a transmission line has a fault when the zero-sequence voltage or zero-sequence current is greater than a preset threshold and / or the phase current is greater than a preset current threshold; and determines that the transmission line has not a fault when the zero-sequence voltage or zero-sequence current is less than or equal to a preset threshold and the phase current is less than or equal to a preset current threshold.

[0052] For example, the preset threshold corresponding to the sequence voltage can be 15% of the system phase voltage of the collector line. For instance, for a collector line with a typical voltage level of 35kV and a phase voltage of approximately 20.2kV, the preset voltage threshold can be 3kV.

[0053] The preset threshold for zero-sequence current can be 5A.

[0054] For example, the preset current threshold can be 1.2 to 1.5 times the maximum load current of the transmission line. For instance, for a transmission line with a maximum load current of 400A, the preset current threshold can be in the range of 480A to 600A.

[0055] Based on this possible implementation method, by establishing a joint threshold criterion of zero-sequence voltage or zero-sequence current and phase current, the speed and reliability of initial fault diagnosis in transmission lines are effectively improved. The technical effect is as follows: utilizing the characteristic that an increase in zero-sequence voltage or zero-sequence current often accompanies an abnormal phase current during a fault, a comprehensive judgment is made using AND / OR logic. This allows for the rapid capture of obvious fault signs through a single electrical quantity exceeding its limit, while reliably eliminating interference and avoiding false triggering when neither threshold exceeds its limit. Thus, while ensuring rapid detection response, it significantly enhances anti-interference capability and the robustness of the criterion, providing accurate and efficient start-up conditions for subsequent advanced fault analysis (such as traveling wave ranging).

[0056] S204. The fault distance determination device determines the preliminary fault length based on the current traveling wave and the line type of the first line when a fault occurs in the transmission line.

[0057] The first line is the sub-line where the traveling wave detection device is located.

[0058] It should be noted that the traveling current wave includes the initial traveling wave front and the reflected traveling wave front.

[0059] As one possible implementation, the fault distance determination device determines the time difference between the moment when the traveling wave detection device detects the initial traveling wave front and the moment when the traveling wave detection device detects the reflected traveling wave front.

[0060] For example, the fault distance determination device takes the moment when the traveling wave detection device detects the initial traveling wave front as the first moment and the moment when the traveling wave detection device detects the reflected traveling wave front as the second moment, and determines the time difference between the first moment and the second moment.

[0061] The fault distance determination device uses half of the product of the time difference and the first traveling wave velocity as the initial fault length; the first traveling wave velocity is the propagation speed of the traveling wave in the first type of line; the first line type is the first line type.

[0062] For example, the fault distance determination device determines the line type of the first sub-line where the traveling wave detection device is located, i.e., the first line type. Then, the fault distance determination device obtains the propagation speed of the traveling wave in the line of the first line type, i.e. the first traveling wave speed. Finally, the fault distance determination device takes half of the product of the time difference and the first traveling wave speed as the preliminary fault length.

[0063] Based on this possible implementation, the initial fault length from the detection point to the fault point is directly calculated by acquiring the time difference between the initial traveling wave front and the reflected traveling wave front captured by the traveling wave detection device, multiplying it by a preset first traveling wave velocity, and taking half of the result. This scheme utilizes the naturally generated traveling wave front and its reflected signal when a fault occurs, without the need for additional detection signals or synchronization with equipment on the other side. It achieves single-end measurement, simple calculation, and rapid response, which is beneficial for quickly and accurately locating the fault section after a transmission line fault, providing crucial information for subsequent fault isolation and repair.

[0064] S205. The fault distance determination device determines the target fault length of the fault point from the traveling wave detection device and the target line type of the sub-line where the fault point is located, based on the preliminary fault length, the line length of each sub-line, and the line type of each sub-line.

[0065] As one possible implementation, firstly, the fault distance determination device obtains the equivalent line length of the second sub-line among multiple sub-lines; the line type of the second sub-line is the second line type, which is different from the first line type, and the line type of the first line is the first line type.

[0066] For example, the fault distance determination device acquires a first traveling wave velocity and a second traveling wave velocity; the first traveling wave velocity is the propagation speed of the traveling wave in a line of a first line type, and the second traveling wave velocity is the propagation speed of the traveling wave in a line of a second line type; the product of the target ratio and the line length of the second sub-line is used as the equivalent line length of the second sub-line; the target ratio is the ratio of the first traveling wave velocity to the second traveling wave velocity.

[0067] It should be noted that the specific details of this example can be found in the following descriptions of the detailed implementation of this application, and will not be described here.

[0068] Secondly, the fault distance determination device determines the equivalent transmission line length of the transmission line based on the line length of the third sub-line and the equivalent line length of the second sub-line; the line type of the third line is the first line type, and the third sub-line includes the first sub-line.

[0069] For example, the fault distance determination device connects the third sub-line with a length equal to the line length and the second sub-line with a length equal to the equivalent line length in sequence according to the connection relationship between the third sub-line and the second sub-line in the transmission line, thereby obtaining the equivalent transmission line length of the transmission line.

[0070] For example, if a transmission line includes three third sub-lines and three second sub-lines, with the first third sub-line having a length of 1 kilometer, the second third sub-line having a length of 2 kilometers, and the third third sub-line having a length of 3 kilometers, and the equivalent length of the first second sub-line having a length of 1 kilometer, the equivalent length of the second second sub-line having a length of 2 kilometers, and the equivalent length of the third second sub-line having a length of 3 kilometers, then the fault distance determining device determines the equivalent length of the transmission line to be 12 kilometers.

[0071] Secondly, the fault distance determination device determines the target sub-line where the fault point is located based on the equivalent transmission line and the initial fault length.

[0072] For example, the fault distance determination device determines the fault point in the equivalent transmission line of the transmission line with the distance between it and the traveling wave detection device as the preliminary fault length; and takes the sub-line where the fault point is located as the target sub-line.

[0073] It should be noted that the specific details of this example can be found in the following descriptions of the detailed implementation of this application, and will not be described here.

[0074] Secondly, the fault distance determination device determines the first distance between the fault point and the target endpoint of the target sub-line based on the line type of the target sub-line; the target endpoint is the endpoint of the target sub-line that is closest to the traveling wave detection device. For example, the fault distance determination device determines the difference between the preliminary fault length and the third distance as the fourth distance; the third distance is the sum of the line length of the third sub-line between the traveling wave detection device and the target sub-line and the equivalent line length of the second sub-line; the ratio of the fourth distance to the target ratio is used as the first distance; the target ratio is the ratio of the first traveling wave velocity to the second traveling wave velocity; the first traveling wave velocity is the propagation speed of the traveling wave in the first type of line, and the second traveling wave velocity is the propagation speed of the traveling wave in the second type of line.

[0075] It should be noted that the specific details of this example can be found in the following descriptions of the detailed implementation of this application, and will not be described here.

[0076] Secondly, the fault distance determination device uses the first distance and the second distance as the target fault length and the line type of the target sub-line as the target line type; the second distance is the sum of the line lengths of the sub-lines between the target sub-line and the traveling wave detection device.

[0077] For example, if the target sub-line is the third sub-line counting from the first sub-line in the transmission line, the fault distance determining device uses the sum of the line lengths of the two sub-lines before the third sub-line as the second distance.

[0078] For example, if the length of the first sub-line in a transmission line, i.e. the first sub-line where the traveling wave detection device is located, is 1 kilometer, and the length of the next sub-line, i.e. the second sub-line, is 2 kilometers, then the fault distance determination device determines the second distance to be 3 kilometers.

[0079] Subsequently, the fault distance determination device adds the second distance and the first distance to obtain the target fault length, and uses the line type of the target sub-line as the target line type.

[0080] Based on this possible implementation, by equating transmission lines containing different line types to a single line type (the first line type) and calculating the equivalent transmission line length, the actual sub-line to which the fault point belongs can be accurately located on the equivalent line based on the preliminary fault length. Then, by combining the actual type of the target sub-line, the specific fault location within it can be calculated, ultimately obtaining the true distance from the fault point to the detection device and its corresponding line type. This effectively solves the problem of traveling wave ranging error caused by different wave velocities under mixed line types, improving the accuracy and reliability of fault location.

[0081] Based on S201-S205, the method first calculates the initial fault length based on the first line where the traveling wave detection device is located and whose line type is known. Then, it performs equivalent conversion and precise positioning by combining the specific lengths and types of all sub-lines (including cables and overhead lines) in the transmission line. This effectively overcomes the positioning error caused by the traditional traveling wave ranging method in mixed lines (cable-overhead lines) where the time difference is directly converted into a single fixed wave speed due to the wave speed difference of different types of lines. It realizes a progressive ranging from initial coarse positioning to precise calibration based on the actual line structure, which significantly improves the accuracy of fault distance determination in complex line structures containing cables and overhead lines with different wave speed characteristics.

[0082] The above is a general description of the fault distance determination method provided in this application. The fault distance determination device provided in this application will be further described below with reference to the accompanying drawings.

[0083] In a design, such as Figure 3 As shown in the embodiment of this application, in S205, the fault distance determination device obtains the equivalent line length of the second sub-line among multiple sub-lines, which may specifically include the following steps: S301, The fault distance determination device acquires the first traveling wave velocity and the second traveling wave velocity.

[0084] Wherein, the first traveling wave velocity is the propagation speed of the traveling wave in the first type of line, and the second traveling wave velocity is the propagation speed of the traveling wave in the second type of line.

[0085] As one possible implementation method, combined with Figure 1 The fault distance determination device receives a message from an electronic device, which includes a first traveling wave velocity and a second traveling wave velocity. The fault distance determination device obtains the first traveling wave velocity and the second traveling wave velocity from the message.

[0086] S302, The fault distance determination device uses the product of the target ratio and the line length of the second sub-line as the equivalent line length of the second sub-line.

[0087] The target ratio is the ratio of the first traveling wave velocity to the second traveling wave velocity.

[0088] As one possible implementation, the fault distance determination device uses the ratio of the first traveling wave velocity to the second traveling wave velocity as the target ratio. Subsequently, the fault distance determination device uses the product of the target ratio and the line length of the second sub-line as the equivalent line length of the second sub-line.

[0089] Based on S301-S302, by calculating and applying the ratio of the first traveling wave velocity to the second traveling wave velocity, the actual length of the second line type sub-line is converted into an equivalent line length based on the wave velocity of the first line type. This achieves the unification of multiple line types under the same wave velocity reference for length measurement and calculation. This operation effectively eliminates the impact of differences in traveling wave propagation velocity caused by different line types (such as cables and overhead lines) on fault location, laying a key foundation for accurate fault interval judgment and distance calculation under a unified wave velocity reference system, thereby significantly improving the overall accuracy and reliability of fault location for mixed lines.

[0090] In a design, such as Figure 4 As shown in the embodiment of this application, in S205, the fault distance determination device determines the target sub-line where the fault point is located based on the equivalent transmission line and the preliminary fault length. Specifically, this may include the following steps: S401, The fault distance determination device determines the fault point in the equivalent transmission line of the transmission line whose distance from the traveling wave detection device is the preliminary fault length.

[0091] As one possible implementation, the fault distance determination device determines a point in the equivalent transmission line of the transmission line at a distance equal to the preliminary fault length from the traveling wave detection device, and uses this point as the fault point.

[0092] S402, The fault distance determination device takes the sub-line where the fault point is located as the target sub-line.

[0093] As one possible implementation, the fault distance determination device locates a sub-line containing the fault point in the equivalent transmission line of the transmission line and uses that sub-line as the target sub-line.

[0094] Based on S401-S402, by placing the initial fault length on the equivalent transmission line (i.e., a virtual line where all sub-lines have been uniformly converted to the first line type wave velocity reference) for location, the actual physical sub-line to which the fault point belongs can be intuitively and accurately mapped. This method uses the equivalent length as a unified scale, avoiding misjudgment of intervals caused by directly interpreting the wave velocity differences of different line types on the actual mixed line, thereby ensuring the correctness of fault sub-line identification and providing a reliable premise for subsequent accurate fault point location within the target sub-line.

[0095] In a design, such as Figure 5 As shown in the embodiment of this application, in S205, the fault distance determination device determines the first distance between the fault point and the target endpoint of the target sub-line based on the line type of the target sub-line. Specifically, this may include the following steps: S501, The fault distance determination device uses the difference between the preliminary fault length and the third distance as the fourth distance.

[0096] The third distance is the sum of the length of the third sub-line between the traveling wave detection device and the target sub-line and the equivalent length of the second sub-line.

[0097] As one possible implementation, the fault distance determination device adds the line length of the third sub-line between the traveling wave detection device and the target sub-line to the equivalent line length of the second sub-line to obtain the third distance.

[0098] For example, if the target sub-line is the third sub-line counting from the first sub-line in the transmission line, the fault distance determination device uses the sum of the line length of the third sub-line and the equivalent line length of the second sub-line among the two sub-lines preceding the third sub-line as the third distance.

[0099] S502, The fault distance determination device uses the ratio of the fourth distance to the target ratio as the first distance.

[0100] The target ratio is the ratio of the first traveling wave velocity to the second traveling wave velocity; the first traveling wave velocity is the propagation speed of the traveling wave in a first-type line, and the second traveling wave velocity is the propagation speed of the traveling wave in a second-type line.

[0101] As one possible implementation, the fault distance determination device uses the ratio of the first traveling wave velocity to the second traveling wave velocity as the target ratio, and then uses the ratio of the fourth distance to the target ratio as the first distance.

[0102] Based on S501-S502, the equivalent remaining length (fourth distance) of the fault point entering the target sub-line is first calculated under a unified wave velocity reference. Then, this equivalent length is used to calculate the actual physical distance (first distance) under the actual type of the target sub-line using the wave velocity ratio (target ratio), thereby accurately determining the specific location of the fault point inside the target sub-line. This step effectively solves the last key link in accurate fault location: accurately decomposing and restoring the total equivalent distance from the detection point to the fault point into the actual hybrid line structure, and finally obtaining the true distance from the fault point to the endpoint of its sub-line, ensuring the accuracy of the entire process from fault interval identification to specific point location.

[0103] The above mainly describes the solution provided by the embodiments of this application from the perspective of the fault distance determination device executing the fault distance determination method. To achieve the above functions, the fault distance determination device includes hardware structures and / or software modules corresponding to each function. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments disclosed herein, the embodiments of this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0104] This application embodiment can divide the fault distance determination device into functional modules according to the above method example. For example, each function can be divided into a separate functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. Optionally, the module division in this application embodiment is illustrative and only represents one logical functional division; other division methods may be used in actual implementation. Furthermore, "module" here can refer to an application-specific integrated circuit (ASIC), a circuit, a processor and memory executing one or more software or firmware programs, integrated logic circuits, and / or other devices that can provide the above functions.

[0105] When using functional module division Figure 6 A schematic diagram of a fault distance determination device is shown. Figure 6 As shown, the fault distance determination device 60 includes an acquisition module 601 and a processing module 602.

[0106] In some embodiments, the fault distance determination device 60 may further include a storage module ( Figure 6 (not shown in the image) is used to store program instructions and data.

[0107] The transmission line includes an acquisition module 601, which acquires the line length and line type of each of the multiple sub-lines of the transmission line; the line type includes cable or overhead line. A processing module 602 monitors the zero-sequence voltage or zero-sequence current, phase current, and current traveling wave of the transmission line using a traveling wave detection device located at the beginning of the transmission line. The processing module 602 determines whether a fault has occurred in the transmission line based on the zero-sequence voltage or zero-sequence current and phase current. In the event of a fault in the transmission line, the processing module 602 determines the preliminary fault length based on the current traveling wave and the line type of the first line; the first line is the sub-line where the traveling wave detection device is located. The processing module 602 also determines the target fault length from the fault point to the traveling wave detection device and the target line type of the sub-line where the fault point is located based on the preliminary fault length, the line length of each sub-line, and the line type of each sub-line.

[0108] Optionally, the processing module 602 is used to determine whether a fault has occurred in the transmission line based on the zero-sequence voltage or zero-sequence current and the phase current, including: determining whether a fault has occurred in the transmission line when the zero-sequence voltage or zero-sequence current is greater than a preset threshold and / or the phase current is greater than a preset current threshold; and determining that no fault has occurred in the transmission line when the zero-sequence voltage or zero-sequence current is less than or equal to a preset threshold and the phase current is less than or equal to a preset current threshold.

[0109] Optionally, the current traveling wave includes an initial traveling wave front and a reflected traveling wave front. In the event of a fault in the transmission line, the processing module 602 is used to determine the preliminary fault length based on the current traveling wave and the first line, including: determining the time difference between the moment when the traveling wave detection device detects the initial traveling wave front and the moment when the traveling wave detection device detects the reflected traveling wave front; taking half of the product of the time difference and the first traveling wave velocity as the preliminary fault length; the first traveling wave velocity is the propagation speed of the traveling wave in a line of the first line type; the line type of the first line is the first line type.

[0110] Optionally, the processing module 602 is used to determine the target fault length of the fault point from the traveling wave detection device and the target line type of the sub-line where the fault point is located, based on the preliminary fault length, the line length of each sub-line, and the line type of each sub-line. This includes: obtaining the equivalent line length of the second sub-line among multiple sub-lines; the line type of the second sub-line is a second line type, which is different from the first line type, and the line type of the first line is the first line type; determining the equivalent transmission line length of the transmission line based on the line length of the third sub-line and the equivalent line length of the second sub-line; the line type of the third line is the first line type, and the third sub-line includes the first sub-line; determining the target sub-line where the fault point is located based on the equivalent transmission line length of the transmission line and the preliminary fault length; determining a first distance between the fault point and the target endpoint of the target sub-line based on the line type of the target sub-line; the target endpoint is the endpoint of the target sub-line closest to the traveling wave detection device; using the first distance and the second distance as the target fault length, and the line type of the target sub-line as the target line type; the second distance is the sum of the line lengths of the sub-lines between the target sub-line and the traveling wave detection device.

[0111] Optionally, the processing module 602 is used to obtain the equivalent line length of the second sub-line among multiple sub-lines, including: obtaining a first traveling wave velocity and a second traveling wave velocity; the first traveling wave velocity is the propagation speed of the traveling wave in a line of the first line type, and the second traveling wave velocity is the propagation speed of the traveling wave in a line of the second line type; the product of the target ratio and the line length of the second sub-line is used as the equivalent line length of the second sub-line; the target ratio is the ratio of the first traveling wave velocity to the second traveling wave velocity.

[0112] Optionally, the processing module 602 is used to determine the target sub-line where the fault point is located based on the equivalent transmission line of the transmission line and the initial fault length, including: determining the fault point in the equivalent transmission line of the transmission line whose distance from the traveling wave detection device is the initial fault length; and taking the sub-line where the fault point is located as the target sub-line.

[0113] Optionally, the processing module 602 is used to determine a first distance between the fault point and the target endpoint of the target sub-line according to the line type of the target sub-line, including: taking the difference between the preliminary fault length and the third distance as a fourth distance; the third distance is the sum of the line length of the third sub-line between the traveling wave detection device and the target sub-line and the equivalent line length of the second sub-line; taking the ratio of the fourth distance to the target ratio as the first distance; the target ratio is the ratio of the first traveling wave velocity to the second traveling wave velocity; the first traveling wave velocity is the propagation speed of the traveling wave in the line of the first line type, and the second traveling wave velocity is the propagation speed of the traveling wave in the line of the second line type.

[0114] All relevant content of each step involved in the above method embodiments can be referenced from the functional description of the corresponding functional module, and will not be repeated here.

[0115] When the functions of the above modules are implemented in hardware... Figure 7 A schematic diagram of yet another fault distance determination device is shown. (For example...) Figure 7 As shown, the fault distance determination device 70 includes a processor 701, a memory 702, and a bus 703. The processor 701 and the memory 702 can be connected via the bus 703.

[0116] The processor 701 is the control center of the fault distance determination device 70. It can be a single processor or a collective term for multiple processing elements. For example, the processor 701 can be a general-purpose central processing unit (CPU) or other general-purpose processors. The general-purpose processor can be a microprocessor or any conventional processor.

[0117] As one embodiment, processor 701 may include one or more CPUs, for example Figure 7 CPU 0 and CPU 1 are shown in the diagram.

[0118] The memory 702 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but is not limited thereto.

[0119] As one possible implementation, the memory 702 can exist independently of the processor 701. The memory 702 can be connected to the processor 701 via a bus 703 and is used to store instructions or program code. When the processor 701 calls and executes the instructions or program code stored in the memory 702, it can implement the fault distance determination method provided in the embodiments of this application.

[0120] In another possible implementation, the memory 702 can also be integrated with the processor 701.

[0121] Bus 703 can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. This bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 7 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0122] It should be pointed out that, Figure 7 The structure shown does not constitute a limitation on the fault distance determining device 70. Except... Figure 7 In addition to the components shown, the fault distance determining device 70 may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0123] As an example, combined Figure 6 The functions implemented by the acquisition module 601 and processing module 602 in the fault distance determination device 60 are the same as those of the acquisition module 601 and processing module 602. Figure 7 The processor 701 in it has the same function.

[0124] Optional, such as Figure 7 As shown, the fault distance determination device 70 provided in this application embodiment may further include a communication interface 704.

[0125] Communication interface 704 is used to connect to other devices via a communication network. This communication network can be Ethernet, a wireless access network, a wireless local area network (WLAN), etc. Communication interface 704 may include a receiving unit for receiving data and a transmitting unit for transmitting data.

[0126] In one possible implementation, the communication interface 704 in the fault distance determination device 70 provided in this application embodiment can also be integrated into the processor 701, and this application embodiment does not specifically limit this.

[0127] As a possible product form, the fault distance determination device of this application embodiment can also be implemented using the following: one or more field programmable gate arrays (FPGAs), programmable logic devices (PLDs), controllers, state machines, gate logic, discrete hardware components, any other suitable circuits, or any combination of circuits capable of performing the various functions described throughout this application.

[0128] Through the above description of the embodiments, those skilled in the art will clearly understand that, for the sake of convenience and brevity, only the division of the above functional units is used as an example. In practical applications, the above functions can be assigned to different functional units as needed, that is, the internal structure of the device can be divided into different functional units to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0129] This application also provides a computer-readable storage medium storing a computer program or instructions thereon, which, when executed, causes a computer to perform the various steps in the method flow shown in the above method embodiments.

[0130] Embodiments of this application provide a computer program product containing instructions that, when executed on a computer, cause the computer to perform the various steps in the method flow shown in the above-described method embodiments.

[0131] This application provides a chip system, including: a processor and an interface circuit; the interface circuit is used to receive computer programs or instructions and transmit them to the processor; the processor is used to execute the computer programs or instructions so that the chip system performs each step in the method flow shown in the above method embodiments.

[0132] The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), registers, hard disks, optical fibers, compact disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing, or any other form of computer-readable storage medium in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium may also be a component of the processor. The processor and the storage medium may reside in a purpose-specific ASIC. In the embodiments of this application, the computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0133] Since the fault distance determination device, computer-readable storage medium, and computer program product provided in this embodiment can be applied to the fault distance determination method provided in this embodiment, the technical effects that can be obtained can also be referred to the above method embodiments. The embodiments of this application will not be repeated here.

[0134] Although this application has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings and the disclosure in carrying out the claimed application.

[0135] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely illustrative examples of this application and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if such modifications and modifications of this application fall within the scope of equivalent technology of this application, this application also intends to include such modifications and modifications.

Claims

1. A method for determining fault distance, characterized in that, The method includes: Obtain the line length and line type of each sub-line in a power transmission line; the line type includes cable or overhead line. The zero-sequence voltage or zero-sequence current, phase current and current traveling wave of the transmission line are monitored by a traveling wave detection device located at the beginning of the transmission line. Determine whether the transmission line has a fault based on the zero-sequence voltage or zero-sequence current and phase current. In the event of a fault in the transmission line, the initial fault length is determined based on the current traveling wave and the line type of the first line; the first line is the sub-line where the traveling wave detection device is located. The target fault length of the fault point from the traveling wave detection device and the target line type of the sub-line where the fault point is located are determined based on the preliminary fault length, the line length of each sub-line, and the line type of each sub-line.

2. The method according to claim 1, characterized in that, Determining whether a fault has occurred in the transmission line based on zero-sequence voltage or zero-sequence current and phase current includes: If the zero-sequence voltage or zero-sequence current is greater than a preset threshold and / or the phase current is greater than a preset current threshold, it is determined whether the transmission line has experienced a fault. If the zero-sequence voltage or zero-sequence current is less than or equal to a preset threshold, and the phase current is less than or equal to a preset current threshold, it is determined that no fault has occurred in the transmission line.

3. The method according to claim 1, characterized in that, The current traveling wave includes an initial traveling wave front and a reflected traveling wave front. In the event of a fault in the transmission line, the initial fault length is determined based on the current traveling wave and the first line, including: Determine the time difference between the moment when the traveling wave detection device detects the initial traveling wave front and the moment when the traveling wave detection device detects the reflected traveling wave front; The initial fault length is half of the product of the time difference and the first traveling wave velocity; the first traveling wave velocity is the propagation speed of the traveling wave in a line of the first line type; the line type of the first line is the first line type.

4. The method according to any one of claims 1-3, characterized in that, The target fault length of the fault point from the traveling wave detection device and the target line type of the sub-line where the fault point is located are determined based on the preliminary fault length, the line length of each sub-line, and the line type of each sub-line, including: Obtain the equivalent line length of the second sub-line among multiple sub-lines; the line type of the second sub-line is the second line type, which is different from the first line type, and the line type of the first line is the first line type; The equivalent transmission line length of the transmission line is determined based on the line length of the third sub-line and the equivalent line length of the second sub-line; the line type of the third line is the first line type, and the third sub-line includes the first sub-line; Based on the equivalent transmission line of the transmission line and the preliminary fault length, the target sub-line where the fault point is located is determined. The first distance between the fault point and the target endpoint of the target sub-line is determined based on the line type of the target sub-line; the target endpoint is the endpoint of the target sub-line that is closest to the traveling wave detection device. The first distance and the second distance are taken as the target fault length, and the line type of the target sub-line is taken as the target line type; the second distance is the sum of the line lengths of the sub-lines between the target sub-line and the traveling wave detection device.

5. The method according to claim 4, characterized in that, Obtain the equivalent line length of the second sub-line among multiple sub-lines, including: Obtain a first traveling wave velocity and a second traveling wave velocity; the first traveling wave velocity is the propagation speed of the traveling wave in a line of the first line type, and the second traveling wave velocity is the propagation speed of the traveling wave in a line of the second line type; The product of the target ratio and the line length of the second sub-line is taken as the equivalent line length of the second sub-line; the target ratio is the ratio of the first traveling wave velocity to the second traveling wave velocity.

6. The method according to claim 4, characterized in that, Based on the equivalent transmission line and the preliminary fault length, the target sub-line where the fault point is located is determined, including: The distance between the fault point and the traveling wave detection device in the equivalent transmission line of the transmission line is determined as the preliminary fault length; The sub-line where the fault point is located is designated as the target sub-line.

7. The method according to claim 4, characterized in that, Determine the first distance between the fault point and the target endpoint of the target sub-line based on the line type of the target sub-line, including: The difference between the initial fault length and the third distance is taken as the fourth distance; the third distance is the sum of the line length of the third sub-line between the traveling wave detection device and the target sub-line and the equivalent line length of the second sub-line; The ratio of the fourth distance to the target ratio is taken as the first distance; the target ratio is the ratio of the first traveling wave velocity to the second traveling wave velocity; the first traveling wave velocity is the propagation speed of the traveling wave in the first type of line, and the second traveling wave velocity is the propagation speed of the traveling wave in the second type of line.

8. A fault distance determination device, characterized in that, The device includes: an acquisition module and a processing module; The acquisition module is used to acquire the line length and line type of each sub-line among multiple sub-lines of the transmission line; the line type includes cable or overhead line. The processing module is used to monitor the zero-sequence voltage or zero-sequence current, phase current and current traveling wave of the transmission line through a traveling wave detection device located at the beginning of the transmission line. The processing module is used to determine whether the transmission line has a fault based on the zero-sequence voltage or zero-sequence current and phase current. The processing module is used to determine the preliminary fault length based on the current traveling wave and the line type of the first line when a fault occurs in the transmission line; the first line is the sub-line where the traveling wave detection device is located. The processing module is used to determine the target fault length of the fault point from the traveling wave detection device and the target line type of the sub-line where the fault point is located, based on the preliminary fault length, the line length of each sub-line, and the line type of each sub-line.

9. A fault distance determination device, characterized in that, The fault distance determination device includes: a processor coupled to a memory for storing programs or instructions, which, when executed by the processor, cause the device to perform the method as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program or instructions are executed, they cause the computer to perform the method as described in any one of claims 1 to 7.

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