Traveling wave fault location method, system, device and medium suitable for boundaryless flexible AC / DC loop

Abstract

This invention discloses a traveling wave fault location method, system, equipment, and medium applicable to boundless flexible DC ring networks, relating to the field of flexible DC transmission technology. It aims to solve the technical problems of traditional two-end traveling wave location methods, such as reliance on high-precision synchronization and the difficulty in accurately calibrating wave velocity due to traveling wave dispersion effects. The invention includes: obtaining a first arrival time difference and a second arrival time difference; obtaining the length of the faulty line and the sum of the lengths of other transmission lines in the boundless flexible DC ring network excluding the faulty line; and calculating the distance from the fault point to the first-end protection device and / or the last-end protection device based on the above parameters. This invention eliminates the need for high-precision synchronization between the two-end protection devices, avoiding location failure caused by synchronization failure; it also completely eliminates the traveling wave velocity parameter, fundamentally solving the wave velocity calibration problem; the steps are simple, the parameters are easy to obtain, the computational load is small, and the location accuracy is high, enabling precise fault location in boundless flexible DC ring networks.

Description

Technical Field

[0001] This invention relates to the field of flexible DC transmission technology, and in particular to a traveling wave fault location method, system, equipment and medium applicable to boundless flexible DC ring networks. Background Technology

[0002] Flexible direct current (DC) transmission technology is a key technology for realizing large-scale grid integration of renewable energy and constructing new power systems. However, flexible DC transmission lines are long, laid in complex environments, and prone to frequent and rapid faults, seriously threatening the safe and stable operation of the power grid. To shorten fault repair time and ensure efficient absorption of new energy and reliable power supply, it is urgent to study high-precision fault location technology for flexible DC transmission lines.

[0003] Currently, the mainstream traveling wave double-end positioning technology for flexible DC transmission lines faces serious challenges in synchronization and wave velocity calibration due to the spectral distortion and wave velocity frequency variation characteristics of traveling waves. On the one hand, the limited bandwidth of traditional instrument transformers (sampling rate 50kHz) cannot effectively capture the characteristics of high-frequency traveling waves of 100kHz and above, leading to errors in the calibration of the arrival time of the traveling wave front, which directly affects the synchronization accuracy of the double-end time difference calculation. On the other hand, in the complex topology of multi-end flexible straight lines, the multiple reflections of traveling waves caused by the converter station boundary result in wave front distortion. This, combined with the wave velocity frequency variation characteristics caused by the dispersion effect of traveling waves over long distances, and the asymmetry of propagation paths at each monitoring point amplifying the clock synchronization deviation, makes it difficult for traditional double-end positioning methods to meet the μs-level synchronization accuracy requirements. Therefore, to ensure the efficiency of power grid operation and maintenance, improve power supply reliability, and facilitate the construction of new power systems, it is imperative to overcome the key technologies for fault location that are not dependent on synchronization and are limited by the difficulty in accurately calibrating the traveling wave velocity. Summary of the Invention

[0004] The technical problem to be solved and the technical task proposed by this invention is to improve and refine existing technical solutions, and to provide a traveling wave fault location method, system, device, and medium suitable for boundless flexible straight ring networks, so as to achieve high-precision location of fault points in boundless flexible straight ring networks, get rid of the dependence on high-precision synchronization time in traditional methods, and solve the core problem that the traveling wave dispersion effect makes it difficult to accurately calibrate the wave velocity. To this end, this invention adopts the following technical solution.

[0005] In a first aspect, the present invention provides a traveling wave fault location method applicable to a boundaryless flexible straight ring network, comprising the following steps: 1) Obtain the first arrival time difference and the second arrival time difference, wherein the first arrival time difference is the difference in arrival time of the first two line-mode fault voltage traveling waves with significant amplitude detected by the fault line head-end protection device, and the second arrival time difference is the difference in arrival time of the first two line-mode fault voltage traveling waves with significant amplitude detected by the fault line end protection device. 2) Obtain the length of the faulty line, and the sum of the lengths of other transmission lines in the boundless flexible DC ring network excluding the faulty line; 3) Based on the first arrival time difference, the second arrival time difference, the length of the faulted line, and the sum of the lengths of other transmission lines in the boundless flexible DC ring network excluding the faulted line, calculate the distance from the fault point to the head protection device and / or the end protection device to obtain the location of the fault point.

[0006] This technical solution uses the arrival time difference of single-ended double traveling waves, locally detected by the protection devices at both ends of the faulty line, as the core calculation parameter, instead of relying on the absolute arrival time difference of the two devices as used in traditional methods. Therefore, it does not require the protection devices at both ends to maintain high-precision clock synchronization, fundamentally eliminating the impact of synchronization errors on positioning accuracy. The core calculation process of this solution only requires two arrival time differences, the length of the faulty line, and the sum of the lengths of other lines in the ring network. It does not include the traveling wave velocity parameter, completely avoiding the problem of inaccurate wave velocity calibration caused by the traveling wave dispersion effect. The positioning accuracy is not affected by changes in wave velocity.

[0007] All parameters required for this solution can be obtained directly or indirectly from existing protection devices: the first and second arrival time differences are calculated based on the arrival times of the traveling waves detected by the protection devices; the lengths of the faulty lines and the non-faulty lines in the ring network are known parameters inherent to the line design and ring network topology, requiring no additional data acquisition equipment. Furthermore, this solution fully utilizes the physical characteristic of the converter station outlet refractive index being close to 1 in a boundless flexible DC ring network. It only requires identifying the first two line-mode fault voltage traveling waves with significant amplitudes, filling the technical gap of difficulty in identifying effective reflected waves in boundless scenarios. The solution is simple in its steps, directly adaptable to existing protection devices in flexible DC ring networks, and highly practical for engineering applications.

[0008] As a preferred technical means: In step 3), the distance from the fault point to the first-end protection device is equal to half the length of the fault line plus the correction distance; the correction distance is equal to the difference between the second arrival time difference and the first arrival time difference, divided by twice the sum of the second arrival time difference and the first arrival time difference, and then multiplied by the sum of the lengths of the other transmission lines in the boundless flexible DC ring network excluding the fault line.

[0009] This technical solution clarifies the specific calculation logic of the distance from the fault point to the first-end protection device. It does not introduce traveling wave velocity parameters throughout the process, thus avoiding the positioning errors caused by traveling wave dispersion and wave velocity frequency variation from the root of the algorithm. This significantly improves the accuracy and anti-interference capability of the first-end ranging and positioning. At the same time, the calculation process only relies on the time difference of local detection at both ends and the inherent preset parameters of the line. No additional signal processing or hardware upgrades are required. The engineering implementation threshold is low, and it can be directly integrated into existing protection devices to quickly output the first-end ranging and positioning results.

[0010] As a preferred technical means: In step 3), the distance from the fault point to the end protection device is equal to half the length of the fault line minus the correction distance; the correction distance is equal to the difference between the second arrival time difference and the first arrival time difference, divided by twice the sum of the second arrival time difference and the first arrival time difference, and then multiplied by the sum of the lengths of other transmission lines in the boundless flexible DC ring network excluding the fault line.

[0011] This technical solution provides the specific calculation logic for the distance from the fault point to the end protection device, which complements the calculation of the distance at the beginning. It allows for the selection of calculating the distance from the fault point to either the beginning or the end, or both can be calculated simultaneously for mutual verification. The formula is concise and computationally efficient. The calculation logic of this solution does not rely on the traveling wave velocity or the clock synchronization at both ends, completely avoiding the interference of traveling wave dispersion effects and synchronization deviations on the end-point ranging and positioning results. This ensures the stability and accuracy of end-point ranging and positioning under different fault locations and different transition resistance conditions, and can quickly output accurate end-point positioning results, providing a direct and reliable location reference for the operation and maintenance of faulty lines.

[0012] Secondly, the present invention provides a traveling wave fault location system suitable for boundaryless flexible DC ring networks, which is used to implement the aforementioned traveling wave fault location method, the system comprising: The time detection module is used to detect the arrival times of the first two line-mode fault voltage traveling waves with significant amplitudes at the fault line head protection device and the fault line end protection device, and to calculate the first arrival time difference and the second arrival time difference. The data acquisition module is used to acquire the length of the faulty line and the sum of the lengths of other transmission lines in the boundless flexible DC ring network, excluding the faulty line. The fault location module is used to calculate the distance from the fault point to the head protection device and / or the end protection device based on the first arrival time difference, the second arrival time difference, the length of the fault line, and the lengths of other transmission lines in the boundless flexible DC ring network excluding the fault line.

[0013] This technical solution provides a system architecture corresponding to the aforementioned methods. Through the organic cooperation of three modules, it realizes the hardware or software deployment of the fault location method. It can be directly integrated into the existing line protection system, station control layer equipment, or dispatch master station of the boundless flexible DC ring network. By obtaining the local time difference between the two protection devices through the time detection module, the system architecture completely eliminates the dependence on the high-precision global synchronization time system, significantly reducing the deployment and operation and maintenance costs of the system. The fault location module completes the location calculation only based on the local time difference and the known inherent parameters of the line, without the need to introduce traveling wave velocity parameters, fundamentally solving the wave velocity calibration problem. This ensures the accuracy and reliability of fault location in the boundless flexible DC ring network scenario, can quickly complete the fault point location, effectively shorten the fault repair time, and improve the power supply reliability of the flexible DC power grid.

[0014] As a preferred technical means: the fault location module includes a first fault location unit, used to calculate the distance from the fault point to the head-end protection device; the distance from the fault point to the head-end protection device is equal to half the length of the fault line plus a correction distance; the correction distance is equal to the difference between the second arrival time difference and the first arrival time difference, divided by twice the sum of the second arrival time difference and the first arrival time difference, and then multiplied by the sum of the lengths of other transmission lines in the boundless flexible DC ring network excluding the fault line.

[0015] This technical solution, by setting up a first fault ranging unit responsible for calculating the distance from the fault point to the first-end protection device, improves the execution efficiency and result stability of the ranging calculation. It clarifies the specific calculation logic for the first-end distance, completely avoiding positioning errors caused by traveling wave velocity and synchronization deviations at both ends, thus ensuring high accuracy and strong anti-interference capabilities of the first-end ranging and positioning results. It can stably adapt to the first-end positioning requirements under different fault conditions. The data interaction link between this unit and other modules in the system is simple; it can directly call the output data of the front-end module to complete the calculation without redundant processing steps, and can quickly output the first-end ranging and positioning results, meeting the timeliness requirements for rapid fault handling in flexible DC power grids.

[0016] As a preferred technical means: the fault location module includes a second fault location unit, used to calculate the distance from the fault point to the end protection device; the distance from the fault point to the end protection device is equal to half the length of the fault line minus the correction distance; the correction distance is equal to the difference between the second arrival time difference and the first arrival time difference, divided by twice the sum of the second arrival time difference and the first arrival time difference, and then multiplied by the sum of the lengths of other transmission lines in the boundless flexible DC ring network excluding the fault line.

[0017] This solution incorporates a second fault location unit responsible for calculating the distance from the fault point to the end protection device. This complements the first fault location unit, simultaneously outputting location results from both the beginning and end of the fault location, effectively improving the reliability and redundancy of the fault location results. The specific calculation logic for the end distance is clearly defined, without introducing traveling wave velocity parameters or requiring clock synchronization between the protection devices at both ends. This completely avoids interference from traveling wave dispersion and synchronization deviation on the location results, ensuring the accuracy and stability of the end-point location measurement. The unit's computational logic is simple and efficient, with smooth data interaction with existing modules in the system, enabling rapid calculation of the end distance. This provides accurate and reliable end-point location references for the operation and maintenance of faulty lines in the boundless flexible DC ring network.

[0018] Thirdly, the present invention provides an electronic device, the device comprising one or more processors and one or more memories, wherein the one or more memories store at least one piece of program code, and when the program code is executed by the one or more processors, it implements the aforementioned traveling wave fault location method applicable to a boundless flexible DC ring network.

[0019] Fourthly, the present invention provides a storage medium storing at least one piece of program code, which, when executed by a processor, implements the steps of the aforementioned traveling wave fault location method applicable to a boundless flexible DC ring network.

[0020] Beneficial effects: 1. This technical solution uses the arrival time difference of single-end double traveling waves detected locally by the protection devices at both ends of the faulty line as the core calculation parameter. It does not rely on the high-precision global synchronization time of the protection devices at both ends, completely getting rid of the strong dependence on GPS / BeiDou and other time synchronization systems, and avoiding the interference of synchronization deviation on the positioning results. 2. The core calculation process does not require the introduction of traveling wave velocity parameters, completely eliminating the industry problem of difficult accurate calibration of wave velocity caused by traveling wave dispersion and wave velocity frequency variation in long-distance lines; 3. Adapting to the refractive index close to 1 at the outlet of the flexible DC-DC converter station in a boundaryless scenario, it only requires identifying the first two line-mode fault voltage traveling waves with significant amplitudes, thus filling the technical gap of difficulty in identifying effective reflected waves in boundaryless scenarios. The solution is simple and can be directly adapted to the protection devices of existing flexible DC-DC ring networks, making it highly practical for engineering applications. Attached Figure Description

[0021] Figure 1 This is an overall flowchart of the present invention; Figure 2 This is a schematic diagram of a flexible DC power transmission system constructed according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the fault traveling wave propagation path according to an embodiment of the present invention; Figure 4This is a schematic diagram of the traveling wave measured by the line head protection device in an embodiment of the present invention; Figure 5 This is a schematic diagram of the traveling wave measured by the line end protection device in an embodiment of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0023] Example 1 This embodiment provides a traveling wave fault location method applicable to boundless flexible straight ring networks, such as... Figure 1 As shown, it includes the following steps: S1: Obtain the first arrival time difference and the second arrival time difference. The first arrival time difference is the difference in arrival times of the first two line-mode fault voltage traveling waves with significant amplitudes detected by the fault line head-end protection device, and the second arrival time difference is the difference in arrival times of the first two line-mode fault voltage traveling waves with significant amplitudes detected by the fault line end protection device. S2: Obtain the length of the faulty line, and the sum of the lengths of other transmission lines in the boundless flexible DC ring network excluding the faulty line; S3: Based on the first arrival time difference, the second arrival time difference, the length of the faulty line, and the sum of the lengths of other transmission lines in the boundless flexible DC ring network excluding the faulty line, calculate the distance from the fault point to the head protection device and the tail protection device, and obtain and output the location of the fault point.

[0024] The distance from the fault point to the first-end protection device and the last-end protection device is calculated using the following core formula:

[0025] In the formula, x 1 indicates the distance of the fault location from the first-end protection device. x 2 indicates the distance from the fault location to the end protection device. This indicates the length of the faulty line in a flexible DC ring network. This represents the sum of the lengths of all transmission lines in a flexible DC ring network, excluding faulty lines. This indicates the arrival time difference of the first two significantly amplitude line-mode fault voltage traveling waves detected by the first-end protection device. This represents the arrival time difference of the first two line-mode fault voltage traveling waves with significant amplitudes detected by the end protection device.

[0026] The complete derivation of the above core formula is explained below: Since the traveling wave ranging method of the boundaryless flexible DC ring network requires the arrival time difference of the first two line mode fault voltage traveling waves with significant amplitudes to be detected by the protection devices at both ends, and the time difference detected by the protection devices at both ends is related to the fault distance and is not the same, they will be introduced separately below.

[0027] In some possible implementations, the propagation distance and arrival time of the line-mode fault voltage traveling wave are: First, based on the fact that the refractive index at the outlet of the boundaryless flexible DC ring network converter station is close to 1, the propagation distance of the traveling waves of the first two line-mode fault voltages with significant amplitudes detected by the protection device at the head end of the faulty line is determined to satisfy:

[0028] in, This indicates the propagation distance of the traveling wave of the first significant line-mode fault voltage detected by the first-end protection device. This indicates the propagation distance of the traveling wave of the second significant line-mode fault voltage detected by the first-end protection device. x 1 indicates the distance of the fault location from the first-end protection device. x 2 indicates the distance from the fault location to the end protection device. This represents the sum of the lengths of all transmission lines in a flexible DC ring network, excluding faulty lines. Secondly, the propagation distance of the traveling waves of the first two line-mode fault voltages with significant amplitudes detected by the protection device at the end of the faulty line must satisfy the following:

[0029] in, This indicates the propagation distance of the traveling wave of the first significant line-mode fault voltage detected by the end-of-line protection device. This indicates the propagation distance of the traveling wave of the second significant line-mode fault voltage detected by the end protection device; Finally, the arrival time difference of the first two line-mode fault voltage traveling waves with significant amplitudes, measured by the protection devices at both ends of the faulty line, satisfies the following:

[0030] in, This indicates the arrival time difference of the first two significantly amplitude line-mode fault voltage traveling waves detected by the first-end protection device. This indicates the arrival time difference of the first two significantly amplitude line-mode fault voltage traveling waves detected by the end protection device. v This indicates the traveling wave velocity of the line-mode fault voltage.

[0031] In some possible implementations, the two-end ranging formula based on the travel time difference characteristics of the linear mode travel wave satisfies:

[0032] in, This indicates the length of the faulty line in a flexible DC ring network.

[0033] Among some possible implementations, the two-end ranging formula, unaffected by traveling wave velocity and synchronization time, is as follows: First, determine the relationship between the traveling wave velocity, propagation distance, and the arrival time difference of the traveling wave of the line mode fault voltage, which satisfies the following:

[0034] Then, substituting the above relationship into the derivation of the two-end ranging formula based on the traveling wave time difference characteristics of the linear mode, we can obtain a two-end ranging formula that is unaffected by the traveling wave velocity and synchronization time:

[0035] To verify the effectiveness and superiority of the method provided in this embodiment, some specific examples are provided below: Establish such as Figure 2 The ±400kV flexible DC power grid electromagnetic transient simulation model shown includes modular multilevel converters (MMCs) MMC1 and MMC3 with a rated capacity of 2400MW, MMC2 and MMC4 with a rated capacity of 1600MW, a 200mH current-limiting reactor, and a flexible DC transmission line. L 1. L 2. L 3. L All four lines are 200km long. The DC lines adopt a frequency response model, and the sampling frequency of the protection device is 100kHz.

[0036] Figure 3 This is a schematic diagram of the traveling wave propagation path during a fault. When the transmission line... L 1. A single-pole ground fault occurs f At that time, the protection device at the beginning of the line R The two traveling waves with larger amplitudes detected were the initial traveling wave of the line-mode fault voltage and the traveling wave of the line-mode fault voltage refracted through bus N, Q, and P, respectively. The propagation distances of the two traveling waves were respectively x 1 and x 2+ L 2+ L 3+ L 4; Line end protection device R 5. The two traveling waves with larger amplitudes detected were the initial traveling wave of the line-mode fault voltage and the traveling wave of the line-mode fault voltage refracted through buses M, P, and Q, respectively. The propagation distances of the two traveling waves were respectivelyx 2 and x 1+ L 4+ L 3+ L 2.

[0037] DC transmission lines L Taking a fault as an example, the faults occurred at different distances from the DC transmission line. L 1. Single-pole grounding faults within the zone are set at 20km, 50km, 100km, 150km and 180km respectively, with transition resistances of 0Ω and 200Ω. The fault distances measured by the first-end protection devices are shown in Table 1.

[0038] Table 1. Distance measurement results for different faults

[0039] According to the simulation results in Table 1, under different fault distances and different transition resistances, the simulation results of this method have an error of less than 0.2% compared with the actual fault distance. It can achieve high-precision fault location and has good tolerance to transition resistance.

[0040] Figure 4 For power transmission lines L 1. When a single-pole ground fault occurs, the first-end protection device R Simulation waveform results of 1. Figure 4 In the diagram, the horizontal axis represents time, and the vertical axis represents the amplitude of the line-mode fault voltage. The single-pole ground fault occurs at 1 second, the fault location is 20 km from the first-end protection device, the transition resistance is 0 Ω, the arrival time of the first line-mode fault voltage traveling wave is approximately 1.000067 s, and the arrival time of the second line-mode fault voltage traveling wave is approximately 1.002605 s. By calibrating the time corresponding to the wavelet transform modulus maxima of the first two line-mode traveling waves, the amplitude of the first-end protection device can be obtained. R 1. The time difference Δ between the arrival times of the first two detected line-mode fault voltage traveling waves t 1 is 2.538ms.

[0041] Figure 5 For power transmission lines L 1. When a single-pole ground fault occurs, the end protection device R Simulation waveform results of 5. Figure 5 In the diagram, the horizontal axis represents time, and the vertical axis represents the amplitude of the line-mode fault voltage. The single-pole ground fault occurs at 1 second, the fault location is 180 km from the end-of-line protection device, the transition resistance is 0 Ω, the arrival time of the first line-mode fault voltage traveling wave is approximately 1.000603 s, and the arrival time of the second line-mode fault voltage traveling wave is approximately 1.002072 s. By calibrating the time corresponding to the wavelet transform modulus maxima of the first two line-mode traveling waves, the amplitude of the end-of-line protection device can be obtained. R5. The time difference Δ between the arrival times of the first two detected line-mode fault voltage traveling waves t 2 is 1.469ms.

[0042] The Δ measured by the above simulated transmission line t 1 and Δ t Substituting the values ​​into the core location formula, the calculated measured fault distance is 19.968 km, with an error of less than 0.2% compared to the actual fault distance. Analysis of simulation results under different working conditions shows that the traveling wave fault location method proposed in this invention, applicable to boundless flexible straight ring networks, completely solves the dependence of traditional methods on accurate calibration of synchronization time and traveling wave velocity. It can control the location error within 0.5%, significantly improving the fault location accuracy of boundless flexible straight ring networks.

[0043] Example 2 This embodiment provides a traveling wave fault location system suitable for a boundaryless flexible straight ring network. The system is used to implement the traveling wave fault location method as described in Embodiment 1, and includes a time detection module, a data acquisition module, and a fault ranging module. The time detection module is used to detect the arrival times of the first two line-mode fault voltage traveling waves with significant amplitudes at the fault line head protection device and the fault line end protection device, and to calculate the first arrival time difference and the second arrival time difference. The data acquisition module is used to acquire the length of the faulty line and the sum of the lengths of other transmission lines in the boundless flexible DC ring network, excluding the faulty line. The fault location module is used to calculate the distance from the fault point to the head protection device and / or the end protection device based on the first arrival time difference, the second arrival time difference, the length of the fault line, and the lengths of other transmission lines in the boundless flexible DC ring network excluding the fault line.

[0044] In this embodiment, the detailed functional implementation of each module can be found in the corresponding content of the aforementioned method embodiment one, and will not be repeated here.

[0045] Example 3 This embodiment provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the traveling wave fault location method for a boundless flexible DC ring network as described in Embodiment 1.

[0046] Example 4 This embodiment provides a computer-readable storage medium storing a computer program thereon. When the computer program is executed by a processor, it implements a traveling wave fault location method applicable to a boundless flexible DC ring network as described in Embodiment 1 of this invention.

[0047] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, A and B simultaneously, or B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, at least one of a, b, and c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0048] Those skilled in the art will recognize that the units and algorithm steps described in the embodiments disclosed herein can be implemented using electronic hardware, computer software, or a combination of electronic hardware and software. Whether these functions are implemented in hardware or software 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.

[0049] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0050] In the several embodiments provided in this application, any function, if implemented as a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0051] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A traveling wave fault location method applicable to boundless flexible straight ring networks, characterized in that: Includes the following steps: 1) Obtain the first arrival time difference and the second arrival time difference, wherein the first arrival time difference is the difference in arrival time of the first two line-mode fault voltage traveling waves with significant amplitude detected by the fault line head-end protection device, and the second arrival time difference is the difference in arrival time of the first two line-mode fault voltage traveling waves with significant amplitude detected by the fault line end protection device. 2) Obtain the length of the faulty line, and the sum of the lengths of other transmission lines in the boundless flexible DC ring network excluding the faulty line; 3) Based on the first arrival time difference, the second arrival time difference, the length of the faulted line, and the sum of the lengths of other transmission lines in the boundless flexible DC ring network excluding the faulted line, calculate the distance from the fault point to the head protection device and / or the end protection device to obtain the location of the fault point.

2. The traveling wave fault location method applicable to a boundaryless flexible straight ring network according to claim 1, characterized in that: In step 3), the distance from the fault point to the first-end protection device is equal to half the length of the faulty line plus the correction distance; the correction distance is equal to the difference between the second arrival time difference and the first arrival time difference, divided by twice the sum of the second arrival time difference and the first arrival time difference, and then multiplied by the sum of the lengths of the other transmission lines in the boundless flexible DC ring network excluding the faulty line.

3. The traveling wave fault location method applicable to a boundaryless flexible straight ring network according to claim 1, characterized in that: In step 3), the distance from the fault point to the end protection device is equal to half the length of the faulty line minus the correction distance; the correction distance is equal to the difference between the second arrival time difference and the first arrival time difference, divided by twice the sum of the second arrival time difference and the first arrival time difference, and then multiplied by the sum of the lengths of the other transmission lines in the boundless flexible DC ring network excluding the faulty line.

4. A traveling wave fault location system suitable for boundaryless flexible straight ring networks, characterized in that: The system for implementing the traveling wave fault location method as described in any one of claims 1 to 3 includes: The time detection module is used to detect the arrival times of the first two line-mode fault voltage traveling waves with significant amplitudes at the fault line head protection device and the fault line end protection device, and to calculate the first arrival time difference and the second arrival time difference. The data acquisition module is used to acquire the length of the faulty line and the sum of the lengths of other transmission lines in the boundless flexible DC ring network, excluding the faulty line. The fault location module is used to calculate the distance from the fault point to the head protection device and / or the end protection device based on the first arrival time difference, the second arrival time difference, the length of the fault line, and the lengths of other transmission lines in the boundless flexible DC ring network excluding the fault line.

5. A traveling wave fault location system suitable for boundaryless flexible straight ring networks according to claim 4, characterized in that: The fault location module includes a first fault location unit, used to calculate the distance from the fault point to the head-end protection device; the distance from the fault point to the head-end protection device is equal to half the length of the faulted line plus a correction distance; the correction distance is equal to the difference between the second arrival time difference and the first arrival time difference, divided by twice the sum of the second arrival time difference and the first arrival time difference, and then multiplied by the sum of the lengths of other transmission lines in the boundless flexible DC ring network excluding the faulted line.

6. A traveling wave fault location system suitable for boundaryless flexible straight ring networks according to claim 4, characterized in that: The fault location module includes a second fault location unit for calculating the distance from the fault point to the end protection device. The distance from the fault point to the end protection device is equal to half the length of the fault line minus the correction distance. The correction distance is equal to the difference between the second arrival time difference and the first arrival time difference, divided by twice the sum of the second arrival time difference and the first arrival time difference, and then multiplied by the sum of the lengths of other transmission lines in the boundless flexible DC ring network excluding the fault line.

7. An electronic device, characterized in that: The device includes one or more processors and one or more memories, wherein the one or more memories store at least one piece of program code, and when the program code is executed by the one or more processors, it implements a traveling wave fault location method applicable to a boundless flexible DC ring network as described in any one of claims 1-3.

8. A storage medium storing at least one line of program code, characterized in that, When the program code is executed by the processor, it implements the steps of the traveling wave fault location method applicable to a boundless flexible straight ring network as described in any one of claims 1-3.

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