Fault identification method and system based on current traveling waves

Abstract

The invention provides a fault identification method and system based on current traveling waves. The method comprises the following steps: acquiring an initial three-phase current traveling wave signal on a line after a fault; extracting the initial amplitude of each phase of the initial three-phase current traveling wave signal; carrying out modulus conversion on the initial amplitude of the initial three-phase current traveling wave signal to obtain a single-phase quantity and a plurality of interphase quantities; determining an initial fault type from a grounding fault and an interphase short-circuit fault according to a size relationship between the amplitude of the single-phasor quantity and a first preset threshold value; based on the determined initial fault type, identifying a final fault type and a final fault phase by comparing the amplitude relation of the plurality of interphase quantities, and taking the final fault type and the final fault phase as a fault identification result; the method does not need to depend on complex threshold setting, has the advantages of being simple in calculation, rapid in response, clear in criterion and high in reliability, and effectively improves the accuracy and adaptability of fault recognition.

Description

Technical Field

[0001] This invention relates to the field of power system relay protection technology, and in particular to a fault identification method and system based on current traveling waves. Background Technology

[0002] The distribution network is a crucial component of the power system, and its operational reliability directly impacts power quality. Line faults are a common problem in distribution networks, primarily including phase-to-phase short circuits and grounding faults. Quickly and accurately identifying fault types is key to achieving rapid fault isolation, power restoration, and ensuring system safety.

[0003] Existing fault identification methods mainly rely on steady-state or transient components. Methods based on steady-state components are susceptible to factors such as transition resistance and load fluctuations, resulting in insufficient reliability. While methods based on transient components, such as wavelet transform and neural networks, can utilize initial fault information, they generally suffer from computational complexity, reliance on large amounts of training data, or sensitivity to signal distortion. Therefore, there is an urgent need for a fault identification method that is simple in principle, has clear criteria, and does not rely on complex thresholds. Summary of the Invention

[0004] This invention provides a fault identification method and system based on current traveling waves to solve the technical problems of insufficient reliability and large computational load in the existing technology for line fault identification.

[0005] On one hand, the present invention provides a fault identification method based on current traveling waves, comprising: Collect the initial three-phase current traveling wave signal on the line after the fault; Extract the initial amplitude of each phase of the initial three-phase current traveling wave signal; The initial amplitude of the initial three-phase current traveling wave signal is transformed by modulus to obtain single-phase quantities and multiple interphase quantities; Based on the relationship between the amplitude of a single-phase quantity and the first preset threshold, the initial fault type is determined from ground faults and phase-to-phase short-circuit faults; Based on the determined initial fault type, the final fault type and the final fault phase are identified by comparing the amplitude relationship of multiple phase quantities, which serves as the fault identification result. Output the fault identification results.

[0006] According to the fault identification method based on current traveling wave provided by the present invention, the initial amplitude of the initial three-phase current traveling wave signal is subjected to modulus transformation to obtain single-phase quantities and multiple inter-phase quantities, including: The initial amplitudes of each phase of the initial three-phase current traveling wave signal are added together to obtain the summation result, and one-third of the summation result is taken as a single-phase quantity; Divide the differences between phases A and B, phases A and C, and phases B and C of the initial three-phase current traveling wave signal by three to obtain the corresponding phase-to-phase quantities.

[0007] According to the fault identification method based on current traveling wave provided by the present invention, the initial amplitude of the initial three-phase current traveling wave signal is subjected to modulus transformation to obtain single-phase quantities and multiple inter-phase quantities, as shown in the following formula: ; in, , , These are the initial amplitudes of phases A, B, and C in the initial three-phase current traveling wave signal, respectively. It is a single-phase quantity; These are the phase-to-phase quantities corresponding to phases A and B; These are the interphase quantities corresponding to phases A and C; These are the phase-to-phase quantities corresponding to phases B and C.

[0008] According to the present invention, a fault identification method based on current traveling waves determines the initial fault type from ground faults and phase-to-phase short-circuit faults based on the relationship between the amplitude of a single-phase quantity and a first preset threshold, including: Compare the magnitude of the single-phase quantity with the magnitude of the first preset threshold. If the amplitude of a single-phase quantity is greater than the first preset threshold, the initial fault type is determined to be a ground fault. If the amplitude of a single-phase quantity is less than or equal to the first preset threshold, the initial fault type is determined to be a phase-to-phase short-circuit fault. The first preset threshold is a positive number determined based on the system noise level or on-site debugging.

[0009] According to the present invention, a fault identification method based on current traveling waves identifies the final fault type and the final fault phase by comparing the amplitude relationships of multiple phase-to-phase quantities based on a determined initial fault type, including: When the initial fault type is a ground fault, compare the magnitude relationship of any two of the three phase-to-phase quantities; If two of the three phase-to-phase quantities have the same amplitude, and the amplitude of the third phase-to-phase quantity is less than the first preset threshold, then the final fault type is determined to be a single-phase ground fault, and the faulty phase is the phase that is unrelated to the third phase-to-phase quantity. If two of the three phase-to-phase quantities have the same amplitude, and the amplitude of the third phase-to-phase quantity is greater than the first preset threshold, then the final fault type is determined to be a phase-to-phase grounding fault, and the faulty phase is the phase related to the third phase-to-phase quantity. If the amplitudes of the three phase quantities are equal, the final fault type is determined to be a three-phase ground fault.

[0010] According to the present invention, a fault identification method based on current traveling waves identifies the final fault type and the final fault phase by comparing the amplitude relationships of multiple phase-to-phase quantities based on a determined initial fault type, including: When the initial fault type is a phase-to-phase short-circuit fault, compare the magnitude relationship of any two of the three phase-to-phase quantities; If two of the three phase-to-phase quantities have the same amplitude, and the amplitude of the third phase-to-phase quantity is twice that of the other two phase-to-phase quantities, then the final fault type is determined to be a phase-to-phase fault, and the faulty phase is the phase related to the third phase-to-phase quantity. If the amplitudes of the three phase quantities are equal, the final fault type is determined to be a three-phase ground fault.

[0011] According to the present invention, a fault identification method based on current traveling waves identifies the final fault type and the final fault phase by comparing the amplitude relationships of multiple phase-to-phase quantities based on a determined initial fault type, as the fault identification result, including: When the initial fault type is a ground fault, perform the following steps: If the amplitude of one phase-to-phase quantity is less than that of the other two phase-to-phase quantities, it is determined to be a single-phase ground fault, and the faulty phase is the phase that is not associated with the phase-to-phase quantity with the smallest amplitude. If the absolute value of the difference between the amplitudes of any two phase-to-phase quantities is less than the first preset threshold, and the amplitude of the third phase-to-phase quantity is greater than the first preset threshold, then it is determined to be a two-phase ground fault, and the faulty phases are the two phases associated with the third phase-to-phase quantity.

[0012] According to the present invention, a fault identification method based on current traveling waves identifies the final fault type and the final fault phase by comparing the amplitude relationships of multiple phase-to-phase quantities based on a determined initial fault type, as the fault identification result, including: When the initial fault type is a phase-to-phase short-circuit fault, perform the following steps: If the absolute value of the difference between the amplitudes of two phase-to-phase quantities is less than the first preset threshold, and the absolute value of the difference between the amplitude of the third phase-to-phase quantity and twice the amplitudes of the two phase-to-phase quantities is less than the first preset threshold, then it is determined to be a phase-to-phase short-circuit fault, and the faulty phases are the two phases associated with the third phase-to-phase quantity. If the absolute value of the difference between any two of the amplitudes of the three phase quantities is less than the first preset threshold, then it is determined to be a three-phase short circuit fault.

[0013] According to the fault identification method based on current traveling wave provided by the present invention, the initial three-phase current traveling wave signal on the line after a fault is acquired, including: The signal corresponding to the first traveling wave front reaching the monitoring point on the line after the fault is collected as the initial three-phase current traveling wave signal.

[0014] On the other hand, the present invention also provides a fault identification system based on current traveling waves, comprising: The signal acquisition module is used to acquire the initial three-phase current traveling wave signal on the line after a fault. The current extraction module is used to extract the initial amplitude of each phase of the initial three-phase current traveling wave signal; The current conversion module is used to perform modulus conversion on the initial amplitude of the initial three-phase current traveling wave signal to obtain single-phase quantities and multiple interphase quantities. The initial fault module is used to determine the initial fault type from ground faults and phase-to-phase short-circuit faults based on the relationship between the amplitude of a single-phase quantity and a first preset threshold. The final fault module is used to identify the final fault type and the final fault phase by comparing the amplitude relationship of multiple phase quantities based on a determined initial fault type, and to serve as the fault identification result. The fault output module is used to output the fault identification results.

[0015] The present invention provides a fault identification method and system based on traveling current waves. This method acquires the initial three-phase traveling current wave signal on the line after a fault, extracts its initial amplitude, and performs modulus transformation to obtain single-phase quantities and multiple inter-phase quantities. Then, based on the relationship between the amplitude of the single-phase quantity and a preset threshold, it quickly distinguishes between ground faults and inter-phase short-circuit faults. Finally, by comparing the amplitude relationship of the inter-phase quantities, it accurately identifies the specific fault type and phase. This method, based on the relative comparison of the initial traveling wave amplitude, does not rely on complex threshold settings and has the advantages of simple calculation, fast response, clear criteria, and high reliability, effectively improving the accuracy and adaptability of fault identification. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating the fault identification method based on current traveling waves provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of a fault identification system based on current traveling waves provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention. Detailed Implementation

[0018] 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. Obviously, 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.

[0019] Figure 1 This is a flowchart illustrating the fault identification method based on current traveling waves provided in an embodiment of the present invention. See Figure 1 The fault identification method based on current traveling waves includes the following steps.

[0020] Step 101: Collect the initial three-phase current traveling wave signal on the line after the fault.

[0021] Specifically, step 101 includes: The signal corresponding to the first traveling wave front reaching the monitoring point on the line after the fault is collected as the initial three-phase current traveling wave signal.

[0022] At the moment a fault occurs in a power system, a high-frequency transient signal of current (or voltage) is generated and propagates to both ends of the line; this is called a traveling wave. The first wavefront of this traveling wave (i.e., the initial wavefront) contains the richest, most original fault information, unaffected by subsequent reflected and refracted waves. Accurately capturing this initial traveling wave signal using high-speed sampling devices (such as sensors installed at the outgoing lines of substations) is fundamental to all subsequent analysis steps. Using the signal from the first traveling wavefront has key advantages, such as: information purity: it can minimize the superposition effects of subsequent reflected and refracted traveling waves, ensuring the accuracy of the extracted fault features; rapid response: utilizing information from the initial stage of the fault makes it possible to achieve rapid fault identification and protection actions, meeting the relay protection requirements for speed.

[0023] Step 102: Extract the initial amplitude of each phase of the initial three-phase current traveling wave signal.

[0024] Specifically, the amplitude of the first traveling wave front in each phase can be quantitatively extracted from the acquired three-phase current traveling wave waveform using peak detection or wavefront extraction algorithms.

[0025] Step 103: Perform modulus transformation on the initial amplitude of the initial three-phase current traveling wave signal to obtain single-phase quantities and multiple interphase quantities.

[0026] Specifically, step 103 includes: The initial amplitudes of each phase of the initial three-phase current traveling wave signal are added together to obtain the summation result, and one-third of the summation result is taken as a single-phase quantity; Divide the differences between phases A and B, phases A and C, and phases B and C of the initial three-phase current traveling wave signal by three to obtain the corresponding phase-to-phase quantities.

[0027] In this system, single-phase quantities can be considered as zero modulus, while phase-to-phase quantities can be considered as line modulus. Single-phase quantities reflect the presence of ground current in the system (non-zero during ground faults), while phase-to-phase quantities reflect the differential current relationship under phase-to-phase short circuits or ground faults, thus providing structured criteria for subsequent fault type identification based on amplitude comparison. This transformation converts the original phasors into characteristic moduli that can clearly distinguish between ground faults and short circuit faults, which is beneficial for subsequent fault type determination.

[0028] Step 104: Determine the initial fault type from ground faults and phase-to-phase short-circuit faults based on the relationship between the amplitude of a single-phase quantity and the first preset threshold.

[0029] Specifically, the first preset threshold is a positive number determined based on the system noise level or on-site debugging. The first preset threshold is close to zero, which is essentially a threshold for judging whether it is close enough to zero. It is used to divide the amplitude of the zero modulus into two categories: theoretically zero and significantly non-zero, and then distinguish between ground faults and phase-to-phase short circuits.

[0030] Alternatively, the magnitude of a single-phase quantity can be compared with the magnitude of the phase current or the magnitude of the initial value of the traveling wave between phases.

[0031] Step 105: Based on the determined initial fault type, identify the final fault type and the final fault phase by comparing the amplitude relationship of multiple phase quantities, and use this as the fault identification result.

[0032] Step 106: Output the fault identification results.

[0033] Specifically, the previously identified fault types and fault phases can be packaged into a standard message and uploaded in real time to the substation protection, measurement and control, or distribution automation master station via GOOSE, hard contacts, or serial ports. Simultaneously, the message is displayed on the device interface, event log, and fault waveform file, enabling a comprehensive output of fault information and subsequent rapid isolation and power restoration.

[0034] In this embodiment, the initial three-phase current traveling wave signal on the line after a fault is acquired, its initial amplitude is extracted and modulus transformation is performed to obtain single-phase quantities and multiple inter-phase quantities. Then, based on the relationship between the amplitude of the single-phase quantity and a preset threshold, ground faults and inter-phase short-circuit faults are quickly distinguished. Finally, by comparing the amplitude relationship of the inter-phase quantities, the specific fault type and phase are accurately identified. This method is based on the relative comparison of the initial traveling wave amplitude, does not rely on complex threshold settings, and has the advantages of simple calculation, fast response, clear criteria, and high reliability, effectively improving the accuracy and adaptability of fault identification.

[0035] In one embodiment of this specification, the initial amplitude of the initial three-phase current traveling wave signal is subjected to modulus transformation to obtain single-phase quantities and multiple interphase quantities, as shown in the following formula (1): (1); in, , , These are the initial amplitudes of phases A, B, and C in the initial three-phase current traveling wave signal, respectively. It is a single-phase quantity; These are the phase-to-phase quantities corresponding to phases A and B; These are the interphase quantities corresponding to phases A and C; These are the phase-to-phase quantities corresponding to phases B and C.

[0036] In this embodiment, by using a clear and unified modulus transformation formula, the three-phase current amplitude is decoupled into single-phase quantities and multiple interphase quantities, ensuring the consistency and calculation accuracy of the method in different application scenarios, thereby avoiding identification deviations caused by unclear transformation rules.

[0037] In one embodiment of this specification, the initial fault type is determined from ground faults and phase-to-phase short-circuit faults based on the relationship between the amplitude of a single-phase quantity and a first preset threshold, including: Step 1: Compare the magnitude of the single-phase quantity with the magnitude of the first preset threshold. Step 2: If the amplitude of a single-phase quantity is greater than the first preset threshold, then the initial fault type is determined to be a ground fault. Step 3: If the amplitude of a single-phase quantity is less than or equal to the first preset threshold, the initial fault type is determined to be a phase-to-phase short-circuit fault.

[0038] In this embodiment, the first preset threshold is close to zero, meaning it can be used to distinguish whether the amplitude of a single-phase quantity is significantly greater than zero. If it is greater than the first preset threshold, it indicates that the amplitude of the single-phase quantity is significantly greater than zero. If it is less than or equal to the first preset threshold, it indicates that the amplitude of the single-phase quantity is approximately equal to zero. In summary, if the amplitude of a single-phase quantity is significantly greater than zero, it indicates a ground fault; if it is approximately equal to zero, it indicates a phase-to-phase short-circuit fault.

[0039] In one embodiment of this specification, based on a determined initial fault type, the final fault type and the final fault phase are identified by comparing the amplitude relationships of multiple phase-to-phase quantities, including: When the initial fault type is a ground fault, compare the magnitude relationship of any two of the three phase-to-phase quantities; If two of the three phase-to-phase quantities have the same amplitude, and the amplitude of the third phase-to-phase quantity is less than the first preset threshold, then the final fault type is determined to be a single-phase ground fault, and the faulty phase is the phase that is unrelated to the third phase-to-phase quantity. If two of the three phase-to-phase quantities have the same amplitude, and the amplitude of the third phase-to-phase quantity is greater than the first preset threshold, then the final fault type is determined to be a phase-to-phase grounding fault, and the faulty phase is the phase related to the third phase-to-phase quantity. If the amplitudes of the three phase quantities are equal, the final fault type is determined to be a three-phase ground fault.

[0040] In this embodiment, the two amplitudes are equal, or approximately equal, with the difference between them being approximately zero. For example, if the difference is less than a first preset threshold (abbreviated as ε), they can be considered approximately equal. Specifically, if... and The amplitude difference is approximately zero (e.g., less than the first preset threshold ε), and If the value is less than ε, it is determined to be a phase A ground fault. and The amplitude difference is approximately zero, and If the value is less than ε, it is determined to be a phase B ground fault. and The amplitude difference is approximately zero, and If the value is less than ε, it is determined to be a C-phase ground fault.

[0041] In this embodiment, if and The amplitude difference is approximately zero (e.g., less than the first preset threshold ε) and If the value is greater than ε, it is determined to be a phase BC ground fault. and The amplitude difference is approximately zero, and If the value is greater than ε, it is determined to be an AC phase-to-ground fault. and The amplitude difference is approximately zero, and If the value is greater than ε, it is determined to be an AB phase ground fault. , and If the difference between any two amplitude values ​​is approximately zero, then it is determined to be a three-phase ground fault (ABC).

[0042] In this embodiment, for cases where a ground fault has been identified, by comparing the specific combination relationship of the amplitude values ​​of the three phases (i.e., two are equal and the third is less than or greater than the threshold), the specific ground fault type can be clearly and reliably distinguished and identified, such as whether it is a single-phase ground fault, a two-phase ground fault, or a three-phase ground fault, and the fault phase can be accurately located, thereby achieving refined identification of the ground fault.

[0043] In one embodiment of this specification, based on a determined initial fault type, the final fault type and the final fault phase are identified by comparing the amplitude relationships of multiple phase-to-phase quantities, including: When the initial fault type is a phase-to-phase short-circuit fault, compare the magnitude relationship of any two of the three phase-to-phase quantities; If two of the three phase-to-phase quantities have the same amplitude, and the amplitude of the third phase-to-phase quantity is twice that of the other two phase-to-phase quantities, then the final fault type is determined to be a phase-to-phase fault, and the faulty phase is the phase related to the third phase-to-phase quantity. If the amplitudes of the three phase quantities are equal, the final fault type is determined to be a three-phase ground fault.

[0044] In this embodiment, if and The amplitude difference is approximately zero (e.g., less than ε). yes or If the value is twice the value of the fault, it is determined to be a short circuit between phases B and C. and The amplitude difference is approximately zero. yes or If the value is twice that of the AC phase, it is determined to be an AC phase-to-phase short circuit. and The amplitude difference is approximately zero. yes or If the value is twice the value of the fault, it is determined to be a short circuit between phases A and B. , , If the amplitude difference is approximately zero (e.g., less than ε), it indicates a three-phase short circuit.

[0045] In one embodiment of this specification, based on a determined initial fault type, the final fault type and the final fault phase are identified by comparing the amplitude relationships of multiple phase-to-phase quantities, and this identification result includes: When the initial fault type is a ground fault, perform the following steps: If the amplitude of one phase-to-phase quantity is less than that of the other two phase-to-phase quantities, it is determined to be a single-phase ground fault, and the faulty phase is the phase that is not associated with the phase-to-phase quantity with the smallest amplitude. If the absolute value of the difference between the amplitudes of any two phase-to-phase quantities is less than the first preset threshold, and the amplitude of the third phase-to-phase quantity is greater than the first preset threshold, then it is determined to be a two-phase ground fault, and the faulty phases are the two phases associated with the third phase-to-phase quantity.

[0046] In this embodiment, for example, comparison , , The size. If < and < If so, it is determined to be a phase C ground fault. < and < If so, it is determined to be a phase B ground fault. < and < If so, it is determined to be a phase A ground fault.

[0047] If | - |<ε, and If the value is greater than ε, it is determined to be a BC phase ground fault. If | - |<ε, and If the value is greater than ε, it is determined to be an AC phase-to-ground fault. If | - |<ε, and If the value is greater than ε, then it is determined to be an AB phase ground fault.

[0048] In one embodiment of this specification, based on a determined initial fault type, the final fault type and the final fault phase are identified by comparing the amplitude relationships of multiple phase-to-phase quantities, and this identification result includes: When the initial fault type is a phase-to-phase short-circuit fault, perform the following steps: If the absolute value of the difference between the amplitudes of two phase-to-phase quantities is less than the first preset threshold, and the absolute value of the difference between the amplitude of the third phase-to-phase quantity and twice the amplitudes of the two phase-to-phase quantities is less than the first preset threshold, then it is determined to be a phase-to-phase short-circuit fault, and the faulty phases are the two phases associated with the third phase-to-phase quantity. If the absolute value of the difference between any two of the amplitudes of the three phase quantities is less than the first preset threshold, then it is determined to be a three-phase short circuit fault.

[0049] In this embodiment, for example, comparison , , The size. If | - |<ε, and| -2× If |<ε, then it is determined to be a phase-to-phase short circuit fault (BC). If | - |<ε, and| -2× If |<ε, then it is determined to be an AC phase-to-phase short circuit fault. If | - |<ε, and| -2× If |<ε, then it is determined to be an A / B phase-to-phase short circuit fault. , , If the amplitudes are close and there is no significant minimum, it may be determined to be a three-phase short circuit fault.

[0050] The following describes the modulus current traveling wave at the fault point under different types of fault conditions. Before the fault occurs, the three-phase voltages at the fault point are as follows: , , The phase-to-phase modulus impedances on the line are as follows: , , , ,and .

[0051] 1. Grounding fault: 1) Single-phase grounding (let's assume phase A): The boundary conditions at the fault point are: ; This is the voltage of phase A at the fault location.

[0052] Then the following formula (2) holds true: (2); The following formula (3) can be solved: (3); 2) Two-phase short-circuit grounding (assuming phases BC): The boundary conditions at the fault point are: , , and the following formula (4); (4); The solution is: = .

[0053] 3) Three-phase phase-to-phase short-circuit grounding: The boundary conditions at the fault point are: = ; = = ; 2. Ungrounded fault: 1) Two-phase short circuit (assuming phases A and B): Fault boundary conditions: ; This is the voltage of phase B at the fault location.

[0054] The following formula (5) holds true: (5); The following formula (6) can be solved: (6).

[0055] Based on the same general inventive concept, this invention also protects a fault identification system based on current traveling waves, such as... Figure 2 As shown, Figure 2 This is a schematic diagram of the fault identification system based on traveling current waves provided in an embodiment of the present invention. The fault identification system based on traveling current waves provided by the present invention will be described below. The fault identification system based on traveling current waves described below can be referred to in correspondence with the fault identification method based on traveling current waves described above.

[0056] Fault identification systems based on traveling current waves include: Signal acquisition module 201 is used to acquire the initial three-phase current traveling wave signal on the line after a fault; The current extraction module 202 is used to extract the initial amplitude of each phase of the initial three-phase current traveling wave signal; The current conversion module 203 is used to perform modulus conversion on the initial amplitude of the initial three-phase current traveling wave signal to obtain single-phase quantities and multiple interphase quantities. The initial fault module 204 is used to determine the initial fault type from ground faults and phase-to-phase short circuit faults based on the relationship between the amplitude of the single-phase quantity and the first preset threshold. The final fault module 205 is used to identify the final fault type and the final fault phase based on a determined initial fault type by comparing the amplitude relationship of the multiple phase quantities, and use this as the fault identification result; The fault output module 206 is used to output the fault identification result.

[0057] Figure 3 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention.

[0058] like Figure 3 As shown, the electronic device may include a processor 310, a communications interface 320, a memory 330, and a communication bus 340. The processor 310, communications interface 320, and memory 330 communicate with each other via the communication bus 340. The processor 310 can call logic instructions from the memory 330 to execute a fault identification method based on current traveling waves.

[0059] Furthermore, the logical instructions in the aforementioned memory 330 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, 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 the present invention. 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.

[0060] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer is able to execute the fault identification method based on current traveling wave provided by the above methods.

[0061] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to perform the fault identification method based on current traveling waves provided by the above methods.

[0062] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0063] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fault identification method based on current traveling waves, characterized in that, include: Collect the initial three-phase current traveling wave signal on the line after the fault; Extract the initial amplitude of each phase of the initial three-phase current traveling wave signal; The initial amplitude of the initial three-phase current traveling wave signal is subjected to modulus transformation to obtain single-phase quantities and multiple interphase quantities; Based on the relationship between the amplitude of the single-phase quantity and the first preset threshold, the initial fault type is determined from ground faults and phase-to-phase short-circuit faults; Based on the determined initial fault type, the final fault type and the final fault phase are identified by comparing the amplitude relationship of the multiple phase quantities, which serves as the fault identification result. Output the fault identification results.

2. The fault identification method based on current traveling wave according to claim 1, characterized in that, The modulus transformation of the initial amplitude of the initial three-phase current traveling wave signal to obtain single-phase quantities and multiple interphase quantities includes: The initial amplitudes of each phase of the initial three-phase current traveling wave signal are added together to obtain the summation result, and one-third of the summation result is taken as a single-phase quantity; Divide the differences between phase A and phase B, phase A and phase C, and phase B and phase C of the initial three-phase current traveling wave signal by three to obtain their respective phase-to-phase quantities.

3. The fault identification method based on current traveling waves according to claim 2, characterized in that, The initial amplitude of the initial three-phase current traveling wave signal is subjected to modulus transformation to obtain single-phase quantities and multiple interphase quantities, as shown in the following formula: ； in, , , These are the initial amplitudes of phases A, B, and C in the initial three-phase current traveling wave signal, respectively. It is a single-phase quantity; These are the phase-to-phase quantities corresponding to phases A and B; These are the interphase quantities corresponding to phases A and C; These are the phase-to-phase quantities corresponding to phases B and C.

4. The fault identification method based on current traveling wave according to claim 1, characterized in that, Based on the relationship between the amplitude of the single-phase quantity and a first preset threshold, the initial fault type is determined from ground faults and phase-to-phase short-circuit faults, including: Compare the magnitude of the single-phase quantity with the magnitude of the first preset threshold. If the amplitude of a single-phase quantity is greater than the first preset threshold, the initial fault type is determined to be a ground fault. If the amplitude of a single-phase quantity is less than or equal to the first preset threshold, the initial fault type is determined to be a phase-to-phase short-circuit fault. The first preset threshold is a positive number determined based on the system noise level or on-site debugging.

5. The fault identification method based on current traveling wave according to claim 4, characterized in that, Based on the determined initial fault type, the final fault type and the final fault phase are identified by comparing the amplitude relationships of the multiple phase-to-phase quantities, including: When the initial fault type is a ground fault, compare the magnitude relationship of any two of the three phase-to-phase quantities; If two of the three phase-to-phase quantities have the same amplitude, and the amplitude of the third phase-to-phase quantity is less than the first preset threshold, then the final fault type is determined to be a single-phase ground fault, and the faulty phase is the phase that is unrelated to the third phase-to-phase quantity. If two of the three phase-to-phase quantities have the same amplitude, and the amplitude of the third phase-to-phase quantity is greater than the first preset threshold, then the final fault type is determined to be a phase-to-phase grounding fault, and the faulty phase is the phase related to the third phase-to-phase quantity. If the amplitudes of the three phase quantities are equal, the final fault type is determined to be a three-phase ground fault.

6. The fault identification method based on current traveling wave according to claim 4, characterized in that, Based on the determined initial fault type, the final fault type and the final fault phase are identified by comparing the amplitude relationships of the multiple phase-to-phase quantities, including: When the initial fault type is a phase-to-phase short-circuit fault, compare the magnitude relationship of any two of the three phase-to-phase quantities. If two of the three phase-to-phase quantities have the same amplitude, and the amplitude of the third phase-to-phase quantity is twice that of the other two phase-to-phase quantities, then the final fault type is determined to be a phase-to-phase fault, and the faulty phase is the phase related to the third phase-to-phase quantity. If the amplitudes of the three phase quantities are equal, the final fault type is determined to be a three-phase ground fault.

7. The fault identification method based on current traveling waves according to claim 4, characterized in that, Based on the determined initial fault type, the final fault type and the final fault phase are identified by comparing the amplitude relationships of the multiple phase-to-phase quantities, and this is presented as the fault identification result, including: When the initial fault type is a ground fault, perform the following steps: If the amplitude of one phase-to-phase quantity is less than that of the other two phase-to-phase quantities, it is determined to be a single-phase ground fault. If the absolute value of the difference between the amplitudes of any two phase-to-phase quantities is less than the first preset threshold, and the amplitude of the third phase-to-phase quantity is greater than the first preset threshold, then it is determined to be a two-phase ground fault, and the faulty phases are the two phases associated with the third phase-to-phase quantity.

8. The fault identification method based on current traveling wave according to claim 7, characterized in that, Based on the determined initial fault type, the final fault type and the final fault phase are identified by comparing the amplitude relationships of the multiple phase-to-phase quantities, and this is presented as the fault identification result, including: When the initial fault type is a phase-to-phase short-circuit fault, perform the following steps: If the absolute value of the difference between the amplitudes of two phase-to-phase quantities is less than the first preset threshold, and the absolute value of the difference between the amplitude of the third phase-to-phase quantity and twice the amplitudes of the two phase-to-phase quantities is less than the first preset threshold, then it is determined to be a phase-to-phase short-circuit fault, and the faulty phases are the two phases associated with the third phase-to-phase quantity. If the absolute value of the difference between any two of the amplitudes of the three phase quantities is less than the first preset threshold, then it is determined to be a three-phase short circuit fault.

9. The fault identification method based on current traveling wave according to claim 1, characterized in that, Acquire the initial three-phase current traveling wave signal on the line after the fault, including: The signal corresponding to the first traveling wave front arriving at the monitoring point on the line after the fault is collected as the initial three-phase current traveling wave signal.

10. A fault identification system based on traveling current waves, characterized in that, include: The signal acquisition module is used to acquire the initial three-phase current traveling wave signal on the line after a fault. The current extraction module is used to extract the initial amplitude of each phase of the initial three-phase current traveling wave signal; The current conversion module is used to perform modulus conversion on the initial amplitude of the initial three-phase current traveling wave signal to obtain single-phase quantities and multiple interphase quantities. The initial fault module is used to determine the initial fault type from ground faults and phase-to-phase short circuit faults based on the relationship between the amplitude of the single-phase quantity and the first preset threshold. The final fault module is used to identify the final fault type and the final fault phase by comparing the amplitude relationship of the multiple phase quantities based on a determined initial fault type, and to obtain the fault identification result. The fault output module is used to output the fault identification results.

Images