Alternating current transmission line traveling wave protection lightning stroke interference identification method and system and medium

Abstract

The invention relates to the technical field of power system protection, in particular to an alternating-current transmission line traveling wave protection lightning stroke interference identification method and system and a medium, and the method comprises the steps: collecting three-phase voltage and current components of an alternating-current transmission line when a lightning stroke or a fault occurs; obtaining a fault component according to the three-phase voltage and current component and the normal operation voltage and current component; performing phase-mode transformation on the fault component to obtain a phase-mode decoupling voltage and current component; performing wavelet transformation on the phase-mode decoupling voltage and current components, and determining the arrival time of a fault traveling wave; and current waveform change in a preset time window from the arrival time of the fault traveling wave is monitored, and if the first-mode and second-mode current traveling waves in the preset time window are both reduced until the state is close to the no-current state, lightning stroke interference is judged. Through technologies of phase-mode transformation, wavelet transformation and the like, lightning stroke interference and line faults can be accurately and effectively distinguished, false operation and refusal operation are reduced, and the stability and reliability of a power system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power system protection, and in particular to a method, system and medium for identifying lightning interference for traveling wave protection of an AC transmission line. Background Art

[0002] In modern power systems, the safe and stable operation of AC transmission lines is of vital importance. However, transmission lines are often struck by lightning during operation, which may not only directly lead to line failures, but also produce a transient characteristic signal that is very similar to the real fault traveling wave, namely the lightning interference traveling wave. The existence of this lightning interference traveling wave makes it easy for traditional transmission line protection systems to misjudge when facing lightning strikes, especially when there is no actual line fault but only caused by lightning strikes. The erroneous tripping signal will unnecessarily interrupt the power supply, affecting the stability of the power grid and the user's power experience.

[0003] Specifically, lightning interference traveling waves are mainly divided into two categories: induced lightning and direct lightning. Induced lightning is caused by the change of electromagnetic field generated by lightning discharge, which causes interference on the transmission line through induction. Direct lightning includes three types of situations: lightning towers, lightning arresters and lightning bypasses. Among them, although lightning towers and lightning arresters will not directly cause physical damage to the transmission line, the interference traveling wave characteristics they produce are similar to induced lightning, and it is difficult to effectively distinguish them by traditional detection methods alone.

[0004] For shielding lightning, since it directly acts on the transmission line, the disturbance signal it generates is closer to the real line fault traveling wave, which further aggravates the difficulty of identification of the traveling wave protection system. The existing transmission line protection system often lacks an effective identification mechanism when dealing with lightning interference, resulting in the protection system still mistakenly sending a tripping signal when the lightning strike does not cause a line fault. This false action will cause an unexpected power outage on the non-fault line and affect the continuous and stable operation of the power system. Therefore, there is an urgent need for a method that can effectively distinguish between fault traveling waves and lightning interference traveling waves (including induced lightning and shielding lightning), accurately identify different types of lightning interference, and make effective judgments before the protection action to avoid unnecessary tripping and protection false actions, thereby improving the stability and operation efficiency of the power system. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method, system and medium for identifying lightning interference of traveling wave protection of AC transmission lines.

[0006] In a first aspect, the present invention provides a method for identifying lightning interference for traveling wave protection of an AC transmission line, the method comprising the following steps:

[0007] Collect the three-phase voltage and current components of the AC transmission line when lightning strikes or faults occur, as well as the normal operating voltage and current components under normal operating conditions;

[0008] Obtaining a fault component according to the three-phase voltage and current components and the normal operating voltage and current components; the fault component includes a voltage fault component and a current fault component;

[0009] Performing phase-mode transformation on the fault component to obtain phase-mode decoupled voltage and current components; the phase-mode decoupled voltage and current components include zero-mode, first-mode and second-mode voltage components and current components;

[0010] Performing wavelet transformation on the phase mode decoupled voltage and current components to determine the arrival time of the fault traveling wave;

[0011] Monitor the current waveform changes within a preset time window from the arrival time of the fault traveling wave. If the first-mode and second-mode current traveling waves both decrease until they are close to a current-free state within the preset time window, it is determined to be lightning interference.

[0012] In a further embodiment, the step of obtaining the fault component according to the three-phase voltage and current components and the normal operating voltage and current components comprises:

[0013] The three-phase voltage and current components are subtracted from the normal operating voltage and current components to obtain a fault component.

[0014] In a further embodiment, if any one of the first mode or second mode current traveling waves is not close to a no-current state within the preset time window, it is determined to be a line fault.

[0015] In a further embodiment, the three-phase voltage and current components include three-phase voltage components and three-phase current components;

[0016] The normal operating voltage and current components include the normal three-phase voltage and the normal three-phase current of the AC transmission line in the normal operating state.

[0017] In a further embodiment, the preset time window is 1 ms.

[0018] In a second aspect, the present invention provides a system for identifying lightning interference for traveling wave protection of AC transmission lines, the system comprising:

[0019] A signal acquisition module is used to collect the three-phase voltage and current components of the AC transmission line when a lightning strike or fault occurs, as well as the normal operating voltage and current components under normal operating conditions;

[0020] A fault extraction module, used to obtain a fault component according to the three-phase voltage and current components and the normal operating voltage and current components; the fault component includes a voltage fault component and a current fault component;

[0021] A phase mode decoupling module is used to perform phase mode transformation on the fault component to obtain phase mode decoupled voltage and current components; the phase mode decoupled voltage and current components include zero mode, first mode and second mode voltage components and current components;

[0022] A wavelet transform module is used to perform wavelet transform on the phase mode decoupled voltage and current components to determine the arrival time of the fault traveling wave;

[0023] The interference identification module is used to monitor the current waveform changes within a preset time window from the arrival time of the fault traveling wave. If the first-mode and second-mode current traveling waves are both reduced to a state close to no current within the preset time window, it is determined to be lightning interference.

[0024] In a further embodiment, the fault extraction module is specifically used to:

[0025] The three-phase voltage and current components are subtracted from the normal operating voltage and current components to obtain a fault component.

[0026] In a further embodiment, if any one of the first mode or second mode current traveling waves is not close to a no-current state within the preset time window, it is determined to be a line fault.

[0027] In a further embodiment, the three-phase voltage and current components include three-phase voltage components and three-phase current components;

[0028] The normal operating voltage and current components include the normal three-phase voltage and the normal three-phase current of the AC transmission line in the normal operating state.

[0029] In a third aspect, the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0030] The present invention provides a method, system and medium for identifying lightning interference of AC transmission line traveling wave protection. The method collects three-phase voltage and current components of AC transmission line when lightning strike or fault occurs, and normal operating voltage and current components under normal operating state; obtains fault components according to the three-phase voltage and current components and the normal operating voltage and current components; the fault components include voltage fault components and current fault components; the fault components are subjected to phase mode transformation to obtain phase mode decoupled voltage and current components; the phase mode decoupled voltage and current components include zero mode, one mode and two mode voltage components and current components; the phase mode decoupled voltage and current components are subjected to wavelet transformation to determine the arrival time of the fault traveling wave; monitor the current waveform change within a preset time window from the arrival time of the fault traveling wave, if the one mode and two mode current traveling waves are both reduced until close to the no current state within the preset time window, it is determined to be lightning interference. Compared with the prior art, the method can accurately and effectively distinguish lightning interference and line faults through phase mode transformation and wavelet transformation technology, reduce the occurrence of false operation and refusal to operate, and improve the stability and reliability of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic flow chart of a method for identifying lightning interference for AC transmission line traveling wave protection provided by an embodiment of the present invention;

[0032] Figure 2 It is a schematic diagram of a lightning interference identification process for an AC transmission line provided by an embodiment of the present invention;

[0033] Figure 3 is an example diagram of the AC system topology structure provided by an embodiment of the present invention;

[0034] Figure 4 1 is a schematic diagram of a current waveform of a phase A ground fault provided by an embodiment of the present invention;

[0035] Figure 5 1 is a schematic diagram of a second-mode current waveform of a phase A grounding fault provided by an embodiment of the present invention;

[0036] Figure 6 1 is a schematic diagram of a current waveform of a phase A line struck by lightning provided by an embodiment of the present invention;

[0037] Figure 7 1 is a schematic diagram of a second-mode current waveform of a lightning-struck A-phase line provided by an embodiment of the present invention;

[0038] Figure 8 1 is a schematic diagram of a current waveform of a mode of induction lightning interference provided by an embodiment of the present invention;

[0039] Fig. 9 : is a schematic diagram of a second-mode current waveform of inductive lightning interference provided by an embodiment of the present invention;

[0040] Fig.10 1 is a schematic diagram of a first-mode current waveform of a phase C grounding fault provided by an embodiment of the present invention;

[0041] Fig.11 1 is a schematic diagram of a second-mode current waveform of a phase C grounding fault provided by an embodiment of the present invention;

[0042] Fig.12 The invention is a block diagram of a system for identifying lightning disturbances for AC transmission line traveling wave protection provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The following specifically illustrates the implementation mode of the present invention in conjunction with the accompanying drawings. The embodiments are provided for illustrative purposes only and cannot be understood as limiting the present invention. The accompanying drawings are provided for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0044] refer to Figure 1 The embodiment of the present invention provides a method for identifying lightning interference of traveling wave protection of AC transmission line, such as Figure 1 As shown, the method comprises the following steps:

[0045] S1. Collect the three-phase voltage and current components of the AC transmission line when a lightning strike or fault occurs, as well as the normal operating voltage and current components under normal operating conditions.

[0046] In this embodiment, three-phase voltage and current sensors are respectively connected to the A, B, and C phases of the AC transmission line, and the three-phase voltage and current signals are synchronously collected to ensure the time synchronization between the phases, and the three-phase voltage and current components of the AC transmission line when a lightning strike or a fault occurs are obtained, and the three-phase voltage and current components include three-phase voltage components and three-phase current components; at the same time, when the AC transmission line is in a normal operating state, that is, when no lightning strike or fault occurs, this embodiment captures the voltage and current changes in the normal operating state, and obtains the normal operating voltage and current components of the AC transmission line in the normal operating state, and the normal operating voltage and current components include the normal three-phase voltage and normal three-phase current of the AC transmission line in the normal operating state.

[0047] S2. Obtain a fault component based on the three-phase voltage and current components and the normal operating voltage and current components; the fault component includes a voltage fault component and a current fault component.

[0048] This embodiment obtains the fault component by subtracting the three-phase voltage and current components when the fault occurs from the corresponding components of the normal operating voltage and current components under the normal operating state. Specifically, this embodiment obtains the voltage fault component by subtracting each phase voltage according to the collected three-phase voltage components from the normal three-phase voltage during normal operation; at the same time, each phase current is subtracted according to the collected three-phase current components and the normal three-phase current during normal operation to obtain the current fault component, and the calculated voltage fault component and current fault component are verified to ensure the accuracy and integrity of the data, thereby realizing the calculation of the difference between the three-phase voltage and current components of the AC transmission line when a lightning strike or a fault occurs and the normal operating voltage and current components, and obtaining the voltage fault component and the current fault component, providing strong support for the identification of lightning interference in the power system.

[0049] S3. Perform phase-mode transformation on the fault component to obtain phase-mode decoupled voltage and current components; the phase-mode decoupled voltage and current components include zero-mode, first-mode and second-mode voltage and current components.

[0050] In this embodiment, the fault component is converted from the three-phase coordinate system to the mode coordinate system by using the phase mode transformation formula, and the voltage component and current component of the zero mode, the first mode and the second mode are obtained by decoupling through the phase mode transformation, wherein the phase mode transformation formula is as follows:

[0051]

[0052] In the formula, F a 、F b 、F c are the voltage fault components or current fault components of phases A, B, and C, respectively, and F 0 、F 1 、F 2 They are the voltage components or current components of the zero mode, first mode and second mode after phase mode transformation respectively.

[0053] It should be noted that in the power system, zero mode, first mode and second mode are zero-sequence component, positive-sequence component and negative-sequence component respectively. These components are decoupled from the three-phase system through phase mode transformation. Among them, zero mode represents the balanced component in the three-phase system, that is, the three-phase voltage or current is equal and the phase is the same; first mode represents the positive-sequence component in the three-phase system, that is, the three-phase voltage or current is equal and the phase difference is 120 degrees respectively; second mode represents the negative-sequence component in the three-phase system, that is, the three-phase voltage or current is equal but the phase difference is 240 degrees respectively.

[0054] S4. Perform wavelet transformation on the phase mode decoupled voltage and current components to determine the arrival time of the fault traveling wave.

[0055] S5. Monitor the current waveform changes within a preset time window from the arrival time of the fault traveling wave. If the first-mode and second-mode current traveling waves both decrease until they are close to a current-free state within the preset time window, it is determined to be a lightning interference.

[0056] like Figure 2 As shown, this embodiment uses wavelet transform technology to extract the arrival time of the fault traveling wave. By performing wavelet transform on the current component after phase mode transformation, the arrival time of the fault traveling wave is extracted. The wavelet transform has good time-frequency localization characteristics and can accurately capture the arrival time of the fault traveling wave. Then, the lightning interference or line fault is judged according to the arrival time of the fault traveling wave. If both the first-mode and second-mode current traveling waves decrease until they are close to a no-current state within the preset time window, it is determined to be a lightning interference; if any one of the first-mode or second-mode current traveling waves is not close to a no-current state within the preset time window, it is determined to be a line fault. In this embodiment, the lightning current waveform expression i(t) is shown in the following formula, which is in a double exponential form:

[0057]

[0058] In the formula, I g is the lightning current amplitude; τ 1 , τ 2 are the wave head rising time and half-peak time respectively; t is the current moment.

[0059] AC line fault current traveling wave expression Δi P1 (t) are in the form of:

[0060]

[0061] In the formula, K 1 Represents the traveling wave amplitude coefficient; α 1 is the dispersion constant; θ is the offset phase angle; w 0 is the angular frequency, its value is 100π; x f is the fault distance.

[0062] In a specific embodiment, the preset time window is 1ms. This embodiment monitors the current waveform change within 1ms from the arrival time of the fault traveling wave. Since the lightning current generated by lightning interference will rapidly decay to zero in a short time, and the fault traveling wave generated by the line fault will continue to exist until the fault is removed, therefore, if the first-mode and second-mode current traveling waves are both reduced to close to 0 (that is, the absolute value of the current is less than the preset smaller threshold) at 1ms, it is determined to be lightning interference; if any one of the first-mode or second-mode current traveling waves is not close to 0, it is determined to be a line fault; it should be noted that the current components of the first mode and the second mode, as well as the first-mode and second-mode current traveling waves, all refer to the current components of the first mode and the second mode through phase mode conversion. The current parts of the first and second modes are obtained, where the current components of the first and second modes refer to the two specific modes in the current signal obtained after the phase mode transformation, namely the first mode (positive sequence component) and the second mode (negative sequence component). These components represent the specific distribution characteristics of the current signal in the phase space; the first and second mode current traveling waves are simplified expressions. The first and second mode current traveling waves emphasize that the current components of the first and second modes are waveforms that change with time (i.e., traveling waves). They refer to the current fluctuations caused by faults or other reasons in the power system. They also appear as the current components of the first and second modes after the phase mode transformation. These traveling waves represent the dynamic characteristics of the current signal that change with time.

[0063] To verify the accuracy of the method for distinguishing lightning interference traveling waves from line fault traveling waves in this embodiment, Figure 3 As shown, this embodiment constructs an AC system topology in the PSCAD simulation software. In PSCAD, this embodiment builds a topology including two AC power sources (G1 and G2), both of which have a rated voltage of 230 kV. A measuring point is provided in the AC system topology, and the measuring point indicates the protection installation position. The measurement direction (positive direction) of the current and voltage is defined as from the bus through the measuring point to the line. The data sampling interval is set to 5 microseconds to ensure the accuracy of the data. For the line fault wave characteristics, as shown in FIG. Figure 4 , Figure 5 As shown in Figure 1, when a phase A grounding fault (AG fault) occurs at a distance of 150 km from the line protection, the first and second mode current traveling waves continue to increase within 1 ms, and the absolute values ​​of the currents at 1 ms are significantly greater than 0; similarly, Fig.10 , Fig.11 As shown, in the case of a C-phase grounding fault (CG fault), although the first-mode current traveling wave may be small, the second-mode current traveling wave is not close to 0 at 1 ms. Based on the above characteristics, this embodiment can determine that a line fault has occurred in the system.

[0064] For lightning strikes interfering with traveling wave characteristics, such as Figure 6 , Figure 7 As shown in Figure 1, when lightning strikes phase A, the amplitude of the current traveling wave first rises, then drops rapidly, and drops to nearly 0 within 1ms; Figure 8 , Fig. 9 As shown, in the case of induced lightning interference, the magnitude of the current is extremely low, reaching 10 -13 , and is close to 0 at 1ms. These characteristics indicate that lightning interference has occurred in the AC system. Combined with the above-mentioned traveling wave characteristics and fault component extraction method, this embodiment can implement the lightning interference identification process through the following discrimination method:

[0065] When a line fault occurs, such as a phase A grounding fault (for an AG fault), if the first and second mode current traveling waves continue to increase within 1ms, and the absolute value of the current at 1ms is significantly greater than 0, or in the case of a phase C grounding fault (for a CG fault), the second mode current traveling wave is not close to 0 at 1ms, then it is judged as a line fault;

[0066] When lightning interference occurs, such as lightning strikes the A phase line, if the amplitude of the current traveling wave rises first and then falls within 1ms and has fallen to close to 0 within 1ms, or in the case of induced lightning interference, the current magnitude is extremely low and close to 0 in 1ms (for induced lightning interference), it is judged as lightning interference.

[0067] In summary, this embodiment can effectively distinguish between lightning interference and line faults, verifying its accuracy and reliability in practical applications. By analyzing the current traveling wave, it can accurately identify and respond to lightning interference and line faults in the power system, thereby ensuring the stable operation of the power system.

[0068] The embodiment of the present invention provides a method for identifying lightning interference of AC transmission line traveling wave protection, the method collects three-phase voltage and current components of AC transmission line when lightning or fault occurs, and normal operating voltage and current components under normal operating state; obtains fault components according to the three-phase voltage and current components and the normal operating voltage and current components; the fault components include voltage fault components and current fault components; the fault components are subjected to phase mode transformation to obtain phase mode decoupled voltage and current components; the phase mode decoupled voltage and current components include zero mode, one mode and two mode voltage components and current components; the phase mode decoupled voltage and current components are subjected to wavelet transformation to determine the arrival time of the fault traveling wave; monitor the current waveform change within a preset time window from the arrival time of the fault traveling wave, if the one mode and two mode current traveling waves are both reduced until close to the no current state within the preset time window, it is determined to be lightning interference. Compared with the prior art, the method can accurately and effectively distinguish lightning interference and line faults through phase mode transformation and wavelet transformation technology, reduce the occurrence of false operation and refusal to operate, and improve the stability and reliability of the power system.

[0069] It should be noted that the size of the serial numbers of the above-mentioned processes does not mean 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 the present application.

[0070] In one embodiment, Fig.12 As shown, an embodiment of the present invention provides an AC transmission line traveling wave protection lightning interference identification system, the system comprising:

[0071] The signal acquisition module 101 is used to collect the three-phase voltage and current components of the AC transmission line when a lightning strike or fault occurs, and the normal operating voltage and current components in the normal operating state;

[0072] A fault extraction module 102 is used to obtain a fault component according to the three-phase voltage and current components and the normal operating voltage and current components; the fault component includes a voltage fault component and a current fault component;

[0073] The phase mode decoupling module 103 is used to perform phase mode transformation on the fault component to obtain phase mode decoupled voltage and current components; the phase mode decoupled voltage and current components include zero mode, first mode and second mode voltage components and current components;

[0074] The wavelet transform module 104 is used to perform wavelet transform on the phase mode decoupled voltage and current components to determine the arrival time of the fault traveling wave;

[0075] The interference identification module 105 is used to monitor the current waveform changes within a preset time window from the arrival time of the fault traveling wave. If the first and second mode current traveling waves are both reduced to a state close to no current within the preset time window, it is determined to be lightning interference.

[0076] In this embodiment, the fault extraction module 102 is specifically used to: perform a subtraction operation on the three-phase voltage and current components and the normal operating voltage and current components to obtain a fault component.

[0077] In this embodiment, if any one of the first mode or second mode current traveling waves is not close to a no-current state within the preset time window, it is determined to be a line fault.

[0078] In this embodiment, the three-phase voltage and current components include three-phase voltage components and three-phase current components;

[0079] The normal operating voltage and current components include the normal three-phase voltage and the normal three-phase current of the AC transmission line in the normal operating state.

[0080] For the specific limitations of a system for identifying lightning interference for traveling wave protection of an AC transmission line, please refer to the above-mentioned limitations on a method for identifying lightning interference for traveling wave protection of an AC transmission line, which will not be repeated here. A person of ordinary skill in the art will appreciate that the various modules and steps described in conjunction with the embodiments disclosed in this application can be implemented in hardware, software, or a combination of both. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0081] The embodiment of the present invention provides a system for identifying lightning interference of traveling wave protection of AC transmission lines. The system collects three-phase voltage and current components of the AC transmission line when a lightning strike or fault occurs, and normal operating voltage and current components under normal operating conditions through a signal acquisition module; a fault extraction module obtains a fault component based on the three-phase voltage and current components and the normal operating voltage and current components; the fault component includes a voltage fault component and a current fault component; a phase mode decoupling module performs phase mode transformation on the fault component to obtain a phase mode decoupled voltage and current component; the phase mode decoupled voltage and current component includes voltage components and current components of zero mode, one mode and two mode; a wavelet transformation module performs wavelet transformation on the phase mode decoupled voltage and current components to determine the arrival time of the fault traveling wave; an interference identification module monitors the current waveform change within a preset time window from the arrival time of the fault traveling wave, and if the one mode and two mode current traveling waves are both reduced until close to a current-free state within the preset time window, it is determined to be a lightning interference. Compared with the existing technology, this system can accurately and effectively distinguish lightning interference and line faults through phase mode transformation and wavelet transformation technology, reduce the occurrence of false operation and refusal to operate, and improve the stability and reliability of the power system.

[0082] In one embodiment, the present invention provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the above method are implemented.

[0083] The embodiments of the present invention provide a method, system and medium for identifying lightning interference for traveling wave protection of an AC transmission line. The method for identifying lightning interference for traveling wave protection of an AC transmission line collects line voltage and current components for phase mode transformation, determines the arrival time of the fault traveling wave, and accurately distinguishes between lightning interference and line faults by monitoring changes in the current waveform, thereby effectively improving the reliability and accuracy of transmission line protection and ensuring the safe and stable operation of the power system.

[0084] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., an SSD), etc.

[0085] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods.

[0086] The above-mentioned embodiments only express several preferred implementation modes of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in the technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be regarded as the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be based on the protection scope of the claims.

Claims

1. A method for identifying lightning interference in AC transmission line traveling wave protection, characterized in that: The following steps are involved: Collect the three-phase voltage and current components of the AC transmission line when lightning strikes or faults occur, as well as the normal operating voltage and current components under normal operating conditions; Obtaining a fault component according to the three-phase voltage and current components and the normal operating voltage and current components; The fault components include voltage fault components and current fault components; Performing phase mode transformation on the fault component to obtain phase mode decoupled voltage and current components; The phase-mode decoupling voltage and current components include zero-mode, first-mode and second-mode voltage and current components; Performing wavelet transformation on the phase mode decoupled voltage and current components to determine the arrival time of the fault traveling wave; Monitor the current waveform changes within a preset time window from the arrival time of the fault traveling wave. If the first-mode and second-mode current traveling waves both decrease until they are close to a no-current state within the preset time window, it is determined to be lightning interference.

2. A method for identifying lightning interference for traveling wave protection of AC transmission lines according to claim 1, characterized in that: The step of obtaining the fault component according to the three-phase voltage and current components and the normal operating voltage and current components comprises: The three-phase voltage and current components are subtracted from the normal operating voltage and current components to obtain a fault component.

3. The method for identifying lightning interference of traveling wave protection of AC transmission line according to claim 1, characterized in that: If any one of the first mode or second mode current traveling waves is not close to a no-current state within the preset time window, it is determined to be a line fault.

4. The method for identifying lightning disturbance of AC transmission line traveling wave protection according to claim 1, characterized in that: The three-phase voltage and current components include three-phase voltage components and three-phase current components; The normal operating voltage and current components include the normal three-phase voltage and the normal three-phase current of the AC transmission line in the normal operating state.

5. The method for identifying lightning disturbance of AC transmission line traveling wave protection according to claim 1, characterized in that: The preset time window is 1 ms.

6. A system for identifying lightning disturbances for AC transmission line traveling wave protection, characterized in that: The system comprises: A signal acquisition module is used to collect the three-phase voltage and current components of the AC transmission line when a lightning strike or fault occurs, as well as the normal operating voltage and current components under normal operating conditions; A fault extraction module, used to obtain a fault component according to the three-phase voltage and current components and the normal operating voltage and current components; the fault component includes a voltage fault component and a current fault component; A phase mode decoupling module is used to perform phase mode transformation on the fault component to obtain phase mode decoupled voltage and current components; the phase mode decoupled voltage and current components include zero mode, first mode and second mode voltage components and current components; A wavelet transform module is used to perform wavelet transform on the phase mode decoupled voltage and current components to determine the arrival time of the fault traveling wave; The interference identification module is used to monitor the current waveform changes within a preset time window from the arrival time of the fault traveling wave. If the first-mode and second-mode current traveling waves are both reduced until they are close to a current-free state within the preset time window, it is determined to be lightning interference.

7. The AC transmission line traveling wave protection lightning interference identification system according to claim 6, characterized in that: The fault extraction module is specifically used for: The three-phase voltage and current components are subtracted from the normal operating voltage and current components to obtain a fault component.

8. The AC transmission line traveling wave protection lightning interference identification system according to claim 6, characterized in that: If any one of the first mode or second mode current traveling waves is not close to a no-current state within the preset time window, it is determined to be a line fault.

9. The AC transmission line traveling wave protection lightning interference identification system according to claim 6, characterized in that: The three-phase voltage and current components include three-phase voltage components and three-phase current components; The normal operating voltage and current components include the normal three-phase voltage and the normal three-phase current of the AC transmission line in the normal operating state.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed, the method according to any one of claims 1 to 5 is implemented.

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