Protection method and device based on differential mode current traveling wave, equipment, medium and product

Abstract

The application discloses a protection method and device based on a differential mode current traveling wave, equipment, a medium and a product, and relates to the technical field of power electronics. The protection method based on the differential mode current traveling wave comprises the following steps: acquiring an electrical parameter of a first flexible DC power transmission line; wherein the first flexible DC power transmission line is any flexible DC power transmission line in a same-tower double-circuit flexible DC power transmission line, and the electrical parameter comprises voltage and current; determining a differential mode current traveling wave corresponding to the first flexible DC power transmission line according to the electrical parameter; and performing a protection action on the first flexible DC power transmission line according to the differential mode current traveling wave. According to the scheme disclosed in the application, the flexible DC power transmission line can be protected based on the differential mode current traveling wave, and the reliability of line protection is improved.

Description

Technical Field

[0001] This application belongs to the field of power electronics technology, and in particular relates to a protection method, device, equipment, medium and product based on differential mode current traveling wave. Background Technology

[0002] Safe and stable operation is a basic requirement of power systems. When a fault occurs in the power system, the relay protection device detects the fault and issues a switching action command to promptly disconnect the fault and prevent the fault from spreading, thereby achieving the purpose of protecting the system.

[0003] Flexible DC transmission is a DC transmission technology based on voltage source converters and fully controlled power electronic devices, offering advantages such as high control flexibility and the ability to operate in islanded mode. To conserve transmission corridor space, some flexible DC transmission lines employ a double-circuit wiring configuration on the same tower, which saves costs and improves economic efficiency.

[0004] The characteristics of a double-circuit flexible DC transmission line on the same tower are: self-inductance and mutual inductance exist between the four lines, resulting in coupled wave impedance between the lines. When a fault occurs in one of the flexible DC transmission lines, an initial traveling wave will be generated at the fault point; while the other flexible DC transmission line will also generate a fault-coupled traveling wave due to the coupling between the lines. When the protection device of the other line detects this traveling wave, it may cause the protection to malfunction, affecting the normal power supply of the non-faulty lines.

[0005] In related technologies, the protection method used for double-circuit flexible DC transmission lines on the same tower is generally based on extreme traveling wave protection, which judges the occurrence of faults by the amount of traveling wave on the positive or negative pole. However, this protection method is affected by the coupling between the double-circuit flexible DC transmission lines, which may cause non-faulty lines to malfunction. Summary of the Invention

[0006] This application provides a protection method, device, equipment, medium, and product based on differential mode current traveling wave, which can solve the problem of maloperation of non-faulty lines.

[0007] In a first aspect, embodiments of this application provide a protection method based on differential mode current traveling waves, applied to a double-circuit flexible DC transmission line on the same tower, the method comprising: Obtain the electrical parameters of the first flexible DC transmission line; wherein, the first flexible DC transmission line is any one of the two flexible DC transmission lines on the same tower, and the electrical parameters include voltage and current; Based on the electrical parameters, determine the differential mode current traveling wave corresponding to the first flexible DC transmission line; Based on the differential mode current traveling wave, protection actions are performed on the first flexible DC transmission line.

[0008] Secondly, embodiments of this application provide a protection device based on differential mode current traveling wave, applied to a double-circuit flexible DC transmission line on the same tower. The device includes: The acquisition module is used to acquire the electrical parameters of the first flexible DC transmission line; wherein, the first flexible DC transmission line is any one of the two flexible DC transmission lines on the same tower, and the electrical parameters include voltage and current; The determination module is used to determine the differential mode current traveling wave corresponding to the first flexible DC transmission line based on electrical parameters. The protection module is used to perform protection actions on the first flexible DC transmission line based on the differential mode current traveling wave.

[0009] Thirdly, embodiments of this application provide an electronic device, including: a processor and a memory storing computer program instructions; when the processor executes the computer program instructions, it implements the protection method based on differential mode current traveling wave provided in embodiments of this application.

[0010] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer program instructions, which, when executed by a processor, implement the protection method based on differential-mode current traveling wave provided in embodiments of this application.

[0011] Fifthly, embodiments of this application provide a computer program product, wherein when the instructions in the computer program product are executed by the processor of an electronic device, the electronic device performs the protection method based on differential mode current traveling wave provided in embodiments of this application.

[0012] In this embodiment, the electrical parameters of the first flexible DC transmission line are obtained; wherein the first flexible DC transmission line is any one of the two flexible DC transmission lines on the same tower, and the electrical parameters include voltage and current; based on the electrical parameters, the differential mode current traveling wave corresponding to the first flexible DC transmission line is determined; based on the differential mode current traveling wave, protection actions are performed on the first flexible DC transmission line. This reduces the impact of electromagnetic coupling between the two flexible DC transmission lines on the protection system, reduces the probability of maloperation of non-faulty lines, effectively improves the reliability of line protection, achieves rapid and accurate fault clearing, and reduces power outage losses. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1This is a schematic diagram of a double-circuit flexible DC transmission line on the same tower provided in some embodiments of this application; Figure 2 This is a schematic diagram of the fault component network near the fault point provided in some embodiments of this application; Figure 3 This is a schematic diagram of a four-conductor double-circuit flexible DC transmission line on the same tower provided in some embodiments of this application; Figure 4 These are Peterson equivalent circuit diagrams provided in some embodiments of this application; Figure 5 This is a schematic flowchart of the protection method based on differential mode current traveling wave provided in the embodiments of this application; Figure 6 These are schematic diagrams of voltage waveforms provided in some embodiments of this application; Figure 7 This is a schematic diagram of current waveforms provided in some embodiments of this application; Figure 8 This is a schematic diagram of a differential-mode current traveling wave provided in some embodiments of this application; Figure 9 This is a schematic diagram of the operation of AB-loop flexible DC transmission line protection provided in some embodiments of this application; Figure 10 These are schematic diagrams illustrating the operation of AC-to-flexible DC transmission line protection provided in some embodiments of this application; Figure 11 This is a schematic diagram of the structure of the protection device based on differential mode current traveling wave provided in the embodiments of this application; Figure 12 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0015] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0016] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0017] It should be noted that the acquisition, storage, use, and processing of data in this application embodiment all comply with the relevant provisions of national laws and regulations.

[0018] It should be noted that in the embodiments of this application, certain software, components, models and other existing solutions in the industry may be mentioned. These should be regarded as exemplary and are only intended to illustrate the feasibility of implementing the technical solution of this application. However, it does not mean that the applicant has used or necessarily used the solution.

[0019] The following section will first explain the inventor's discovery that using differential mode current traveling wave as a protection criterion can effectively improve the reliability of protecting flexible DC transmission lines.

[0020] Figure 1 These are schematic diagrams of double-circuit flexible DC transmission lines on the same tower provided in some embodiments of this application; Figure 1 In China, a double-circuit flexible DC transmission line on the same tower includes AB-circuit flexible DC transmission lines and AC-circuit flexible DC transmission lines. A double-circuit flexible DC transmission line on the same tower is divided into the section on the same tower and the section not on the same tower. Among these, in... Figure 1 In the middle, the lines on the same tower to the left of the dividing point are the same tower section, and the lines on the non-same tower to the right of the dividing point are non-same tower section.

[0021] The following example illustrates a single-pole grounding fault occurring on the positive pole of a non-column section of an AB-circuit flexible DC transmission line. The fault component method is used to analyze the AB-circuit flexible DC transmission line. Based on the superposition theorem, the AB-circuit flexible DC transmission line is decomposed into a normal operating section and a faulted section. The fault component network near the fault point is as follows: Figure 2 As shown, Figure 2 This is a schematic diagram of the fault component network near the fault point provided in some embodiments of this application.

[0022] according to Figure 2The fault component network near the fault point shown can be used to formulate the equations for solving the initial traveling wave after the fault occurs. The system-side / load-side equations are shown in formula (1) below: (1) The equation at the fault point is shown in formula (2) below: (2) The equation for the faulty branch is shown in formula (3) below: (3) In formulas (1) to (3), and The initial traveling waves of the fault voltages are for the positive and negative terminals, respectively. and The initial traveling waves of the fault current are shown for the positive and negative terminals, respectively. and These are the voltages at the positive and negative fault points, respectively. and These are the currents in the positive and negative fault branches, respectively. The transition resistance of the faulty branch. The voltage of the additional power supply for the fault. The voltage at the fault point before the fault occurred. Zero-mode impedance This is the impedance of the line mode wave.

[0023] Solving equations (1) to (3) yields the initial traveling wave as shown in equation (4): (4) Ignoring the attenuation of the traveling wave, when the initial traveling wave reaches the boundary between the sections on the same tower and those on different towers, refraction and reflection will occur due to the difference in wave impedance on both sides of the line. Figure 1 The boundary is shown.

[0024] Among them, Figure 1 middle, and These are the initial traveling waves for voltage and current faults, respectively. and These are the refracted traveling waves from voltage and current faults at the line boundary, respectively. and These represent the voltage and current fault reflected traveling waves at the line boundary, respectively. The bold text indicates that these electrical quantities are vectors, encompassing the electrical quantities of all four lines in the double-circuit line. Let the wave impedance matrix of the traveling wave propagating on the same tower section of the line be... The wave impedance matrix of the traveling wave propagating on the non-tower sections of the line is: According to the theory of traveling wave propagation, the following equation (5) can be derived: (5) Substituting the initial traveling wave calculation result shown in formula (4) into formula (5) and performing pole mode transformation, the differential mode components of the voltage and current traveling waves at the AC measurement points of the non-faulty line can be obtained, as shown in formula (6) below: (6) In formula (6), and These are the differential-mode components of the voltage and current traveling waves at the AC measurement points, respectively. The differential mode component of the current traveling wave at the measurement point AB of the faulty line. The impedance of line 1 in the four conductors of a double-circuit flexible DC transmission line on the same tower is given. The mutual impedance between conductors 1 and 2 in a four-conductor double-circuit flexible DC transmission line on the same tower. The mutual impedance between conductors 1 and 3 in a four-conductor double-circuit flexible DC transmission line on the same tower. This refers to the mutual impedance between conductors 1 and 4 of a double-circuit flexible DC transmission line on the same tower. The four conductors of the double-circuit flexible DC transmission line on the same tower are as follows: Figure 3 As shown, Figure 3 This is a schematic diagram of a four-conductor double-circuit flexible DC transmission line on the same tower provided in some embodiments of this application.

[0025] As can be seen from the above formula (6), the differential mode components of the voltage and current traveling waves of the non-faulty AC line both contain This coefficient. Generally speaking... and The difference is very small; when the lines are uniformly transposed, it can be considered... Therefore, the fault reverse traveling wave They also have the same coefficients and properties, so it can be concluded that when a fault occurs in one of the flexible DC transmission lines in a double-circuit flexible DC transmission line on the same tower, the fault voltage, current and the differential mode component of the reverse traveling wave on the non-faulty line are 0, while the fault voltage, current and the differential mode component of the reverse traveling wave on the faulty line have a certain magnitude and are not 0. Therefore, the differential mode traveling wave can be used as a protection criterion to ensure that the protection of the faulty line is correct and that the protection of the non-faulty line does not malfunction.

[0026] When a fault traveling wave passes through a smoothing reactor at the line boundary, it will be reflected. Since the measurement point is adjacent to the smoothing reactor, the traveling wave measured at the measurement point is actually the superposition of the incident traveling wave from the fault point and the reflected traveling wave from the smoothing reactor. Therefore, it is necessary to analyze the reflection process of the traveling wave at the boundary of the smoothing reactor.

[0027] Peterson's law can be used to analyze wave processes at the boundary, where the Peterson equivalent circuit diagram is shown below. Figure 4 As shown, Figure 4 These are Peterson equivalent circuit diagrams provided in some embodiments of this application. Figure 4 middle, The incident voltage traveling wave of the smoothing reactor, For wave impedance, and Let be the voltage and current across the inductor. According to the three-element method of first-order resistor-inductor (RL), taking the moment when the fault traveling wave arrives at the smoothing reactor as time 0, the voltage and current across the smoothing reactor can be obtained as shown in formula (7): (7) In formula (7), Let t be the inductance value of the inductor, and t be the time.

[0028] The voltage across the smoothing reactor is equal to the incident voltage traveling wave plus the reflected voltage traveling wave. The voltage and current reflected traveling waves of the smoothing reactor can be obtained as shown in formula (8): (8) In formula (8), and These are the voltage and current reflected traveling waves of the smoothing reactor, respectively.

[0029] The reflected traveling wave passes through the measurement point and is superimposed with the incident traveling wave to obtain the fault current traveling wave at the measurement point, as shown in the following formula (9): (9) In formula (9), The fault current traveling wave at the measurement point.

[0030] As can be seen from formula (9), on time scales below milliseconds, after reflection and superposition by the smoothing reactor, the fault current traveling wave at the measurement point approaches 0, and then slowly rises to the initial fault current traveling wave transmitted from the line boundary. Because the fault current rises slowly, it is difficult to set the protection threshold using fault discrimination methods based on sudden current changes, and it is easily affected by factors such as transition resistance. As can be seen from formula (9), the fault current traveling wave... The rate of increase is approximately Therefore, using the rise rate of the differential mode current traveling wave as a protection criterion can reliably determine the faults occurring on a double-circuit flexible DC transmission line on the same tower, effectively improving the reliability of protecting flexible DC transmission lines.

[0031] Based on the inventor's discovery that using the rise rate of differential mode current traveling wave as a protection criterion can effectively improve the reliability of protection for flexible DC transmission lines, this application provides a protection method based on differential mode current traveling wave, which can be applied to double-circuit flexible DC transmission lines on the same tower.

[0032] The following description, in conjunction with the accompanying drawings, details the protection method, apparatus, equipment, medium, and product based on differential mode current traveling wave provided in this application through specific embodiments and application scenarios.

[0033] Figure 5 This is a schematic flowchart of the protection method based on differential-mode current traveling wave provided in an embodiment of this application. Figure 5 As shown, protection methods based on differential-mode current traveling waves may include: Step 501: Obtain the electrical parameters of the first flexible DC transmission line; wherein, the first flexible DC transmission line is any one of the two flexible DC transmission lines on the same tower, and the electrical parameters include voltage and current; In some embodiments of this application, a current transformer can be installed in the first flexible DC transmission line to collect electrical parameters according to a first sampling frequency.

[0034] In some embodiments of this application, the first sampling frequency can be set according to actual needs, for example, the first sampling frequency is 1 MHz.

[0035] Step 502: Determine the differential mode current traveling wave corresponding to the first flexible DC transmission line based on the electrical parameters; In some embodiments of this application, step 502 may include: determining whether to activate protection for the first flexible DC transmission line based on electrical parameters; and if activation of protection for the first flexible DC transmission line is determined based on electrical parameters, determining the differential mode current traveling wave corresponding to the first flexible DC transmission line based on the electrical parameters.

[0036] In some embodiments of this application, determining whether to activate protection for the first flexible DC transmission line based on electrical parameters includes: determining to activate protection for the first flexible DC transmission line if the voltage gradient corresponding to the first sampling time is greater than or equal to a first threshold; wherein, the first sampling time is any time when the electrical parameters are collected; and determining not to activate protection for the first flexible DC transmission line if the voltage gradient is less than the first threshold.

[0037] In some embodiments of this application, the first threshold can be set according to actual needs, for example, the first threshold is 5 kV.

[0038] In some embodiments of this application, the protection method based on differential mode current traveling wave provided in this application may further include: determining the voltage gradient corresponding to the first sampling time based on the voltage of N sampling times before the first sampling time and the voltage of N sampling times after the first sampling time, where N is a positive integer.

[0039] In some embodiments of this application, the voltage gradient corresponding to the first sampling time can be determined by the following formula (10): (10) In formula (10), This represents the voltage gradient at sampling time k. The voltage at the j-th sampling time after sampling time k. Let N be the voltage at the j-th sampling time before sampling time k, and N be the number of sampling times.

[0040] In some embodiments of this application, determining the differential-mode current traveling wave corresponding to the first flexible DC transmission line based on electrical parameters may include: performing pole-mode transformation on the current traveling wave corresponding to the first flexible DC transmission line to obtain the differential-mode current traveling wave.

[0041] In some embodiments of this application, the polar mode transformation matrix used in the polar mode transformation of this application embodiments can be .

[0042] Step 503: Perform protection actions on the first flexible DC transmission line based on the differential mode current traveling wave.

[0043] In some embodiments of this application, step 503 may include: determining whether to perform a protection action on the first flexible DC transmission line based on the differential mode current traveling wave; and performing a protection action on the first flexible DC transmission line if it is determined based on the differential mode current traveling wave.

[0044] In some embodiments of this application, determining whether to perform a protection action on the first flexible DC transmission line based on the differential mode current traveling wave may include: selecting M sampling points from the differential mode current traveling wave as calculation points, where M is a positive integer greater than or equal to 2; calculating the rate of change of the differential mode current traveling wave corresponding to two adjacent calculation points to obtain M-1 rates of change; determining that a protection action should be performed on the first flexible DC transmission line if the maximum value among the absolute values ​​of the M-1 rates of change is greater than or equal to a second threshold; and determining that no protection action should be performed on the first flexible DC transmission line if the maximum value is less than the second threshold.

[0045] In some embodiments of this application, the second threshold can be set according to actual needs, for example, the second threshold is 0.01kA / ms.

[0046] In some embodiments of this application, the rate of change of the differential-mode current traveling wave corresponding to two adjacent calculation points can be determined according to the following formula (11): (11) In formula (11), Let n be the rate of change of the differential mode current traveling wave corresponding to adjacent calculation points n and n+1. To calculate the differential mode current traveling wave corresponding to point n+1, To calculate the differential mode current traveling wave corresponding to point n, This is the time interval between calculation point n+1 and calculation point n+1.

[0047] In some embodiments of this application, selecting M sampling points from the differential mode current traveling wave as calculation points may include: selecting the sampling point corresponding to the first sampling time as the starting calculation point; selecting one sampling point as the calculation point every K sampling points until the number of calculation points is M, where K is a positive integer.

[0048] The protection method based on differential mode current traveling wave provided in this application will be described below with specific examples.

[0049] For example, the following uses the above Figure 1 The scenario shown is used as an example for illustration.

[0050] The sending end A supplies power to the receiving ends B and C via a flexible DC transmission line. The section of the line on the same tower is 32 km long, and the section on different towers is 177.4 km long, for a total length of 208.4 km. The power supply is a ±500 kV DC power supply with the positive and negative terminals grounded in the middle. The internal resistance of the power supply is 1 ohm (Ω), and the internal inductance is 0.15 Henry (H).

[0051] A positive ground fault occurred at the midpoint of the non-column section of the AB-circuit flexible DC transmission line, 0.2004 seconds after the instrument transformer began collecting voltage and current data. The initial traveling wave of the fault propagated towards the corresponding measurement point on the instrument transformer.

[0052] The instrument transformers installed on both the AB and AC circuits of the flexible DC transmission line sampled voltage and current at a sampling frequency of 1 MHz. The acquired voltage and current waveforms are shown below. Figure 6 and Figure 7 As shown, Figure 6 These are schematic diagrams of voltage waveforms provided in some embodiments of this application. Figure 7These are schematic diagrams of current waveforms provided in some embodiments of this application. Wherein, Figure 6 The voltages of the AB positive line, AB negative line, AC positive line, and AC negative line are shown. Figure 7 The diagram shows the current in the AB positive circuit, the AB negative circuit, the AC positive circuit, and the AC negative circuit.

[0053] based on Figure 6 The voltage shown and the voltage gradient determined by the above formula (10) are used. When the voltage gradient at the 0.2004th second is greater than the set threshold of 5kV, based on... Figure 7 The current shown is subjected to a pole-mode transformation to obtain a differential-mode current traveling wave. The calculated differential-mode current traveling wave is as follows: Figure 8 As shown, Figure 8 This is a schematic diagram of a differential-mode current traveling wave provided in some embodiments of this application. Figure 8 The differential mode current traveling wave of the AB-circuit flexible DC transmission line and the AC-circuit flexible DC transmission line are shown.

[0054] The sampling point corresponding to 0.2004 seconds was selected as the starting calculation point, from which... Figure 8 In the differential mode current traveling wave shown, one sampling point is selected as the calculation point every 10 sampling points, for a total of 6 calculation points. The change rates of the 5 differential mode current traveling waves corresponding to the AB circuit flexible DC transmission line are calculated using the above formula (11). The change rates of the 5 differential mode current traveling waves are 1.8 kA / ms, 0.78 kA / ms, 1.8 kA / ms, 0.79 kA / ms, and 1.8 kA / ms, respectively. If the maximum value of the change rate of the 5 differential mode current traveling waves is greater than the set threshold of 0.01 kA / ms, then a protection action is performed on the AB circuit flexible DC transmission line. The protection action of the AB circuit flexible DC transmission line is as follows: Figure 9 As shown, Figure 9 This is a schematic diagram of the protection operation of an AB-circuit flexible DC transmission line according to some embodiments of this application. If the maximum value of the rate of change of the five differential-mode current traveling waves corresponding to the AC-circuit flexible DC transmission line is less than the set threshold of 0.01 kA / ms, then no protection operation is performed on the AC-circuit flexible DC transmission line. The protection operation of the AC-circuit flexible DC transmission line is as follows: Figure 10 As shown, Figure 10 This is a schematic diagram of the operation of AC-return flexible DC transmission line protection provided in some embodiments of this application.

[0055] In this embodiment, the electrical parameters of the first flexible DC transmission line are obtained; wherein the first flexible DC transmission line is any one of the two flexible DC transmission lines on the same tower, and the electrical parameters include voltage and current; based on the electrical parameters, the differential mode current traveling wave corresponding to the first flexible DC transmission line is determined; based on the differential mode current traveling wave, protection actions are performed on the first flexible DC transmission line. This reduces the impact of electromagnetic coupling between the two flexible DC transmission lines on the protection system, lowering the probability of maloperation of non-faulty lines. It effectively improves the reliability of line protection, achieves rapid and accurate fault clearing, and reduces power outage losses.

[0056] This application also provides a protection device based on differential mode current traveling wave, such as... Figure 11 As shown. Figure 11 This is a schematic diagram of the structure of the protection device based on differential mode current traveling wave provided in the embodiments of this application. The protection device 1100 based on differential mode current traveling wave may include: The acquisition module 1101 is used to acquire the electrical parameters of the first flexible DC transmission line; wherein, the first flexible DC transmission line is any one of the two flexible DC transmission lines on the same tower, and the electrical parameters include voltage and current; The determination module 1102 is used to determine the differential mode current traveling wave corresponding to the first flexible DC transmission line based on electrical parameters. The protection module 1103 is used to perform protection actions on the first flexible DC transmission line based on the differential mode current traveling wave.

[0057] In some embodiments of this application, the determining module 1102 may specifically be used for: Based on the electrical parameters, determine whether to activate the protection for the first flexible DC transmission line; When the starting protection of the first flexible DC transmission line is determined based on the electrical parameters, the differential mode current traveling wave corresponding to the first flexible DC transmission line is determined based on the electrical parameters.

[0058] In some embodiments of this application, the determining module 1102 may specifically be used for: If the voltage gradient at the first sampling time is greater than or equal to the first threshold, the protection of the first flexible DC transmission line is initiated; wherein, the first sampling time is any time when the electrical parameters are collected. If the voltage gradient is less than the first threshold, it is determined that the protection of the first flexible DC transmission line will not be activated.

[0059] In some embodiments of this application, the determining module 1102 may also be used for: The voltage gradient corresponding to the first sampling moment is determined based on the voltages at N sampling moments before the first sampling moment and the voltages at N sampling moments after the first sampling moment, where N is a positive integer.

[0060] In some embodiments of this application, the determining module 1102 may specifically be used for: The differential mode current traveling wave is obtained by performing pole mode transformation on the current traveling wave corresponding to the first flexible DC transmission line.

[0061] In some embodiments of this application, the protection module 1103 is specifically used for: Based on the differential mode current traveling wave, determine whether to perform protection actions on the first flexible DC transmission line; If the protection action for the first flexible DC transmission line is determined based on the differential mode current traveling wave, then the protection action for the first flexible DC transmission line is performed.

[0062] In some embodiments of this application, the protection module 1103 is specifically used for: M sampling points are selected from the differential mode current traveling wave as calculation points, where M is a positive integer greater than or equal to 2; Calculate the rate of change of the differential mode current traveling wave corresponding to two adjacent calculation points to obtain M-1 rates of change; If the maximum value among the absolute values ​​of M-1 rates of change is greater than or equal to the second threshold, it is determined that a protection action should be performed on the first flexible DC transmission line. If the maximum value is less than the second threshold, it is determined that no protection action will be performed on the first flexible DC transmission line.

[0063] In some embodiments of this application, the protection module 1103 is specifically used for: The sampling point corresponding to the first sampling time is selected as the starting calculation point; Every K sampling points, one sampling point is selected as the calculation point, until the number of calculation points is M, where K is a positive integer.

[0064] Figure 12 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application.

[0065] The electronic device 1200 may include a processor 1201 and a memory 1202 storing computer program instructions.

[0066] Specifically, the processor 1201 may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application.

[0067] Memory 1202 may include mass storage for data or instructions. For example, and not limitingly, memory 1202 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 1202 may include removable or non-removable (or fixed) media. Where appropriate, memory 1202 may be internal or external to an electronic device. In some specific embodiments, memory 1202 is a non-volatile solid-state memory.

[0068] In some specific embodiments, the memory may include read-only memory (ROM), random access memory (RAM), disk storage media devices, optical storage media devices, flash memory devices, and electrical, optical, or other physical / tangible memory storage devices. Therefore, typically, the memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the differential-mode current traveling wave-based protection method according to this application.

[0069] The processor 1201 reads and executes computer program instructions stored in the memory 1202 to implement the protection method based on differential mode current traveling wave provided in the embodiments of this application.

[0070] In one example, the electronic device may also include a communication interface 1203 and a bus 1204. For example, Figure 12 As shown, the processor 1201, memory 1202, and communication interface 1203 are connected through bus 1204 and complete communication with each other.

[0071] The communication interface 1203 is mainly used to realize communication between various modules, devices, units and / or equipment in the embodiments of this application.

[0072] Bus 1204 includes hardware, software, or both, that couples components of an electronic device together. For example, and not limitingly, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local Bus (VLB) bus, or other suitable buses, or a combination of two or more of these. Where appropriate, bus 1204 may include one or more buses. Although specific buses are described and illustrated in the embodiments of this application, this application considers any suitable bus or interconnection.

[0073] The electronic device can execute the protection method based on differential mode current traveling wave provided in the embodiments of this application, thereby achieving the corresponding technical effects of the protection method based on differential mode current traveling wave provided in the embodiments of this application.

[0074] In addition, in conjunction with the protection method based on differential-mode current traveling waves in the above embodiments, this application also provides a computer-readable storage medium for implementation. The computer-readable storage medium stores computer program instructions; when these computer program instructions are executed by a processor, they implement the protection method based on differential-mode current traveling waves provided in this application. Examples of computer-readable storage media include non-transitory computer-readable media, such as ROM, RAM, magnetic disks, or optical disks.

[0075] This application provides a computer program product. When the instructions in the computer program product are executed by the processor of an electronic device, the electronic device performs the protection method based on differential mode current traveling wave provided in this application, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0076] It should be clarified that this application is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of this application is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of this application.

[0077] The functional blocks shown in the above-described block diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. Programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried on a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable read-only memory (EROM), floppy disks, compact disc read-only memory (CD-ROM), optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0078] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0079] The aspects of this disclosure have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that these instructions, executable via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by special-purpose hardware performing the specified functions or actions, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0080] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A protection method based on differential mode current traveling wave, characterized in that, The method is applied to a double-circuit flexible DC transmission line on the same tower, and the method includes: Obtain the electrical parameters of the first flexible DC transmission line; wherein, the first flexible DC transmission line is any one of the two flexible DC transmission lines on the same tower, and the electrical parameters include voltage and current; Based on the electrical parameters, determine the differential mode current traveling wave corresponding to the first flexible DC transmission line; Based on the differential mode current traveling wave, protection actions are performed on the first flexible DC transmission line.

2. The method according to claim 1, characterized in that, The step of determining the differential-mode current traveling wave corresponding to the first flexible DC transmission line based on the electrical parameters includes: Based on the electrical parameters, determine whether to activate the protection for the first flexible DC transmission line; When the activation protection of the first flexible DC transmission line is determined based on the electrical parameters, the differential mode current traveling wave corresponding to the first flexible DC transmission line is determined based on the electrical parameters.

3. The method according to claim 2, characterized in that, The step of determining whether to activate the protection for the first flexible DC transmission line based on the electrical parameters includes: If the voltage gradient at the first sampling time is greater than or equal to a first threshold, it is determined to activate the protection of the first flexible DC transmission line; wherein, the first sampling time is any time when the electrical parameters are collected; If the voltage gradient is less than the first threshold, it is determined that the protection of the first flexible DC transmission line will not be activated.

4. The method according to claim 3, characterized in that, The method further includes: The voltage gradient corresponding to the first sampling time is determined based on the voltages at N sampling times before the first sampling time and the voltages at N sampling times after the first sampling time, where N is a positive integer.

5. The method according to claim 1, characterized in that, The step of determining the differential-mode current traveling wave corresponding to the first flexible DC transmission line based on the electrical parameters includes: The differential mode current traveling wave is obtained by performing pole mode transformation on the current traveling wave corresponding to the first flexible DC transmission line.

6. The method according to claim 1, characterized in that, The step of performing protection actions on the first flexible DC transmission line based on the differential mode current traveling wave includes: Based on the differential mode current traveling wave, determine whether to perform protection action on the first flexible DC transmission line; If the protection action for the first flexible DC transmission line is determined based on the differential mode current traveling wave, the protection action for the first flexible DC transmission line is performed.

7. The method according to claim 6, characterized in that, The step of determining whether to perform protection action on the first flexible DC transmission line based on the differential mode current traveling wave includes: M sampling points are selected from the differential mode current traveling wave as calculation points, where M is a positive integer greater than or equal to 2; Calculate the rate of change of the differential mode current traveling wave corresponding to two adjacent calculation points to obtain M-1 rates of change; If the maximum value among the absolute values ​​of the M-1 rates of change is greater than or equal to the second threshold, it is determined that a protection action should be performed on the first flexible DC transmission line. If the maximum value is less than the second threshold, it is determined that no protection action will be performed on the first flexible DC transmission line.

8. The method according to claim 7, characterized in that, The step of selecting M sampling points from the differential mode current traveling wave as calculation points includes: The sampling point corresponding to the first sampling time is selected as the starting calculation point; Every K sampling points, one sampling point is selected as the calculation point, until the number of calculation points is M, where K is a positive integer.

9. A protection device based on differential mode current traveling wave, characterized in that, The device is applied to a double-circuit flexible DC transmission line on the same tower, and the device includes: The acquisition module is used to acquire the electrical parameters of the first flexible DC transmission line; wherein the first flexible DC transmission line is any one of the two flexible DC transmission lines on the same tower, and the electrical parameters include voltage and current; The determination module is used to determine the differential mode current traveling wave corresponding to the first flexible DC transmission line based on the electrical parameters. The protection module is used to perform protection actions on the first flexible DC transmission line based on the differential mode current traveling wave.

10. An electronic device, characterized in that, The electronic device includes: a processor and a memory storing computer program instructions; The processor reads and executes the computer program instructions to implement the protection method based on differential mode current traveling wave as described in any one of claims 1-8.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer program instructions, which, when executed by a processor, implement the protection method based on differential-mode current traveling wave as described in any one of claims 1-8.

12. A computer program product, characterized in that, When the instructions in the computer program product are executed by the processor of the electronic device, the electronic device performs the protection method based on differential mode current traveling wave as described in any one of claims 1-8.

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