Wind power generation system power collection line fault detection method, device, medium and equipment

Abstract

The application discloses a wind power generation system power collection line fault detection method and device, medium and equipment. The method comprises the following steps: for any target phase in three-phase alternating current, voltage sampling and current sampling are respectively performed on the power collection line collection bus end and the power collection line inner side end, the first voltage and the first current of the collection bus end at each sampling time are obtained, and the second voltage and the second current of the branch line inner side end at each sampling time are obtained; whether the predetermined fault prediction condition is met is determined based on the first voltage; when it is determined that the fault prediction condition is met, the first transient high-frequency energy of the collection bus end is determined based on the first voltage and the first current, and the second transient high-frequency energy of the power collection line inner side end is determined based on the second voltage and the second current; fault detection is performed based on the first transient high-frequency energy and the second transient high-frequency energy, and a target detection result is obtained. The application can accurately and timely perform fault detection.

Description

Technical Field

[0001] This invention relates to the field of wind power generation technology, and in particular to a method, device, medium and equipment for detecting faults in the collector lines of a wind power generation system. Background Technology

[0002] In recent years, with the popularization of new energy power generation and the continuous development of new energy sources such as photovoltaic and wind power, the proportion of clean energy in my country's energy structure has been increasing. Among them, deep-sea wind power, due to its abundant resources and high power generation utilization rate, has been established as the main battlefield for new energy development. To solve the problem of large-scale transmission of deep-sea wind power, flexible low-frequency AC transmission (FLAC) technology has emerged. This technology typically operates in low-frequency bands such as 20 Hz, which can not only significantly suppress the charging current of submarine cables and reduce transmission losses, but also eliminate the need to build large offshore converter platforms, thus possessing the characteristics of short construction period and superior economic efficiency. Therefore, it has become another mainstream technical route besides power frequency AC and flexible DC transmission.

[0003] However, the widespread application of flexible low-frequency transmission systems has brought new challenges to relay protection. In offshore wind power transmission systems using flexible low-frequency transmission, collectors connect permanent magnet direct-drive wind turbines (PMSGs) and modular multilevel matrix converters (M3Cs). The fault response characteristics of these fully power electronic devices are entirely controlled by their control logic. Once a fault occurs, the system exhibits significant "weak feeder" characteristics, meaning the fault current amplitude is limited, the waveform is distorted, and the phase is controlled, no longer possessing the significant power frequency abrupt changes provided by traditional synchronous power supplies. This makes it difficult for traditional differential protection or overcurrent protection based on power frequency quantities to sensitively identify faults, posing a risk of failure to operate and seriously endangering system safety.

[0004] Furthermore, the low-frequency operation characteristics present a fundamental bottleneck to the speed of protection action. Due to the reduced system fundamental frequency, the signal period is correspondingly longer (e.g., 50ms at 20Hz). Existing phasor extraction algorithms typically require at least one cycle of data window to ensure calculation accuracy. This means that protection devices must tolerate a longer inherent delay, making it difficult to meet the rapid protection requirements of power electronic equipment with poor overcurrent tolerance. More critically, in the initial transient phase of a fault, the rapid adjustment of power electronic equipment causes voltage and current signals to exhibit high non-stationarity and non-sinusoidal characteristics. At this time, the physical meaning of the phasors extracted based on steady-state assumptions is ambiguous, belonging to "pseudo-phasors" or "pseudo-sequence components." Protection criteria constructed based on this are prone to fluctuations or misjudgments during transient processes, failing to balance speed and reliability.

[0005] Therefore, there is an urgent need for a fault detection method for power collection lines to solve the problem that existing technologies cannot accurately and timely detect faults. Summary of the Invention

[0006] In view of this, the present invention provides a method, device, medium and equipment for detecting faults in the collector lines of a wind power generation system, the main purpose of which is to solve the problem that it is currently impossible to accurately and timely detect faults in the collector lines.

[0007] To address the aforementioned problems, this application provides a method for detecting faults in the collector lines of a wind power generation system, comprising: For any target phase in a three-phase AC power supply, voltage and current sampling are performed at the busbar end and the inner end of the collector line, respectively, to obtain the first voltage at the busbar end, the first current at the busbar end, the second voltage at the inner end of the branch line, and the second current at the inner end of the collector line at each sampling time. Based on each of the first voltages, determine whether the predetermined fault prediction conditions are met; When it is determined that the fault prediction conditions are met, the first transient high-frequency energy at the bus terminal is determined based on each of the first voltages and each of the first currents, and the second transient high-frequency energy at the inner end of the collector line is determined based on each of the second voltages and each of the second currents. Fault detection is performed based on the first transient high-frequency energy and the second transient high-frequency energy to obtain the target detection result.

[0008] Optionally, determining whether a predetermined fault prediction condition is met based on each of the first voltages specifically includes: The voltage change rate is determined based on each of the first voltages; The voltage change rate is compared with a predetermined voltage change rate threshold; When the voltage change rate is less than or equal to the voltage change rate threshold, it is determined that the fault prediction condition has not been met. When the voltage change rate is greater than the voltage change rate threshold, the fault prediction condition is determined to be met.

[0009] Optionally, determining the first transient high-frequency energy at the bus terminal based on each of the first voltages and each of the first currents, and determining the second transient high-frequency energy at the inner end of the branch based on each of the second voltages and each of the second currents, specifically includes: Based on a predetermined passband frequency range, each of the first voltages, each of the first currents, each of the second voltages, and each of the second currents are filtered to obtain a first transient high-frequency voltage component corresponding to each of the first voltages, a first transient high-frequency current component corresponding to each of the first currents, a second transient high-frequency voltage component corresponding to each of the second voltages, and a second transient high-frequency current component corresponding to each of the second currents. The first transient high-frequency energy is determined based on each of the first transient high-frequency voltage components and each of the first transient high-frequency current components. The second transient high-frequency energy is determined based on each of the second transient high-frequency voltage components and each of the second transient high-frequency current components.

[0010] Optionally, the predetermined passband frequency range is 950 Hz to 1050 Hz.

[0011] Optionally, the step of performing fault detection based on the first transient high-frequency energy and the second transient high-frequency energy to obtain the target detection result specifically includes: The target transient high-frequency energy is determined based on the first transient high-frequency energy and the second transient high-frequency energy; Fault detection is performed based on the target transient high-frequency energy and the predetermined transient high-frequency energy range to obtain the target detection result.

[0012] Optionally, the step of performing fault detection based on the target transient high-frequency energy and a predetermined transient high-frequency energy range to obtain the target detection result specifically includes: The target transient high-frequency energy is compared with a predetermined transient high-frequency energy range; When the target transient high-frequency energy is within the predetermined transient high-frequency energy range, it is determined that no fault has occurred; When the target transient high-frequency energy is outside the predetermined transient high-frequency energy range, it is determined that a fault has occurred within the collector line area or outside the collector line area.

[0013] Optionally, before performing fault detection, the method further includes: The transient high-frequency energy threshold is determined based on the first transient high-frequency energy coefficient of the collector line when the wind power generation system is operating normally and the second transient high-frequency energy coefficient of the collector line when the wind farm is operating at its maximum capacity. The transient high-frequency energy range is determined based on the transient high-frequency energy threshold.

[0014] To address the aforementioned problems, this application provides a fault detection device for the collector lines of a wind power generation system, comprising: The acquisition module is used to sample the voltage and current at the busbar end and the inner end of the collector line for any target phase in the three-phase AC power supply, respectively, to obtain the first voltage at the busbar end, the first current at the busbar end, the second voltage at the inner end of the branch line, and the second current at the inner end of the collector line at each sampling time. The prediction module is used to determine whether a predetermined fault prediction condition is met based on each of the first voltages; The determination module is used to determine the first transient high-frequency energy at the bus terminal based on each of the first voltages and each of the first currents when the fault prediction conditions are met, and to determine the second transient high-frequency energy at the inner end of the collector line based on each of the second voltages and each of the second currents. The detection module is used to perform fault detection based on the first transient high-frequency energy and the second transient high-frequency energy to obtain the target detection result.

[0015] To address the aforementioned problems, this application provides a storage medium storing a computer program that, when executed by a processor, implements the steps of the wind power generation system collector line fault detection method described above.

[0016] To address the aforementioned problems, this application provides an electronic device, comprising at least a memory and a processor. The memory stores a computer program, and the processor, when executing the computer program in the memory, implements the steps of the wind power generation system collector line fault detection method described above.

[0017] The wind power generation system collector line fault detection method, device, medium, and equipment in this application predicts faults by using the first voltage at the collector bus end. This eliminates the need to wait for the fault to develop into obvious characteristics, triggering subsequent detection processes in advance. It avoids the delay problem of traditional detection methods that rely on steady-state fault signals, and can quickly capture the transient characteristics of the initial stage of the fault, buying time for fault handling and reducing the risk of fault escalation. By calculating the transient high-frequency energy at the collector bus end and the inner end of the branch line respectively, and utilizing the transient component / high-frequency transient component generated instantaneously after the fault occurs—that is, by calculating the transient energy within a short time window—sub-frequency level rapid fault identification is achieved, providing a guarantee for subsequent rapid fault isolation and protecting the safety of power electronic equipment.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0019] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a flowchart illustrating a method for detecting faults in the collector lines of a wind power generation system, as described in an embodiment of this application. Figure 2 This is a topology diagram of the offshore wind power generation system in the embodiments of this application; Figure 3(a) shows the equivalent circuit diagram when there is a fault in the area; Figure 3(b) is the equivalent circuit diagram when there is an external fault on the N-side region; Figure 3(c) is the equivalent circuit diagram when there is a fault outside the M-side region; Figure 4 This is a structural block diagram of a fault detection device for a wind power generation system's collector line, according to another embodiment of this application. Detailed Implementation

[0020] Various embodiments and features of this application are described herein with reference to the accompanying drawings.

[0021] It should be understood that various modifications can be made to the embodiments described herein. Therefore, the above description should not be considered as limiting, but merely as an example of embodiments. Other modifications within the scope and spirit of this application will be apparent to those skilled in the art.

[0022] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the present application and, together with the general description of the present application given above and the detailed description of the embodiments given below, serve to explain the principles of the present application.

[0023] These and other features of this application will become apparent from the following description of preferred forms of embodiments given as non-limiting examples, with reference to the accompanying drawings.

[0024] It should also be understood that although this application has been described with reference to some specific examples, those skilled in the art can certainly implement many other equivalent forms of this application.

[0025] The above and other aspects, features and advantages of this application will become more apparent when taken in conjunction with the accompanying drawings and in view of the following detailed description.

[0026] Specific embodiments of this application are described thereafter with reference to the accompanying drawings; however, it should be understood that the claimed embodiments are merely examples of this application, which can be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to avoid unnecessary or redundant details that could obscure the application. Therefore, the specific structural and functional details claimed herein are not intended to be limiting, but merely to serve as a representative basis for teaching those skilled in the art to use this application in a variety of substantially any suitable detailed structures.

[0027] This specification may use the phrases “in one embodiment,” “in another embodiment,” “in yet another embodiment,” or “in other embodiments,” all of which may refer to one or more of the same or different embodiments according to this application.

[0028] This application provides a method for detecting faults in the collector lines of a wind power generation system, which can be specifically applied to electronic devices such as terminal servers. Figure 1 As shown, it includes the following steps: Step S101: For any target phase in the three-phase AC power, voltage and current sampling are performed on the bus terminal and the inner end of the collector line respectively to obtain the first voltage at the bus terminal, the first current at the bus terminal, the second voltage at the inner end of the branch line, and the second current at the inner end of the collector line at each sampling time. In this application, the offshore wind power generation system can specifically be a Flexible Low-Frequency Transmission System (LFTS), the topology of which is as follows: Figure 2 As shown, the system includes: land-based locations, low-frequency transmission lines, and wind farms. Each wind farm corresponds to a collector line, and the collected power lines are connected to the low-frequency transmission lines via transformers on the wind turbine side.

[0029] In this embodiment, voltage and current acquisition devices can be pre-installed at the convergence / N-terminal of each collector line to acquire the first voltage and the first current. Similarly, voltage and current acquisition devices can be installed at the inner end of any collector line / branch / M-terminal to acquire the second voltage and the second current.

[0030] Step S102: Determine whether the predetermined fault prediction conditions are met based on each of the first voltages; In the specific implementation process, this step can determine the voltage change rate based on the first voltage, and then determine whether the fault prediction conditions are met based on the voltage change rate.

[0031] Step S103: When it is determined that the fault prediction conditions are met, the first transient high-frequency energy / first pause energy at the bus terminal is determined based on each of the first voltages and each of the first currents, and the second transient high-frequency energy / second transient energy at the inner end of the collector line is determined based on each of the second voltages and each of the second currents. In this step, the first voltage, first current, second voltage, and second current can be filtered using filters to obtain the first transient high-frequency voltage component / first transient voltage component corresponding to each first voltage, the first transient high-frequency current component / first transient current component corresponding to each first current, the second transient high-frequency voltage component / second transient voltage component corresponding to each second voltage, and the second transient high-frequency current component / second transient current component corresponding to each second current. Subsequently, the first transient high-frequency energy / first transient energy can be determined based on the first transient high-frequency voltage component / first transient voltage component and the first transient high-frequency current component / first transient current component; similarly, the second transient high-frequency energy / second transient energy can be determined based on the second transient high-frequency voltage component / second transient voltage component and the second transient high-frequency current component / second transient current component.

[0032] Step S104: Fault detection is performed based on the first transient high-frequency energy and the second transient high-frequency energy to obtain the target detection result.

[0033] In the specific implementation process of this step, the first transient high-frequency energy and the second transient high-frequency energy can be added together to obtain the target transient high-frequency energy, so as to facilitate fault detection based on the target transient high-frequency energy.

[0034] The method in this embodiment predicts faults by using the first voltage at the bus terminal, eliminating the need to wait for the fault to develop into obvious characteristics and triggering subsequent detection processes in advance. This avoids the delay problem of traditional detection relying on steady-state fault signals, and can quickly capture transient characteristics in the early stages of a fault, buying time for fault handling and reducing the risk of fault escalation. By calculating the transient high-frequency energy at the bus terminal and the inner end of the branch line respectively, and utilizing the transient component / high-frequency transient component generated instantaneously after the fault occurs, i.e., by calculating the transient energy within a short time window, sub-cycle-level rapid fault identification is achieved, providing a guarantee for the rapid subsequent fault isolation and protecting the safety of power electronic equipment.

[0035] Another embodiment of this application provides a method for detecting faults in the collector lines of a wind power generation system, including the following steps: Step S201: For any target phase in the three-phase AC power, voltage and current sampling are performed on the bus terminal and the inner end of the collector line respectively to obtain the first voltage at the bus terminal, the first current at the bus terminal, the second voltage at the inner end of the branch line, and the second current at the inner end of the collector line at each sampling time. In this step, taking phase A as the target phase as an example (the processing logic for phases B and C is the same), the line voltage and current are collected in real time at the inner end / M end and the busbar end / N end of the flexible low-frequency collector line through voltage transformers and current transformers. , , , The acquired continuous analog signals are then... The sampling frequency is discretized to obtain the voltage sampling sequence. , and current sampling sequence , That is, to obtain each first voltage Each first current Each second voltage and each second current .

[0036] Step S202: Determine the voltage change rate based on each of the first voltages; In this step, the voltage collected at the busbar / N terminal of the collector line is... The rate of change of voltage .

[0037] Step S203: Compare the voltage change rate with a predetermined voltage change rate threshold; In this step, since the voltage at terminal N drops rapidly at the moment a fault occurs, this characteristic can be used to construct a criterion for fault prediction:

[0038] in, This is the voltage change rate threshold, which can be set and adjusted according to actual needs. For example, Can be taken .

[0039] Step S204: When the voltage change rate is less than or equal to the voltage change rate threshold, it is determined that the fault prediction condition is not met, and the process returns to step S201; when the voltage change rate is greater than the voltage change rate threshold, it is determined that the fault prediction condition is met, and step S205 is executed. Step S205: Based on a predetermined passband frequency range, filter the first voltage, the first current, the second voltage, and the second current to obtain a first transient high-frequency voltage component corresponding to each first voltage, a first transient high-frequency current component corresponding to each first current, a second transient high-frequency voltage component corresponding to each second voltage, and a second transient high-frequency current component corresponding to each second current. In this step, the predetermined passband frequency range is 950 Hz to 1050 Hz.

[0040] Specifically, for direct-drive wind turbines (PMSG), an equivalent circuit is constructed based on the conduction state of the converter bridge arm during a fault. Based on the principle of impedance simplification in parallel circuits (i.e., when the impedance of the capacitor branch is much smaller than the impedance of the parallel inductor branch, the inductor branch can be ignored), the linearization condition is derived as follows:

[0041] in, For grid-side filter capacitors; The impedance of the parallel inductor branch; ω is the angular frequency.

[0042] When this condition is met, the impedance of the direct-drive fan can be reduced. Equivalent to linear impedance ( (Equivalent inductance).

[0043] For the M3C converter, an impedance network including bridge arm inductors, submodule capacitors, and capacitance to ground is constructed based on the current flow path under short-circuit faults. Based on the high-frequency low-impedance bypass principle (the bridge arm branch can be ignored when its impedance is much smaller than that of the bridge arm branch), the linearization condition is derived as follows:

[0044] in, This is a low-frequency side ground filter capacitor; For bridge arm inductance; For submodule capacitors; This represents the number of sub-modules involved.

[0045] When this condition is met, the M3C impedance It can be equivalent to linear impedance. ( (This is the system's equivalent inductance).

[0046] Therefore, based on the above mechanism analysis, it is also required that the frequency be lower than the transient dominant frequency of the cable line capacitance. (Approximately 1800 Hz), therefore the predetermined passband frequency range is determined to be: 950 Hz to 1050 Hz.

[0047] In the specific implementation process, this step can utilize a passband frequency of The Chebyshev filter, for each first voltage Each second voltage Each first current and each second current Filtering is performed to extract the fault transient high-frequency voltage component and transient high-frequency current component of phase A, thus obtaining the first transient high-frequency voltage component / first transient voltage component. First transient high-frequency current component / First transient current component Second transient high-frequency voltage component / second transient voltage component and the second transient high-frequency current component / the second transient current component .

[0048] Step S206: Determine the first transient high-frequency energy based on each of the first transient high-frequency voltage components and each of the first transient high-frequency current components. In the specific implementation of this step, the first transient high-frequency energy / the first transient energy The calculation formula is as follows:

[0049] in, The first transient high-frequency voltage component / the first transient voltage component; It represents the first transient high-frequency current component / the first transient current component. This represents the number of sampling points within the time window T divided by the number of sampling times. This refers to the sequence number of the sampling point / sampling time.

[0050] Step S207: Determine the second transient high-frequency energy based on each of the second transient high-frequency voltage components and each of the second transient high-frequency current components; In this step, the second transient high-frequency energy / the second transient energy The calculation formula is as follows:

[0051] in, The second transient high-frequency voltage component / the second transient voltage component; It represents the second transient high-frequency current component / the second transient current component. This represents the number of sampling points within the time window T divided by the number of sampling times. This refers to the sequence number of the sampling point / sampling time.

[0052] Step S208: Determine the target transient high-frequency energy based on the first transient high-frequency energy and the second transient high-frequency energy;

[0053] in, The second transient high-frequency energy / the second transient energy; The first transient high-frequency energy / the first transient energy. The target transient high-frequency energy / target transient energy.

[0054] Step S209: Perform fault detection based on the target transient high-frequency energy and the predetermined transient high-frequency energy range to obtain the target detection result.

[0055] In the specific implementation process of this step, the target transient high-frequency energy can be... With respect to the predetermined transient high-frequency energy range Comparison; in the target transient high-frequency energy Located in the predetermined transient high-frequency energy range Within, that is, when When it is determined that no fault has occurred; at the target transient high-frequency energy Located in the predetermined transient high-frequency energy range Outside of, that is, when or At that time, it is determined whether the fault occurred within the collector line area or outside the collector line area. Specifically, when A fault has been identified within the collector line area. At that time, it was determined that a fault occurred outside the collection line area.

[0056] In this embodiment, to prevent misjudgment of faults due to fluctuations in the output of the direct-drive fan and measurement errors, the protection action threshold / transient high-frequency energy threshold can be adjusted. Adaptive tuning is performed to adaptively adjust the transient high-frequency energy range. That is, before fault detection, the method further includes: determining a transient high-frequency energy threshold based on the first transient high-frequency energy coefficient of the collector line during normal operation of the wind power generation system and the second transient high-frequency energy coefficient of the collector line under the maximum operating mode of the wind farm in the wind power generation system; and determining the transient high-frequency energy range based on the transient high-frequency energy threshold. Specifically, the transient high-frequency energy coefficient (i.e., the first transient high-frequency energy coefficient) of the collector line during normal operation of the flexible low-frequency AC transmission system can be used as a basis. ) and the transient high-frequency energy coefficient of the collector line when the wind farm selects the maximum operating mode (i.e., the second transient high-frequency energy coefficient) ), combined with reliability coefficients to calculate transient high-frequency energy thresholds Transient high-frequency energy threshold The calculation formula is:

[0057] in, The first transient high-frequency energy coefficient; The second transient high-frequency energy coefficient; This is the reliability coefficient, which can be set to, for example, 1.1.

[0058] In this application, the fault diagnosis principle is as follows: When a fault occurs within the protected area, the high-frequency fault current flows out of the protected line from the M and N terminals. ), the sum of both ends As shown in Figure 3(a), where The equivalent high-frequency impedance of the N-terminal external system is... The equivalent impedance of the system outside terminal M is given. The equivalent high-frequency impedance of the fan branch connected to T between MN is given. This refers to the high-frequency fault current flowing through the T-connected fan branch between MN. This refers to the high-frequency fault current at the fault point.

[0059] When a fault occurs outside the N-terminal zone, the high-frequency fault current flows from the fault point through the N-terminal into the protected line. ), flowing out from end M ( However, after the T-junction branch is split, The sum of both ends As shown in Figure 3(b); When a fault occurs outside the M-terminal area, symmetrically, , The sum of both ends As shown in Figure 3(c).

[0060] Therefore, based on the above analysis, it can be concluded that when the following conditions are met... (i.e., target transient high-frequency energy) It is a negative value, and its absolute value is greater than the threshold. If a fault occurs in phase A, the protection device immediately issues a trip command; if the following conditions are met... (That is, the target transient high-frequency energy is positive and the amplitude exceeds the threshold) If ), then it is determined to be an external fault; if If so, it is determined to be operating normally.

[0061] In this embodiment, when a fault is detected within the zone, protection can be activated, for example, by issuing a trip command through the protection device. When a fault is detected outside the zone or no fault has occurred, protection may not be activated, meaning the protection device will not operate.

[0062] In this application, faults are predicted by the first voltage at the bus terminal, eliminating the need to wait for the fault to develop to obvious characteristics and triggering subsequent detection processes in advance. This avoids the delay problem of traditional detection relying on steady-state fault signals, and can quickly capture the transient characteristics of the initial stage of the fault, buying time for fault handling and reducing the risk of fault escalation. By calculating the transient high-frequency energy at the bus terminal and the inner end of the branch line respectively, and utilizing the transient component / high-frequency transient component generated instantaneously after the fault occurs, i.e., by calculating the transient energy within a short time window, sub-cycle-level rapid fault identification is achieved, providing a guarantee for the rapid subsequent fault clearing and protecting the safety of power electronic equipment. The method in this application is a novel collector protection method that eliminates dependence on power frequency phasors, utilizes fault transient high-frequency characteristic information, and adapts to the characteristics of flexible low-frequency systems, enabling rapid and accurate clearing of faults within the area.

[0063] Another embodiment of this application provides a fault detection device for the collector line of a wind power generation system, such as... Figure 4 As shown, it includes: The acquisition module 11 is used to sample the voltage and current at the busbar end and the inner end of the collector line for any target phase in the three-phase AC power, respectively, to obtain the first voltage at the busbar end, the first current at the busbar end, the second voltage at the inner end of the branch line, and the second current at the inner end of the collector line at each sampling time. The prediction module 12 is used to determine whether a predetermined fault prediction condition is met based on each of the first voltages; The determination module 13 is used to determine the first transient high-frequency energy at the bus end based on each of the first voltages and each of the first currents when the fault prediction conditions are met, and to determine the second transient high-frequency energy at the inner end of the collector line based on each of the second voltages and each of the second currents. The detection module 14 is used to perform fault detection based on the first transient high-frequency energy and the second transient high-frequency energy to obtain the target detection result.

[0064] In this embodiment, the prediction module is specifically used to: determine the voltage change rate based on each of the first voltages; compare the voltage change rate with a predetermined voltage change rate threshold; determine that the fault prediction condition is not met when the voltage change rate is less than or equal to the voltage change rate threshold; and determine that the fault prediction condition is met when the voltage change rate is greater than the voltage change rate threshold.

[0065] In this embodiment, the determining module is specifically used to: filter each of the first voltages, each of the first currents, each of the second voltages, and each of the second currents based on a predetermined passband frequency range to obtain a first transient high-frequency voltage component corresponding to each of the first voltages, a first transient high-frequency current component corresponding to each of the first currents, a second transient high-frequency voltage component corresponding to each of the second voltages, and a second transient high-frequency current component corresponding to each of the second currents; determine the first transient high-frequency energy based on each of the first transient high-frequency voltage components and each of the first transient high-frequency current components; and determine the second transient high-frequency energy based on each of the second transient high-frequency voltage components and each of the second transient high-frequency current components.

[0066] In this embodiment, the predetermined passband frequency range is 950 Hz to 1050 Hz.

[0067] In this embodiment, the detection module is specifically used to: determine the target transient high-frequency energy based on the first transient high-frequency energy and the second transient high-frequency energy; perform fault detection based on the target transient high-frequency energy and a predetermined transient high-frequency energy range, and obtain the target detection result.

[0068] In this embodiment, the detection module is specifically used to: compare the target transient high-frequency energy with a predetermined transient high-frequency energy range; determine that no fault has occurred when the target transient high-frequency energy is within the predetermined transient high-frequency energy range; and determine that a fault has occurred within the collector line area or outside the collector line area when the target transient high-frequency energy is outside the predetermined transient high-frequency energy range.

[0069] In this embodiment, the wind power generation system collector line fault detection device further includes an interval determination module. The interval determination module is used to: determine the transient high-frequency energy threshold based on the first transient high-frequency energy coefficient of the collector line when the wind power generation system is operating normally and the second transient high-frequency energy coefficient of the collector line when the wind farm is operating at its maximum capacity in the wind power generation system before fault detection; and determine the transient high-frequency energy interval based on the transient high-frequency energy threshold.

[0070] In this embodiment, the fault is predicted by the first voltage at the bus terminal, eliminating the need to wait for the fault to develop to obvious characteristics and triggering subsequent detection processes in advance. This avoids the delay problem of traditional detection relying on steady-state fault signals, and can quickly capture the transient characteristics of the initial stage of the fault, buying time for fault handling and reducing the risk of fault escalation. By calculating the transient high-frequency energy at the bus terminal and the inner end of the branch line respectively, and utilizing the transient component / high-frequency transient component generated instantaneously after the fault occurs, i.e., by calculating the transient energy within a short time window, sub-cycle-level rapid fault identification is achieved, providing a guarantee for the rapid subsequent fault clearing and protecting the safety of power electronic equipment. The method in this application is a novel collector protection method that is free from dependence on power frequency phasors, utilizes fault transient high-frequency characteristic information, and adapts to the characteristics of flexible low-frequency systems, enabling rapid and accurate clearing of faults within the area.

[0071] Another embodiment of this application provides a storage medium storing a computer program, which, when executed by a processor, implements the following method steps: Step 1: For any target phase in the three-phase AC power, perform voltage sampling and current sampling at the bus terminal and the inner end of the collector line respectively, to obtain the first voltage at the bus terminal, the first current at the bus terminal, the second voltage at the inner end of the branch line, and the second current at the inner end of the collector line at each sampling time. Step 2: Determine whether the predetermined fault prediction conditions are met based on each of the first voltages; Step 3: When it is determined that the fault prediction conditions are met, the first transient high-frequency energy at the bus terminal is determined based on each of the first voltages and each of the first currents, and the second transient high-frequency energy at the inner end of the collector line is determined based on each of the second voltages and each of the second currents. Step 4: Perform fault detection based on the first transient high-frequency energy and the second transient high-frequency energy to obtain the target detection result.

[0072] The specific implementation process of the above method steps can be found in the embodiments of the above-mentioned method for detecting faults in the collection lines of any wind power generation system, and will not be repeated here.

[0073] In this application, faults are predicted by the first voltage at the bus terminal, eliminating the need to wait for the fault to develop to obvious characteristics and triggering subsequent detection processes in advance. This avoids the delay problem of traditional detection relying on steady-state fault signals, and can quickly capture the transient characteristics of the initial stage of the fault, buying time for fault handling and reducing the risk of fault escalation. By calculating the transient high-frequency energy at the bus terminal and the inner end of the branch line respectively, and utilizing the transient component / high-frequency transient component generated instantaneously after the fault occurs, i.e., by calculating the transient energy within a short time window, sub-cycle-level rapid fault identification is achieved, providing a guarantee for the rapid subsequent fault clearing and protecting the safety of power electronic equipment. The method in this application is a novel collector protection method that eliminates dependence on power frequency phasors, utilizes fault transient high-frequency characteristic information, and adapts to the characteristics of flexible low-frequency systems, enabling rapid and accurate clearing of faults within the area.

[0074] Another embodiment of this application provides an electronic device, including at least a memory and a processor. The memory stores a computer program, and the processor, when executing the computer program in the memory, performs the following method steps: Step 1: For any target phase in the three-phase AC power, perform voltage sampling and current sampling at the bus terminal and the inner end of the collector line respectively, to obtain the first voltage at the bus terminal, the first current at the bus terminal, the second voltage at the inner end of the branch line, and the second current at the inner end of the collector line at each sampling time. Step 2: Determine whether the predetermined fault prediction conditions are met based on each of the first voltages; Step 3: When it is determined that the fault prediction conditions are met, the first transient high-frequency energy at the bus terminal is determined based on each of the first voltages and each of the first currents, and the second transient high-frequency energy at the inner end of the collector line is determined based on each of the second voltages and each of the second currents. Step 4: Perform fault detection based on the first transient high-frequency energy and the second transient high-frequency energy to obtain the target detection result.

[0075] The specific implementation process of the above method steps can be found in the embodiments of the above-mentioned method for detecting faults in the collection lines of any wind power generation system, and will not be repeated here.

[0076] In this application, faults are predicted by the first voltage at the bus terminal, eliminating the need to wait for the fault to develop to obvious characteristics and triggering subsequent detection processes in advance. This avoids the delay problem of traditional detection relying on steady-state fault signals, and can quickly capture the transient characteristics of the initial stage of the fault, buying time for fault handling and reducing the risk of fault escalation. By calculating the transient high-frequency energy at the bus terminal and the inner end of the branch line respectively, and utilizing the transient component / high-frequency transient component generated instantaneously after the fault occurs, i.e., by calculating the transient energy within a short time window, sub-cycle-level rapid fault identification is achieved, providing a guarantee for the rapid subsequent fault clearing and protecting the safety of power electronic equipment. The method in this application is a novel collector protection method that eliminates dependence on power frequency phasors, utilizes fault transient high-frequency characteristic information, and adapts to the characteristics of flexible low-frequency systems, enabling rapid and accurate clearing of faults within the area.

[0077] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. Those skilled in the art can make various modifications or equivalent substitutions to this application within the scope and nature of this application, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. A method for detecting faults in the collector lines of a wind power generation system, characterized in that, include: For any target phase in a three-phase AC power supply, voltage and current sampling are performed at the busbar end and the inner end of the collector line, respectively, to obtain the first voltage at the busbar end, the first current at the busbar end, the second voltage at the inner end of the branch line, and the second current at the inner end of the collector line at each sampling time. Based on each of the first voltages, determine whether the predetermined fault prediction conditions are met; When it is determined that the fault prediction conditions are met, the first transient high-frequency energy at the bus terminal is determined based on each of the first voltages and each of the first currents, and the second transient high-frequency energy at the inner end of the collector line is determined based on each of the second voltages and each of the second currents. The target transient high-frequency energy is obtained by summing the first transient high-frequency energy and the second transient high-frequency energy. Fault detection is performed based on the target transient high-frequency energy and the predetermined transient high-frequency energy range to obtain the target detection result.

2. The method as described in claim 1, characterized in that, The step of determining whether a predetermined fault prediction condition is met based on each of the first voltages specifically includes: The voltage change rate is determined based on each of the first voltages; The voltage change rate is compared with a predetermined voltage change rate threshold; When the voltage change rate is less than or equal to the voltage change rate threshold, it is determined that the fault prediction condition has not been met. When the voltage change rate is greater than the voltage change rate threshold, the fault prediction condition is determined to be met.

3. The method as described in claim 1, characterized in that, The determination of the first transient high-frequency energy at the bus terminal based on each of the first voltages and each of the first currents, and the determination of the second transient high-frequency energy at the inner end of the branch based on each of the second voltages and each of the second currents, specifically includes: Based on a predetermined passband frequency range, each of the first voltages, each of the first currents, each of the second voltages, and each of the second currents are filtered to obtain a first transient high-frequency voltage component corresponding to each of the first voltages, a first transient high-frequency current component corresponding to each of the first currents, a second transient high-frequency voltage component corresponding to each of the second voltages, and a second transient high-frequency current component corresponding to each of the second currents. The first transient high-frequency energy is determined based on each of the first transient high-frequency voltage components and each of the first transient high-frequency current components. The second transient high-frequency energy is determined based on each of the second transient high-frequency voltage components and each of the second transient high-frequency current components.

4. The method as described in claim 3, characterized in that, The predetermined passband frequency range is 950 Hz to 1050 Hz.

5. The method as described in claim 1, characterized in that, The fault detection based on the target transient high-frequency energy and a predetermined transient high-frequency energy range, to obtain the target detection result, specifically includes: The target transient high-frequency energy is compared with a predetermined transient high-frequency energy range; When the target transient high-frequency energy is within the predetermined transient high-frequency energy range, it is determined that no fault has occurred; When the target transient high-frequency energy is outside the predetermined transient high-frequency energy range, it is determined that a fault has occurred within the collector line area or outside the collector line area.

6. The method according to any one of claims 1-5, characterized in that, Before performing fault detection, the method further includes: The transient high-frequency energy threshold is determined based on the first transient high-frequency energy coefficient of the collector line when the wind power generation system is operating normally and the second transient high-frequency energy coefficient of the collector line when the wind farm is operating at its maximum capacity. The transient high-frequency energy range is determined based on the transient high-frequency energy threshold.

7. A fault detection device for a wind power generation system's collector line, characterized in that, include: The acquisition module is used to sample the voltage and current at the busbar end and the inner end of the collector line for any target phase in the three-phase AC power supply, respectively, to obtain the first voltage at the busbar end, the first current at the busbar end, the second voltage at the inner end of the branch line, and the second current at the inner end of the collector line at each sampling time. The prediction module is used to determine whether a predetermined fault prediction condition is met based on each of the first voltages; The determination module is used to determine the first transient high-frequency energy at the bus terminal based on each of the first voltages and each of the first currents when the fault prediction conditions are met, and to determine the second transient high-frequency energy at the inner end of the collector line based on each of the second voltages and each of the second currents. The detection module is used to sum the first transient high-frequency energy and the second transient high-frequency energy to obtain the target transient high-frequency energy; Fault detection is performed based on the target transient high-frequency energy and the predetermined transient high-frequency energy range to obtain the target detection result.

8. A storage medium, characterized in that, The storage medium stores a computer program, which, when executed by a processor, implements the steps of the wind power generation system collector line fault detection method according to any one of claims 1-6.

9. An electronic device, characterized in that, It includes at least a memory and a processor, wherein the memory stores a computer program, and the processor, when executing the computer program in the memory, implements the steps of the wind power generation system collector line fault detection method according to any one of claims 1-6.

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