Direct current system ground fault positioning system and method

Abstract

The invention provides a DC system grounding fault positioning system and method. The system comprises a topology construction module, an AC signal injection module, a branch detection module and a fault positioning module. A topology structure chart is generated through the topology construction module, and a basis is provided for fault positioning. The alternating current signal injection module, the branch detection module and the fault positioning module are tightly matched, the branch of the mth grade included in the suspected fault branch is detected according to the branch grade of the branch in the topological graph, the branch of the direct current system is detected according to the branch grade by setting the branch grade, the invalid detection step is avoided, and the detection efficiency is improved. The fault positioning time is shortened, and the problems that the grounding fault positioning efficiency is low and the fault point is difficult to quickly determine in the direct current system are effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of DC grounding fault detection, and in particular to a DC system grounding fault locating system and method. Background Art

[0002] As a key component of power supply, DC systems are used in communication base stations, rail transit, data centers, power system relay protection, and other fields. Their safe and stable operation is directly related to the reliability of the DC system. If a ground fault in a DC system cannot be located and corrected in a timely manner, it can cause serious consequences such as equipment damage, malfunctioning of protective devices, and even system paralysis. Therefore, fast and accurate ground fault location technology is a core requirement for ensuring the normal operation of DC systems.

[0003] Currently, the mainstream technologies for locating ground faults in DC systems include the DC disconnection method and the online monitoring method. The DC disconnection method sequentially disconnects each branch of the DC system and observes changes in the ground fault signal to determine the faulty branch. However, the DC disconnection method is cumbersome and disrupts system operation, making it unsuitable for critical DC systems where power outages are unacceptable. The online monitoring method, typically based on busbar insulation monitoring devices, determines the presence of a ground fault by monitoring busbar voltage changes. However, the online monitoring method can only determine the occurrence of a fault, not its precise location, and has limited detection capabilities for transient or intermittent ground faults. Summary of the Invention

[0004] The present invention provides a DC system ground fault location system and method, which are used to solve the defect of low efficiency of DC system ground fault location in the prior art.

[0005] In one aspect, the present invention provides a DC system ground fault location system, comprising: a topology construction module, an AC signal injection module, a branch detection module, and a fault location module; The topology building module is configured to: Acquire physical layout information of the DC system and generate a topology diagram; the topology diagram includes a plurality of nodes, wherein the nodes form branches of different branch levels; a branch of the nth level includes a plurality of branches of the mth level; The AC signal injection module is configured as follows: In response to an abnormal signal generated by the DC system, an AC voltage of a preset amplitude is input into the DC system, and a fault detection instruction is generated based on a triggering time of the abnormal signal; The branch detection module is configured to: In response to the fault detection instruction, acquiring an AC grounding signal of the n-th level branch, and analyzing the AC grounding signal to determine a suspected fault branch among the n-th level branches; The fault location module is configured to: Based on the branch level, the m-th level branches included in the suspected fault branch are detected step by step until the fault point is located.

[0006] Optionally, the topology building module includes: The physical layout acquisition unit is configured as follows: Obtain the connection relationship of devices in the DC system; The topology generation unit is configured to: Building a node-branch model based on the connection relationship, generating a topological structure diagram, and calculating a spatial distance parameter between the branch and the positive pole of the DC system; Based on the spatial distance parameter, a branch level of the branch is determined.

[0007] Optionally, the fault location module includes: a path planning unit, a step-by-step detection unit and a result analysis unit; The path planning unit is configured to: According to the spatial distance parameter, a high detection priority is set for a branch that is close to the positive pole of the DC system, and a low detection priority is set for a branch that is far from the positive pole of the DC system, and an optimal detection path is generated according to the high detection priority and the low detection priority; The step-by-step detection unit is configured as follows: Testing branches of different branch levels according to the optimal testing path to generate a testing result; The result analysis unit is configured to: The detection results are compared and combined with the spatial distance parameters to locate the fault point.

[0008] Optionally, the path planning unit is further configured to: Obtaining a historical failure rate of the branch; sorting the branches with high detection priority in descending order according to the historical failure rates; The branches with high detection priority are detected in sequence.

[0009] Optionally, it also includes a device debugging and optimization module; The device debugging optimization module is configured to: Simulate instantaneous insulation faults of different resistance values ​​using controllable ground resistance, and record the detection response time and positioning error under the corresponding fault scenarios; constructing a parameter optimization controller to compare the response time with a preset sensitivity threshold or to compare the positioning error with the error threshold; If the response time is greater than the preset response time or the positioning error is greater than the preset positioning error, the output parameters of the AC signal injection module and the sampling rate of the branch detection module are adjusted through a PID control algorithm.

[0010] Optionally, the equipment debugging and optimization module also includes a harmonic monitoring unit.

[0011] The harmonic monitoring unit is configured to: monitoring harmonics generated by the DC system after the AC voltage is injected; If the harmonics exceed a preset limit, the output parameter of the AC signal injection module is adjusted.

[0012] Optionally, the branch detection module is further provided with a wireless communication module and a control unit; The control unit is configured to: Acquiring an AC ground signal transmitted by the wireless communication module; performing preprocessing on the AC ground signal; Calculating the time domain characteristics and frequency domain characteristics of the AC ground signal; The time domain features and the frequency domain features are input into a fault diagnosis model, and a fault analysis report including the fault location is output; the fault diagnosis model is a model that uses an integrated learning algorithm to fuse random forest and support vector machine.

[0013] Optionally, an early warning module is also included; The early warning module is configured to: Real-time acquisition of bus voltage and branch current of DC system; Calculating a multidimensional feature vector according to the bus voltage and the branch current; Based on the multi-dimensional feature vector, determining whether a fault occurs in the DC system; If a fault occurs in the DC system, a ground fault signal is generated.

[0014] Optionally, the AC signal injection module is further configured to: In response to the ground fault signal, an AC voltage of a preset amplitude is input into the DC system.

[0015] On the other hand, the present invention also provides a method for locating a ground fault in a DC system, comprising: Acquire physical layout information of the DC system and generate a topology diagram; the topology diagram includes a plurality of nodes, wherein the nodes form branches of different branch levels; a branch of the nth level includes a plurality of branches of the mth level; In response to an abnormal signal generated by the DC system, an AC voltage of a preset amplitude is input into the DC system, and a fault detection instruction is generated based on a triggering time of the abnormal signal; In response to the fault detection instruction, acquiring an AC grounding signal of the n-th level branch, and analyzing the AC grounding signal to determine a suspected fault branch among the n-th level branches; Based on the branch level, the m-th level branches included in the suspected fault branch are detected step by step until the fault point is located.

[0016] On the other hand, the present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, any of the above-described methods for locating a ground fault in a DC system is implemented.

[0017] On the other hand, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the above-mentioned methods for locating a ground fault in a DC system.

[0018] On the other hand, the present invention further provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the computer program implements any of the above-mentioned methods for locating a ground fault in a DC system.

[0019] As can be seen from the above technical solutions, the present invention provides a system and method for locating ground faults in a DC system. The system includes a topology construction module, an AC signal injection module, a branch detection module, and a fault location module. The topology construction module generates a topology diagram, providing a basis for fault location. The AC signal injection module, the branch detection module, and the fault location module work closely together to detect the mth-level branches contained in the suspected fault branches based on the branch levels of the branches in the topology diagram. By setting the branch level, the branches of the DC system are detected according to the branch level, avoiding invalid detection steps, shortening the fault location time, and effectively solving the problems of low efficiency in ground fault location in the DC system and difficulty in quickly determining the fault point. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is one of the structural diagrams of the DC system ground fault location system provided by an embodiment of the present invention; Figure 2 This is the second structural diagram of the DC system grounding fault location system provided by an embodiment of the present invention; Figure 3 This is a schematic diagram of the topology module structure provided by an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a fault location module provided by an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the device debugging and optimization module provided by an embodiment of the present invention; Figure 6 Schematic diagram of the structure of the branch detection module provided by an embodiment of the present invention; Figure 7 It is a structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0022] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0023] Figure 1 This is one of the structural diagrams of the DC system grounding fault location system provided by an embodiment of the present invention.

[0024] like Figure 1 As shown, the DC system ground fault location system provided by the embodiment of the present invention includes: a topology construction module 101, an AC signal injection module 102, a branch detection module 103 and a fault location module 104.

[0025] The topology building module 101 is configured to: The physical layout information of the DC system 105 is obtained, and a topology diagram is generated.

[0026] The topology diagram includes a plurality of nodes, and the nodes form branches of different branch levels. A branch of the nth level includes a plurality of branches of the mth level.

[0027] Specifically, a topology diagram is a graphical representation method used to intuitively display the connection relationship between various devices in DC system 105. Nodes represent various devices in DC system 105, such as power supplies, loads, switches, etc., while the lines between nodes represent current transmission paths, i.e., branches.

[0028] Branch levels are classified based on their location and importance in DC system 105. For example, the main bus, as the primary transmission path in DC system 105, has the highest branch level, designated as Level 1. Branches branching from the main bus are classified as Level 2, Level 3, and so on.

[0029] A branch at level n is directly connected to a branch at level n-1. A branch at level n may contain multiple branches at lower levels, i.e. branches at level m, where m = n+1.

[0030] For example, in a DC system 105, its main bus is a first-level branch. Two secondary buses branch out from the main bus, namely bus A and bus B, which constitute the second-level branch. Then, two smaller branches branch out from bus A, which are respectively connected to two important loads. The two smaller branches are the third-level branches. Bus B may only branch out one branch connected to the backup power supply, and the backup power supply branch is also the third level. Through such a hierarchical division, the topology diagram can clearly show the overall layout of the DC system 105 and the connection relationship between branches at all levels, providing a reference basis for subsequent AC signal injection, early warning, branch detection and fault location.

[0031] The AC signal injection module 102 is configured as follows: In response to the abnormal signal generated by the DC system 105, an AC voltage of a preset amplitude is input into the DC system 105, and a fault detection instruction is generated based on the triggering time of the abnormal signal.

[0032] A DC system ground fault occurs when insulation performance degrades or is damaged in a portion of the DC system 105, causing current to flow to the ground through the ground path, thereby generating an abnormal signal. The abnormal signal may manifest as voltage fluctuations, current changes, or instability in the DC system 105.

[0033] Upon detecting an abnormal signal in the DC system 105, the AC signal injection module 102 immediately activates and injects an AC voltage of a preset amplitude into the DC system 105. The AC voltage propagates through the DC system 105, interacting with the impedance of the DC system 105 and the ground fault point, resulting in changes in voltage and current.

[0034] It is understood that the AC signal injection module 102 activates fault characteristics in the DC system 105 by injecting AC voltage, making ground faults, which are previously difficult to detect, easier to identify. Furthermore, based on the triggering time of the abnormal signal, the AC signal injection module 102 can generate a fault detection instruction. This fault detection instruction activates the branch detection module 103 to perform a test on the DC system 105.

[0035] For example, in a complex DC system 105, the insulation layer of a branch circuit breaks down due to aging, causing current to flow to the ground through the broken point. At this point, the voltage and current sensors in DC system 105 will detect abnormal voltage fluctuations and current changes. However, the ground insulation fault in DC system 105 is irregular and transient. Therefore, after detecting the abnormal voltage fluctuations and current changes, AC signal injection module 102 injects an AC voltage of a preset amplitude. This AC voltage propagates through DC system 105 to the ground fault point, interacting with the ground fault point, resulting in more significant changes in voltage and current, facilitating the detection of the fault point by branch detection module 103.

[0036] At the same time, the AC signal injection module 102 generates a fault detection instruction based on the triggering time of the abnormal signal and sends the fault detection instruction to the branch detection module 103, which then detects the DC system 105. By injecting the AC signal, the fault point is continuously exposed, making it easier to locate the fault point.

[0037] The branch detection module 103 is configured to: In response to the fault detection instruction, an AC grounding signal of the n-th level branch is acquired, and the AC grounding signal is analyzed to determine a suspected fault branch among the n-th level branches.

[0038] The fault location module 104 is configured to: Based on the branch level, the m-th level branches contained in the suspected fault branch are detected step by step until the fault point is located.

[0039] When the AC signal injection module 102 detects abnormal voltage fluctuations and current changes and generates a fault detection instruction, the branch detection module 103 immediately takes action. Branch detection module 103 first obtains the AC grounding signal of the n-th level branch. The AC grounding signal is generated by the interaction between the AC voltage injected into the DC system 105 and the ground fault point. Branch detection module 103 conducts in-depth analysis of the AC grounding signal and, by comparing signal characteristics of different branches, such as amplitude, frequency, and phase, accurately identifies suspected faulty branches within the n-th level.

[0040] Fault location module 104, based on branch level information, adopts a step-by-step detection strategy. For example, in the same embodiment, fault location module 104 begins with the suspected faulty branch and progressively detects branches down to the mth level. During the detection process, fault location module 104 also records and analyzes the AC grounding signal characteristics of each branch. Through continuous comparison and screening, it gradually narrows the fault scope until the fault point is finally located.

[0041] For example, in DC system 105, the insulation layer of a secondary branch breaks, causing a ground fault. At this point, AC signal injection module 102 detects the abnormal signal and generates a fault detection instruction. Branch detection module 103 responds to the instruction by acquiring the AC ground signal from the secondary branch and, through analysis, identifies the secondary branch as a suspected faulty branch. Subsequently, fault location module 104 begins to progressively detect the tertiary branches underlying the suspected faulty branch, ultimately locating the specific fault point by carefully recording and analyzing the signal characteristics of each tertiary branch.

[0042] In some embodiments, as Figure 3 As shown, the topology construction module 101 includes: a physical layout acquisition unit 1011 and a topology generation unit 1012 .

[0043] The physical layout acquisition unit 1011 is configured as follows: The connection relationship of the devices in the DC system 105 is obtained.

[0044] The topology generation unit 1012 is configured to: A node-branch model is constructed based on the connection relationship, a topology diagram is generated, and the spatial distance from the branch to the positive pole of the DC system 105 is calculated.

[0045] Based on the spatial distance, the branch level of the branch is determined.

[0046] Specifically, the physical layout acquisition unit 1011 can collect connection information of all devices in the DC system 105 through a sensor network or manual input, including electrical connections and physical location relationships between devices. Electrical connections and physical location relationships are the basis for building an accurate topology structure.

[0047] The topology generation unit 1012 utilizes advanced algorithms and techniques to transform the complex connectivity of the DC system 105 into an intuitive node-branch model. In this model, each device is abstracted as a node, and the connections between devices are considered branches. Based on this node-branch model, a topology diagram is automatically generated, clearly displaying the overall layout of the DC system 105. Simultaneously, the actual spatial distance from each branch to the positive terminal of the DC system 105 is calculated. Branches are then appropriately classified based on their spatial distance, ensuring that faults can be quickly and accurately located and addressed.

[0048] For example, a DC system 105 includes multiple power supply devices, load devices, and cables connecting the devices. To effectively manage and locate potential ground faults, the physical layout acquisition unit 1011 first automatically collects the connection information of all devices through a sensor network deployed at various locations in the DC system 105. The device connection information records in detail the electrical connection status between devices and the relative positions of the devices in physical space. For example, which load devices a power supply device is connected to, as well as the actual direction and length of these connecting cables. At the same time, in order to address possible coverage blind spots or faults in the sensor network, a manual input function is provided, allowing operation and maintenance personnel to supplement or correct connection information based on actual on-site conditions.

[0049] Next, topology generation unit 1012 uses graph theory algorithms and visualization techniques to transform the collected complex connection relationships into an intuitive node-branch model. In this node-branch model, each power device, load device, and the connecting cables between them are abstracted as nodes and branches. Based on this node-branch model, a topology diagram is automatically generated, clearly showing the overall layout and connection relationships of DC system 105.

[0050] In addition, the topology generation unit 1012 also calculates the spatial distance from each branch to the positive pole of the DC system 105. The branches are assigned a grade based on the spatial distance. For example, the closer the branch is to the positive pole, the higher the grade, and vice versa. By grading the branches, it is helpful to quickly narrow the search range and improve the efficiency of locating the ground fault during the ground fault location process. At the same time, considering that there may be multiple paths to the same device or node in the DC system 105, the topology generation unit 1012 also performs a weight analysis on these paths and assigns a weight value to each path based on factors such as the length of the path and the type of connected device. The size of the weight value reflects the importance of the path in the DC system 105, providing more detailed reference information for subsequent fault location.

[0051] In some embodiments, as Figure 4 As shown, the fault location module 104 includes: a path planning unit 1041 , a step-by-step detection unit 1042 and a result analysis unit 1043 .

[0052] The path planning unit 1041 is configured to: According to the spatial distance, the detection priority of the branch is set, and the optimal detection path is generated according to the detection priority; the detection priority is inversely proportional to the spatial distance.

[0053] The step-by-step detection unit 1042 is configured to: According to the optimal detection path, branches of different branch levels are detected to generate detection results.

[0054] The result analysis unit 1043 is configured to: According to the detection results and combined with the spatial distance parameters, the fault point is located.

[0055] Path planning unit 1041 performs path planning based on the spatial distance and branch level provided by topology generation unit 1012. In this embodiment of the present invention, branch detection priorities are set based on spatial distance. The detection priority is inversely proportional to the spatial distance, i.e., branches closer to the positive pole of DC system 105 are assigned a higher detection priority. By setting detection priorities, path planning unit 1041 can generate an optimal detection path. The optimal detection path can efficiently guide the detection process and prioritize the areas most likely to cause failures.

[0056] The step-by-step detection unit 1042 starts to detect branches of different branch levels based on the optimal detection path generated by the path planning unit 1041. The detection process will be carried out according to the detection priority to ensure that branches with higher levels and closer to the positive pole are detected first.

[0057] After receiving the detection results generated by the step-by-step detection unit 1042, the result analysis unit 1043 combines the spatial distance information to determine the location of the fault. This unit conducts an in-depth analysis of the detection results and uses the spatial distance information to assist in determining the specific location of the fault. This allows the result analysis unit 1043 to more accurately locate the fault, improving the accuracy and efficiency of fault location.

[0058] For example, a branch in DC system 105 is close to the positive pole and has a higher branch level. When a fault occurs, path planning unit 1041 will first include it in the optimal detection path, and step-by-step detection unit 1042 will prioritize its detection. If the detection results indicate an abnormality in this branch, result analysis unit 1043 will combine its spatial distance parameters and determine that this branch is likely the fault point. The system can then quickly and accurately locate the fault point, providing strong support for subsequent troubleshooting.

[0059] In some embodiments, the path planning unit 1041 is further configured to: Obtain the historical failure rate of a branch line.

[0060] Sort the branches of the same level in descending order according to their historical failure rates to obtain the detection priority of the branches of the same level.

[0061] Detect branches according to the detection priority of branches of the same level.

[0062] The path planning unit 1041 obtains the historical failure rate of each branch. This historical failure rate can be obtained by querying the history records or maintenance logs of the DC system 105. The historical failure rate reflects the frequency of failures in each branch over a period of time. For example, if a branch experienced three failures in the past year, while another branch experienced no failures during the same period, the historical failure rate of the former is higher than that of the latter.

[0063] The path planning unit 1041 will sort the branches of the same level in descending order according to the historical failure rate. For branches of the same level, the branch with the highest historical failure rate will be detected first.

[0064] For example, DC system 105 has two branches A and B of the same level. Branch A has experienced two faults in the past year, while branch B has not. During route planning, the DC system ground fault location system prioritizes branch A over branch B to ensure that branch A is prioritized for detection when a fault occurs.

[0065] Finally, the path planning unit 1041 arranges the detection order according to the detection priority of the branches of the same level. During the detection process, the branches that are more prone to failure in the past will be detected first to ensure that the maximum potential failure can be discovered within a limited time.

[0066] According to the historical failure rate, the detection order of the branches is sorted to improve the efficiency of fault detection.

[0067] In some embodiments, as Figure 2 As shown, the DC system grounding fault location system provided by the embodiment of the present invention further includes an equipment debugging and optimization module 106 .

[0068] The device debugging optimization module 106 is configured to: The instantaneous insulation faults with different resistance values ​​are simulated by controllable grounding resistance, and the detection response time and positioning error under the corresponding fault scenarios are recorded.

[0069] Build parameter-optimizing controllers that compare response time to a preset sensitivity threshold or positioning error to an error threshold.

[0070] If the response time is greater than the preset response time or the positioning error is greater than the preset positioning error, the output parameters of the AC signal injection module 102 and the sampling rate of the branch detection module 103 are adjusted through the PID control algorithm.

[0071] Specifically, by simulating instantaneous insulation faults of different resistance values ​​using a controllable grounding resistor, various fault conditions that may occur during actual operation can be simulated, thereby comprehensively testing the DC system 105. For example, different resistance values ​​can be set to simulate insulation faults of varying degrees, thereby observing the system's performance under different fault scenarios.

[0072] Next, record the detection response time and location error for the corresponding fault scenario. Detection response time refers to the time from fault occurrence to detection and response, while location error refers to the deviation between the located fault location and the actual fault location. Response time and location error can reflect the performance of the DC system ground fault location system.

[0073] The parameter optimization controller is used to compare the detection response time with a preset sensitivity threshold and the positioning error with an error threshold. The preset sensitivity threshold and error threshold are used to determine whether the DC system ground fault location system performance meets the requirements.

[0074] If the response time is greater than the preset response time or the positioning error is greater than the preset positioning error, it indicates that the performance of the DC system ground fault location system does not meet the expected requirements. In this case, it is necessary to adjust the output parameters of the AC signal injection module 102 and the sampling rate of the branch detection module 103 using the PID control algorithm. The PID control algorithm is a commonly used control algorithm that changes the output of the DC system ground fault location system by adjusting control parameters to achieve the desired performance indicators.

[0075] For example, suppose that during a simulation test, the DC system ground fault location system detects a fault with a response time of 0.5 seconds, while the preset sensitivity threshold is 0.3 seconds. In this case, the device debugging and optimization module 106 determines that the response time exceeds the threshold and activates the PID control algorithm to adjust the output parameters of the AC signal injection module 102. After multiple adjustments and optimizations, the response time is ultimately reduced to less than 0.3 seconds, meeting the preset requirement.

[0076] Likewise, if the positioning error exceeds the standard, the device debugging optimization module 106 may also reduce the error by adjusting the sampling rate of the branch detection module 103. For example, the sampling rate may be increased to improve the precision and accuracy of detection, thereby reducing the positioning error.

[0077] In some embodiments, as Figure 5 As shown, the equipment debugging and optimization module 106 further includes a harmonic monitoring unit 1061 .

[0078] The harmonic monitoring unit 1061 is configured to: The DC system 105 is monitored for harmonics generated after the AC voltage is injected.

[0079] If the harmonics exceed the preset limit, the output parameters of the AC signal injection module 102 are adjusted.

[0080] Specifically, by real-time monitoring of the harmonic content in DC system 105, harmonic monitoring unit 1061 can promptly detect and address harmonic excesses. Excessive harmonics can disrupt the stable operation of DC system 105 and even cause failures. Therefore, when harmonic monitoring unit 1061 detects that harmonics exceed preset limits, it responds quickly by adjusting the output parameters of AC signal injection module 102 to suppress harmonic generation, thereby ensuring stable operation of DC system 105 and accurate fault location.

[0081] For example, when the frequency of the AC voltage injected into the DC system 105 is close to the natural frequency of the components in the DC system 105, resonance occurs, resulting in an increase in harmonic content. At this time, the harmonic monitoring unit 1061 will detect the abnormal situation and dynamically adjust the voltage amplitude, frequency and other parameters of the AC signal injection module 102 through a PID control algorithm or other control strategy to reduce the harmonic content and prevent the injected AC voltage from adversely affecting the stable operation of the DC system 105. By providing the harmonic monitoring unit 1061, not only the anti-interference ability of the DC system 105 is improved, but also the accuracy of fault location is ensured.

[0082] In some embodiments, as Figure 6 As shown, the branch detection module 103 is further provided with a wireless communication module 1031 and a control unit 1032 .

[0083] The control unit 1032 is configured to: Acquire the AC ground signal transmitted by the wireless communication module 1031.

[0084] Perform preprocessing on the AC ground signal.

[0085] Calculate the time domain and frequency domain characteristics of the AC ground signal.

[0086] Input time domain features and frequency domain features to the fault diagnosis model, and output a fault analysis report containing the fault location; the fault diagnosis model is a model that uses an integrated learning algorithm to fuse random forest and support vector machine.

[0087] Specifically, the wireless communication module 1031 is an electronic module that implements wireless communication functions and can transmit data through electromagnetic waves. For example, a WIFI module, a Bluetooth module, and a radio frequency module can all be configured as the wireless communication module 1031. The AC ground signal is transmitted to the control unit 1032 through the wireless communication module 1031.

[0088] After the control unit 1032 acquires the AC ground signal, it may be subject to electromagnetic interference and noise during transmission. Therefore, the AC ground signal is de-noised and processed using digital filtering techniques. For example, a finite impulse response filter or an infinite impulse response filter is used to remove high-frequency noise and low-frequency drift in the signal. The de-noised AC ground signal is then normalized to adjust its amplitude to a fixed range, for example, to [0, 1] or [-1, 1]. This facilitates feature calculation and model processing, and reduces the impact of data scale differences on the calculation results.

[0089] Time domain features are characteristic parameters that describe the characteristics and changing patterns of AC grounding signals in the time dimension, such as mean, variance, and peak value. By analyzing time domain features, we can understand the basic form, changing trend, and fluctuation of AC grounding signals, and provide time dimension information for fault diagnosis.

[0090] Frequency domain features are characteristic parameters obtained by converting the time domain to the frequency domain, such as the dominant frequency, bandwidth, amplitude, and phase of the frequency domain components. Frequency domain features can reveal the frequency composition and energy distribution of a signal, helping to identify fault characteristics that are not easily detected in time domain features.

[0091] Therefore, when calculating the time and frequency domain characteristics of an AC ground signal, we can calculate its mean, variance, peak value, rise time, and fall time. The mean reflects the average level of the AC ground signal; the variance reflects the fluctuation of the AC ground signal; the peak value represents the maximum amplitude of the AC ground signal; and the rise time and fall time describe how quickly the AC ground signal changes from one state to another. By calculating these time domain characteristics, we can intuitively reflect the signal's temporal characteristics.

[0092] The Fourier transform converts time-domain features into frequency-domain features to obtain the signal's spectral distribution. Frequency-domain features such as the dominant frequency, bandwidth, and amplitude and phase of each frequency component of the AC grounding signal are calculated. The dominant frequency represents the frequency with the highest energy concentration in the AC grounding signal; the bandwidth reflects the frequency distribution of the AC grounding signal; and the amplitude and phase of each frequency component help analyze the composition and frequency characteristics of the AC grounding signal.

[0093] After calculating the time and frequency domain features, they are used as input data into the fault diagnosis model. This model uses an ensemble learning algorithm that combines the random forest and support vector machine algorithms. The random forest algorithm constructs multiple decision trees and integrates their predictions to make decisions, demonstrating its robustness to noise and generalization capabilities. The support vector machine classifies data by finding the optimal hyperplane. The fault diagnosis model is trained using historical fault data to learn feature models corresponding to different fault types. When fed with the time and frequency domain features, it can determine whether a fault exists in DC system 105.

[0094] After the fault diagnosis model outputs a diagnostic result including the fault location, control unit 1032 generates a fault analysis report based on a preset report template. This report not only includes the fault location but also lists the time and frequency domain characteristics of the detected AC grounding signal, as well as the basis and confidence level of the model's diagnosis. This allows maintenance personnel to quickly understand the fault and perform targeted repairs and resolution.

[0095] In some embodiments, as Figure 2 As shown, the DC system grounding fault location system provided by the embodiment of the present invention further includes an early warning module 107 .

[0096] The early warning module 107 is configured to: The bus voltage and branch current of the DC system 105 are collected in real time.

[0097] A multi-dimensional feature vector is calculated according to the bus voltage and the branch current.

[0098] Based on the multi-dimensional feature vector, it is determined whether a fault occurs in the DC system 105 .

[0099] If a fault occurs in the DC system 105 , a ground fault signal is generated.

[0100] Specifically, early warning module 107 is equipped with a voltage sensor and a current sensor to collect real-time data on the bus voltage and branch currents of DC system 105. For example, in a certain data center's DC power supply system, the voltage sensor uses the Hall effect principle to quickly respond to bus voltage changes, converting the analog voltage signal into a digital signal and transmitting it to early warning module 107. The current sensor uses a Rogowski coil to perform non-contact measurement of each branch current, with a collection frequency of 100 times per second to ensure continuous and accurate current data.

[0101] After receiving the bus voltage and branch current data, the early warning module 107 begins calculating a multidimensional feature vector. This multidimensional feature vector includes the voltage and current values, as well as derived features such as the voltage fluctuation coefficient and current imbalance. For example, if a branch current suddenly increases within a short period of time while the bus voltage shows a downward trend, the calculated current imbalance and voltage fluctuation coefficient will change significantly. The derived features, such as the voltage value, current data, voltage fluctuation coefficient, and current imbalance, form the multidimensional feature vector.

[0102] The multidimensional feature vector is used to determine whether a fault occurs in the DC system 105. For example, the calculated multidimensional feature vector is input into a fault judgment model, and the fault judgment model analyzes the learned fault feature pattern. If the fault judgment model identifies that the voltage fluctuation coefficient in the multidimensional feature vector exceeds the threshold and the current imbalance of a branch increases abnormally, and other relevant feature conditions are met, it is determined that a fault occurs in the DC system 105.

[0103] Upon determining a fault in DC system 105, early warning module 107 immediately generates a ground fault signal. This ground fault signal contains information such as the time of fault occurrence, the number of the suspected faulty branch, and the fault type. The ground fault signal is transmitted to AC signal injection module 102 via a communication protocol, either wired or wirelessly, and simultaneously triggers an audible and visual alarm device to alert maintenance personnel to prompt action. For example, upon receiving the fault signal in DC system 105, maintenance personnel can use the DC system ground fault location system to locate the fault point and begin maintenance work.

[0104] In some embodiments, the AC signal injection module 102 is further configured to: In response to the ground fault signal, an AC voltage of a preset amplitude is input into the DC system 105 .

[0105] Among them, since the ground fault of the DC system is instantaneous, the fault point may disappear after the early warning module 107 generates the ground fault signal. Therefore, after the AC signal injection module 102 responds to the ground fault signal, it inputs an AC voltage of a preset amplitude into the DC system 105 to expose the ground fault point, thereby determining the specific location of the fault point.

[0106] Based on the same general inventive concept, the present invention further provides a method for locating a ground fault in a DC system. The DC system ground fault locating method provided by the present invention is described below. The DC system ground fault locating method described below and the DC system ground fault locating system described above can be referenced to each other.

[0107] An embodiment of the present invention provides a method for locating a ground fault in a DC system, comprising: 201. Obtain physical layout information of the DC system 105 and generate a topology diagram.

[0108] The topological structure diagram includes a number of nodes, and the nodes form branches of different branch levels; the n-th level branch contains a number of m-th level branches.

[0109] 202. In response to an abnormal signal generated by the DC system 105, an AC voltage of a preset amplitude is input into the DC system 105, and a fault detection instruction is generated based on a triggering time of the abnormal signal.

[0110] 203. In response to the fault detection instruction, obtain an AC grounding signal of the n-th level branch, analyze the AC grounding signal, and determine a suspected fault branch in the n-th level branch; 204. Based on the branch level, detect the m-th level branches included in the suspected fault branch step by step until the fault point is located.

[0111] Figure 7 It is a structural diagram of an electronic device provided by an embodiment of the present invention.

[0112] like Figure 7 As shown, the electronic device may include: a processor 710, a communication interface 720, a memory 730, and a communication bus 740. The processor 710, the communication interface 720, and the memory 730 communicate with each other via the communication bus 740. The processor 710 may call logic instructions in the memory 730 to execute the DC system ground fault location method.

[0113] Furthermore, the logic instructions in the aforementioned memory 730 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product, stored in a storage medium, includes instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0114] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the DC system grounding fault location method provided by the above methods.

[0115] In another aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is configured to execute the DC system grounding fault location method provided by the above methods when the computer program is executed by a processor.

[0116] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0117] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A DC system ground fault location system, characterized in that: include: Topology building module, AC signal injection module, branch detection module and fault location module; The topology building module is configured to: Acquire physical layout information of the DC system and generate a topology diagram; the topology diagram includes a plurality of nodes, wherein the nodes form branches of different branch levels; a branch of the nth level includes a plurality of branches of the mth level; The AC signal injection module is configured as follows: In response to an abnormal signal generated by the DC system, an AC voltage of a preset amplitude is input into the DC system, and a fault detection instruction is generated based on a triggering time of the abnormal signal; The branch detection module is configured to: In response to the fault detection instruction, acquiring an AC grounding signal of the n-th level branch, and analyzing the AC grounding signal to determine a suspected fault branch among the n-th level branches; The fault location module is configured to: Based on the branch level, the m-th level branches included in the suspected fault branch are detected step by step until the fault point is located.

2. The DC system ground fault location system according to claim 1, characterized in that: The topology building module includes: The physical layout acquisition unit is configured as follows: Obtaining a connection relationship between devices in the DC system; The topology generation unit is configured to: Building a node-branch model based on the connection relationship, generating a topological structure diagram, and calculating the spatial distance from the branch to the positive pole of the DC system; Based on the spatial distance, a branch level of the branch is determined.

3. The DC system ground fault location system according to claim 2, characterized in that: The fault location module includes: a path planning unit, a step-by-step detection unit and a result analysis unit; The path planning unit is configured to: According to the spatial distance, setting the detection priority of the branch, and generating an optimal detection path according to the detection priority; the detection priority is inversely proportional to the spatial distance; The step-by-step detection unit is configured as follows: Testing branches of different branch levels according to the optimal testing path to generate a testing result; The result analysis unit is configured to: The fault point is located based on the detection result and combined with the spatial distance parameter.

4. The DC system ground fault location system according to claim 3, characterized in that: The path planning unit is further configured to: Obtaining a historical failure rate of the branch; Sort the branches of the same level in descending order according to the historical failure rates to obtain detection priorities of the branches of the same level; The branches are detected according to the detection priority of the branches of the same level.

5. The DC system ground fault location system according to claim 1, characterized in that: It also includes equipment debugging and optimization modules; The device debugging optimization module is configured to: Simulate instantaneous insulation faults of different resistance values ​​using controllable ground resistance, and record the detection response time and positioning error under the corresponding fault scenarios; constructing a parameter optimization controller to compare the response time with a preset sensitivity threshold or to compare the positioning error with the error threshold; If the response time is greater than the preset response time or the positioning error is greater than the preset positioning error, the output parameters of the AC signal injection module and the sampling rate of the branch detection module are adjusted through a PID control algorithm.

6. The DC system ground fault location system according to claim 5, characterized in that: The equipment debugging and optimization module also includes a harmonic monitoring unit; The harmonic monitoring unit is configured to: monitoring harmonics generated by the DC system after the AC voltage is injected; If the harmonics exceed a preset limit, the output parameter of the AC signal injection module is adjusted.

7. The DC system ground fault location system according to claim 1, characterized in that: The branch detection module is also provided with a wireless communication module and a control unit; The control unit is configured to: Acquiring an AC ground signal transmitted by the wireless communication module; performing preprocessing on the AC ground signal; Calculating the time domain characteristics and frequency domain characteristics of the AC ground signal; The time domain features and the frequency domain features are input into a fault diagnosis model, and a fault analysis report including the fault location is output; the fault diagnosis model is a model that uses an integrated learning algorithm to fuse random forest and support vector machine.

8. The DC system ground fault location system according to claim 1, characterized in that: It also includes an early warning module; The early warning module is configured to: collecting the bus voltage and branch current of the DC system in real time; Calculating a multidimensional feature vector according to the bus voltage and the branch current; Based on the multidimensional feature vector, determining whether a fault occurs in the DC system; If a fault occurs in the DC system, a ground fault signal is generated.

9. The DC system ground fault location system according to claim 8, characterized in that: The AC signal injection module is further configured as follows: In response to the ground fault signal, an AC voltage of a preset amplitude is input into the DC system.

10. A method for locating a ground fault in a DC system, characterized in that: include: Acquire physical layout information of the DC system and generate a topology diagram; the topology diagram includes a plurality of nodes, wherein the nodes form branches of different branch levels; a branch of the nth level includes a plurality of branches of the mth level; In response to an abnormal signal generated by the DC system, an AC voltage of a preset amplitude is input into the DC system, and a fault detection instruction is generated based on a triggering time of the abnormal signal; In response to the fault detection instruction, acquiring an AC grounding signal of the n-th level branch, and analyzing the AC grounding signal to determine a suspected fault branch among the n-th level branches; Based on the branch level, the m-th level branches included in the suspected fault branch are detected step by step until the fault point is located.

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