Direct current ground fault troubleshooting device and method

Abstract

The application discloses a kind of direct current ground fault troubleshooting equipment and method, it is related to electric power operation technical field, main purpose is to solve the existing direct current ground fault The troubleshooting cannot meet the demand of not power outage, it is not conducive to the safe and stable operation of power grid problem.Direct current ground fault troubleshooting equipment mainly includes power module, processor and rectifier component;The power module is used to power supply to the processor and the rectifier component;The processor is used to obtain the second monitoring voltage of the bus monitoring system under the condition that the to-be-troubleshoot branch and the direct current bus are disconnected;Determine the troubleshooting result of the to-be-troubleshoot branch according to the second monitoring voltage and normal operating condition;The rectifier component is used to switch the to-be-troubleshoot branch from direct current bus power supply to the rectifier component power supply in response to the fault troubleshooting instruction of the to-be-troubleshoot branch.For troubleshooting direct current ground fault in electric power secondary circuit.

Description

Technical Field

[0001] This invention relates to the field of power operation technology, and in particular to a DC grounding fault investigation device and method. Background Technology

[0002] The DC system (also known as the secondary circuit) of a substation is an operating system composed of battery banks and floating chargers connected in parallel to supply DC loads. It is used to control, indicate, monitor, and protect the operation of the secondary circuits. Under normal circumstances, the positive and negative terminals of the DC power supply are insulated from ground (+110V and -110V respectively). When a single ground fault occurs in the secondary circuit of the substation, it does not affect the operation of the DC system (only causing uneven voltage distribution). However, when two or more ground faults occur, it will cause short circuits between the positive and negative terminals, leading to malfunctions or failures to operate of switches and protection devices, directly affecting the safe and stable operation of the entire power grid. Therefore, timely and accurate investigation of ground faults in the secondary circuit plays a crucial role in protecting the safe and stable operation of the power grid.

[0003] The existing method for troubleshooting DC grounding in secondary circuits is mainly the circuit-pulling method. The circuit-pulling method involves disconnecting each line one by one and judging whether there is a grounding point based on the observed voltage changes. Although this method is simple, it requires the experience of technicians to disconnect the circuit breakers of lines that may be faulty and to continuously observe the voltage changes for a period of time to analyze whether the line is faulty. This can lead to power outages for normally operating equipment, which cannot meet the requirements of uninterrupted maintenance and is not conducive to the safe and stable operation of the power grid. Summary of the Invention

[0004] In view of this, the present invention provides a DC grounding fault investigation device and method, the main purpose of which is to solve the problem that the existing DC grounding fault investigation methods cannot meet the needs of uninterrupted power supply maintenance and are not conducive to the safe and stable operation of the power grid.

[0005] According to one aspect of the present invention, a DC grounding fault troubleshooting device is provided, comprising:

[0006] Power modules, processors, and rectifier components;

[0007] The power module is used to supply power to the processor and the rectifier assembly;

[0008] The processor is configured to acquire the second monitoring voltage of the bus monitoring system when the branch to be investigated is disconnected from the DC bus; and determine the investigation result of the branch to be investigated based on the second monitoring voltage and normal operating conditions.

[0009] The rectifier component is used to switch the DC bus power supply of the branch to be investigated to the power supply of the rectifier component in response to the fault investigation command of the branch to be investigated.

[0010] Furthermore, the rectifier assembly includes: a controller, a first rectifier module, and a second rectifier module, wherein the first rectifier module and the second rectifier module are connected in series;

[0011] The controller is configured to send a first pulse width modulation signal to the first rectifier module and a second pulse width modulation signal to the second rectifier module according to the target power supply parameters.

[0012] The first rectifier module is used to generate a first electrical signal based on the first pulse width modulation signal, and the second rectifier module is used to generate a second electrical signal based on the second pulse width modulation signal.

[0013] The target power supply parameters are configured based on the DC module power supply parameters of the DC bus, and the first electrical signal and the second electrical signal are reverse voltage signals with the same voltage range.

[0014] Furthermore, the device also includes: a multi-switch;

[0015] Each sub-switch of the multi-switch is used to connect to a branch circuit to be investigated;

[0016] The processor is also configured to, in response to any of the troubleshooting instructions for the branch to be troubleshooted, control the sub-switch corresponding to the branch to be troubleshooted to switch the DC bus power supply to the rectifier component power supply.

[0017] Furthermore, the device also includes: a wireless communication module and a display;

[0018] The wireless communication module is used to communicate wirelessly with the bus monitoring system and send the second monitoring voltage obtained from the bus monitoring system to the processor.

[0019] The processor is further configured to receive the second monitoring voltage sent by the wireless communication module, determine the investigation result of the branch to be investigated based on the second monitoring voltage and the normal operating conditions, and send the investigation result to the display so as to display the investigation result on the display.

[0020] According to another aspect of the present invention, a method for troubleshooting DC grounding faults is provided, comprising:

[0021] When the DC bus is powered, the first monitoring voltage of the bus monitoring system is obtained. When the first monitoring voltage does not meet the normal operating conditions of the DC bus, the branch to be investigated is determined from the branch of the DC bus power supply.

[0022] A DC grounding fault diagnosis device is connected in parallel to the branch to be diagnosed. The DC grounding fault diagnosis device includes a rectifier component, which is used to generate a DC signal that matches the branch to be diagnosed.

[0023] In response to the fault investigation command of the branch to be investigated, the branch to be investigated is switched from DC bus power supply to rectifier component power supply, and the second monitoring voltage of the bus monitoring system is obtained when the branch to be investigated is disconnected from the DC bus;

[0024] The investigation results of the branch to be investigated are determined based on the second monitoring voltage and the normal operating conditions.

[0025] Further, the normal operating conditions include a normal voltage range; the step of determining the investigation result of the branch to be investigated based on the second monitoring voltage and the normal operating conditions includes:

[0026] If the second monitoring voltage does not recover to the normal voltage range within a preset time period, the branch to be investigated is determined to be a non-DC grounding fault branch.

[0027] If the second monitoring voltage recovers to the normal voltage range within a preset time period, then the branch to be investigated is determined to be a DC grounding fault branch.

[0028] Furthermore, after determining that the branch to be investigated is a DC ground fault branch, the method further includes:

[0029] The network level of the branch to be investigated is determined from the DC system topology network, which includes the connection relationships between branches at different levels;

[0030] If the network level is the lowest network level, then the branch to be investigated is determined to be a branch to be repaired;

[0031] If the network level is not the lowest network level, then obtain the interval distance of at least one subordinate associated branch of the branch to be investigated.

[0032] The target branch is determined from the associated branches based on the interval distance.

[0033] The lower-level target branch is designated as the branch to be investigated, and the process of connecting the DC grounding fault investigation equipment in parallel to the power supply bus of the branch to be investigated is returned.

[0034] Further, determining the lower-level target branch from the lower-level associated branches based on the interval distance includes:

[0035] Calculate the interval distance difference between each of the lower-level associated branches based on the interval distance;

[0036] If the interval distance difference is less than the preset distance threshold, then the periodic investigation information of the lower-level associated branch is obtained, and the lower-level target branch is determined based on the periodic investigation information.

[0037] If any of the interval distance differences is greater than a preset distance threshold, then the lower-level target branch is determined from the lower-level associated branches based on the interval distance.

[0038] Furthermore, the periodic investigation information includes investigation time and investigation results, and the step of determining the lower-level target branch based on the periodic investigation information includes:

[0039] The lower-level associated branch with the most failures in the investigation results is identified as a lower-level candidate branch.

[0040] If the number of lower-level candidate branches is greater than a preset threshold, then the investigation time interval is calculated based on the investigation time, and the lower-level candidate branch with the longest investigation time interval is determined as the lower-level target branch.

[0041] Furthermore, before determining the network level of the branch to be investigated from the DC system topology, the method further includes:

[0042] Obtain global branch information and circuit connection relationships between branches on the DC bus. The global branch information includes the branch identifier of the global branch and the interval distance between every two branches.

[0043] The network level of each branch is determined based on the circuit connection relationship described above;

[0044] The DC system topology network under the DC bus is constructed based on the network hierarchy and the distance information.

[0045] By employing the above-described technical solutions, the technical solutions provided by the embodiments of the present invention have at least the following advantages:

[0046] This invention provides a DC grounding fault investigation device and method. The DC grounding fault investigation device in this embodiment includes a power module, a processor, and a rectifier assembly. The power module supplies power to the processor and the rectifier assembly. The processor acquires the second monitoring voltage of the bus monitoring system when the branch to be investigated is disconnected from the DC bus. Based on the second monitoring voltage and normal operating conditions, it determines the investigation result of the branch to be investigated. The rectifier assembly, in response to a fault investigation command from the branch to be investigated, switches the power supply of the branch to be investigated from the DC bus to the power supply of the rectifier assembly. During the fault investigation process, the DC grounding fault investigation device serves as a backup power source for the branch to be investigated, avoiding prolonged power outages during the DC grounding fault investigation process, reducing the risk of branch power outages, and ensuring the accuracy of DC grounding fault investigation. This meets the requirements of uninterrupted maintenance and is more conducive to the safe and stable operation of the power grid.

[0047] 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, it can be implemented according to the contents of the specification. In order to make the above and other objects, features and advantages of the present invention more obvious and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0048] 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:

[0049] Figure 1 This diagram illustrates a block diagram of a DC grounding fault troubleshooting device provided by an embodiment of the present invention.

[0050] Figure 2 A block diagram of a rectifier assembly provided in an embodiment of the present invention is shown;

[0051] Figure 3 The diagram shows a rectifier module circuit diagram of a rectifier assembly provided in an embodiment of the present invention;

[0052] Figure 4 A flowchart of a DC grounding fault troubleshooting method provided by an embodiment of the present invention is shown;

[0053] Figure 5 A schematic diagram of a DC system topology network structure provided by an embodiment of the present invention is shown. Detailed Implementation

[0054] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0055] The existing methods for troubleshooting DC grounding in secondary circuits mainly rely on the "pull-circuit method." This method involves disconnecting each circuit one by one and judging whether a grounding point exists based on observed voltage changes. While simple, this method requires experienced technicians to disconnect circuit breakers on potentially faulty lines and continuously observe voltage changes for a period of time to analyze whether a fault exists. This can lead to power outages for normally operating equipment, failing to meet the requirements of uninterrupted maintenance and hindering the safe and stable operation of the power grid. This invention provides a DC grounding fault troubleshooting device, such as... Figure 1 As shown, the device includes: a power module 11, a processor 12, and a rectifier assembly 13;

[0056] The power module 11 is used to supply power to the processor 12 and the rectifier assembly 13;

[0057] The processor 12 is configured to acquire the second monitoring voltage of the bus monitoring system when the branch to be investigated is disconnected from the DC bus; and determine the investigation result of the branch to be investigated based on the second monitoring voltage and normal operating conditions.

[0058] The rectifier component 13 is used to switch the power supply of the branch to be investigated from the DC bus to the power supply of the rectifier component 13 in response to the fault investigation command of the branch to be investigated.

[0059] In this embodiment of the invention, the power module 11 provides power of corresponding voltage to the rectifier assembly 13 and the processor 12, enabling the processor 12 and the rectifier assembly 13 to operate normally. For example, the power module 11 provides a power supply with a voltage range of 2.0 to 3.6V to the controller in the rectifier assembly 13. The power module can be an AC-DC converter circuit capable of converting external power to DC power, or it can be a battery that outputs DC power; the processor can be a microcontroller or a programmable system-on-a-chip, and this embodiment of the invention does not impose specific limitations. The rectifier assembly 13 is used to convert the input AC signal into a DC signal that matches the power supply parameters of the DC module of the DC bus, that is, the DC signal generated by the rectifier assembly is equal to or approximately equal to the voltage output by the DC module of the DC bus.

[0060] It should be noted that the DC bus is the only power supply bus for the branch to be investigated. When analyzing whether the branch to be investigated is a DC ground fault branch, in order to obtain the second monitoring voltage of the DC monitoring system when the branch to be investigated is isolated from the DC power supply bus, it is necessary to disconnect the branch to be investigated from the DC power supply bus. At this time, the electrical equipment under the branch to be investigated will be in a de-energized state. By connecting the DC ground fault investigation equipment in parallel to the branch to be investigated, when the connection between the branch to be investigated and the DC bus is disconnected, the rectifier assembly 13 acts as a backup power source, replacing the DC bus to supply power to the branch to be investigated, so as to realize the investigation of DC ground faults without power interruption, thereby maintaining the normal and stable operation of electrical equipment under the DC system and ensuring the safe and stable operation of the power grid.

[0061] This invention provides another DC grounding fault troubleshooting device, such as... Figure 2 As shown, the rectifier assembly 13 includes: a controller 131, a first rectifier assembly 132, and a second rectifier assembly 133, wherein the first rectifier module and the second rectifier module are connected in series.

[0062] The controller 131 is used to send a first pulse width modulation signal to the first rectifier module and a second pulse width modulation signal to the second rectifier module according to the target power supply parameters.

[0063] The first rectifier module 132 is used to generate a first electrical signal based on the first pulse width modulation signal, and the second rectifier module 133 is used to generate a second electrical signal based on the second pulse width modulation signal.

[0064] In this embodiment of the invention, the overall circuit diagram of the first rectifier module 132 and the second rectifier module 133 is as follows: Figure 3As shown in the diagram. D1-D8 are rectifier diodes, C1 and C2 are non-polarized capacitors, T is a transformer, and L and N are the AC input terminals of the transformer. The first rectifier module 132 and the second rectifier module 133 generate corresponding DC signals from the input AC signals according to the Pulse Width Modulation (PWM) signals sent by the controller. The first and second signals are reverse voltage signals with the same voltage range. The target power supply parameters are configured based on the DC module power supply parameters of the DC bus. For example, if the DC bus power supply voltage in the substation is ±115V, a first PWM signal corresponding to 0 to -115V and a second PWM signal corresponding to 0 to +115V can be generated to instruct the controller to generate a first PWM signal corresponding to 0 to -115V and a second PWM signal corresponding to 0 to +115V, respectively. The first pulse width modulation signal, after being processed by the first rectifier component 132, can output a voltage of 0 to -115V; the second pulse width modulation signal, after being processed by the second rectifier component 133, can output a voltage of 0 to +115V. Since the first rectifier module 132 and the second rectifier module 133 are connected in series within the rectifier component 13, the overall output of the rectifier component 13 is ±115V. The controller model can be TMS320LF2407, or other control chips; this embodiment of the invention does not impose specific limitations. The controller can be a chip used independently within the rectifier component, or the controller function can be executed by a processor.

[0065] It should be noted that the supply voltage range of the DC bus in the substation is distributed within the positive and negative intervals. The rectifier assembly is built based on the controller 131 and a series-connected dual rectifier module. The circuit is simple, and the components are of low cost, thus reducing the cost of DC grounding fault diagnosis equipment and facilitating its widespread use.

[0066] Furthermore, the DC grounding fault diagnosis equipment also includes a multi-switch; each sub-switch of the multi-switch is used to connect to a branch to be diagnosed; the processor 12 is also used to respond to a fault diagnosis command of any branch to be diagnosed, control the corresponding sub-switch of the branch to be diagnosed, and switch the DC bus power supply to the rectifier component power supply. The DC grounding fault diagnosis equipment is connected to the branch to be diagnosed based on the multi-switch. When a branch to be diagnosed needs to be diagnosed, there is no need for manual wiring; the power supply of the current branch to be diagnosed can be switched to the rectifier component by controlling the on / off state of different sub-switches in the multi-switch, thereby realizing automatic switching between multiple branches to be diagnosed, improving the ease of use and diagnosis efficiency of the DC grounding fault diagnosis equipment.

[0067] Furthermore, the DC grounding fault diagnosis equipment also includes a wireless communication module and a display. The wireless communication module is used to wirelessly communicate with the bus monitoring system, sending the second monitoring voltage obtained from the bus monitoring system to the processor 12. The processor 12 is also used to receive the second monitoring voltage sent by the wireless communication module, determine the diagnosis result of the branch to be diagnosed based on the second monitoring voltage and normal operating conditions, and send the diagnosis result to the display for presentation. By configuring a wireless communication module and a display in the DC grounding fault diagnosis equipment, wireless transmission of monitoring data from the bus monitoring system can be achieved, thereby improving the convenience of acquiring monitoring data. Simultaneously, displaying the diagnosis results on the display makes it easier for users to obtain the results, thus improving the visualization level of the equipment.

[0068] This invention provides a DC grounding fault diagnosis device. The DC grounding fault diagnosis device in this embodiment includes a power module, a processor, and a rectifier assembly. The power module supplies power to the processor and the rectifier assembly. The processor acquires the second monitoring voltage of the bus monitoring system when the branch to be diagnosed is disconnected from the DC bus. Based on the second monitoring voltage and normal operating conditions, it determines the diagnosis result of the branch to be diagnosed. The rectifier assembly, in response to a fault diagnosis command from the branch to be diagnosed, switches the power supply of the branch to be diagnosed from the DC bus to the power supply of the rectifier assembly. During the fault diagnosis process, the DC grounding fault diagnosis device serves as a backup power source for the branch to be diagnosed, avoiding prolonged power outages during the DC grounding fault diagnosis process, reducing the risk of branch power outages, and ensuring the accuracy of DC grounding fault diagnosis. This meets the requirements for uninterrupted maintenance and is more conducive to the safe and stable operation of the power grid.

[0069] Furthermore, as a response to the above Figure 1 The application of the device shown in this invention provides a method for troubleshooting DC grounding faults, such as... Figure 4 As shown, the method includes:

[0070] 201. Obtain the first monitoring voltage of the bus monitoring system under DC bus power supply conditions. When the first monitoring voltage does not meet the normal operating conditions of the DC bus, determine the branch to be investigated from the branch of the DC bus power supply.

[0071] 202. Connect the DC grounding fault investigation equipment in parallel to the branch to be investigated.

[0072] 203. In response to the fault investigation command of the branch to be investigated, the branch to be investigated is switched from DC bus power supply to rectifier component power supply, and the second monitoring voltage of the bus monitoring system is obtained when the branch to be investigated is disconnected from the DC bus.

[0073] 204. Determine the investigation results of the branch to be investigated based on the second monitoring voltage and the normal operating conditions.

[0074] In this embodiment of the invention, under normal operation of the DC system, the bus voltage is monitored by a bus monitoring system. When the first monitored voltage does not meet the current normal operating conditions of the DC bus, it indicates that a DC grounding fault needs to be investigated in the line. The branch to be investigated is then determined from the branches supplied by the DC bus, and a DC grounding fault investigation device is connected in parallel to the branch to be investigated. The branch to be investigated can be one, two, or more. The normal operating conditions can be configured based on historical monitoring voltage data under normal operating conditions, or they can be configured based on operating experience. The method for determining the branch to be investigated can be any branch in the line, or it can be determined based on the distance of the branch and the probability of a fault occurring. This embodiment of the invention does not specifically limit the method for determining the branch to be investigated and the normal operating conditions.

[0075] It should be noted that the DC grounding fault diagnosis equipment includes a rectifier component, which is used to generate a DC signal that matches the branch to be diagnosed. First, the rectifier component is connected in parallel to the branch to be diagnosed. When the connection between the branch to be diagnosed and the DC bus is disconnected, the rectifier component acts as a backup virtual bus to supply power to the branch. This satisfies the requirement of disconnecting the DC bus from the branch to be diagnosed during fault diagnosis and analysis, while also preventing power loss in the branch to be diagnosed. This ensures the normal operation of the power grid control equipment connected to the branch to be diagnosed, as well as the safe and stable operation of the power grid.

[0076] In one embodiment of the present invention, for further explanation and limitation, the step of determining the investigation result of the branch to be investigated based on the second monitoring voltage and the normal operating conditions includes:

[0077] If the second monitoring voltage does not recover to the normal voltage range within a preset time period, the branch to be investigated is determined to be a non-DC grounding fault branch.

[0078] If the second monitoring voltage recovers to the normal voltage range within a preset time period, then the branch to be investigated is determined to be a DC grounding fault branch.

[0079] In this embodiment of the invention, normal operating conditions include the normal voltage range. When the branch under investigation is isolated from the DC bus, the second monitoring voltage of the bus monitoring system is acquired. If it recovers to the normal voltage range within a preset time period (i.e., after disconnecting the branch under investigation, the DC bus monitoring voltage meets the normal operating conditions), it can be determined that the abnormal DC bus monitoring voltage is caused by the branch under investigation, and the branch under investigation is identified as a DC grounding fault branch. Conversely, if the second monitoring voltage fails to recover to the normal voltage range within the preset time period (i.e., after disconnecting the branch under investigation, the DC bus monitoring voltage still does not meet the normal operating conditions), it can be determined that the branch under investigation is not the cause of the abnormal DC bus monitoring voltage, and the branch under investigation is identified as a non-DC grounding fault branch.

[0080] In one embodiment of the present invention, for further explanation and limitation, after determining that the branch to be investigated is a DC ground fault branch, the method further includes:

[0081] Determine the network level of the branch to be investigated from the DC system topology;

[0082] If the network level is the lowest network level, then the branch to be investigated is determined to be a branch to be repaired;

[0083] If the network level is not the lowest network level, then obtain the interval distance of at least one subordinate associated branch of the branch to be investigated.

[0084] The target branch is determined from the associated branches based on the interval distance.

[0085] The lower-level target branch is designated as the branch to be investigated, and the process of connecting the DC grounding fault investigation equipment in parallel to the power supply bus of the branch to be investigated is returned.

[0086] In this embodiment of the invention, the branches under the DC bus also include lower-level branches. A DC grounding fault may occur in the current branch or in a lower-level branch. Therefore, a DC system topology network is pre-constructed based on the branch distribution under the DC bus. The DC system topology network includes the connection relationships between branches at different levels, a unique branch identifier for each branch, and the distance between any two branches. Specifically, global branch information and the circuit connection relationships between each branch under the DC bus are obtained. The global branch information includes the branch identifier of each global branch and the distance between any two branches. The network level of each branch is determined based on the circuit connection relationships. The DC system topology network under the DC bus is constructed based on the network level and distance information. For example, as... Figure 5The diagram shows a schematic of a DC system topology network, including three branch network levels. L1 and L2 are branches at the highest network level, L2m is a subordinate branch of L2, and L2mn is a branch at the lowest network level, also a subordinate branch of L2m. Branches at non-lowest network levels are also connected to subordinate branches. The lowest network level is the end of the DC system topology network. K secondary devices are connected to the lowest network level. The troubleshooting equipment shown in the diagram is the DC grounding fault troubleshooting equipment.

[0087] After identifying the branch to be investigated as a DC ground fault branch, the network level of the branch to be investigated is determined from the DC system topology based on its branch identifier. If the current network level of the branch to be investigated is the lowest network level, meaning there are no lower-level related branches that could cause the branch to meet the fault investigation conditions, then the branch to be investigated is determined to be the branch with the DC ground fault and needs repair, thus being designated as a branch to be repaired. If the current network level of the branch to be investigated is not the lowest network level, meaning there are no lower-level related branches that could cause the branch to meet the fault investigation conditions, further investigation of lower-level related branches is required.

[0088] It should be noted that DC systems have numerous wiring connections, some indoors and some outdoors within substations, resulting in a complex distribution. Relying on on-site maintenance personnel to locate the hierarchical and connection relationships between these branches is highly demanding, difficult, and time-consuming, requiring significant experience from the personnel. By constructing a DC system topology network and analyzing the network after identifying the branch to be investigated as having a DC grounding fault, manual searching of the branch is avoided, improving the efficiency and accuracy of fault location and thus enhancing the overall efficiency of fault diagnosis.

[0089] In one embodiment of the present invention, for further explanation and limitation, the step of determining the lower-level target branch from the lower-level associated branches based on the interval distance includes:

[0090] Calculate the interval distance difference between each of the lower-level associated branches based on the interval distance;

[0091] If the interval distance difference is less than the preset distance threshold, then the periodic investigation information of the lower-level associated branch is obtained, and the lower-level target branch is determined based on the periodic investigation information.

[0092] If any of the interval distance differences is greater than a preset distance threshold, then the lower-level target branch is determined from the lower-level associated branches based on the interval distance.

[0093] In this embodiment of the invention, the interval distance refers to the distance between any two branch investigation points. The interval distance difference of lower-level associated branches is the difference in distance from any two investigation points of lower-level associated branches to the current branch to be investigated. For example, if the distance from lower-level associated branch L21 to the branch to be investigated is 'a', and the distance from lower-level associated branch L22 to the branch to be investigated is 'b', then the interval distance difference between lower-level associated branches L21 and L22 is 'ab'. If the interval distance difference of all lower-level associated branches is less than a preset distance threshold, it indicates that the distribution of lower-level associated branches is relatively concentrated, and it is not suitable to use distance to determine the branch to be investigated next. In this case, the periodic investigation information of lower-level associated branches determines the lower-level target branch. If the distance difference between any subordinate associated branches exceeds a preset distance threshold, it indicates the existence of distant subordinate associated branches, suggesting a dispersed distribution of these branches. Subordinate associated branches can be investigated from closest to furthest, with the branch with the smallest distance being designated as the first target branch. If the target branch is found to be normal, the subordinate associated branches are then identified and investigated in ascending order of distance. In this case, a multi-switch of a DC grounding fault detection device can be used for multi-branch investigation. For example, if there are 30 subordinate associated branches and the multi-switch has 10 sub-switches, the 10 closest branches are connected first, followed by the 10 slightly further apart. If no DC grounding fault is found in any of the 20 subordinate associated branches, measurements are finally taken from the 10 furthest branches. The preset distance threshold can be customized based on the actual branch distribution in the application environment; this embodiment does not impose specific limitations.

[0094] By calculating the interval distance difference of the lower-level related branches, the distribution of the lower-level related branches can be quickly identified, providing the most suitable data basis for selecting the lower-level target branches, thereby improving the efficiency of investigation.

[0095] In one embodiment of the present invention, for further explanation and limitation, the step of determining the lower-level target branch based on the periodic investigation information includes:

[0096] The lower-level associated branch with the most failures in the investigation results is identified as a lower-level candidate branch.

[0097] If the number of lower-level candidate branches is greater than a preset threshold, then the investigation time interval is calculated based on the investigation time, and the lower-level candidate branch with the longest investigation time interval is determined as the lower-level target branch.

[0098] In this embodiment of the invention, when the number of subordinate associated branches is large and their distribution is relatively concentrated, periodic investigation information is considered as the basis for determining the subordinate target branch. The periodic investigation information includes investigation time and investigation results, i.e., the investigation time and results in historical investigation records. First, the number of faults in the investigation results is counted, and the subordinate associated branch with the most faults is determined as the subordinate candidate branch. If the number of faults in all subordinate associated branches is consistent, making it impossible to filter out a few subordinate candidate branches with a large number of faults (i.e., the number of subordinate candidate branches exceeds a preset threshold), then the subordinate candidate branch with the longest investigation time interval is determined as the subordinate target branch. The preset threshold is customized based on the actual number of branches in the application environment; this embodiment of the invention does not impose a specific limitation.

[0099] This invention provides a method for troubleshooting DC grounding faults. In an embodiment of this invention, by acquiring the first monitoring voltage of a bus monitoring system under DC bus power supply conditions, when the first monitoring voltage does not meet the normal operating conditions of the DC bus, a branch to be investigated is determined from the branches powered by the DC bus. A DC grounding fault investigation device is connected in parallel to the branch to be investigated. The DC grounding fault investigation device includes a rectifier component, which is used to generate a DC signal matching the branch to be investigated. In response to a fault investigation command for the branch to be investigated, the branch to be investigated is connected to the DC bus... The power supply is switched to the rectifier assembly, and the second monitoring voltage of the bus monitoring system is obtained when the branch to be investigated is disconnected from the DC bus. Based on the second monitoring voltage and the normal operating conditions, the investigation result of the branch to be investigated is determined. During the fault investigation process, the DC grounding fault investigation equipment is used as a backup power source for the branch to be investigated, avoiding prolonged power outages during the DC grounding fault investigation process, reducing the risk of branch power outages, and ensuring the accuracy of DC grounding fault investigation. This meets the requirements of uninterrupted maintenance and is more conducive to the safe and stable operation of the power grid.

[0100] It is obvious to those skilled in the art that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby storing them in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those presented herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0101] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for troubleshooting DC grounding faults, characterized in that, The method is implemented based on a DC grounding fault diagnosis device, which includes: a power module, a processor, a multi-switch and a rectifier assembly, wherein the power module supplies power to the processor and the rectifier assembly; The method includes: The processor obtains the first monitoring voltage of the bus monitoring system under DC bus power supply conditions. When the first monitoring voltage does not meet the normal operating conditions of the DC bus, the branch to be investigated is determined from the branch of the DC bus power supply. The DC grounding fault diagnosis equipment is connected in parallel to the branch to be diagnosed. Each sub-switch of the multi-switch is connected to a branch to be diagnosed, so as to switch the power supply of the connected branch to be diagnosed to the rectifier component. The rectifier component is used to generate a DC signal that matches the branch to be diagnosed. In response to the fault troubleshooting command of the branch to be troubleshooted, the rectifier component switches the branch to be troubleshooted from DC bus power supply to the rectifier component power supply, and obtains the second monitoring voltage of the bus monitoring system when the branch to be troubleshooted is disconnected from the DC bus through the processor; The processor determines the investigation result of the branch to be investigated based on the second monitoring voltage and the normal operating conditions. The investigation result includes branches with non-DC grounding faults and branches with DC grounding faults. After determining that the branch to be investigated is a DC ground fault branch, the method further includes: The processor determines the network level of the branch to be investigated from the DC system topology network, which includes the connection relationships between branches at different levels; If the network level is the lowest network level, then the branch to be investigated is determined to be a branch to be repaired; If the network level is not the lowest network level, then obtain the interval distance of at least one subordinate associated branch of the branch to be investigated. Determining a lower-level target branch from the lower-level associated branches based on the interval distance specifically includes: calculating the interval distance difference of each of the lower-level associated branches based on the interval distance; if all interval distance differences are less than a preset distance threshold, obtaining periodic investigation information of the lower-level associated branches and determining the lower-level target branch based on the periodic investigation information; if any interval distance difference is greater than a preset distance threshold, determining the lower-level target branch from the lower-level associated branches based on the interval distance; wherein, when the lower-level associated branch is greater than the total of the multiple switches... In the case of a large number of cases, the lower-level associated branches are connected to the rectifier assembly in batches according to the order of the interval distance from smallest to largest for troubleshooting; wherein, the periodic troubleshooting information includes troubleshooting time and troubleshooting results; the lower-level target branch is determined based on the periodic troubleshooting information, including: determining the lower-level associated branch with the most faults in the troubleshooting results as the lower-level candidate branch; if the number of lower-level candidate branches is greater than a preset number threshold, the troubleshooting time interval is calculated based on the troubleshooting time, and the lower-level candidate branch with the longest troubleshooting time interval is determined as the lower-level target branch; The lower-level target branch is designated as the branch to be investigated, and the process of connecting the DC grounding fault investigation equipment in parallel to the power supply bus of the branch to be investigated is returned.

2. The method according to claim 1, characterized in that, The normal operating conditions include the normal voltage range; determining the investigation result of the branch to be investigated based on the second monitoring voltage and the normal operating conditions includes: If the second monitoring voltage does not recover to the normal voltage range within a preset time period, the branch to be investigated is determined to be a non-DC grounding fault branch. If the second monitoring voltage recovers to the normal voltage range within a preset time period, then the branch to be investigated is determined to be a DC grounding fault branch.

3. The method according to claim 1, characterized in that, Before determining the network level of the branch to be investigated from the DC system topology network, the method further includes: Obtain global branch information and circuit connection relationships between branches on the DC bus. The global branch information includes the branch identifier of the global branch and the interval distance between every two branches. The network level of each branch is determined based on the circuit connection relationship described above; Based on the network hierarchy and distance information, construct the DC system topology network under the DC bus.

4. A DC grounding fault diagnosis device, characterized in that, The device is used to perform the operation corresponding to the DC grounding fault investigation method as described in any one of claims 1-3. The DC grounding fault investigation device is connected in parallel with the power supply bus to the branch to be investigated, and includes: a power module, a processor and a rectifier assembly. The rectifier assembly includes a controller and a first rectifier module and a second rectifier module, and the first rectifier module and the second rectifier module are connected in series. The power module is used to supply power to the processor and the rectifier assembly; The processor is configured to acquire the second monitoring voltage of the bus monitoring system when the branch to be investigated is disconnected from the DC bus; and determine the investigation result of the branch to be investigated based on the second monitoring voltage and normal operating conditions. The rectifier component is used to switch the DC bus power supply of the branch to be troubleshooted to the power supply of the rectifier component in response to the fault troubleshooting command of the branch to be troubleshooted. The controller sends a first pulse width modulation signal to the first rectifier module and a second pulse width modulation signal to the second rectifier module according to the target power supply parameters. The first rectifier module generates a first electrical signal according to the first pulse width modulation signal, and the second rectifier module generates a second electrical signal according to the second pulse width modulation signal. The target power supply parameters are configured based on the DC module power supply parameters of the DC bus. The first electrical signal is a reverse voltage signal with the same voltage range as the second electrical signal to match the power supply output of the DC bus. The device also includes a multi-switch, each of the sub-switches of which is used to connect to a branch circuit to be investigated, so as to switch the power supply of the connected branch circuit to the rectifier component.

5. The device according to claim 4, characterized in that, The device also includes: a wireless communication module and a display; The wireless communication module is used to communicate wirelessly with the bus monitoring system and send the second monitoring voltage obtained from the bus monitoring system to the processor. The processor is further configured to receive the second monitoring voltage sent by the wireless communication module, determine the investigation result of the branch to be investigated based on the second monitoring voltage and the normal operating conditions, and send the investigation result to the display so as to display the investigation result on the display.

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