Distribution line adaptive diagnosis method and system for fault positioning

Abstract

The invention is suitable for the technical field of intelligent fault diagnosis of a power distribution system, and provides a fault positioning-oriented power distribution line adaptive diagnosis method and system, and the method comprises the steps: obtaining the operation state data of a bridge crane cluster, and recognizing whether a current bus is in a regenerative current disturbance working condition or not based on the operation state data; when the current bus is identified to be in the regenerative current disturbance working condition, selecting a plurality of historical samples which are consistent with the current bridge crane working condition but have different feedback current amplitudes from the operation state data; and obtaining a historical direction offset according to a direction offset difference value between the historical current direction measured in the historical sample and the historical reference direction under the normal operation condition. The problem of bus current direction distortion caused by feedback current in the bridge crane heavy load lowering process can be effectively solved, and the technical effect that the real current direction of the distribution line can still be accurately obtained under the strong disturbance working condition is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of intelligent fault diagnosis of power distribution systems, and particularly relates to a power distribution line adaptive diagnosis method and system for fault location. BACKGROUND

[0002] In the fault location technology of power distribution lines, the current direction criterion is a kind of widely used core detection means, which determines the line section to which the fault point belongs by judging the change of the power flow direction of the current before and after the fault occurs. In most conventional load scenarios, the power flow direction of the power distribution system is stable and easy to judge, and the traditional directional protection or directional measurement device can accurately reflect the real current direction of the line and complete the sectional fault location accordingly. However, in modern port, electric lifting equipment cluster, industrial hoisting system and other scenarios with regenerative braking characteristics, the load will generate significant feedback current when lowering heavy objects, causing the bus power flow direction to reverse or fluctuate sharply in a short time, making it difficult for the traditional direction criterion to distinguish between load disturbance and direction change caused by line fault.

[0003] In the prior art, common solutions include increasing the action threshold of the direction criterion, setting a fixed direction correction amount, participating in auxiliary judgment through voltage, or setting a shielding logic for regenerative braking. However, these methods generally have the problem of insufficient adaptability. First, raising the threshold will reduce the sensitivity of the direction criterion to actual faults, resulting in missed judgment. Second, the fixed correction amount cannot cover the varying disturbance characteristics under different lifting weights, different lowering speeds and different feedback intensities, and the correction effect often deviates from the real current direction. Third, the shielding logic will make the system "blind" during regenerative disturbance, making it impossible to determine the fault section and affecting the implementation of protection selectivity. With the increasing size of the bridge crane cluster, the accelerating operation rhythm and the increasingly complex regenerative current disturbance characteristics, the limitations of traditional methods are increasingly obvious, making it difficult to meet the high accuracy and high reliability requirements of modern power distribution systems.

[0004] The core technical problem to be solved by the present application is that the transient shift of the feedback current to the current direction under regenerative braking conditions will directly interfere with the fault location process, and existing methods cannot automatically correct the direction according to different disturbance levels and different working conditions, resulting in distortion of the direction criterion. SUMMARY

[0005] The purpose of the present application is to provide a power distribution line adaptive diagnosis method and system for fault location, which aims to solve the problems raised in the background art.

[0006] The present application is implemented as follows: a power distribution line adaptive diagnosis method for fault location, the method comprising: Obtain the running state data of the bridge crane cluster, and identify whether the current bus is in a regenerative current disturbance working condition based on the running state data; When it is identified that the current bus is in the regenerative current disturbance working condition, select a plurality of historical samples from the running state data, which are consistent with the current bridge crane operation working condition but have different feedback current amplitudes, obtain a historical direction offset from a direction offset difference value between a historical current direction measured in the historical samples and a historical reference direction in a normal working condition; Obtain the current current direction, and calculate a current direction offset based on a current reference direction of the current bus in the normal working condition; Calculate a direction correction factor according to a deviation degree relationship between the historical direction offset and the current direction offset, and correct the current current direction by using the direction correction factor to obtain a corrected current direction; Determine the fault section of the power distribution line based on the corrected current direction.

[0007] As a further limitation of the technical scheme of the embodiment of the application, the step of obtaining the running state data of the bridge crane cluster and identifying whether the current bus is in a regenerative current disturbance working condition based on the running state data comprises: Obtain the running state data of the bridge crane cluster, and identify whether the current bus is in a regenerative current disturbance working condition based on the running state data; Analyze the running state data to identify whether the bridge crane cluster is currently in a regenerative braking working condition; When it is identified that the current bus is in the regenerative current disturbance working condition, select a plurality of historical samples from the running state data, which are consistent with the current bridge crane operation working condition but have different feedback current amplitudes, obtain a historical direction offset from a direction offset difference value between a historical current direction measured in the historical samples and a historical reference direction in a normal working condition; When the preset condition is met, identify the current bus running state as a regenerative current disturbance working condition.

[0008] As a further limitation of the technical scheme of the embodiment of the application, the preset condition comprises at least one of the hoisting weight exceeding a preset weight threshold, the lowering speed exceeding a preset speed threshold, and the number of bridge cranes in regenerative braking exceeding a preset number threshold.

[0009] As a further limitation of the technical scheme of the embodiment of the application, when it is identified that the current bus is in the regenerative current disturbance working condition, the step of selecting a plurality of historical samples from the running state data, which are consistent with the current bridge crane operation working condition but have different feedback current amplitudes, and obtaining a historical direction offset from a direction offset difference value between a historical current direction measured in the historical samples and a historical reference direction in a normal working condition comprises: When it is identified that the current bus is in the regenerative current disturbance working condition, a plurality of historical samples consistent with the current bridge crane operation working condition but different in feedback current amplitude are selected from the operation state data; A corresponding historical current direction value is extracted from the historical samples, and a historical reference direction of the historical samples in the normal operation working condition is extracted; A direction offset difference value between the historical current direction and the historical reference direction is calculated; The direction offset difference values corresponding to the plurality of historical samples are statistically processed to obtain a historical direction offset; the statistical processing includes at least one of weighted average, mean value calculation or median value calculation.

[0010] As a further limitation of the technical scheme of the embodiment of the application, the step of calculating a direction correction factor according to the offset degree relationship between the historical direction offset and the current direction offset, and correcting the current current direction by using the direction correction factor to obtain a corrected current direction includes: A direction correction factor is calculated according to the offset degree relationship between the historical direction offset and the current direction offset; A false direction component caused by the regenerative current disturbance in the current current direction is determined according to the direction correction factor; The false direction component is deducted from the current current direction to obtain a corrected current direction, and the corrected current direction is used as a fault direction criterion for fault location.

[0011] A power distribution line adaptive diagnosis system for fault location, the system includes: An operation state recognition module, configured to acquire operation state data of a bridge crane cluster, and recognize whether a current bus is in a regenerative current disturbance working condition based on the operation state data; A historical sample processing module, configured to, when it is identified that the current bus is in the regenerative current disturbance working condition, select a plurality of historical samples consistent with the current bridge crane operation working condition but different in feedback current amplitude from the operation state data, and obtain a historical direction offset according to a direction offset difference value between a historical current direction measured in the historical samples and a historical reference direction in a normal operation working condition; A current offset calculation module, configured to acquire a current current direction, and calculate a current direction offset based on a current reference direction of the current bus in the normal operation working condition; A direction correction module, configured to calculate a direction correction factor according to the offset degree relationship between the historical direction offset and the current direction offset, and correct the current current direction by using the direction correction factor to obtain a corrected current direction; A fault section determination module, configured to determine a fault section of the power distribution line based on the corrected current direction.

[0012] As a further limitation of the technical scheme of the embodiment of the present application, the operation state recognition module specifically comprises: An operation data acquisition unit is configured to acquire operation state data of the bridge crane cluster, wherein the operation state data comprises real-time bus voltage of the bridge crane cluster, and hoisting weight, lowering speed, driving motor operation mode, frequency converter feedback state, and number of bridge cranes simultaneously in regenerative braking of each bridge crane; A working condition analysis unit is configured to analyze the operation state data, and identify whether the bridge crane cluster is currently in a regenerative braking working condition; A disturbance judgment unit is configured to, when it is identified that the bridge crane cluster is in the regenerative braking working condition, acquire the hoisting weight, the lowering speed, and the number of bridge cranes simultaneously in regenerative braking, and judge whether the three satisfy a preset condition sufficient to affect the direction of bus current; A disturbance recognition unit is configured to, when the preset condition is satisfied, identify the current bus operation state as a regenerative current disturbance working condition.

[0013] As a further limitation of the technical scheme of the embodiment of the present application, the preset condition comprises at least one of the following: the hoisting weight exceeds a preset weight threshold, the lowering speed exceeds a preset speed threshold, and the number of bridge cranes simultaneously in regenerative braking exceeds a preset number threshold.

[0014] As a further limitation of the technical scheme of the embodiment of the present application, the historical sample processing module specifically comprises: A sample screening unit is configured to, when it is identified that the current bus is in the regenerative current disturbance working condition, select a plurality of historical samples with different feedback current amplitudes from the operation state data, which are consistent with the current bridge crane operation working condition; A historical data extraction unit is configured to extract corresponding historical current direction values from the historical samples, and extract a historical reference direction of the historical samples in a normal operation working condition; An offset difference calculation unit is configured to calculate a direction offset difference value between the historical current direction and the historical reference direction; An offset amount generation unit is configured to statistically process the direction offset difference values corresponding to the plurality of historical samples to obtain a historical direction offset amount, wherein the statistical processing comprises at least one of weighted average, mean value calculation, or median value calculation.

[0015] As a further limitation of the technical scheme of the embodiment of the present application, the direction correction module specifically comprises: A correction factor calculation unit is configured to calculate a direction correction factor according to a relationship between the historical direction offset amount and the current direction offset amount; A false component recognition unit is configured to determine a false direction component caused by the regenerative current disturbance in the current current direction according to the direction correction factor; A direction correction unit is configured to deduct a false direction component from the current direction to obtain a corrected current direction, and the corrected current direction is used as a fault direction criterion for fault location.

[0016] Compared with the prior art, the application effectively solves the problem of bus current direction distortion caused by feedback current during the heavy load release process of the bridge crane by introducing a regenerative current disturbance identification mechanism and an adaptive direction correction strategy based on historical offset characteristics, and realizes the technical effect of accurately obtaining the real current direction of the distribution line under strong disturbance conditions. Compared with the traditional fault location method which relies on fixed threshold or single direction criterion, the application can automatically adjust the direction correction factor according to different bridge crane operating states and feedback current amplitudes, making the fault section judgment more robust and reliable, significantly reducing the misjudgment probability, and improving the safety and operation efficiency of the distribution system. Since the application can adapt to various distribution scenarios containing regenerative braking load such as port bridge cranes, mechanical ports, electric lifting equipment, etc., it has good engineering universality and deployment feasibility, and has wide application prospects in the fields of smart distribution network, port automation, electrified factory, etc. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The flowchart of the method provided for the embodiment of the application; Figure 2 The flowchart of identifying the regenerative current disturbance working condition in the method provided for the embodiment of the application; Figure 3 The flowchart of obtaining the historical direction offset in the method provided for the embodiment of the application; Figure 4 The flowchart of correcting the bus current direction in the method provided for the embodiment of the application; Figure 5 The application architecture diagram of the system provided for the embodiment of the application; Figure 6 The structural block diagram of the running state identification module in the system provided for the embodiment of the application; Figure 7 The structural block diagram of the historical sample processing module in the system provided for the embodiment of the application; Figure 8 The structural block diagram of the direction correction module in the system provided for the embodiment of the application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the application clearer, the application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the application and do not limit the application.

[0019] Figure 1A flow chart of the method provided by the embodiment of the application is shown.

[0020] Specifically, the power distribution line adaptive diagnosis method for fault location comprises the following steps. In step S100, the operating state data of the bridge crane cluster is acquired, and whether the current bus is in the regenerative current disturbance working condition is identified based on the operating state data.

[0021] Specifically, Figure 2 A flow chart of identifying the regenerative current disturbance working condition is shown.

[0022] In the embodiment of the application, the operating state data of the bridge crane cluster is acquired, and whether the current bus is in the regenerative current disturbance working condition is identified based on the operating state data, which comprises the following steps. In step S101, the operating state data of the bridge crane cluster is acquired, and the operating state data comprises the real-time voltage of the bus of the bridge crane cluster, the hoisting weight of each bridge crane, the lowering speed, the driving motor operating mode, the frequency converter feedback state, and the number of bridge cranes in the regenerative braking state. In step S102, the operating state data is analyzed to identify whether the bridge crane cluster is in the regenerative braking working condition. In step S103, when it is identified that the bridge crane cluster is in the regenerative braking working condition, the hoisting weight, the lowering speed, and the number of bridge cranes in the regenerative braking state are acquired, and it is determined whether the three satisfy the preset condition sufficient to affect the bus current direction, and the preset condition comprises at least one of the following: the hoisting weight exceeds a preset weight threshold, the lowering speed exceeds a preset speed threshold, and the number of bridge cranes in the regenerative braking state exceeds a preset number threshold. In step S104, when the preset condition is satisfied, the current bus operating state is identified as the regenerative current disturbance working condition.

[0023] In the embodiment of the application, the operating state data is usually collected in real time by the monitoring system, the driving control system, and the bus monitoring device of the bridge crane, and the data comprises the real-time voltage information of the bus of the bridge crane cluster, which is used to reflect whether the current bus is in the power supply state or there is a trend of energy feedback; and the data further comprises the hoisting weight of each bridge crane, the lowering speed, the driving motor operating mode, the frequency converter feedback state, and the number of bridge cranes in the regenerative braking state, wherein the hoisting weight is used to represent the mechanical load carried by the bridge crane, the lowering speed is used to represent the mechanical motion state of the bridge crane in the lowering process, the driving motor operating mode is used to represent one of the driving, braking, or regenerative braking modes, the frequency converter feedback state is used to represent whether there is a case of feedback of electric energy from the load side to the bus, and the number of bridge cranes in the regenerative braking state is used to represent the overall magnitude of the feedback current. The above operating state data comprehensively reflects the dynamic state and the electrical state of the bridge crane cluster in the operation process, and is the basic data source for judging whether the bus is likely to appear the regenerative current disturbance.

[0024] The regenerative braking working condition refers to a working condition in which the bridge crane is in the process of lowering a heavy object or rapid braking, the motor is in a power generation state, mechanical potential energy or kinetic energy is converted into electric energy through the driving device, and the electric energy is fed back to the bus through the frequency converter. In this working condition, the operation mode of the bridge crane driving motor will be displayed as a regenerative braking mode, and the feedback state of the frequency converter is turned on, indicating that the bridge crane is applying reverse power to the bus. In addition, if multiple bridge cranes are in the regenerative braking working condition at the same time, the feedback currents may be superimposed, forming a disturbance phenomenon that affects the direction of the bus current. Therefore, by analyzing the operation mode of the driving motor, the feedback state of the frequency converter, and the number of bridge cranes in the regenerative braking at the same time, it can be judged whether the current bridge crane cluster as a whole is in the regenerative braking working condition.

[0025] The preset condition is used to define typical regenerative working conditions that are sufficient to affect the direction of the bus current, for example, when the hoisted weight exceeds the preset weight threshold, the larger load will release more gravitational potential energy during lowering, resulting in stronger regenerative current feedback; when the lowering speed exceeds the preset speed threshold, due to the acceleration of kinetic energy conversion, larger transient feedback current may also be generated; when the number of bridge cranes in the regenerative braking at the same time exceeds the preset number threshold, the superimposed feedback currents of multiple bridge cranes may cause significant reverse power flow of the bus. Therefore, any one of the above conditions being met can be considered as the current regenerative braking working condition reaching a sufficient strength to affect the direction of the bus current.

[0026] When it is judged that the preset condition is met, the current bus operating state can be identified as a regenerative current disturbance working condition. This identification process means that there may be obvious feedback current interference in the current bus, causing the current direction to deviate. At this time, the subsequent current direction criterion, direction deviation calculation and fault section positioning need to be processed based on the corrected current data to ensure the accuracy of fault positioning.

[0027] Further, the power distribution line adaptive diagnosis method for fault positioning further comprises the following steps: Step S200, when it is identified that the current bus is in the regenerative current disturbance working condition, a plurality of historical samples with different feedback current amplitudes are selected from the operation state data which are consistent with the current bridge crane operation working condition, and the historical direction deviation is obtained according to the direction deviation between the measured historical current direction in the historical samples and the historical reference direction under the normal operation working condition.

[0028] Specifically, Figure 3 A flowchart for obtaining the historical direction deviation is shown.

[0029] When it is identified that the current bus is in the regenerative current disturbance working condition, a plurality of historical samples consistent with the current bridge crane operation working condition but different in feedback current amplitude are selected from the operation state data, and the historical direction deviation is obtained according to the direction deviation difference between the historical current direction measured in the historical samples and the historical reference direction in the normal operation working condition, and the historical direction deviation specifically includes the following steps: Step S201, when it is identified that the current bus is in the regenerative current disturbance working condition, a plurality of historical samples consistent with the current bridge crane operation working condition but different in feedback current amplitude are selected from the operation state data; Step S202, the corresponding historical current direction value is extracted from the historical samples, and the historical reference direction of the historical samples in the normal operation working condition is extracted; Step S203, the direction deviation difference between the historical current direction and the historical reference direction is calculated; Step S204, the direction deviation difference corresponding to the plurality of historical samples is statistically processed to obtain the historical direction deviation; the statistical processing includes at least one of weighted average, mean value calculation or median value calculation.

[0030] In the embodiment of the application, the operation working condition consistent means that the bridge crane has the same hoisting weight interval, similar lowering speed interval, same driving motor operation mode and same operation type at the historical time and the current time, for example, all in the heavy object lowering process. These conditions are used to ensure that the current and the historical sample have consistent load characteristics and motion characteristics, so that the historical sample can cover different intensity of regenerative current disturbance, and facilitate the induction and statistics of the subsequent direction deviation behavior.

[0031] The historical current direction value is the instantaneous current direction measured by the current transformer or the direction element when the regenerative current disturbance occurs, which may be offset due to the feedback effect of the regenerative current. The historical reference direction is used to represent the true current direction in the normal operation working condition of the sample, i.e. when the bus does not exist regenerative current disturbance, which can be obtained by historical normal working condition record, power flow calculation or preset operation model. By comparing the historical current direction and the historical reference direction, the direction deviation difference of each sample can be obtained, which is used to quantitatively describe the influence degree of the regenerative current disturbance on the current direction under the same working condition.

[0032] The statistical processing can adopt at least one of weighted average, mean value calculation, and median value calculation, wherein the weighted average can give different weights according to factors such as feedback current amplitude, sample occurrence frequency, or operation duration, so as to enhance the influence of high correlation samples in the offset determination process; the mean value calculation is suitable for a large number of uniformly distributed historical samples; and the median value calculation can reduce the influence of abnormal samples on the overall offset. After the plurality of historical offset difference values are processed by the above statistical methods, a historical directional offset with overall representativeness can be obtained, which fully reflects the typical offset degree of the regenerative current disturbance to the current direction under the same operation condition. In the subsequent direction correction process, the historical directional offset will be used as the basis for calculating the direction correction factor, so that the corrected current direction can more accurately exclude the influence of the regenerative current disturbance and ensure the reliability of the fault direction criterion.

[0033] Further, the power distribution line adaptive diagnosis method for fault location further comprises the following steps: In step S300, the current current direction is obtained, and the current directional offset is calculated based on the current reference direction of the current bus under the normal operation condition.

[0034] In the embodiment of the application, the current current direction is obtained from the current acquisition device or the direction measurement unit of the bus. The current current direction is usually measured in real time by the current transformer, the direction element or the synchronous sampling device installed on the bus side, and the direction reflects the actual flow direction of the bus current at the current instant. When the bridge crane cluster is in the regenerative braking condition, the feedback current may flow into the bus, and the current current direction may be opposite or offset from the typical power flow direction, so it is necessary to further correct the current current direction.

[0035] The so-called normal operation condition refers to the current power flow direction of the current bus when it is not disturbed by the regenerative current. The direction reflects the natural flow trend of the current when the power distribution line supplies power to the conventional load. The reference direction can be obtained by normal operation historical data, power flow calculation results based on real-time load, or reference direction provided by the power grid operation scheduling system, or can be calibrated in the system initialization stage. Under these normal conditions, the bus current direction is usually stable and is not affected by the bridge crane feedback current, so it can be used as a reference for judging the directional offset.

[0036] The current direction offset is used to quantitatively describe the degree of deviation of the current direction from the normal direction, and the greater the value, the more significant the influence of the regenerative current disturbance on the current direction. The current direction offset can be obtained by calculating the direction difference, angle offset or logical direction comparison between the current direction and the reference direction. Among them, when the direction criterion is based on the binary direction signal (such as forward / reverse), the offset can be determined by the difference judgment method; when the direction criterion is based on the phase angle, the offset can be calculated by the angle difference; when the direction criterion is based on the incremental measurement, the offset can be obtained by the current incremental direction change trend.

[0037] Further, the power distribution line adaptive diagnosis method for fault location further comprises the following steps: Step S400, calculating a direction correction factor according to the offset degree relationship between the historical direction offset and the current direction offset, and correcting the current current direction by using the direction correction factor to obtain the corrected current direction.

[0038] Specifically, Figure 4 A flow chart for correcting the bus current direction is shown.

[0039] Among them, calculating a direction correction factor according to the offset degree relationship between the historical direction offset and the current direction offset, and correcting the current current direction by using the direction correction factor to obtain the corrected current direction specifically comprises the following steps: Step S401, calculating a direction correction factor according to the offset degree relationship between the historical direction offset and the current direction offset; Step S402, determining a false direction component caused by the regenerative current disturbance in the current current direction according to the direction correction factor; Step S403, deducting the false direction component from the current current direction to obtain the corrected current direction, and using the corrected current direction as the fault direction criterion for fault location.

[0040] In the embodiment of the present application, the purpose of calculating a direction correction factor according to the offset degree relationship between the historical direction offset and the current direction offset is to adaptively correct the current direction according to the offset rule of the regenerative current disturbance under different operating conditions, so that it can be restored to a direction state closer to the true power flow. The historical direction offset reflects the typical direction offset degree of the bus during the past regenerative current disturbance under the same operating condition; the current direction offset reflects the offset degree caused by the current disturbance. By comparing the two, the relative strength relationship between the current disturbance and the historical disturbance can be determined, so that the direction correction factor is determined, so that the correction process has adaptivity, rather than relying on fixed threshold or fixed offset correction.

[0041] The significance of the direction correction factor is that it reflects the relative proportional relationship between the influence degree of the current renewable current disturbance on the direction deviation and the historical similar disturbance. When the current direction deviation is close to the historical direction deviation, it means that the intensity of the current disturbance is consistent with that of the historical typical disturbance, and the current current direction can be directly corrected according to the correction amplitude corresponding to the historical deviation; when the current direction deviation is greater than the historical direction deviation, it means that the intensity of the current renewable disturbance is greater, and a larger correction factor needs to be used to sufficiently deduct the false direction component; when the current direction deviation is less than the historical direction deviation, a smaller correction factor can be used to prevent over-correction from causing misjudgment. In this way, the direction correction factor can automatically adjust the correction amplitude according to different disturbance degrees, so that the corrected current direction is closer to the true direction.

[0042] In specific implementation, the deviation degree relationship can be a proportional relationship of the deviation, a normalization result of the deviation difference, or a weighted comparison result between the historical deviation and the current deviation, which can be used to determine the intensity of the current disturbance relative to the historical disturbance. For example, the ratio of the historical direction deviation to the current direction deviation can be used as the direction correction factor, so that the correction amplitude and the deviation degree are in a linear relationship, or a nonlinear relationship can be used to achieve more flexible mapping to adapt to different disturbance modes.

[0043] The false direction component refers to the deviation caused by the feedback effect of the renewable current, which deviates from the normal operating power flow direction. This deviation is not caused by line faults, but by temporary reverse power flow phenomenon caused by renewable current disturbance. When identifying the false direction component, the current direction deviation and the direction correction factor can be combined to estimate the deviation size that needs to be deducted from the current current direction, so as to obtain a compensation amount consistent with the intensity of the historical disturbance.

[0044] Finally, by deducting the false direction component from the current current direction, the corrected current direction can be obtained. The corrected current direction represents the true power flow direction after excluding the influence of renewable current disturbance. Therefore, the corrected current direction can be used as the final direction criterion for fault judgment, ensuring that the fault section can still be determined according to the true direction in the presence of renewable disturbance, thereby improving the accuracy and reliability of fault location.

[0045] Further, the power distribution line adaptive diagnosis method for fault location further includes the following steps: Step S500, determining the fault section of the power distribution line based on the corrected current direction.

[0046] In the embodiment of the present application, the modified current direction has eliminated the false direction component caused by the disturbance of the regenerated current, and thus can reflect the real change of the power flow direction of the line in the case of no disturbance. When a fault occurs, the downstream load current will have a significant mutation, resulting in an identifiable direction reversal or direction mode change of the current direction upstream and downstream of the fault point, and thus the modified current direction can be used as a reliable input for judging the fault section.

[0047] In the actual judgment process, the modified current direction can be compared with the topology of the distribution line. The distribution line is usually composed of multiple branch lines and trunk lines, and each line section is connected through a branch node. The modified current direction corresponds to the upstream and downstream relationship between each line section. When a fault occurs in a certain section, the current direction of the section will change significantly, for example, the current direction originally pointing to the load side may suddenly point to the power supply side due to the fault point. By comparing the direction change with the node position in the line topology, the section where the current direction changes abnormally can be identified, and it can be inferred that the fault is located between the upstream and downstream of the section.

[0048] To improve the accuracy of fault location, the modified direction information from different measurement points can be compared. In a line equipped with multiple measurement devices, each device can provide the modified current direction at the point. By comparing the direction changes at different nodes, the range of the section where the fault may be located can be gradually narrowed. For example, when the modified current direction of a certain node is consistent with the direction of the upstream node, but is contradictory or reversed with the direction of the downstream node, it can be usually judged that the fault is located in the line section between the node and the downstream node.

[0049] In addition, the change amplitude or trend of the modified current direction can also be analyzed to further refine the judgment of the fault point. For example, in some cases, the greater the direction mutation amplitude, the closer the fault point to the measurement point. The time sequence of the direction changes at multiple nodes can also further assist in judging the range affected by the fault. By combining the direction change amplitude, the time sequence of the direction change, and the line topology, fine fault section positioning based on the direction criterion can be achieved.

[0050] Through the above steps, the embodiment of the present application can accurately identify the line section where the fault is located, achieve the purpose of reliable fault location in the presence of regenerated current disturbance, improve the fault handling efficiency, reduce unnecessary line inspection range, and improve the operation reliability of the distribution system.

[0051] Further, Figure 5 The application architecture diagram of the system provided by the embodiment of the present application is shown.

[0052] In a further preferred embodiment provided by the present application, a power distribution line adaptive diagnosis system for fault location comprises: The running state recognition module 100 is configured to acquire running state data of the bridge crane cluster and recognize whether the current bus is in a regenerative current disturbance working condition based on the running state data.

[0053] Specifically, Figure 6 A structural block diagram of the running state recognition module 100 in the system provided by the embodiment of the present application is shown.

[0054] In a preferred embodiment provided by the present application, the running state recognition module 100 specifically comprises: The running data acquisition unit 101 is configured to acquire running state data of the bridge crane cluster, wherein the running state data comprises real-time voltage of the bus of the bridge crane cluster and hoisting weight, lowering speed, driving motor running mode, frequency converter feedback state and the number of bridge cranes in regenerative braking of each bridge crane; The working condition analysis unit 102 is configured to analyze the running state data and recognize whether the bridge crane cluster is in a regenerative braking working condition; The disturbance judgment unit 103 is configured to, when it is recognized that the bridge crane cluster is in the regenerative braking working condition, acquire the hoisting weight, the lowering speed and the number of bridge cranes in regenerative braking, and judge whether the three satisfy preset conditions sufficient to affect the direction of the bus current, wherein the preset conditions comprise at least one of the hoisting weight exceeding a preset weight threshold, the lowering speed exceeding a preset speed threshold and the number of bridge cranes in regenerative braking exceeding a preset number threshold; The disturbance recognition unit 104 is configured to, when the preset conditions are satisfied, recognize the current bus running state as a regenerative current disturbance working condition.

[0055] Further, the power distribution line adaptive diagnosis system for fault location further comprises: The historical sample processing module 200 is configured to, when it is recognized that the current bus is in the regenerative current disturbance working condition, select a plurality of historical samples consistent with the current bridge crane operation working condition but having different feedback current amplitudes from the running state data, and acquire a historical direction deviation based on a direction deviation difference between a historical current direction measured in the historical samples and a historical reference direction in a normal operation working condition.

[0056] Specifically, Figure 7 A structural block diagram of the historical sample processing module 200 in the system provided by the embodiment of the present application is shown.

[0057] In a preferred embodiment provided by the present application, the historical sample processing module 200 specifically comprises: The sample screening unit 201 is configured to select a plurality of historical samples from the operation state data, the historical samples being consistent with the current bridge crane operation condition but different in feedback current amplitude when it is identified that the current bus is in the regenerative current disturbance condition; The historical data extraction unit 202 is configured to extract corresponding historical current direction values from the historical samples and extract historical reference directions of the historical samples in the normal operation condition. The offset difference calculation unit 203 is configured to calculate direction offset difference values between the historical current directions and the historical reference directions. The offset generation unit 204 is configured to statistically process the direction offset difference values corresponding to the plurality of historical samples to obtain a historical direction offset, the statistical processing including at least one of weighted average, mean value calculation or median value calculation.

[0058] Further, the power distribution line adaptive diagnosis system for fault location further comprises: The current offset calculation module 300 is configured to obtain a current current direction and calculate a current direction offset based on a current reference direction of the current bus in the normal operation condition.

[0059] Further, the power distribution line adaptive diagnosis system for fault location further comprises: The direction correction module 400 is configured to calculate a direction correction factor according to a relationship between the historical direction offset and the current direction offset, and correct the current current direction by using the direction correction factor to obtain a corrected current direction.

[0060] Specifically, Figure 8 A structure block diagram of the direction correction module 400 in the system provided by the embodiment of the application is shown.

[0061] In the preferred embodiment provided by the application, the direction correction module 400 specifically comprises: The correction factor calculation unit 401 is configured to calculate a direction correction factor according to a relationship between the historical direction offset and the current direction offset. The false component identification unit 402 is configured to determine a false direction component caused by the regenerative current disturbance in the current current direction according to the direction correction factor. The direction correction unit 403 is configured to subtract the false direction component from the current current direction to obtain a corrected current direction, and use the corrected current direction as a fault direction criterion for fault location.

[0062] Further, the power distribution line adaptive diagnosis system for fault location further comprises: The fault section determination module 500 is configured to determine a fault section of the power distribution line based on the corrected current direction.

[0063] It should be understood that, although the steps in the flowcharts of the embodiments of the present application are shown in a certain order following the arrows, the steps do not have to be executed in the order following the arrows. Unless otherwise specified herein, the steps do not have strict order limitation, and can be executed in other orders. Moreover, at least some of the steps in the embodiments can include multiple sub-steps or multiple stages, which do not have to be executed at the same time, but can be executed at different times, and the execution order of the sub-steps or stages does not have to be sequential, but can be round-robin or alternately executed with at least some of the other steps or sub-steps or stages of the other steps.

[0064] It can be understood by those skilled in the art that all or part of the processes in the above-mentioned embodiments can be completed by a computer program instructing related hardware, and the program can be stored in a non-volatile computer readable storage medium, and when the program is executed, the processes of the above-mentioned embodiments can be included. Wherein, any reference to memory, storage, database or other medium used in the embodiments provided in the present application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM) and the like.

[0065] The technical features of the above-mentioned embodiments can be combined in any way. In order to make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described, but as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0066] The above embodiments only express several implementation manners of the present application, which are described in a more specific and detailed manner, but should not be understood as a limitation on the patent scope of the present application. It should be noted that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

[0067] The above merely describes the preferred embodiments of the present application and should not be used to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. An adaptive diagnostic method for power distribution lines oriented towards fault location, characterized in that, The method includes: Acquire the operating status data of the bridge crane cluster, and identify whether the current busbar is under regenerative current disturbance condition based on the operating status data; When the current busbar is identified as being under regenerative current disturbance conditions, several historical samples that are consistent with the current crane operation conditions but have different feedback current amplitudes are selected from the operating status data. The historical direction offset is obtained based on the difference between the historical current direction measured in the historical samples and the historical reference direction under normal operating conditions. Obtain the current current direction and calculate the current direction offset based on the current reference direction of the current bus under normal operating conditions; The direction correction factor is calculated based on the offset relationship between the historical direction offset and the current direction offset, and the current current direction is corrected using the direction correction factor to obtain the corrected current direction. The fault location of the power distribution line is determined based on the corrected current direction.

2. The adaptive diagnostic method for power distribution lines oriented towards fault location according to claim 1, characterized in that, The steps for acquiring the operational status data of the bridge crane cluster and identifying whether the current busbar is under regenerative current disturbance conditions based on the operational status data include: The operation status data of the bridge crane cluster is obtained, including the real-time voltage of the bridge crane cluster bus, the lifting weight of each bridge crane, the lowering speed, the driving motor operation mode, the frequency converter feedback status, and the number of bridge cranes simultaneously in regenerative braking. Analyze the operational status data to identify whether the bridge crane cluster is currently in regenerative braking mode; When it is identified as being in regenerative braking mode, the lifting weight, lowering speed and number of bridge cranes simultaneously in regenerative braking are obtained, and it is determined whether the three meet the preset conditions that are sufficient to affect the direction of the bus current. When preset conditions are met, the current busbar operating status is identified as a regenerative current disturbance condition.

3. The adaptive diagnostic method for power distribution lines oriented towards fault location according to claim 1, characterized in that, The preset conditions include at least one of the following: the lifting weight exceeds a preset weight threshold, the lowering speed exceeds a preset speed threshold, and the number of bridge cranes under regenerative braking exceeds a preset number threshold.

4. The adaptive diagnostic method for power distribution lines oriented towards fault location according to claim 1, characterized in that, When the current busbar is identified as being under regenerative current disturbance conditions, the steps for obtaining the historical directional offset based on the difference between the historical current direction measured in the historical samples and the historical reference direction under normal operating conditions include: When the current busbar is identified as being under regenerative current disturbance conditions, several historical samples that are consistent with the current crane operation conditions but have different feedback current amplitudes are selected from the operating status data. Extract the corresponding historical current direction values ​​from the historical samples, and extract the historical reference direction of the historical samples under normal operating conditions; Calculate the difference in directional offset between the historical current direction and the historical reference direction; The directional offset differences corresponding to multiple historical samples are statistically processed to obtain the historical directional offset; the statistical processing includes at least one of weighted average, mean calculation or median calculation.

5. The adaptive diagnostic method for power distribution lines oriented towards fault location according to claim 1, characterized in that, The steps of calculating a direction correction factor based on the offset relationship between historical and current direction offsets, and then using this correction factor to correct the current direction to obtain the corrected current direction include: The orientation correction factor is calculated based on the relationship between the historical orientation offset and the current orientation offset. The spurious direction component caused by regenerative current disturbance in the current current direction is determined based on the direction correction factor; The false direction component is subtracted from the current current direction to obtain the corrected current direction, which is then used as the fault direction criterion for fault location.

6. An adaptive diagnostic system for power distribution lines oriented towards fault location, characterized in that, The system includes: The operation status identification module is used to acquire the operation status data of the bridge crane cluster and identify whether the current busbar is under regenerative current disturbance condition based on the operation status data. The historical sample processing module is used to select several historical samples from the operating status data that are consistent with the current crane operation conditions but have different feedback current amplitudes when the current busbar is identified as being under regenerative current disturbance conditions. The historical direction offset is obtained based on the difference between the historical current direction measured in the historical samples and the historical reference direction under normal operating conditions. The current offset calculation module is used to obtain the current current direction and calculate the current direction offset based on the current reference direction of the current bus under normal operating conditions. The direction correction module is used to calculate the direction correction factor based on the offset relationship between the historical direction offset and the current direction offset, and to use the direction correction factor to correct the current direction to obtain the corrected current direction. The fault section determination module is used to determine the fault section of the power distribution line based on the corrected current direction.

7. The adaptive diagnostic system for power distribution lines oriented towards fault location according to claim 6, characterized in that, The operation status identification module specifically includes: The operation data acquisition unit is used to acquire the operation status data of the bridge crane cluster. The operation status data includes the real-time voltage of the bridge crane cluster bus, as well as the lifting weight, lowering speed, drive motor operation mode, inverter feedback status, and the number of bridge cranes simultaneously in regenerative braking of each bridge crane. The operating condition analysis unit is used to analyze the operating status data and identify whether the bridge crane cluster is currently in regenerative braking mode. The disturbance judgment unit is used to obtain the hoisting weight, lowering speed and number of bridge cranes simultaneously under regenerative braking when the condition is identified as being under regenerative braking, and to determine whether the three factors meet the preset conditions that are sufficient to affect the direction of the bus current. The disturbance identification unit is used to identify the current bus operating state as a regenerative current disturbance condition when preset conditions are met.

8. The adaptive diagnostic system for power distribution lines oriented towards fault location according to claim 6, characterized in that, The preset conditions include at least one of the following: the lifting weight exceeds a preset weight threshold, the lowering speed exceeds a preset speed threshold, and the number of bridge cranes under regenerative braking exceeds a preset number threshold.

9. The adaptive diagnostic system for power distribution lines oriented towards fault location according to claim 8, characterized in that, The historical sample processing module specifically includes: The sample screening unit is used to select several historical samples from the operating status data that are consistent with the current crane operation conditions but have different feedback current amplitudes when the current busbar is identified as being under regenerative current disturbance conditions. The historical data extraction unit is used to extract the corresponding historical current direction value from the historical samples and extract the historical reference direction of the historical samples under normal operating conditions. The offset difference calculation unit is used to calculate the directional offset difference between the historical current direction and the historical reference direction; The offset generation unit is used to perform statistical processing on the directional offset differences corresponding to multiple historical samples to obtain historical directional offsets; the statistical processing includes at least one of weighted average, mean calculation or median calculation.

10. The adaptive diagnostic system for power distribution lines oriented towards fault location according to claim 9, characterized in that, The direction correction module specifically includes: The correction factor calculation unit is used to calculate the direction correction factor based on the offset relationship between the historical direction offset and the current direction offset; The false component identification unit is used to determine the false direction component caused by the regenerative current disturbance in the current current direction based on the direction correction factor; The direction correction unit is used to subtract the false direction component from the current current direction to obtain the corrected current direction, and uses the corrected current direction as the fault direction criterion for fault location.

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