Hydroelectric generating unit excitation carbon brush vibration and direct current cooperative monitoring method

Abstract

This invention discloses a method for coordinated monitoring of excitation carbon brush vibration and DC current in hydropower units, relating to the field of hydropower equipment operation monitoring technology. The method includes the following steps: collecting carbon brush vibration data and DC current data, aligning them according to a unified time scale, and selecting continuous time segments from the aligned data that simultaneously exhibit high-frequency vibration and low-frequency oscillation characteristics and whose DC current variation amplitude is below a preset fluctuation threshold, thus defining them as areas of concern for anomalies. This invention, through time alignment and coordinated analysis of vibration and DC current data, enables the identification of gradual changes in carbon brush contact status, revealing hidden anomalies with insignificant amplitudes. Furthermore, by constructing contact pressure change paths and delineating dangerous sections, risks are prioritized and key time locations are identified, thereby enabling early detection of carbon brush breakage risks and reducing the impact of unit operation anomalies.

Description

Technical Field

[0001] This invention relates to the field of hydropower equipment operation monitoring technology, specifically to a method for coordinated monitoring of excitation carbon brush vibration and DC current of hydropower units. Background Technology

[0002] Coordinated monitoring of excitation carbon brush vibration and DC current in hydro-generator units refers to an operational monitoring technology that, during the operation of a hydro-generator unit, focuses on the contact state between the carbon brush and the slip ring in the excitation system. This involves synchronously acquiring the mechanical vibration signal of the carbon brush and the DC current signal of the excitation circuit, and analyzing the temporal correspondence and changing trends of these two signals to achieve online identification and early warning of abnormalities in the carbon brush's operating status. Specifically, during long-term operation, carbon brushes may experience enhanced vibration due to factors such as wear, changes in spring pressure, poor contact, or arc discharge. Simultaneously, the DC current may fluctuate, experience increased pulsation, or exhibit localized distortion. By coordinating the interpretation of vibration amplitude changes and current fluctuation characteristics, it is possible to distinguish between simple mechanical disturbances and abnormal electrical contact, identifying problems such as carbon brush skipping, unstable contact, or obstructed current transmission.

[0003] The existing technology has the following shortcomings:

[0004] In existing technologies, the operating status of excitation carbon brushes is often judged based on a single vibration signal or a single DC current change. When the vibration signal simultaneously exhibits high-frequency, fragmented fluctuations and a low-frequency, slow oscillation trend, and the current only shows slight fluctuations, this type of composite change often has insignificant amplitude and rhythm, and existing monitoring methods easily mistake it for normal operating fluctuations and ignore it. In reality, such superimposed changes cause the contact pressure between the carbon brush and the slip ring to gradually shift over time, resulting in a continuous imbalance in the local stress state. This can easily lead to individual carbon brushes bearing excessive mechanical and current density loads for extended periods, resulting in hidden heat accumulation. Once the load fluctuates, the carbon brush may suddenly break, leading to excitation abnormalities or even the risk of unit shutdown.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a method for coordinated monitoring of vibration of excitation carbon brush and DC current in hydropower units, so as to solve the problems in the background art mentioned above.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for coordinated monitoring of vibration of excitation carbon brush and DC current of hydropower unit, comprising the following steps:

[0008] Collect carbon brush vibration data and DC current data, and align them according to a unified time scale. Select continuous time segments from the aligned data that simultaneously exhibit high-frequency jitter and low-frequency oscillation characteristics and whose DC current variation is below a preset fluctuation threshold, and identify them as abnormal areas of interest.

[0009] Based on the scope of interest in anomalies, the vibration fluctuation density, swing direction and current change amplitude are extracted at each time location and organized in chronological order to construct an offset result that reflects the process of contact force change.

[0010] Based on the offset results, the locations where the contact pressure changes from concentration to expansion and then to aggravation along the time progression are identified, and dangerous sections where the carbon brush load continues to increase are delineated based on the locations of the changes;

[0011] The focus of operation is adjusted in chronological order around the dangerous sections. By suppressing the accumulation of high-frequency jitter and limiting the repeated impact of low-frequency oscillation on the contact position, the force changes corresponding to the offset results are adjusted.

[0012] Based on the adjusted changes, the vibration and current changes in the danger zone were continuously compared, and the risk levels were reordered along the time progression to determine the critical time location where the carbon brush would break.

[0013] Preferably, the steps for determining the scope of abnormal concern are as follows:

[0014] Collect carbon brush vibration data and DC current data, divide the continuous time scale position according to a unified time scale, and map the carbon brush vibration data and DC current data to the same time axis to form aligned data corresponding to each point;

[0015] Extract the vibration value changes at each time scale position in the aligned data, decompose the vibration value into high-frequency jitter features and low-frequency oscillation features, and simultaneously read the DC current change amplitude at the corresponding time scale position to form a composite feature record containing vibration change information and current change information.

[0016] Select time scale positions in composite feature records that simultaneously possess high-frequency jitter characteristics, low-frequency oscillation characteristics, and DC current change amplitude below a preset fluctuation threshold, and connect consecutively arranged time scale positions into continuous time segments.

[0017] Record the start and end time scale positions of continuous time segments, and maintain a point-by-point correspondence between the carbon brush vibration data and DC current data within the continuous time segments to identify the areas of interest for abnormality.

[0018] Preferably, the offset result construction steps are as follows:

[0019] Expand the time scale position within the abnormal interest range, read the corresponding carbon brush vibration data and DC current data, and form a continuous time scale sequence;

[0020] Extract the changes in carbon brush vibration data at each time scale position, record the changes in vibration values ​​between adjacent time scale positions, and form the vibration fluctuation density;

[0021] Organize the direction of vibration value changes between continuous time scale positions to determine the corresponding oscillation direction;

[0022] Read the DC current data at each time scale position, record the current value difference between adjacent time scale positions, and form the current change amplitude;

[0023] By integrating the vibration fluctuation density, oscillation direction, and current change amplitude, and arranging them in chronological order, an offset result reflecting the process of contact force change is formed.

[0024] Preferably, the vibration fluctuation density is formed by recording the number of increases and decreases in vibration values ​​at adjacent time scale positions, the oscillation direction is determined by the increasing and decreasing states of vibration values ​​at continuous time scale positions, and the current change amplitude is formed by the difference in DC current values ​​at adjacent time scale positions and associated with the corresponding time scale positions one by one.

[0025] Preferably, the steps for delineating dangerous sections are as follows:

[0026] Read the vibration fluctuation density, swing direction and current change amplitude corresponding to each time scale position in the offset result, arrange them in time order, and compare the offset state of adjacent time scale positions. Mark the time scale position where the vibration fluctuation density is concentrated and the swing direction is consistent as the position where the contact pressure begins to concentrate.

[0027] Continue the time sequence to expand the offset state, record the changes in the distribution range of vibration fluctuation density and the distribution of swing direction, and mark the time scale position where the vibration fluctuation density and swing direction extend outward at the same time as the contact pressure continues to expand.

[0028] Continue to organize the offset state along the time axis, compare the continuous changes in vibration fluctuation density and the changes in current amplitude, and mark the time scale position where the vibration fluctuation density accumulates continuously and the current amplitude changes synchronously as the position where the contact pressure gradually increases.

[0029] Connect the points where the contact pressure begins to concentrate, the points where the contact pressure continues to expand, and the points where the contact pressure gradually increases to form a continuous interval, and retain the offset results of the corresponding time scale positions;

[0030] Collect all time scale positions within a continuous interval, identify the dangerous sections, and record the start and end time scale positions of the dangerous sections.

[0031] Preferably, the location where the contact pressure begins to concentrate is determined by the concentrated distribution of vibration fluctuation density at a continuous time scale position and the consistent swing direction; the location where the contact pressure continues to expand is determined by the expansion of the vibration fluctuation density distribution range and the change in the swing direction distribution range; and the location where the contact pressure gradually intensifies is determined by the continuous change of vibration fluctuation density and the synchronous change of current amplitude.

[0032] Preferably, the force change adjustment steps are as follows:

[0033] Expand the offset results corresponding to each time scale position within the danger zone, read the vibration fluctuation density, swing direction and current change amplitude, and arrange them in time order to form a continuous change path;

[0034] The process handles the changes in vibration fluctuation density in a continuously changing path, records the relationship between adjacent time scale positions, divides the continuously occurring vibration fluctuation density into cumulative segments, and adjusts the distribution position of vibration fluctuation density to form an intermittent distribution state.

[0035] The changes in the swing direction in a continuously changing path are analyzed, the continuous and consistent swing direction is divided into segments, the distribution of the swing direction is adjusted, and the swing direction is correlated with the current change amplitude to form the adjusted offset result.

[0036] Preferably, during the adjustment of the vibration fluctuation density distribution position, the vibration fluctuation density change within the continuous time scale position is divided into segments, and the vibration fluctuation density within the same segment is rearranged in chronological order, while maintaining the correspondence between each time scale position, so as to form a dispersed distribution structure.

[0037] Preferably, the steps for determining the key time location are as follows:

[0038] The changes after adjustment within the danger zone are analyzed, and the vibration fluctuation density, swing direction, and current change amplitude at each time scale position are read and arranged in chronological order to form a continuous corresponding sequence.

[0039] Organize the correspondence between vibration fluctuation density and current change amplitude in continuous corresponding sequences, and record the point-by-point changes in swing direction to form a corresponding distribution structure;

[0040] The positions of each time scale in the sorting correspondence distribution structure are arranged according to the synchronous changes in vibration fluctuation density and current change amplitude to form a risk level sorting sequence;

[0041] By connecting the time scale positions at the beginning of the risk level ranking sequence, the corresponding vibration fluctuation density, oscillation direction, and current change amplitude are recorded to determine the critical time position when the carbon brush breaks.

[0042] Preferably, during the formation of the risk level ranking sequence, the corresponding relationship between each time scale position is determined based on the continuity of vibration fluctuation density change, the consistency of current change amplitude change, and the trajectory of swing direction change. The time scale positions where vibration fluctuation density change and current change amplitude change occur synchronously are given priority, thus limiting the range of determination of key time positions.

[0043] The technical effects and advantages provided by the present invention in the above technical solution are as follows:

[0044] This invention aligns carbon brush vibration data and DC current data with a unified time scale, and performs screening and correlation analysis on the composite changes of high-frequency jitter characteristics and low-frequency oscillation characteristics. This establishes a correspondence between vibration changes and current changes in the time dimension, thereby enabling the identification of continuous change processes with insignificant amplitudes. This allows for the continuous characterization of gradual changes in the carbon brush contact state. Compared to single-signal judgment methods, this invention can detect contact force shift trends earlier and improve the ability to perceive hidden abnormal states.

[0045] This invention constructs a contact pressure change path based on the offset results, and by delineating dangerous sections and adjusting the time sequence of force changes, it enables vibration and current changes to form a controllable evolution process within the dangerous sections. On this basis, the risk level is reordered and key time positions are locked, thereby realizing the early location of potential carbon brush breakage risks. This helps guide targeted interventions during operation and reduces the impact of sudden anomalies on unit operation. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0047] Figure 1 This is a flowchart of a method for coordinating monitoring of vibration of excitation carbon brush and DC current in a hydroelectric generator unit according to the present invention. Detailed Implementation

[0048] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art.

[0049] This invention provides, for example Figure 1 The method for coordinated monitoring of excitation carbon brush vibration and DC current in a hydropower unit includes the following steps:

[0050] Collect carbon brush vibration data and DC current data, and align them according to a unified time scale. Select continuous time segments from the aligned data that simultaneously exhibit high-frequency jitter and low-frequency oscillation characteristics and whose DC current variation is below a preset fluctuation threshold, and identify them as abnormal areas of interest.

[0051] During the continuous operation of a hydroelectric generator unit, the contact state between the carbon brush and the slip ring changes constantly over time. A correlation exists between vibration performance and current changes. By organizing the vibration performance and current changes over a unified time frame and selecting specific combinations of features, time intervals reflecting the abnormal evolution of the contact state can be separated from continuous operating data, thus providing a stable data source for subsequent analysis. The specific implementation steps are as follows:

[0052] During carbon brush operation, carbon brush vibration data and DC current data are continuously recorded. The collected carbon brush vibration data is divided into continuous sampling points according to a fixed time interval, and the DC current data is divided into corresponding sampling points according to the same time interval. The carbon brush vibration data and DC current data are mapped to the same time axis through a unified time scale, so that each time scale position corresponds to a set of carbon brush vibration data and DC current data. In the process of dividing the time scale, the continuous running time is divided into segments according to a preset time interval, and the start time of each segment is used as a time marker. The carbon brush vibration data and DC current data are respectively assigned to the corresponding time marker positions, so that the carbon brush vibration data and DC current data form a point-to-point correspondence in the time dimension, thereby obtaining aligned data with a unified time scale.

[0053] Based on the aligned data, the carbon brush vibration data at each time scale position is further subdivided. The carbon brush vibration data is split along the time axis into a rapidly changing part and a slowly changing part. The rapidly changing part is extracted by comparing the vibration value changes between adjacent time scales to reflect the continuous fluctuations, reflecting the high-frequency jitter characteristics. The slowly changing part is extracted by observing the overall trend of the vibration value changes within multiple consecutive time scales to reflect the low-frequency oscillation characteristics. After completing the vibration data division, the DC current data corresponding to the same time scale position is correlated with the vibration data. The change value of DC current data between adjacent time scales is read point by point, and the change range is recorded. The high-frequency jitter characteristics and low-frequency oscillation characteristics in the vibration data are combined and organized with the DC current change values ​​of the corresponding time scales, so that each time scale position forms a composite feature record that simultaneously contains vibration change information and current change information.

[0054] For all time scale positions that have formed composite feature records, they are filtered point by point in chronological order. During the filtering process, each time scale position is judged to meet three conditions simultaneously: the presence of high-frequency jitter characteristics, the presence of low-frequency oscillation characteristics, and the DC current change amplitude being lower than a preset fluctuation threshold. When the same time scale position meets the above three conditions, the time scale position is marked as the target time point, and the subsequent time scale positions are judged to continuously meet the same conditions along the time axis. When multiple consecutive time scale positions meet the above three conditions, these time scale positions are connected in chronological order to form a continuous time segment. During the connection process, only the target time points that are uninterruptedly arranged on the time axis are retained. Time scale positions that do not meet the conditions in the middle are not included in the connection range, so that each continuous time segment is composed of time scale positions that continuously meet the conditions, thereby ensuring that the continuous time segment can completely reflect the continuous process of the synchronous occurrence of vibration composite changes and current changes.

[0055] Each continuous time segment is systematically organized, with its start and end time scale positions on the time axis recorded. All time scale positions within the continuous time segment are then grouped into the same identifier range. Each continuous time segment is numbered as an independent interval, ensuring that each interval corresponds to a complete time range. Simultaneously, the point-to-point correspondence between the corresponding carbon brush vibration data and DC current data is preserved within each interval, maintaining a consistent time structure with the aligned data. Through this process, each interval contains not only continuous time information but also complete vibration and current composite characteristics, thus identifying each interval as an area of ​​anomaly interest. This provides a continuous and clearly defined data foundation for subsequent force change analysis around this area of ​​anomaly interest.

[0056] Based on the scope of interest in anomalies, the vibration fluctuation density, swing direction and current change amplitude are extracted at each time location and organized in chronological order to construct an offset result that reflects the process of contact force change.

[0057] Given a defined area of ​​concern, to transform the temporal changes in the carbon brush contact state within this area into a continuously expressible result, the vibration and current changes at various time points within the area of ​​concern are analyzed point-by-point. A unified time sequence is used to establish the correspondence between multiple features, thereby generating an offset result that reflects the changes in contact force. The specific implementation steps are as follows:

[0058] From the starting time scale to the ending time scale of the area of ​​interest on the time axis, all time scale positions covered by this area are expanded sequentially. For each time scale position, the corresponding carbon brush vibration data and DC current data are read, and the reading results are arranged in chronological order to form a continuous time series. During the arrangement process, the original time interval relationship between each time scale position is kept unchanged, so that the continuous correspondence between adjacent time scale positions in the time series is maintained. At the same time, an independent recording unit is established at each time scale position, so that each recording unit contains the carbon brush vibration data and DC current data corresponding to that time scale position. This forms a complete time scale sequence structure covering the area of ​​interest, providing a continuous data foundation for subsequent extraction of vibration fluctuation density, oscillation direction, and current change amplitude at each time scale position.

[0059] For each time scale position in the time scale sequence, the corresponding carbon brush vibration data is processed point by point. The vibration values ​​of the current time scale position are continuously compared with those of the previous and next time scale positions. By recording the number of times the vibration value increases or decreases between adjacent time scales, the position of each change is marked, and the order of the changes is recorded in chronological order. At the same time, the total number of changes in the vibration value within a unit time range is counted, and the number of changes is bound to the corresponding time range, so that each time scale position forms a set of fluctuation records reflecting the frequency of vibration changes. Based on this, all the change records within the time range corresponding to the same time scale position are summarized, so that the time scale position corresponds to a complete vibration fluctuation density description, so that the vibration fluctuation density can specifically reflect the contact fluctuation process of the carbon brush at that time position.

[0060] Using the same time scale sequence, the vibration change trend at each time scale position is continuously unfolded. By selecting the vibration values ​​at the current time scale position and several consecutive time scale positions before and after it, the direction of change of the vibration values ​​on the time axis is determined segment by segment. When the vibration values ​​at several consecutive time scale positions increase, it is recorded as one direction state; when the vibration values ​​at several consecutive time scale positions decrease, it is recorded as another direction state. The time scale positions where the direction state changes are marked separately. At the same time, the direction state within the time range of each time scale position is classified, so that each time scale position has clear swing direction information. The swing direction information is bound to the corresponding time scale position, so that the overall trend of vibration change is continuously expressed on the time axis.

[0061] After extracting the vibration fluctuation density and oscillation direction point by point, the DC current data in the same time scale sequence is processed point by point. The DC current value at the current time scale position is compared with the DC current value at the previous time scale position, and the difference between the two is recorded. This difference is used as the current change amplitude at the current time scale position. At the same time, the current change direction between adjacent time scales is recorded. The current value increases are marked as one type of change, and the current value decreases are marked as another type of change. The current change amplitude and change direction are included in the recording unit of the current time scale position, so that each time scale position has complete current change information. After processing all time scale positions, the current change amplitude, vibration fluctuation density, and oscillation direction are integrated at the same time scale position, so that the three types of features form a point-by-point correspondence on the time axis.

[0062] After extracting and integrating the vibration fluctuation density, oscillation direction, and current variation amplitude at all time scale positions, the three types of features at each time scale position are arranged continuously in chronological order, while maintaining the original order between time scales. By expanding the three types of features at continuous time scale positions as a whole, the changes in vibration fluctuation density, oscillation direction, and current variation amplitude are made to form a continuous connection on the time axis. The above continuous connection is then organized into a sequence structure that changes continuously over time. This transforms the multi-feature change process within the abnormal focus area into an offset result that reflects the change process of contact force, so that the offset result fully records the continuous change of the carbon brush contact state over time within the abnormal focus area.

[0063] Based on the offset results, the locations where the contact pressure changes from concentration to expansion and then to aggravation along the time progression are identified, and dangerous sections where the carbon brush load continues to increase are delineated based on the locations of the changes;

[0064] After obtaining the offset results, the process of carbon brush contact state changing over time is refined segment by continuously expanding the offset results on the time axis. The location of the change in contact pressure from concentration to expansion and then to intensification is identified in the time dimension, thus forming a clear division of the carbon brush load variation range. The specific implementation steps are as follows:

[0065] Following the order of the offset results on the time axis, the vibration fluctuation density, swing direction, and current change amplitude corresponding to each time scale position are read point by point. The offset state of the current time scale position is compared with that of the previous time scale position. During the comparison process, the distribution of vibration fluctuation density in continuous time scale positions is expanded. When the vibration fluctuation density of multiple adjacent time scale positions appears in the same time range and the swing direction changes in a consistent manner within the time range, the corresponding time scale position is marked as the starting point of the contact pressure concentration position. At the same time, the specific order of the time scale position in the time axis is recorded, so that the initial change of contact pressure is clearly marked in the time dimension.

[0066] Around the marked point where the contact pressure begins to concentrate, the offset results of subsequent time scale positions are continuously expanded according to the time progression direction. The distribution range of vibration fluctuation density in subsequent time scale positions is recorded segment by segment. By comparing the change in the coverage range of vibration fluctuation density in the current time scale position with that in the previous time scale position, the process of vibration fluctuation density gradually extending from a single area to adjacent areas is identified. At the same time, the trajectory of the change in the swing direction in continuous time scale positions is tracked, and the distribution range of the swing direction in multiple time scale positions is organized. When the distribution range of vibration fluctuation density and the change range of swing direction both show an outward extension on the time axis, the corresponding time scale position is marked as the contact pressure continuous expansion position. These time scale positions are continuously recorded in chronological order, so that the contact pressure expansion process forms a continuous segment on the time axis.

[0067] For the time segment where the contact pressure has been continuously expanding, the subsequent time scale positions are processed point by point along the time axis. The changes in vibration fluctuation density at each time scale position are gradually accumulated and recorded. The vibration fluctuation density at each time scale position is compared with the vibration fluctuation density at the previous time scale position, and the continuous changes in vibration fluctuation density on the time axis are recorded. At the same time, the changes in current amplitude at the corresponding time scale position are synchronously unfolded. The changes in current amplitude at each time scale position are recorded point by point in chronological order. When the vibration fluctuation density shows a continuous cumulative change at multiple consecutive time scale positions, and the current amplitude changes synchronously at the same time scale position, these time scale positions are marked as positions where the contact pressure gradually intensifies. The marking results are arranged in chronological order so that the contact pressure intensification process forms a continuous distribution on the time axis.

[0068] After identifying the locations where contact pressure begins to concentrate, continues to expand, and gradually intensifies, the three types of change locations are organized in chronological order. The time scale positions corresponding to each type of change location are continuously connected, with the location where contact pressure begins to concentrate as the starting segment, the location where contact pressure continues to expand as the middle segment, and the location where contact pressure gradually intensifies as the subsequent segment. The connection between the three types of change locations on the time axis is maintained, so that the process of contact pressure changing from concentration to expansion to intensification forms a complete and continuous interval on the time axis. At the same time, the offset result corresponding to each time scale position is retained within this continuous interval, so that the change process within this interval can fully reflect the coordinated changes in vibration fluctuation density, oscillation direction, and current change amplitude.

[0069] After constructing the continuous interval, the offset results corresponding to each time scale position within the continuous interval are classified as a whole. All time scale positions, including the positions where contact pressure begins to concentrate, the positions where contact pressure continues to expand, and the positions where contact pressure gradually intensifies, are uniformly designated as dangerous sections. The start and end time scale positions of the dangerous sections on the time axis are clearly marked, so that the dangerous sections form a time range with clear boundaries. At the same time, the point-to-point correspondence between vibration fluctuation density, oscillation direction, and current change amplitude is retained within the dangerous sections, so that the dangerous sections can fully reflect the change process of carbon brush load continuously increasing over time, thereby providing continuous and locatable time basis for subsequent processing.

[0070] The focus of operation is adjusted in chronological order around the dangerous sections. By suppressing the accumulation of high-frequency jitter and limiting the repeated impact of low-frequency oscillation on the contact position, the force changes corresponding to the offset results are adjusted.

[0071] Given a clearly defined timeframe for the hazardous zone, the offset results within the hazardous zone are analyzed point-by-point along a chronological order. By combining this with the correlation between vibration and current changes on the time axis, targeted adjustments are made to the force change process, thereby redistributing the contact state's change path over time. The specific steps are as follows:

[0072] Along the time scale from the start to the end of the dangerous section, all time scale positions within the dangerous section are read point by point. The offset result corresponding to each time scale position is expanded into three types of information: vibration fluctuation density, swing direction, and current change amplitude. These are then arranged continuously in chronological order, maintaining a consistent time interval between each time scale position. This creates a complete and continuous sequence of offset result changes for the entire dangerous section. Within this sequence, the changes in vibration fluctuation density between adjacent time scale positions are compared point by point. Simultaneously, the trajectory of the swing direction change in the continuous time scale is recorded segment by segment, and the changes in current change amplitude on the time axis are synchronously expanded. Through this process, the offset results within the dangerous section are reorganized according to the development process of force changes, creating a sequential change path for vibration fluctuation density, swing direction, and current change amplitude on the time axis. This allows for the adjustment of operational focus along the time sequence, ensuring that each time scale position has a clear sequential position within this change path.

[0073] Based on the offset results of the established time-series change path, the change process of vibration fluctuation density in continuous time scale positions is processed segment by segment. The vibration fluctuation density at each time scale position is compared with the vibration fluctuation density at the previous time scale position. The direction and number of changes of vibration fluctuation density on the time axis are recorded. The repeated occurrence of vibration fluctuation density in continuous time scale positions is marked point by point. For vibration fluctuation density changes that occur continuously in multiple adjacent time scale positions, they are divided into cumulative segments within the same time range. Within the cumulative segment, the vibration fluctuation density at each time scale position is redistributed. By changing the distribution position of vibration fluctuation density on the time axis, the vibration fluctuation density changes that originally occurred concentrated in continuous time scale positions are dispersed to different time scale positions, thereby interrupting the continuous superposition process of vibration fluctuation density on the time axis. This makes the vibration fluctuation density present an intermittent distribution state in the entire danger zone. The adjusted vibration fluctuation density is rewritten into the offset results of the corresponding time scale position, thereby suppressing the high-frequency jitter accumulation process.

[0074] After the vibration fluctuation density distribution adjustment is completed, the oscillation direction in the same time sequence change path is processed point by point. The oscillation direction at each time scale position is compared with the oscillation direction at adjacent time scale positions, and the change of the oscillation direction on the time axis is recorded. The time period in which the oscillation direction remains consistent in consecutive time scale positions is marked. The time period in which the oscillation direction acts continuously in the same direction is divided into repeated action segments. Within the repeated action segment, the distribution position of the oscillation direction is readjusted. By changing the position of the oscillation direction on the time axis, the oscillation direction no longer acts continuously on the same contact position in adjacent time scale positions, but alternates between different time scale positions, thereby weakening the continuous influence of the oscillation direction on the same contact position. At the same time, the adjusted oscillation direction is re-correlated with the current change amplitude at the corresponding time scale position, so that the change relationship of the current change amplitude on the time axis is consistent with the adjusted oscillation direction. Finally, a new correspondence is formed between the vibration fluctuation density, oscillation direction, and current change amplitude on the time axis, thus completing the entire process of adjusting the force change corresponding to the offset result.

[0075] To fully understand the specific implementation of this process, the following example further illustrates the details: Assume that within a certain dangerous section, the time scale is from t1 to t10, with corresponding vibration fluctuation densities of 12, 15, 18, 22, 25, 27, 30, 32, 35, and 38, respectively. The oscillation direction remains the same from t1 to t5, and switches to another direction from t6 to t10. The current variation amplitudes are 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, and 1.2, respectively. After performing a time-series expansion of this dangerous section, the above three types of data are arranged in chronological order to form a sequence of shift results. When identifying the cumulative process of vibration fluctuation density, it is found that the vibration fluctuation density continuously increases and the number of changes is dense within the time scale from t3 to t8. Therefore, t3 to t8 is classified as high-frequency vibration. The system accumulates vibrations in a specific segment and redistributes the vibration density within that segment. For example, the previously consecutive sequence of 18, 22, 25, 27, 30, 32 is adjusted to 18, 25, 22, 30, 27, 32, resulting in an intermittent distribution of vibration changes on the time axis. The oscillation direction is then processed, identifying t1 to t5 as a segment with continuous action in the same direction. By changing the action sequence, the original directional distribution is adjusted so that t1, t3, t5 are the original directions, while t2 and t4 are inserted in another direction, preventing continuous action in the same direction. After these adjustments, the adjusted vibration density and oscillation direction are re-correlated to the respective time scale positions, maintaining the original time sequence of current variation amplitudes from 0.3 to 1.2, thus establishing a new correspondence among the three types of data and adjusting the force changes corresponding to the offset results.

[0076] Based on the adjusted changes, the vibration and current changes in the danger zone were continuously compared, and the risk levels were reordered along the time progression to determine the critical time location where the carbon brush broke.

[0077] After adjusting for stress changes in the hazardous area, the adjusted changes are continuously analyzed. By combining the correlation between vibration and current changes on the time axis, the changes in the carbon brush's operating state over time are analyzed point-by-point. This allows for a re-prioritization of risk levels and the clear identification of critical time points. The specific implementation steps are as follows:

[0078] Along the time scale from the start to the end of the dangerous section, the adjusted changes are analyzed point by point. The vibration fluctuation density, swing direction, and current change amplitude corresponding to each time scale position are read and arranged in chronological order, forming a continuous sequence on the time axis. In this sequence, the vibration fluctuation density of the current time scale position is compared point by point with that of the previous time scale position, and the changes in vibration fluctuation density on the time axis are recorded. At the same time, the change trajectory of the swing direction in the continuous time scale positions is recorded segment by segment, and the changes in current change amplitude between adjacent time scale positions are analyzed point by point, so that each time scale position has complete vibration change information and current change information. Through the above processing, a continuous corresponding sequence containing vibration fluctuation density, swing direction, and current change amplitude is formed within the dangerous section, thus completing the preparation process for continuous comparison of vibration changes and current changes.

[0079] Given the established continuous correspondence sequence, the relationship between vibration and current changes at each time scale position is analyzed point by point. The vibration fluctuation density is compared with the current change amplitude at the corresponding time scale position, and the change in the swing direction at that time scale position is considered. The corresponding state between vibration and current changes is recorded. By continuously comparing the corresponding states between adjacent time scale positions, cases where the vibration fluctuation density change and current change amplitude change simultaneously at the same time scale position are marked. Cases where the vibration fluctuation density change and current change amplitude change do not appear synchronously on the time axis are recorded separately. In this process, all time scale positions are classified according to the changes in the correspondence, so that a time distribution structure based on the correspondence between vibration and current changes is formed within the danger zone, thus making the correspondence between each time scale position clearly distinguishable.

[0080] After establishing the corresponding time distribution structure, each time scale position is organized point by point along the time progression direction. The order of each time scale position in the time series is recorded. Combined with the number of changes in vibration fluctuation density in continuous time scale positions, the trajectory of change in oscillation direction in continuous time scale positions, and the change in current amplitude on the time axis, the change state of each time scale position is uniformly organized. During the organization process, the time scale positions where the changes in vibration fluctuation density and current amplitude are synchronous in continuous time scale positions are arranged first in chronological order, and the time scale positions where the changes in vibration fluctuation density and current amplitude are discontinuous in chronological order are arranged last in chronological order. This makes all time scale positions form a new sorting order on the time axis according to the degree of risk development, thereby completing the reordering of risk degree along the time progression direction.

[0081] After ranking the risk levels, the time scale positions are expanded segment by segment. The time scale positions at the beginning of the ranking are connected continuously, and the vibration fluctuation density, oscillation direction, and current change amplitude corresponding to these time scale positions are expanded point by point. By recording the changes in vibration fluctuation density, oscillation direction, and current change amplitude segment by segment in the continuous time scale positions, the time range in which vibration changes and current changes occur continuously on the time axis is marked, and the start and end time scale positions within this time range are determined. This time range is then used as the critical time position for carbon brush breakage, so that the critical time position forms a continuous interval with clear time boundaries within the danger zone, providing a specific basis for the time positioning of carbon brush operation risks.

[0082] This invention aligns carbon brush vibration data and DC current data with a unified time scale, and performs screening and correlation analysis on the composite changes of high-frequency jitter characteristics and low-frequency oscillation characteristics. This establishes a correspondence between vibration changes and current changes in the time dimension, thereby enabling the identification of continuous change processes with insignificant amplitudes. This allows for the continuous characterization of gradual changes in the carbon brush contact state. Compared to single-signal judgment methods, this invention can detect contact force shift trends earlier and improve the ability to perceive hidden abnormal states.

[0083] This invention constructs a contact pressure change path based on the offset results, and by delineating dangerous sections and adjusting the time sequence of force changes, it enables vibration and current changes to form a controllable evolution process within the dangerous sections. On this basis, the risk level is reordered and key time positions are locked, thereby realizing the early location of potential carbon brush breakage risks. This helps guide targeted interventions during operation and reduces the impact of sudden anomalies on unit operation.

[0084] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for monitoring the vibration and DC current of the excitation carbon brush of a hydroelectric generating unit, characterized in that, Includes the following steps: Collect carbon brush vibration data and DC current data, and align them according to a unified time scale. Select continuous time segments from the aligned data that simultaneously exhibit high-frequency jitter and low-frequency oscillation characteristics and whose DC current variation is below a preset fluctuation threshold, and identify them as abnormal areas of interest. Based on the scope of interest in anomalies, the vibration fluctuation density, swing direction and current change amplitude are extracted at each time location and organized in chronological order to construct an offset result that reflects the process of contact force change. Based on the offset results, the locations where the contact pressure changes from concentration to expansion and then to intensification along the time progression direction are identified, and dangerous sections where the carbon brush load continues to increase are delineated based on the locations of the changes; The focus of operation is adjusted in chronological order around the dangerous sections. By suppressing the accumulation of high-frequency jitter and limiting the repeated impact of low-frequency oscillation on the contact position, the force changes corresponding to the offset results are adjusted. Based on the adjusted changes, the vibration changes and current changes in the danger zone were continuously compared, and the risk level was reordered along the time progression to determine the critical time location where the carbon brush broke. The steps for determining the scope of abnormal concerns are as follows: Collect carbon brush vibration data and DC current data, divide the continuous time scale position according to a unified time scale, and map the carbon brush vibration data and DC current data to the same time axis to form aligned data corresponding to each point; Extract the vibration value changes at each time scale position in the aligned data, decompose the vibration value into high-frequency jitter features and low-frequency oscillation features, and simultaneously read the DC current change amplitude at the corresponding time scale position to form a composite feature record; Filter the time scale positions in composite feature records that simultaneously possess high-frequency jitter characteristics, low-frequency oscillation characteristics, and DC current change amplitude below a preset fluctuation threshold, and connect the consecutively arranged time scale positions into a continuous time segment. Record the start and end time scale positions of continuous time segments, maintain a point-by-point correspondence between the carbon brush vibration data and DC current data within the continuous time segments, and identify the abnormal areas of concern. The steps for constructing the offset result are as follows: Expand the time scale position within the abnormal interest range, read the corresponding carbon brush vibration data and DC current data, and form a continuous time scale sequence; Extract the changes in carbon brush vibration data at each time scale position, record the changes in vibration values ​​between adjacent time scale positions, and form the vibration fluctuation density; Organize the direction of vibration value changes between continuous time scale positions to determine the corresponding oscillation direction; Read the DC current data at each time scale position, record the current value difference between adjacent time scale positions, and form the current change amplitude; By integrating the vibration fluctuation density, oscillation direction, and current change amplitude, and arranging them in chronological order, an offset result reflecting the process of contact force change is formed; The steps for delineating dangerous sections are as follows: Read the vibration fluctuation density, swing direction and current change amplitude corresponding to each time scale position in the offset result, arrange them in time order, and compare the offset state of adjacent time scale positions. Mark the time scale position where the vibration fluctuation density is concentrated and the swing direction is consistent as the position where the contact pressure begins to concentrate. Continue the time sequence to expand the offset state, record the changes in the distribution range of vibration fluctuation density and the distribution of swing direction, and mark the time scale position where the vibration fluctuation density and swing direction extend outward at the same time as the contact pressure continues to expand. Continue to organize the offset state along the time axis, compare the continuous changes in vibration fluctuation density and the changes in current amplitude, and mark the time scale position where the vibration fluctuation density accumulates continuously and the current amplitude changes synchronously as the position where the contact pressure gradually increases. Connect the points where the contact pressure begins to concentrate, the points where the contact pressure continues to expand, and the points where the contact pressure gradually increases to form a continuous interval, and retain the offset results of the corresponding time scale positions; Collect all time scale positions within a continuous interval, identify the dangerous sections, and record the start and end time scale positions of the dangerous sections.

2. The method for monitoring the vibration and DC current of the excitation carbon brush of a hydroelectric generating set according to claim 1, characterized in that, The vibration fluctuation density is formed by recording the number of increases and decreases in vibration values ​​at adjacent time scale positions. The oscillation direction is determined by the increasing and decreasing states of vibration values ​​at continuous time scale positions. The current change amplitude is formed by the difference in DC current values ​​at adjacent time scale positions and is associated with the corresponding time scale positions one by one.

3. The method for coordinated monitoring of excitation carbon brush vibration and DC current in a hydropower unit according to claim 1, characterized in that, The location where the contact pressure begins to concentrate is determined by the concentrated distribution of vibration fluctuation density at a continuous time scale position and the consistent swing direction. The location where the contact pressure continues to expand is determined by the expansion of the distribution range of vibration fluctuation density and the change in the distribution range of swing direction. The location where the contact pressure gradually intensifies is determined by the continuous change of vibration fluctuation density and the synchronous change of current amplitude.

4. The method for coordinated monitoring of excitation carbon brush vibration and DC current of a hydroelectric generator according to claim 1, characterized in that, The steps for adjusting for changes in force are as follows: Expand the offset results corresponding to each time scale position within the danger zone, read the vibration fluctuation density, swing direction and current change amplitude, and arrange them in time order to form a continuous change path; The process handles the changes in vibration fluctuation density in a continuously changing path, records the relationship between adjacent time scale positions, divides the continuously occurring vibration fluctuation density into cumulative segments, and adjusts the distribution position of vibration fluctuation density to form an intermittent distribution state. The changes in the swing direction in a continuously changing path are analyzed, the continuous and consistent swing direction is divided into segments, the distribution of the swing direction is adjusted, and the swing direction is correlated with the current change amplitude to form the adjusted offset result.

5. The method for coordinated monitoring of excitation carbon brush vibration and DC current in a hydropower unit according to claim 4, characterized in that, During the adjustment of the vibration fluctuation density distribution position, the vibration fluctuation density change within the continuous time scale position is divided into segments, and the vibration fluctuation density within the same segment is rearranged in chronological order, while keeping the correspondence between the time scale positions unchanged, so as to form a dispersed distribution structure.

6. The method for coordinated monitoring of excitation carbon brush vibration and DC current of a hydroelectric generator according to claim 4, characterized in that, The steps for determining the key time location are as follows: The changes after adjustment within the danger zone are analyzed, and the vibration fluctuation density, swing direction, and current change amplitude at each time scale position are read and arranged in chronological order to form a continuous corresponding sequence. Organize the correspondence between vibration fluctuation density and current change amplitude in continuous corresponding sequences, and record the point-by-point correspondence distribution structure in combination with the change of swing direction; The positions of each time scale in the sorting correspondence distribution structure are arranged according to the synchronous changes in vibration fluctuation density and current change amplitude to form a risk level sorting sequence; By connecting the time scale positions at the beginning of the risk level ranking sequence, the corresponding vibration fluctuation density, oscillation direction, and current change amplitude are recorded to determine the critical time position when the carbon brush breaks.

7. The method for coordinated monitoring of excitation carbon brush vibration and DC current in a hydropower unit according to claim 6, characterized in that, During the formation of the risk level ranking sequence, the correspondence between each time scale position is determined based on the continuity of vibration fluctuation density change, the consistency of current change amplitude change, and the trajectory of swing direction change. The time scale positions where vibration fluctuation density change and current change amplitude change occur synchronously are prioritized, thus limiting the range of determination of key time positions.

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