A method for accurately measuring the opening and closing time of a disconnecting switch

Abstract

This invention relates to the field of online detection and condition monitoring technology for power system switchgear, and discloses a method for accurately measuring the opening and closing time of disconnecting switches. By synchronously collecting voltage data on both sides of the disconnecting switch to construct a voltage difference sequence, the action interval is extracted through differential and sliding window energy analysis. Within this interval, differential features are used to determine the action index and convert it into the action time. The average voltage difference before and after the action time is calculated to determine the action type. The stability of the action time is evaluated by combining a reference action time and statistical analysis of multiple measurement deviations. Simultaneously, key data from the entire process are compiled into an identifiable dataset. Through these steps, the measurement of the opening and closing behavior and action time of disconnecting switches is achieved, overcoming the problems of asynchronous single-sided sampling or mechanical triggering, poor reliability of threshold and zero-crossing detection, and difficulty in quantifying time stability, thus providing an improved means for disconnecting switch condition assessment without adding complex hardware.

Description

Technical Field

[0001] This invention relates to the field of online detection and condition monitoring technology for power system switching equipment, specifically a method for accurately measuring the opening and closing time of disconnecting switches. Background Technology

[0002] Currently, disconnecting switches, as crucial devices in power systems used to establish clear line disconnections and ensure safe isolation, directly impact the safety of system operation and the reliability of fault handling through their opening and closing times. On-site engineering projects typically require quantitative assessments of the opening and closing processes of disconnecting switches to determine factors such as mechanism aging, spring energy storage adequacy, and transmission chain jamming. However, existing technologies for measuring the opening and closing times of disconnecting switches largely rely on structural contact detection or simple electrical threshold judgments, resulting in insufficient measurement accuracy and robustness.

[0003] In existing technologies, a common method involves adding auxiliary contacts or limit switches to the disconnecting switch mechanism, indirectly reflecting the opening and closing time by measuring the moment the auxiliary contacts turn on or off. This method requires mechanical modification or additional devices to the existing switch body, increasing equipment complexity and maintenance workload. Furthermore, there is an inherent deviation between the timing of the auxiliary contacts' action and the actual electrical behavior of the main contacts when they connect or disconnect, making it impossible to directly reflect changes in the main circuit voltage state, resulting in inconsistencies between the time measurement results and the actual electrical opening and closing times. After a period of operation, the auxiliary contacts themselves may experience poor contact or wear, further reducing measurement reliability. Another method detects changes in the amplitude of the main circuit current or voltage, determining the opening or closing action when the acquired signal exceeds a certain fixed threshold. For example, some schemes use the moment when the main circuit current jumps from zero to its rated value or falls from its rated value to zero as the action time reference, or use the phase voltage or line voltage exceeding a certain set threshold as the criterion. This type of method often only utilizes the amplitude information of a single quantity, ignoring the dynamic characteristics of voltage and current waveforms during transient processes. When the system contains harmonics, transient oscillations, electromagnetic interference, or sampling noise, single threshold discrimination is prone to misjudgment or jitter. When voltage or current changes are step-like, multi-stage, or gradually changing, it is difficult to accurately pinpoint the true inflection point. Furthermore, fixed thresholds often require manual adjustment based on field experience, resulting in poor adaptability and hindering standardized implementation. Some technical solutions attempt to use high-speed cameras, photoelectric encoders, or mechanical travel sensors to measure the movement trajectory of disconnector switch contacts, and then calculate the opening and closing times from the start and end points of the movement. These methods are highly dependent on field installation conditions, alignment accuracy, and ambient lighting, resulting in high equipment costs and making large-scale deployment in conventional substations impractical. Simultaneously, a conversion relationship still exists between mechanical or optical displacement signals and the electrical disconnection and connection times of the main circuit, requiring the establishment of an additional mechanical-electrical correspondence model, increasing the overall system complexity.

[0004] Therefore, this case aims to propose a precise measurement method for the opening and closing time of disconnecting switches. This method involves deploying voltage sampling devices on both sides of the disconnecting switch to simultaneously record the voltages on both sides and construct a discrete voltage difference sequence. First-order and second-order differential methods are used to reveal the slope and curvature characteristics of voltage changes. A sliding window is used to calculate the second-order differential energy function, accurately locating the energy peak interval during the operation. Within this interval, the most significant action index is extracted and converted into the action time by comparing the zero-crossing value with the first-order differential amplitude. The average value of the voltage difference before and after the operation is then used to determine the switch action type. Finally, the stability of the action time is quantified by measuring the average and standard deviation of the statistical deviations multiple times. Summary of the Invention

[0005] This invention provides a method for accurately measuring the opening and closing time of a disconnecting switch, thereby helping to solve the problems mentioned in the background art.

[0006] This invention provides the following technical solution: a method for accurately measuring the opening and closing time of a disconnecting switch, comprising:

[0007] Voltage sampling devices are installed on both sides of the disconnecting switch to collect the voltage on both sides simultaneously. The samples are then arranged according to the discrete time sampling point index to form a discrete sequence of voltage difference between the two ends of the disconnecting switch.

[0008] The discrete sequence of voltage difference across the disconnecting switch is time-differentiated to generate a first-order voltage difference sequence, and then time-differentiated again to generate a second-order voltage difference sequence.

[0009] By squaring and accumulating the second-order difference values ​​of the voltage difference using a sliding window on the second-order difference sequence, a second-order difference energy function sequence is constructed, and the energy peak index and high energy range are obtained.

[0010] Within the high-energy range, the discrete-time sampling point index of the sign change of the second-order difference of voltage difference is retrieved and a zero-crossing index set is formed. The first-order difference amplitude of voltage difference at the zero-crossing point is compared, and the one with the largest amplitude is selected as the action index and converted into the action time.

[0011] The analysis window is captured on both sides of the action time to calculate the average voltage difference before the action and the average voltage difference after the action, and the action type is marked as closing, opening or not determined according to the magnitude relationship.

[0012] Obtain the reference action time, calculate the action time deviation, and combine the action time, action type, and action time deviation into a single measurement action result data item;

[0013] Perform multiple independent operations, collect the average and standard deviation of the action time deviation, and mark the action time stability based on the standard deviation;

[0014] The discrete sequence of voltage difference across the disconnecting switch, the first-order differential sequence of voltage difference, the second-order differential sequence of voltage difference, the second-order differential energy function sequence, the set of zero-crossing indices, the action index, the action time, and the action type are combined to form a single measurement data record, which is then combined into a multi-measurement dataset and assigned a unique number.

[0015] Optionally, the step of deploying voltage sampling devices on both sides of the disconnecting switch to synchronously collect the voltage on both sides and arrange them according to the discrete-time sampling point index to form a discrete sequence of voltage differences across the disconnecting switch specifically includes:

[0016] The voltage sampling device is configured to include a first voltage sampling probe and a second voltage sampling probe. The first voltage sampling probe is set at the left terminal of the disconnecting switch, and the second voltage sampling probe is set at the right terminal of the disconnecting switch. The location of the first voltage sampling probe is defined as the left sampling point, and the location of the second voltage sampling probe is defined as the right sampling point. The continuous time voltage signals on both sides of the disconnecting switch are collected through the left sampling point and the right sampling point, respectively.

[0017] Set the voltage sampling frequency parameter, and set the time interval between two adjacent voltage samples to the reciprocal of the voltage sampling frequency. By accumulating the sampling time interval on the time axis from the start of sampling, each discrete sampling moment is obtained in sequence, and a discrete time sampling point index is assigned to each discrete sampling moment. At the same time, the total number of discrete time sampling points in the entire sampling process is set.

[0018] At each discrete sampling time, the discrete left voltage sample value is obtained through the left sampling point, and the discrete right voltage sample value is obtained through the right sampling point. All discrete left voltage sample values ​​are arranged in the order of discrete time sampling point index to form the left discrete voltage sequence, and all discrete right voltage sample values ​​are arranged in the order of discrete time sampling point index to form the right discrete voltage sequence.

[0019] At each discrete-time sampling point index, the corresponding discrete voltage sampling value on the left is subtracted from the corresponding discrete voltage sampling value on the right to obtain the voltage difference value across the disconnecting switch at the corresponding discrete sampling time. All voltage difference values ​​at discrete sampling times are arranged in the order of discrete-time sampling point indices to form a discrete sequence of voltage differences across the disconnecting switch.

[0020] Optionally, the step of performing time-difference generation of a first-order voltage difference sequence from the discrete sequence of voltage differences across the disconnecting switch, and then performing time-difference generation of a second-order voltage difference sequence, specifically includes:

[0021] In the discrete sequence of voltage differences across the disconnecting switch, starting from the second discrete time sampling point index, for each current discrete time sampling point, the voltage difference value at the current discrete time sampling point and the voltage difference value at the previous discrete time sampling point are obtained. The first-order difference value of the voltage difference at the current discrete time sampling point is calculated by subtracting the previous voltage difference value from the current voltage difference value and dividing by the sampling time interval. The first-order difference values ​​at all discrete time sampling points are arranged in the order of the discrete time sampling point index to form the first-order difference sequence of voltage differences.

[0022] In the first-order difference sequence of voltage difference, starting from the third discrete-time sampling point index, for each current discrete-time sampling point, the first-order difference value at the current discrete-time sampling point and the first-order difference value at the previous discrete-time sampling point are obtained. The second-order difference value of voltage difference at the current discrete-time sampling point is calculated by subtracting the previous first-order difference value from the current first-order difference value and dividing by the sampling time interval. The second-order difference values ​​at all discrete-time sampling points are arranged in the order of the discrete-time sampling point index to form the second-order difference sequence of voltage difference.

[0023] Optionally, the step of accumulating the squared values ​​of the second-order voltage difference on the second-order voltage difference sequence by sliding window to construct a second-order difference energy function sequence and obtain the energy peak index and high energy range specifically includes:

[0024] Set the sliding window half-width parameter so that the length of the sliding window determined by the sliding window half-width parameter is less than the total number of discrete-time sampling points of the voltage difference second-order difference sequence;

[0025] In the second-order difference sequence of voltage difference, starting from the discrete-time sampling point index that is close to the beginning of the sequence and satisfies the condition of complete coverage of the sliding window, each discrete-time sampling point is selected as the center discrete-time sampling point index of the window in turn. For each center discrete-time sampling point index of the window, local second-order difference data with the center discrete-time sampling point index of the window as the midpoint and the length determined by the half-width parameter of the sliding window is extracted.

[0026] For each voltage difference second-order difference value in each local second-order difference data, a squaring operation is performed, and all squaring results within the same local data are accumulated. The accumulated result is used as the second-order difference energy value at the index of the discrete-time sampling point at the center of the window. All accumulated results are arranged in the order of the discrete-time sampling point index at the center of the window to form a second-order difference energy function sequence.

[0027] In the second-order difference energy function sequence, each energy value is traversed, the size of all energy values ​​is compared, the global maximum energy value is obtained, and in the case of multiple global maximum energy values, the smallest index of the discrete time sampling point at the center of the window is selected as the energy peak index.

[0028] The energy peak index is multiplied by the sampling time interval and combined with the sampling start time to convert it into the time corresponding to the energy peak. The energy peak index and the range of discrete time sampling points on both sides that match the half-width parameter of the sliding window are taken as the high energy range containing the opening and closing action characteristics of the disconnecting switch.

[0029] Optionally, the step of retrieving discrete-time sampling point indices of the sign change of the second-order difference voltage difference within the high-energy range and forming a set of zero-crossing indices, comparing the first-order difference voltage difference amplitudes at zero-crossing points, selecting the one with the largest amplitude as the action index, and converting it into the action time, specifically includes:

[0030] Within the high-energy range, following the discrete-time sampling point index order, for each current discrete-time sampling point, the second-order difference value of the voltage difference at the current discrete-time sampling point and the second-order difference value of the voltage difference at the previous discrete-time sampling point are obtained, and the product of these two second-order difference values ​​of the voltage difference is calculated.

[0031] When the product of the second-order difference of the voltage difference at a certain discrete-time sampling point and the second-order difference of the voltage difference at the previous discrete-time sampling point is negative, the corresponding discrete-time sampling point index is added to the zero-crossing index set, and the number of each discrete-time sampling point index in the zero-crossing index set and the total number of discrete-time sampling points in the zero-crossing index set are recorded; when there are no discrete-time sampling points with negative products in the high-energy range, the zero-crossing index set is set to an empty set;

[0032] When the zero-crossing index set contains one or more discrete-time sampling point indices, for each discrete-time sampling point index in the zero-crossing index set, the first-order difference value at the corresponding discrete-time sampling point in the first-order difference sequence of voltage difference is obtained, the absolute value of the corresponding first-order difference value is taken to obtain the first-order difference amplitude of voltage difference, and a comparison operation is performed between the first-order difference amplitudes of voltage difference of all zero-crossing discrete-time sampling points. The zero-crossing discrete-time sampling point index with the largest amplitude is selected as the action index.

[0033] When the set of zero cross-indexes is empty, the energy peak index is directly used as the action index;

[0034] The action index is multiplied by the sampling time interval and combined with the sampling start time to convert it into the action time.

[0035] Optionally, the step of capturing analysis windows on both sides of the action time, calculating the average voltage difference before and after the action, and marking the action type as closing, opening, or undetermined according to their magnitude, specifically includes:

[0036] Based on the position of the action index in the discrete sequence of voltage difference across the disconnector and the total number of discrete time sampling points in the discrete sequence of voltage difference across the disconnector, obtain the half-width parameter of the voltage difference analysis window before and after the action, so that the entire range of the analysis window before the action is located before the action index and the entire range of the analysis window after the action is located after the action index.

[0037] In the discrete sequence of voltage difference across the disconnector, several consecutive discrete time sampling points before the action index are used as the pre-action analysis window range. The voltage difference value at each discrete time sampling point within the pre-action analysis window range is obtained. All voltage difference values ​​within the pre-action analysis window range are summed and divided by the number of discrete time sampling points to calculate the average voltage difference before action.

[0038] In the discrete sequence of voltage differences across the disconnecting switch, several consecutive discrete time sampling points after the action index are used as the post-action analysis window range. The voltage difference value at each discrete time sampling point within the post-action analysis window range is obtained. All voltage difference values ​​within the post-action analysis window range are summed and divided by the number of discrete time sampling points to calculate the average voltage difference after the action.

[0039] The average voltage difference after the action is compared with the average voltage difference before the action. When the average voltage difference after the action is greater than the average voltage difference before the action, the action type of this operation is marked as closing; when the average voltage difference after the action is less than the average voltage difference before the action, the action type of this operation is marked as opening; when the average voltage difference after the action is equal to the average voltage difference before the action, the action type of this operation is marked as undetermined.

[0040] Optionally, the step of obtaining the reference action time, calculating the action time deviation, and combining the action time, action type, and action time deviation into a single measurement action result data item specifically includes:

[0041] For disconnecting switches, a calibration test of the operating time is performed in advance under rated operating conditions to obtain the reference operating time of the disconnecting switch;

[0042] In a specific measurement process, the action time obtained through voltage difference analysis is acquired, and the obtained action time is subtracted from the reference action time to calculate the action time deviation of this measurement.

[0043] The action time, action type, and action time deviation obtained in this measurement are combined into a single measurement action result data item according to a fixed field order.

[0044] The result data of a single measurement action is output to a preset data processing module or data storage module and associated with the corresponding measurement record.

[0045] Optionally, the step of performing multiple independent operations, collecting the average and standard deviation of the action time deviation, and marking the action time stability based on the standard deviation specifically includes:

[0046] Perform multiple independent opening and closing operations on the same disconnecting switch under the same operating conditions. In each opening and closing operation, obtain the corresponding action time deviation of the opening and closing operation, and record the action time deviation of each operation in sequence to form an action time deviation sequence.

[0047] Sum all action time deviations in the action time deviation sequence, and divide the sum by the total number of opening and closing operations to calculate the average action time deviation of all operations;

[0048] For each action time deviation in the action time deviation sequence, calculate the difference between the action time deviation and the average action time deviation, perform a square operation on all differences and sum them, divide the sum of squares by the total number of opening and closing operations and then perform a square root operation to calculate the standard deviation of the action time deviation.

[0049] When the standard deviation of the action time is equal to zero, the action time stability of the disconnecting switch is marked as completely stable; when the standard deviation of the action time is greater than zero, the action time stability of the disconnecting switch is marked as fluctuating.

[0050] Optionally, the step of forming a single measurement data record from the discrete sequence of voltage differences across the disconnecting switch, the first-order differential sequence of voltage differences, the second-order differential sequence of voltage differences, the second-order differential energy function sequence, the zero-crossing index set, the action index, the action time, and the action type, and combining them into a multi-measurement dataset and assigning a unique number, specifically includes:

[0051] For each opening and closing operation, obtain the discrete sequence of voltage difference across the disconnector for the corresponding opening and closing operation, obtain the first-order differential voltage difference sequence constructed from the discrete sequence of voltage difference across the disconnector, obtain the second-order differential voltage difference sequence constructed from the first-order differential voltage difference sequence, obtain the second-order differential energy function sequence constructed based on the second-order differential voltage difference sequence and the sliding window, obtain the set of zero-crossing indices that satisfy the zero-crossing condition in the second-order differential voltage difference sequence, obtain the action index selected by comparing the first-order differential voltage difference amplitude at the zero-crossing index, obtain the action time converted from the action index, obtain the action type determined by comparing the average voltage difference before and after the action, and combine the discrete sequence of voltage difference across the disconnector, the first-order differential voltage difference sequence, the second-order differential voltage difference sequence, the second-order differential energy function sequence, the set of zero-crossing indices, the action index, the action time, and the action type to form a single measurement data record for the corresponding opening and closing operation;

[0052] The multiple single measurement data records corresponding to multiple opening and closing operations are combined into a multiple measurement dataset according to the operation sequence or preset sequence. The multiple measurement dataset is used as a set structure to describe the complete measurement information of the same disconnecting switch under multiple independent operations.

[0053] Each set of multiple measurement datasets is assigned a unique number, and the unique number is combined with the corresponding multiple measurement dataset to form a numbered data pair. The data pairs enable the identification, indexing and traceability management of different batches of measurement datasets.

[0054] The present invention has the following beneficial effects:

[0055] 1. By deploying voltage sampling probes on both sides of the disconnecting switch and sampling synchronously according to an index, a discrete sequence of the voltage difference between the two sides can be directly obtained. This deeply integrates time synchronization and difference calculation, avoiding the problems of traditional single-sided voltage measurement being greatly affected by power supply fluctuations and requiring external trigger signals; it improves the timing consistency and integrity of data acquisition; in practical applications, accurate timing data can be obtained without additional triggering equipment; compared with existing technologies, this solution reduces hardware complexity and lowers synchronization errors.

[0056] 2. By performing first-order and second-order differences on the primary discrete sequence according to the index, the rate of change and curvature of the voltage difference are revealed respectively. Simultaneously using two levels of difference, the abrupt change and transition features in the action signal are fully extracted; this enhances the sensitivity of subsequent energy analysis to action edges; it overcomes the shortcomings of traditional methods that rely solely on first-order difference and are susceptible to noise interference, and that second-order difference ignores the rate of change; compared with existing technologies, this method takes into account both signal roughness and oscillation detection, improving the reliability of action timing location.

[0057] 3. By using a sliding window to accumulate squares on the second-order difference sequence, an energy function sequence is formed, and a global peak index and its corresponding window are selected. Using the local second-order difference energy as an accurate identifier of the action interval can robustly highlight the characteristics of large-amplitude actions; it suppresses the interference of small perturbations and single noise pulses, ensuring that the selected interval contains the main action; it avoids misjudgment caused by environmental electromagnetic interference in reality; compared with the peak detection of existing technologies, which are easily affected by threshold settings, this method adapts to the window size and index range, making it more versatile.

[0058] 4. Within the high-energy range, the sign change of the second-order difference is retrieved and compared with the corresponding first-order amplitude, selecting the point with the largest amplitude as the action index. Combining the sign change of the second-order difference and the magnitude of the first-order amplitude as dual criteria, this method ensures the accuracy of the action position and distinguishes different action stages; it enhances the ability to distinguish continuous oscillations or multiple bounce actions; it solves the defect of using only zero-crossing, which is easily affected by small noises leading to false crossovers; compared with existing simple zero-crossing methods, this method can accurately distinguish between true action crossovers and noise crossovers.

[0059] 5. At the selected action moment, the voltage difference sequence before and after is extracted, the average value is calculated, and then compared. The results are then marked as closed, open, or undetermined, respectively. This simplifies action type identification to average value comparison, requiring no additional feature design; it is simple to operate, highly real-time, and applicable to various voltage waveforms; it solves the problem of traditional methods requiring complex models or template matching to determine the action direction; compared to complex methods based on machine learning or spectrum analysis, this solution is lightweight and easy to implement.

[0060] 6. The action time, type, and relative deviation are combined into ordered triplet outputs. A unified data structure is constructed, which facilitates subsequent storage, transmission, and statistics; the data format is standardized, reducing system integration costs; the problem of inconsistent and difficult-to-integrate output formats of different devices or algorithms is solved; compared with directly outputting raw waveforms or logs, this method is more conducive to rapid backend parsing and visualization.

[0061] 7. Calculate the average and standard deviation of multiple independent action deviations, and quantify stability based on the standard deviation. Introducing statistical indicators to evaluate action consistency allows for qualitative labeling of switching performance; provides quantitative diagnostic basis for decision-making regarding equipment health and maintenance cycles; overcomes the limitation of relying solely on single measurement accuracy to understand long-term stability; and compared to existing methods that only report single deviations, this method considers both accuracy and reliability analysis.

[0062] 8. Pack all key sequences with indices, times, and types, and assign them unique numbers to form data pairs. This method aggregates complete measurement chain information at once, facilitating traceability and data tracking; it enables unified management and batch identification of large-scale measurement data; it solves the pain points of scattered storage and difficulty in correlation analysis; unlike traditional methods that only store result values, this method provides full-process data, providing a data foundation for in-depth diagnosis and algorithm iteration. Attached Figure Description

[0063] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0064] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0065] Example, refer to Figure 1 A method for accurately measuring the opening and closing time of a disconnecting switch, comprising:

[0066] Voltage sampling devices are installed on both sides of the disconnecting switch to collect the voltage on both sides simultaneously. The samples are then arranged according to the discrete time sampling point index to form a discrete sequence of voltage difference between the two ends of the disconnecting switch.

[0067] The discrete sequence of voltage difference across the disconnecting switch is time-differentiated to generate a first-order voltage difference sequence, and then time-differentiated again to generate a second-order voltage difference sequence.

[0068] By squaring and accumulating the second-order difference values ​​of the voltage difference using a sliding window on the second-order difference sequence, a second-order difference energy function sequence is constructed, and the energy peak index and high energy range are obtained.

[0069] Within the high-energy range, the discrete-time sampling point index of the sign change of the second-order difference of voltage difference is retrieved and a zero-crossing index set is formed. The first-order difference amplitude of voltage difference at the zero-crossing point is compared, and the one with the largest amplitude is selected as the action index and converted into the action time.

[0070] The analysis window is captured on both sides of the action time to calculate the average voltage difference before the action and the average voltage difference after the action, and the action type is marked as closing, opening or not determined according to the magnitude relationship.

[0071] Obtain the reference action time, calculate the action time deviation, and combine the action time, action type, and action time deviation into a single measurement action result data item;

[0072] Perform multiple independent operations, collect the average and standard deviation of the action time deviation, and mark the action time stability based on the standard deviation;

[0073] The discrete sequence of voltage difference across the disconnecting switch, the first-order differential sequence of voltage difference, the second-order differential sequence of voltage difference, the second-order differential energy function sequence, the set of zero-crossing indices, the action index, the action time, and the action type are combined to form a single measurement data record, which is then combined into a multi-measurement dataset and assigned a unique number.

[0074] First, voltage sampling devices are deployed on both sides of the switch to synchronously acquire the voltages on both sides and construct a high-resolution discrete voltage difference sequence, overcoming the timing asynchrony problem caused by relying on single-side sampling or mechanical triggering. Then, first-order and second-order differential operations are performed sequentially. The first-order differential quickly reveals the rapid changes in the opening and closing transients, while the second-order differential is sensitive to curvature abrupt changes, clearly distinguishing the action signal from periodic ripples and low-amplitude disturbances. Subsequently, an energy function is constructed on the second-order differential sequence through sliding window square accumulation, adaptively highlighting the high-energy region of the action segment without requiring manual threshold setting, eliminating the misjudgment caused by the threshold dependence of traditional peak detection. Further, in high-energy... Within the interval, discrete-time sampling point indices of the sign change of the second-order differential voltage difference are retrieved and a zero-crossing index set is formed. The first-order differential voltage difference amplitudes at zero-crossing points are compared, and the one with the largest amplitude is selected as the action index and converted into the action time. This fundamentally solves the problem of single zero-crossing points being easily triggered by noise pulses. A fixed window is extracted before and after the action time to calculate the average voltage difference before and after. Closing and opening can be distinguished by simple comparison of magnitude, eliminating the dependence on complex models or template libraries. Finally, the deviation is obtained by comparing with the rated reference time, and the average and standard deviation are calculated by multiple measurements to quantify the stability of the action time, providing an objective basis for switch performance evaluation.

[0075] The step of deploying voltage sampling devices on both sides of the disconnecting switch to synchronously collect the voltage on both sides and arrange them according to the discrete time sampling point index to form a discrete sequence of voltage difference across the disconnecting switch specifically includes:

[0076] The voltage sampling device is configured to include a first voltage sampling probe and a second voltage sampling probe. The first voltage sampling probe is set at the left terminal of the disconnecting switch, and the second voltage sampling probe is set at the right terminal of the disconnecting switch. The location of the first voltage sampling probe is defined as the left sampling point, and the location of the second voltage sampling probe is defined as the right sampling point. The continuous time voltage signals on both sides of the disconnecting switch are collected through the left sampling point and the right sampling point, respectively.

[0077] Set the voltage sampling frequency parameter, and set the time interval between two adjacent voltage samples to the reciprocal of the voltage sampling frequency. By accumulating the sampling time interval on the time axis from the start of sampling, each discrete sampling moment is obtained in sequence, and a discrete time sampling point index is assigned to each discrete sampling moment. At the same time, the total number of discrete time sampling points in the entire sampling process is set.

[0078] At each discrete sampling time, the discrete left voltage sample value is obtained through the left sampling point, and the discrete right voltage sample value is obtained through the right sampling point. All discrete left voltage sample values ​​are arranged in the order of discrete time sampling point index to form the left discrete voltage sequence, and all discrete right voltage sample values ​​are arranged in the order of discrete time sampling point index to form the right discrete voltage sequence.

[0079] At each discrete-time sampling point index, the corresponding discrete voltage sampling value on the left is subtracted from the corresponding discrete voltage sampling value on the right to obtain the voltage difference value across the disconnecting switch at the corresponding discrete sampling time. All voltage difference values ​​at discrete sampling times are arranged in the order of discrete-time sampling point indices to form a discrete sequence of voltage differences across the disconnecting switch.

[0080] Voltage sampling probes are installed on both sides of the disconnecting switch, and these are recorded as sampling points. and The corresponding voltage signals are denoted as follows: , ;in, This is a voltage sampling point located on the left side of the disconnect switch; This is a voltage sampling point located on the right side of the disconnect switch; In continuous time downsampling point Instantaneous voltage at the point; In continuous time downsampling point Instantaneous voltage at the point; It is a continuous-time variable;

[0081] Set the voltage sampling frequency to The time interval between two adjacent samples is ;

[0082] Calculate the first Each sampling time , ;in, For the index of discrete-time sampling points; This represents the total number of sampling points throughout the entire sampling process.

[0083] The discrete voltage sequence was acquired: , ;in, , At the sampling time respectively Sampling point Sampling points The measured discrete voltage values;

[0084] Construct a discrete sequence of voltage differences across the switch:

[0085] , ;in, To be at the sampling time The voltage difference across the disconnector switch.

[0086] The process of performing time-difference calculus on the discrete sequence of voltage difference across the disconnecting switch to generate a first-order voltage difference sequence, and then performing time-difference calculus again to generate a second-order voltage difference sequence, specifically includes:

[0087] In the discrete sequence of voltage differences across the disconnecting switch, starting from the second discrete time sampling point index, for each current discrete time sampling point, the voltage difference value at the current discrete time sampling point and the voltage difference value at the previous discrete time sampling point are obtained. The first-order difference value of the voltage difference at the current discrete time sampling point is calculated by subtracting the previous voltage difference value from the current voltage difference value and dividing by the sampling time interval. The first-order difference values ​​at all discrete time sampling points are arranged in the order of the discrete time sampling point index to form the first-order difference sequence of voltage differences.

[0088] In the first-order difference sequence of voltage difference, starting from the third discrete-time sampling point index, for each current discrete-time sampling point, the first-order difference value at the current discrete-time sampling point and the first-order difference value at the previous discrete-time sampling point are obtained. The second-order difference value of voltage difference at the current discrete-time sampling point is calculated by subtracting the previous first-order difference value from the current first-order difference value and dividing by the sampling time interval. The second-order difference values ​​at all discrete-time sampling points are arranged in the order of the discrete-time sampling point index to form the second-order difference sequence of voltage difference.

[0089] The first-order difference sequence of voltage difference is calculated as follows:

[0090] , ;in, In the first First-order difference of voltage difference at each sampling point;

[0091] The second-order difference sequence of voltage difference is calculated as follows:

[0092] , ;in, In the first The second-order difference of the voltage difference at each sampling point.

[0093] The step of accumulating the squared values ​​of the second-order voltage difference on the second-order voltage difference sequence by sliding window to construct a second-order difference energy function sequence and obtain the energy peak index and high energy range specifically includes:

[0094] Set the sliding window half-width parameter so that the length of the sliding window determined by the sliding window half-width parameter is less than the total number of discrete-time sampling points of the voltage difference second-order difference sequence;

[0095] In the second-order difference sequence of voltage difference, starting from the discrete-time sampling point index that is close to the beginning of the sequence and satisfies the condition of complete coverage of the sliding window, each discrete-time sampling point is selected as the center discrete-time sampling point index of the window in turn. For each center discrete-time sampling point index of the window, local second-order difference data with the center discrete-time sampling point index of the window as the midpoint and the length determined by the half-width parameter of the sliding window is extracted.

[0096] For each voltage difference second-order difference value in each local second-order difference data, a squaring operation is performed, and all squaring results within the same local data are accumulated. The accumulated result is used as the second-order difference energy value at the index of the discrete-time sampling point at the center of the window. All accumulated results are arranged in the order of the discrete-time sampling point index at the center of the window to form a second-order difference energy function sequence.

[0097] In the second-order difference energy function sequence, each energy value is traversed, the size of all energy values ​​is compared, the global maximum energy value is obtained, and in the case of multiple global maximum energy values, the smallest index of the discrete time sampling point at the center of the window is selected as the energy peak index.

[0098] The energy peak index is multiplied by the sampling time interval and combined with the sampling start time to convert it into the time corresponding to the energy peak. The energy peak index and the range of discrete time sampling points on both sides that match the half-width parameter of the sliding window are taken as the high energy range containing the opening and closing action characteristics of the disconnecting switch.

[0099] Set the half width of the sliding window to And satisfy: ;

[0100] For each index The energy function is constructed as follows:

[0101] ;in, For an index The second-order difference energy value constructed around the center; This is a temporary index variable used during the summation process; In the first Second-order difference values ​​at each sampling point;

[0102] In the index set In the process, determine the index that satisfies both conditions S301 and S302. Specifically:

[0103] S301, , ;

[0104] S302, , ;

[0105] in, Energy function The index that first reaches the global maximum value among all candidate indexes;

[0106] And calculate: ;in, Energy Peak Index The corresponding time point.

[0107] The process of retrieving discrete-time sampling point indices of the sign change of the second-order differential voltage difference within the high-energy range and forming a set of zero-crossing indices, comparing the first-order differential voltage difference amplitudes at zero-crossing points, selecting the one with the largest amplitude as the action index, and converting it into the action time, specifically includes:

[0108] Within the high-energy range, following the discrete-time sampling point index order, for each current discrete-time sampling point, the second-order difference value of the voltage difference at the current discrete-time sampling point and the second-order difference value of the voltage difference at the previous discrete-time sampling point are obtained, and the product of these two second-order difference values ​​of the voltage difference is calculated.

[0109] When the product of the second-order difference of the voltage difference at a certain discrete-time sampling point and the second-order difference of the voltage difference at the previous discrete-time sampling point is negative, the corresponding discrete-time sampling point index is added to the zero-crossing index set, and the number of each discrete-time sampling point index in the zero-crossing index set and the total number of discrete-time sampling points in the zero-crossing index set are recorded; when there are no discrete-time sampling points with negative products in the high-energy range, the zero-crossing index set is set to an empty set;

[0110] When the zero-crossing index set contains one or more discrete-time sampling point indices, for each discrete-time sampling point index in the zero-crossing index set, the first-order difference value at the corresponding discrete-time sampling point in the first-order difference sequence of voltage difference is obtained, the absolute value of the corresponding first-order difference value is taken to obtain the first-order difference amplitude of voltage difference, and a comparison operation is performed between the first-order difference amplitudes of voltage difference of all zero-crossing discrete-time sampling points. The zero-crossing discrete-time sampling point index with the largest amplitude is selected as the action index.

[0111] When the set of zero cross-indexes is empty, the energy peak index is directly used as the action index;

[0112] The action index is multiplied by the sampling time interval and combined with the sampling start time to convert it into the action time.

[0113] In the interval Within, for each integer index Check the product :

[0114] If a certain index satisfy: Then add the index to the set of zero cross indices: ;in, A set of indices that satisfy the zero-crossing condition; Zero-cross set The first in One element; The index of the element in the zero-cross set; Zero-cross set The number of elements in the middle;

[0115] If no condition is met. Then let It is an empty set;

[0116] S401, when At that time, for each calculate: ;in, For zero cross index The first difference value at; For zero cross index The absolute value of the first difference at the given point;

[0117] In all The following conditions must be met: , index And determine: , ;in, For all The index number corresponding to the maximum value in the middle; Index of the final selected action; The time for determining the action of the disconnecting switch in response to voltage changes;

[0118] S402, when At that time, take it directly: , .

[0119] The process of capturing analysis windows on both sides of the action time, calculating the average voltage difference before and after the action, and marking the action type as closing, opening, or undetermined according to their magnitude includes:

[0120] Based on the position of the action index in the discrete sequence of voltage difference across the disconnector and the total number of discrete time sampling points in the discrete sequence of voltage difference across the disconnector, obtain the half-width parameter of the voltage difference analysis window before and after the action, so that the entire range of the analysis window before the action is located before the action index and the entire range of the analysis window after the action is located after the action index.

[0121] In the discrete sequence of voltage difference across the disconnector, several consecutive discrete time sampling points before the action index are used as the pre-action analysis window range. The voltage difference value at each discrete time sampling point within the pre-action analysis window range is obtained. All voltage difference values ​​within the pre-action analysis window range are summed and divided by the number of discrete time sampling points to calculate the average voltage difference before action.

[0122] In the discrete sequence of voltage differences across the disconnecting switch, several consecutive discrete time sampling points after the action index are used as the post-action analysis window range. The voltage difference value at each discrete time sampling point within the post-action analysis window range is obtained. All voltage difference values ​​within the post-action analysis window range are summed and divided by the number of discrete time sampling points to calculate the average voltage difference after the action.

[0123] The average voltage difference after the action is compared with the average voltage difference before the action. When the average voltage difference after the action is greater than the average voltage difference before the action, the action type of this operation is marked as closing; when the average voltage difference after the action is less than the average voltage difference before the action, the action type of this operation is marked as opening; when the average voltage difference after the action is equal to the average voltage difference before the action, the action type of this operation is marked as undetermined.

[0124] Calculate the window length before and after the action: ;in, This is the half-width of the window used to calculate the average voltage difference before and after the action;

[0125] use Calculate the average voltage difference before the action, specifically:

[0126] ;in, For action index Previously, length was Voltage difference within the window The average value;

[0127] use Calculate the average voltage difference after the action, specifically as follows:

[0128] ;in, For action index After that, the length is Voltage difference within the window The average value;

[0129] according to and The size relationship determines the action type, specifically:

[0130] ;in, This is the result of determining the type of action of the disconnecting switch.

[0131] The process of obtaining the reference action time, calculating the action time deviation, and combining the action time, action type, and action time deviation into a single measurement action result data item specifically includes:

[0132] For disconnecting switches, a calibration test of the operating time is performed in advance under rated operating conditions to obtain the reference operating time of the disconnecting switch;

[0133] In a specific measurement process, the action time obtained through voltage difference analysis is acquired, and the obtained action time is subtracted from the reference action time to calculate the action time deviation of this measurement.

[0134] The action time, action type, and action time deviation obtained in this measurement are combined into a single measurement action result data item according to a fixed field order.

[0135] The result data of a single measurement action is output to a preset data processing module or data storage module and associated with the corresponding measurement record.

[0136] Obtain the reference operating time of the disconnector under rated operating conditions, denoted as ;

[0137] The motion time deviation is calculated as follows: ;in, This is the difference between the measured motion time and the reference motion time.

[0138] The resulting data items, which include action time, action type, and action time deviation, are constructed as follows:

[0139] ;in, The data items representing the result of a single measurement action are ordered triples;

[0140] Output action time Action type and action time deviation ;

[0141] Output data .

[0142] The process of performing multiple independent operations, collecting the average and standard deviation of the action time deviations, and marking the action time stability based on the standard deviation specifically includes:

[0143] Perform multiple independent opening and closing operations on the same disconnecting switch under the same operating conditions. In each opening and closing operation, obtain the corresponding action time deviation of the opening and closing operation, and record the action time deviation of each operation in sequence to form an action time deviation sequence.

[0144] Sum all action time deviations in the action time deviation sequence, and divide the sum by the total number of opening and closing operations to calculate the average action time deviation of all operations;

[0145] For each action time deviation in the action time deviation sequence, calculate the difference between the action time deviation and the average action time deviation, perform a square operation on all differences and sum them, divide the sum of squares by the total number of opening and closing operations and then perform a square root operation to calculate the standard deviation of the action time deviation.

[0146] When the standard deviation of the action time is equal to zero, the action time stability of the disconnecting switch is marked as completely stable; when the standard deviation of the action time is greater than zero, the action time stability of the disconnecting switch is marked as fluctuating.

[0147] Perform on disconnect switch Each operation is a separate operation. In each operation, the action time of the operation is determined by using the voltage difference data collected in that operation, along with the calculated first-order voltage difference, second-order voltage difference, energy function, and zero-crossing index set. This action time is denoted as... , ;in, The number of independent operations performed on the disconnector switch; Index for the number of independent operations; For the first The action time determined in this operation;

[0148] calculate The average time of each operation is ;

[0149] calculate The standard deviation of the time for each operation is ;

[0150] when When the operating time stability of the disconnecting switch is reached, it is marked as having a completely stable operating time.

[0151] when At that time, the stability of the operating time of the disconnecting switch is marked as fluctuating.

[0152] The process involves creating a single measurement data record from the discrete sequence of voltage differences across the disconnecting switch, the first-order differential sequence of voltage differences, the second-order differential sequence of voltage differences, the second-order differential energy function sequence, the zero-crossing index set, the action index, the action time, and the action type. This record is then combined into a multi-measurement dataset and assigned a unique number. Specifically, this includes:

[0153] For each opening and closing operation, obtain the discrete sequence of voltage difference across the disconnector for the corresponding opening and closing operation, obtain the first-order differential voltage difference sequence constructed from the discrete sequence of voltage difference across the disconnector, obtain the second-order differential voltage difference sequence constructed from the first-order differential voltage difference sequence, obtain the second-order differential energy function sequence constructed based on the second-order differential voltage difference sequence and the sliding window, obtain the set of zero-crossing indices that satisfy the zero-crossing condition in the second-order differential voltage difference sequence, obtain the action index selected by comparing the first-order differential voltage difference amplitude at the zero-crossing index, obtain the action time converted from the action index, obtain the action type determined by comparing the average voltage difference before and after the action, and combine the discrete sequence of voltage difference across the disconnector, the first-order differential voltage difference sequence, the second-order differential voltage difference sequence, the second-order differential energy function sequence, the set of zero-crossing indices, the action index, the action time, and the action type to form a single measurement data record for the corresponding opening and closing operation;

[0154] The multiple single measurement data records corresponding to multiple opening and closing operations are combined into a multiple measurement dataset according to the operation sequence or preset sequence. The multiple measurement dataset is used as a set structure to describe the complete measurement information of the same disconnecting switch under multiple independent operations.

[0155] Each set of multiple measurement datasets is assigned a unique number, and the unique number is combined with the corresponding multiple measurement dataset to form a numbered data pair. The data pairs enable the identification, indexing and traceability management of different batches of measurement datasets.

[0156] For the This operation will compile the following data into a single measurement record:

[0157] , , , , ;in, For the first The set of voltage difference sequences for each operation; For the first The set of first-order difference sequences for each operation; For the first The set of second-order difference sequences for the next operation; For the first The set of energy function sequences for each operation; For the first In the next operation, the first Voltage difference at each sampling point; For the first In the next operation, the first The first-order difference of the voltage difference corresponding to each sampling point; For the first In the next operation, the first The second-order difference of the voltage difference corresponding to each sampling point; For the first In this operation, the index is used The value of the second-order difference energy function centered at the center; For the first Record the measurement data for each operation; For the first The set of indices that satisfy the zero-crossing condition in this operation; For the first The final action index determined in this operation; For the first The final action timing determined in this operation; For the first The action type is determined in this operation;

[0158] Will Data records corresponding to this operation Composing a dataset based on multiple measurements:

[0159] ;in, For the reason Single measurement data record A dataset consisting of multiple measurements;

[0160] For each set of multiple measurement datasets Assign a unique number And form numbered data pairs. .

[0161] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0162] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A precise measurement method for opening and closing time of a disconnector, characterized in that, include: Voltage sampling devices are installed on both sides of the disconnecting switch to collect the voltage on both sides simultaneously. The samples are then arranged according to the discrete time sampling point index to form a discrete sequence of voltage difference between the two ends of the disconnecting switch. The discrete sequence of voltage difference across the disconnecting switch is time-differentiated to generate a first-order voltage difference sequence, and then time-differentiated again to generate a second-order voltage difference sequence. By squaring and accumulating the second-order difference values ​​of the voltage difference using a sliding window on the second-order difference sequence, a second-order difference energy function sequence is constructed, and the energy peak index and high energy range are obtained. Within the high-energy range, the discrete-time sampling point index of the sign change of the second-order difference of voltage difference is retrieved and a zero-crossing index set is formed. The first-order difference amplitude of voltage difference at the zero-crossing point is compared, and the one with the largest amplitude is selected as the action index and converted into the action time. The analysis window is captured on both sides of the action time to calculate the average voltage difference before the action and the average voltage difference after the action, and the action type is marked as closing, opening or not determined according to the magnitude relationship. Obtain the reference action time, calculate the action time deviation, and combine the action time, action type, and action time deviation into a single measurement action result data item; Perform multiple independent operations, collect the average and standard deviation of the action time deviation, and mark the action time stability based on the standard deviation; The discrete sequence of voltage difference across the disconnecting switch, the first-order differential sequence of voltage difference, the second-order differential sequence of voltage difference, the second-order differential energy function sequence, the set of zero-crossing indices, the action index, the action time, and the action type are combined to form a single measurement data record, which is then combined into a multi-measurement dataset and assigned a unique number.

2. The method for accurately measuring the opening and closing time of a disconnecting switch according to claim 1, characterized in that, The step of deploying voltage sampling devices on both sides of the disconnecting switch to synchronously collect the voltage on both sides and arrange them according to the discrete time sampling point index to form a discrete sequence of voltage difference across the disconnecting switch specifically includes: The voltage sampling device is configured to include a first voltage sampling probe and a second voltage sampling probe. The first voltage sampling probe is set at the left terminal of the disconnecting switch, and the second voltage sampling probe is set at the right terminal of the disconnecting switch. The location of the first voltage sampling probe is defined as the left sampling point, and the location of the second voltage sampling probe is defined as the right sampling point. The continuous time voltage signals on both sides of the disconnecting switch are collected through the left sampling point and the right sampling point, respectively. Set the voltage sampling frequency parameter, and set the time interval between two adjacent voltage samples to the reciprocal of the voltage sampling frequency. By accumulating the sampling time interval on the time axis from the start of sampling, each discrete sampling moment is obtained in sequence, and a discrete time sampling point index is assigned to each discrete sampling moment. At the same time, the total number of discrete time sampling points in the entire sampling process is set. At each discrete sampling time, the discrete left voltage sample value is obtained through the left sampling point, and the discrete right voltage sample value is obtained through the right sampling point. All discrete left voltage sample values ​​are arranged in the order of discrete time sampling point index to form the left discrete voltage sequence, and all discrete right voltage sample values ​​are arranged in the order of discrete time sampling point index to form the right discrete voltage sequence. At each discrete-time sampling point index, the corresponding discrete voltage sampling value on the left is subtracted from the corresponding discrete voltage sampling value on the right to obtain the voltage difference value across the disconnecting switch at the corresponding discrete sampling time. All voltage difference values ​​at discrete sampling times are arranged in the order of discrete-time sampling point indices to form a discrete sequence of voltage differences across the disconnecting switch.

3. The method for accurately measuring the opening and closing time of a disconnecting switch according to claim 2, characterized in that, The process of performing time-difference calculus on the discrete sequence of voltage difference across the disconnecting switch to generate a first-order voltage difference sequence, and then performing time-difference calculus again to generate a second-order voltage difference sequence, specifically includes: In the discrete sequence of voltage differences across the disconnecting switch, starting from the second discrete time sampling point index, for each current discrete time sampling point, the voltage difference value at the current discrete time sampling point and the voltage difference value at the previous discrete time sampling point are obtained. The first-order difference value of the voltage difference at the current discrete time sampling point is calculated by subtracting the previous voltage difference value from the current voltage difference value and dividing by the sampling time interval. The first-order difference values ​​at all discrete time sampling points are arranged in the order of the discrete time sampling point index to form the first-order difference sequence of voltage differences. In the first-order difference sequence of voltage difference, starting from the third discrete-time sampling point index, for each current discrete-time sampling point, the first-order difference value at the current discrete-time sampling point and the first-order difference value at the previous discrete-time sampling point are obtained. The second-order difference value of voltage difference at the current discrete-time sampling point is calculated by subtracting the previous first-order difference value from the current first-order difference value and dividing by the sampling time interval. The second-order difference values ​​at all discrete-time sampling points are arranged in the order of the discrete-time sampling point index to form the second-order difference sequence of voltage difference.

4. The method for accurately measuring the opening and closing time of a disconnecting switch according to claim 3, characterized in that, The step of accumulating the squared values ​​of the second-order voltage difference on the second-order voltage difference sequence by sliding window to construct a second-order difference energy function sequence and obtain the energy peak index and high energy range specifically includes: Set the sliding window half-width parameter so that the length of the sliding window determined by the sliding window half-width parameter is less than the total number of discrete-time sampling points of the voltage difference second-order difference sequence; In the second-order difference sequence of voltage difference, starting from the discrete-time sampling point index that is close to the beginning of the sequence and satisfies the condition of complete coverage of the sliding window, each discrete-time sampling point is selected as the center discrete-time sampling point index of the window in turn. For each center discrete-time sampling point index of the window, local second-order difference data with the center discrete-time sampling point index of the window as the midpoint and the length determined by the half-width parameter of the sliding window is extracted. For each voltage difference second-order difference value in each local second-order difference data, a squaring operation is performed, and all squaring results within the same local data are accumulated. The accumulated result is used as the second-order difference energy value at the index of the discrete-time sampling point at the center of the window. All accumulated results are arranged in the order of the discrete-time sampling point index at the center of the window to form a second-order difference energy function sequence. In the second-order difference energy function sequence, each energy value is traversed, the size of all energy values ​​is compared, the global maximum energy value is obtained, and in the case of multiple global maximum energy values, the smallest index of the discrete time sampling point at the center of the window is selected as the energy peak index. The energy peak index is multiplied by the sampling time interval and combined with the sampling start time to convert it into the time corresponding to the energy peak. The energy peak index and the range of discrete time sampling points on both sides that match the half-width parameter of the sliding window are taken as the high energy range containing the opening and closing action characteristics of the disconnecting switch.

5. The method for accurately measuring the opening and closing time of a disconnecting switch according to claim 4, characterized in that, The process of retrieving discrete-time sampling point indices of the sign change of the second-order differential voltage difference within the high-energy range and forming a set of zero-crossing indices, comparing the first-order differential voltage difference amplitudes at zero-crossing points, selecting the one with the largest amplitude as the action index, and converting it into the action time, specifically includes: Within the high-energy range, following the discrete-time sampling point index order, for each current discrete-time sampling point, the second-order difference value of the voltage difference at the current discrete-time sampling point and the second-order difference value of the voltage difference at the previous discrete-time sampling point are obtained, and the product of these two second-order difference values ​​of the voltage difference is calculated. When the product of the second-order difference of the voltage difference at a certain discrete-time sampling point and the second-order difference of the voltage difference at the previous discrete-time sampling point is negative, the corresponding discrete-time sampling point index is added to the zero-crossing index set, and the number of each discrete-time sampling point index in the zero-crossing index set and the total number of discrete-time sampling points in the zero-crossing index set are recorded; when there are no discrete-time sampling points with negative products in the high-energy range, the zero-crossing index set is set to an empty set; When the zero-crossing index set contains one or more discrete-time sampling point indices, for each discrete-time sampling point index in the zero-crossing index set, the first-order difference value at the corresponding discrete-time sampling point in the first-order difference sequence of voltage difference is obtained, the absolute value of the corresponding first-order difference value is taken to obtain the first-order difference amplitude of voltage difference, and a comparison operation is performed between the first-order difference amplitudes of voltage difference of all zero-crossing discrete-time sampling points. The zero-crossing discrete-time sampling point index with the largest amplitude is selected as the action index. When the set of zero cross-indexes is empty, the energy peak index is directly used as the action index; The action index is multiplied by the sampling time interval and combined with the sampling start time to convert it into the action time.

6. The method for accurately measuring the opening and closing time of a disconnecting switch according to claim 5, characterized in that, The process of capturing analysis windows on both sides of the action time, calculating the average voltage difference before and after the action, and marking the action type as closing, opening, or undetermined according to their magnitude includes: Based on the position of the action index in the discrete sequence of voltage difference across the disconnector and the total number of discrete time sampling points in the discrete sequence of voltage difference across the disconnector, obtain the half-width parameter of the voltage difference analysis window before and after the action, so that the entire range of the analysis window before the action is located before the action index and the entire range of the analysis window after the action is located after the action index. In the discrete sequence of voltage difference across the disconnector, several consecutive discrete time sampling points before the action index are used as the pre-action analysis window range. The voltage difference value at each discrete time sampling point within the pre-action analysis window range is obtained. All voltage difference values ​​within the pre-action analysis window range are summed and divided by the number of discrete time sampling points to calculate the average voltage difference before action. In the discrete sequence of voltage differences across the disconnecting switch, several consecutive discrete time sampling points after the action index are used as the post-action analysis window range. The voltage difference value at each discrete time sampling point within the post-action analysis window range is obtained. All voltage difference values ​​within the post-action analysis window range are summed and divided by the number of discrete time sampling points to calculate the average voltage difference after the action. The average voltage difference after the action is compared with the average voltage difference before the action. When the average voltage difference after the action is greater than the average voltage difference before the action, the action type of this operation is marked as closing; when the average voltage difference after the action is less than the average voltage difference before the action, the action type of this operation is marked as opening; when the average voltage difference after the action is equal to the average voltage difference before the action, the action type of this operation is marked as undetermined.

7. The method for accurately measuring the opening and closing time of a disconnecting switch according to claim 6, characterized in that, The process of obtaining the reference action time, calculating the action time deviation, and combining the action time, action type, and action time deviation into a single measurement action result data item specifically includes: For disconnecting switches, a calibration test of the operating time is performed in advance under rated operating conditions to obtain the reference operating time of the disconnecting switch; In a specific measurement process, the action time obtained through voltage difference analysis is acquired, and the obtained action time is subtracted from the reference action time to calculate the action time deviation of this measurement. The action time, action type, and action time deviation obtained in this measurement are combined into a single measurement action result data item according to a fixed field order. The result data of a single measurement action is output to a preset data processing module or data storage module and associated with the corresponding measurement record.

8. The method for accurately measuring the opening and closing time of a disconnecting switch according to claim 7, characterized in that, The process of performing multiple independent operations, collecting the average and standard deviation of the action time deviations, and marking the action time stability based on the standard deviation specifically includes: Perform multiple independent opening and closing operations on the same disconnecting switch under the same operating conditions. In each opening and closing operation, obtain the corresponding action time deviation of the opening and closing operation, and record the action time deviation of each operation in sequence to form an action time deviation sequence. Sum all action time deviations in the action time deviation sequence, and divide the sum by the total number of opening and closing operations to calculate the average action time deviation of all operations; For each action time deviation in the action time deviation sequence, calculate the difference between the action time deviation and the average action time deviation, perform a square operation on all differences and sum them, divide the sum of squares by the total number of opening and closing operations and then perform a square root operation to calculate the standard deviation of the action time deviation. When the standard deviation of the action time is equal to zero, the action time stability of the disconnecting switch is marked as completely stable; when the standard deviation of the action time is greater than zero, the action time stability of the disconnecting switch is marked as fluctuating.

9. The method for accurately measuring the opening and closing time of a disconnecting switch according to claim 8, characterized in that, The process involves creating a single measurement data record from the discrete sequence of voltage differences across the disconnecting switch, the first-order differential sequence of voltage differences, the second-order differential sequence of voltage differences, the second-order differential energy function sequence, the zero-crossing index set, the action index, the action time, and the action type. This record is then combined into a multi-measurement dataset and assigned a unique number. Specifically, this includes: For each opening and closing operation, obtain the discrete sequence of voltage difference across the disconnector for the corresponding opening and closing operation, obtain the first-order differential voltage difference sequence constructed from the discrete sequence of voltage difference across the disconnector, obtain the second-order differential voltage difference sequence constructed from the first-order differential voltage difference sequence, obtain the second-order differential energy function sequence constructed based on the second-order differential voltage difference sequence and the sliding window, obtain the set of zero-crossing indices that satisfy the zero-crossing condition in the second-order differential voltage difference sequence, obtain the action index selected by comparing the first-order differential voltage difference amplitude at the zero-crossing index, obtain the action time converted from the action index, obtain the action type determined by comparing the average voltage difference before and after the action, and combine the discrete sequence of voltage difference across the disconnector, the first-order differential voltage difference sequence, the second-order differential voltage difference sequence, the second-order differential energy function sequence, the set of zero-crossing indices, the action index, the action time, and the action type to form a single measurement data record for the corresponding opening and closing operation; The multiple single measurement data records corresponding to multiple opening and closing operations are combined into a multiple measurement dataset according to the operation sequence or preset sequence. The multiple measurement dataset is used as a set structure to describe the complete measurement information of the same disconnecting switch under multiple independent operations. Each set of multiple measurement datasets is assigned a unique number, and the unique number is combined with the corresponding multiple measurement dataset to form a numbered data pair. The data pairs enable the identification, indexing and traceability management of different batches of measurement datasets.

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