A method and system for analyzing circuit breaker breaking parameters based on phase domain trajectory analysis

Abstract

This invention discloses a method and system for analyzing circuit breaker breaking parameters based on phase domain trajectory analysis. The method includes: first, constructing a time-domain waveform expression for the short-circuit current; after acquiring the fault waveform, mapping the time-domain sampling points to the polar coordinate plane by defining reference points and sampling windows to form a phase domain trajectory and drawing it; then, performing waveform reproduction and similarity analysis, adjusting the initial phase of the sinusoidal AC component and the attenuated DC component to reproduce a high-precision time-domain waveform and improve the short-circuit current time-domain waveform expression; next, using vectorized matching technology based on digital channel names and kurtosis algorithms to screen out associated circuit breakers with displacement in the fault recording; then, calculating key parameters such as the DC time constant, fault current duration, and RMS value of the total current, and comparing and verifying them with the rated parameters of the circuit breaker. This improves the accuracy and real-time performance of circuit breaker breaking capacity assessment, providing an efficient and automated method for circuit breaker performance evaluation and anomaly diagnosis after power grid faults.

Description

Technical Field

[0001] This invention belongs to the field of power equipment detection and protection technology, and in particular relates to a method and system for analyzing circuit breaker breaking parameters based on phase domain trajectory analysis. Background Technology

[0002] As a critical control and protection device in power systems, the attenuation time constant after a fault change, the duration of the fault current, and the effective value of the load current are the core criteria for evaluating the breaking capacity of circuit breakers and are crucial for ensuring the safe and stable operation of the power grid. Existing fault waveform processing methods have significant shortcomings. Traditional methods rely on fixed thresholds or simple filtering, which are ill-suited for complex current waveforms (such as signals containing harmonics and noise interference), leading to large errors in identifying the start / end times of the fault current and inaccurate extraction of the load current peak value. Regarding computational algorithms, conventional root mean square (RMS) algorithms have poor adaptability to non-sinusoidal waveforms, and the least squares method for fitting attenuation curves does not consider data weights and is easily affected by noise. Furthermore, traditional methods rely on manual analysis of waveform data, which is inefficient and susceptible to subjective bias. Summary of the Invention

[0003] This invention provides a method and system for analyzing circuit breaker breaking parameters based on phase domain trajectory analysis, which solves the technical problem of inaccurate waveform data extraction leading to unreliable verification results.

[0004] In a first aspect, the present invention provides a method for analyzing circuit breaker breaking parameters based on phase domain trajectory analysis, comprising:

[0005] Construct a time-domain expression for the initial short-circuit current that includes a sinusoidal AC component and a decaying DC component;

[0006] Acquire short-circuit current time-domain waveform data, and digitally sample the short-circuit current time-domain waveform data to obtain at least one discrete time-domain sampling point, wherein the time-domain sampling point is the first sampling point after the zero-crossing point of the sinusoidal AC component from negative to positive.

[0007] The at least one time-domain sampling point is mapped to the polar coordinate plane to form a phase-domain trajectory. The polar angle of the phase-domain trajectory corresponds to the phase of the short-circuit current time-domain waveform, and the polar radius of the phase-domain trajectory corresponds to the instantaneous value of the short-circuit current.

[0008] The first short-circuit feature quantity under the sinusoidal AC component and the second short-circuit feature quantity under the attenuated DC component are extracted from the phase domain trajectory. The first short-circuit feature quantity and the second feature quantity are optimized according to the preset iterative optimization strategy to obtain the first target short-circuit feature quantity and the second target short-circuit feature quantity.

[0009] The initial short-circuit current time-domain expression is corrected based on the first target short-circuit characteristic quantity and the second target short-circuit characteristic quantity, and the target short-circuit current time-domain waveform data is reconstructed based on the corrected initial short-circuit current time-domain expression.

[0010] The circuit breaker status channel in the time-domain waveform data of the target short-circuit current is determined by keyword vectorization technology, and the target circuit breaker with displacement is detected in the circuit breaker status channel by kurtosis algorithm.

[0011] Calculate the attenuation time constant, fault current duration, and effective load current value of the target circuit breaker, and determine whether the attenuation time constant, fault current duration, and effective load current value are within the corresponding parameter threshold range.

[0012] Secondly, the present invention provides a circuit breaker breaking parameter analysis system based on phase domain trajectory analysis, comprising:

[0013] The module is configured to construct an initial short-circuit current time-domain expression that includes a sinusoidal AC component and a decaying DC component.

[0014] The sampling module is configured to acquire short-circuit current time-domain waveform data, and to perform digital sampling on the short-circuit current time-domain waveform data to obtain at least one discrete time-domain sampling point, wherein the time-domain sampling point is the first sampling point after the zero-crossing point of the sinusoidal AC component from negative to positive.

[0015] The mapping module is configured to map the at least one time-domain sampling point to a polar coordinate plane to form a phase-domain trajectory, wherein the polar angle of the phase-domain trajectory corresponds to the phase of the short-circuit current time-domain waveform, and the polar radius of the phase-domain trajectory corresponds to the instantaneous value of the short-circuit current.

[0016] The optimization module is configured to extract a first short-circuit feature quantity under the sinusoidal AC component and a second short-circuit feature quantity under the attenuated DC component in the phase domain trajectory, and optimize the first short-circuit feature quantity and the second feature quantity according to a preset iterative optimization strategy to obtain a first target short-circuit feature quantity and a second target short-circuit feature quantity.

[0017] The correction module is configured to correct the initial short-circuit current time-domain expression based on the first target short-circuit characteristic quantity and the second target short-circuit characteristic quantity, and reconstruct the target short-circuit current time-domain waveform data based on the corrected initial short-circuit current time-domain expression.

[0018] The determination module is configured to determine the circuit breaker state channel in the target short-circuit current time-domain waveform data based on keyword vectorization technology, and to detect the target circuit breaker with displacement in the circuit breaker state channel based on kurtosis algorithm.

[0019] The analysis module is configured to calculate the attenuation time constant, fault current duration, and effective value of load current of the target circuit breaker, and determine whether the attenuation time constant, the fault current duration, and the effective value of load current are within the corresponding parameter threshold range.

[0020] Thirdly, an electronic device is provided, comprising: at least one processor, and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the steps of the circuit breaker breaking parameter analysis method based on phase domain trajectory analysis according to any embodiment of the present invention.

[0021] Fourthly, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein when the program instructions are executed by a processor, the processor performs the steps of the circuit breaker breaking parameter analysis method based on phase domain trajectory analysis according to any embodiment of the present invention.

[0022] The circuit breaker breaking parameter analysis method and system based on phase domain trajectory analysis proposed in this application converts the waveform into a polar coordinate trajectory, utilizes the trajectory geometric features to achieve accurate parameter extraction, reconstructs a high-precision time-domain waveform expression, and performs circuit breaker correlation and parameter calculation based on the high-precision waveform, significantly improving analysis efficiency and accuracy. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A flowchart illustrating a circuit breaker breaking parameter analysis method based on phase domain trajectory analysis, provided as an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of the phase domain trajectory of a specific embodiment provided in this invention;

[0026] Figure 3 A structural block diagram of a circuit breaker breaking parameter analysis system based on phase domain trajectory analysis is provided in an embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0029] Please see Figure 1 The diagram shows a flowchart of a circuit breaker breaking parameter analysis method based on phase domain trajectory analysis according to this application.

[0030] like Figure 1 As shown, the circuit breaker breaking parameter analysis method based on phase domain trajectory analysis specifically includes the following steps:

[0031] Step S101: Construct an initial short-circuit current time-domain expression that includes a sinusoidal AC component and a decaying DC component.

[0032] In this step, the time-domain expression for the initial short-circuit current is:

[0033] ,

[0034] ,

[0035] ,

[0036] In the formula, Let be the short-circuit current at time t. This represents the amplitude of the steady-state sinusoidal current before the short circuit. This represents the initial phase of the steady-state sinusoidal circuit before the short circuit. Angular frequency, The moment the short circuit occurs. Let be the sinusoidal AC component of the short-circuit current at time t. Let be the decaying DC component of the short-circuit current at time t. For the optimized amplitude, For the optimized initial phase, This is the initial value for attenuation. This is the decay time constant.

[0037] Step S102: Obtain short-circuit current time-domain waveform data, and perform digital sampling on the short-circuit current time-domain waveform data to obtain at least one discrete time-domain sampling point, wherein the time-domain sampling point is the first sampling point after the zero-crossing point of the sinusoidal AC component from negative to positive.

[0038] Step S103: Map the at least one time-domain sampling point to the polar coordinate plane to form a phase-domain trajectory. The polar angle of the phase-domain trajectory corresponds to the phase of the short-circuit current time-domain waveform, and the polar radius of the phase-domain trajectory corresponds to the instantaneous value of the short-circuit current.

[0039] In this step, the expression for calculating the polar angle of the phase domain trajectory is:

[0040] ,

[0041] ,

[0042] In the formula, The polar angle of the nth sampling point index. For sampling window, For system frequency, The sampling frequency;

[0043] The expression for calculating the polar radius of the phase domain trajectory is:

[0044] ,

[0045] In the formula, The polar radius of the nth sampling point is... The sampling current value is the number of the nth sampling point.

[0046] It should be noted that after the phase domain trajectory is formed, the polar coordinates are created and the graph is plotted using the function `polarplot(theta, rho)` in Matlab software, where `theta` is the polar angle and `rho` is the polar radius. Under the phase domain trajectory, the recorded wave exhibits a spiral trajectory, composed of an "apple-shaped" positive half-wave and a "balloon-shaped" negative half-wave, the magnitude of which decreases with time. At this point, the DC component decays to 0, and the trajectory converges into a circle. The phase domain trajectory diagram is shown below. Figure 2 As shown, the black solid line and the red solid line represent the normal steady-state sinusoidal current and the short-circuit current, respectively, while the green dashed line and the blue dashed line represent the attenuated DC component and the sinusoidal AC component in the short-circuit current, respectively.

[0047] Step S104: Extract the first short-circuit feature quantity under the sinusoidal AC component and the second short-circuit feature quantity under the attenuated DC component from the phase domain trajectory, and optimize the first short-circuit feature quantity and the second feature quantity according to the preset iterative optimization strategy to obtain the first target short-circuit feature quantity and the second target short-circuit feature quantity.

[0048] In this step, after forming the phase domain trajectory of the short-circuit current, it is combined with the time domain waveform for analysis and calculation. Short-circuit characteristic quantities can be directly extracted and calculated. Taking a typical phase domain trajectory diagram as an example, the amplitude of the sinusoidal component is... initial phase , and Let M be the polar radius and polar angle of point c, respectively. Under the attenuated DC component, let M be the initial value of the attenuated DC component and the attenuation time constant. The solution requires consideration of time-domain relationships. Locate the points of in-phase within the time-domain waveform, i.e., points with a 360° phase difference in the encounter trajectory. Taking points a, b, d, and e as examples, the time-domain attenuation equation is: ,in, , , , For time intervals, , , , The times corresponding to points a, b, d, and e are the times of the time domain waveforms minus the time of the fault start. , , , Let M be the polar radius corresponding to points a, b, d, and e. Solve for M and... .

[0049] It should be noted that the first short-circuit feature quantity is optimized according to a preset iterative optimization strategy to obtain the first target short-circuit feature quantity, which specifically includes:

[0050] Initial settings: Set precision (cm), calculate initial phase Phase adjustment initial interval Let the initial interval boundaries be adjusted as follows: ;

[0051] Interval bisection: Calculate the midpoint a of the interval [b1, b2], and use the value of a to divide the interval into two parts: [b1, a] and [a, b2].

[0052] Correlation coefficient calculation: Calculate the midpoints of intervals [b1, a] and [a, b2], i.e., the initial phases: a1 and a2, respectively. Calculate the correlation coefficients c1 and c2 between the reproduced sine waveform and the original waveform when the initial phases are equal to a1 and a2.

[0053] Interval update judgment: Determine whether c1≥c2 is true. If it is true, let b2=a. If it is not true, let b1=a.

[0054] Precision determination: Determine whether c1≥cM or c2≥cM is true. If true, the adjustment ends. If false, return to the "interval bisection" step and repeat the subsequent process.

[0055] Output: When the accuracy judgment is met and the adjustment is finished, take the midpoint a of the interval [b1, b2] as the final initial phase and output the optimized amplitude and initial phase.

[0056] The second short-circuit feature is optimized according to a preset iterative optimization strategy to obtain the second target short-circuit feature, which specifically includes:

[0057] Initial input conditions: Calculate the raw data of the DC component and find the initial attenuation value. , Sampling time when =M Set the precision to cM;

[0058] Initialize the interval: calculate =1%M, sampling time Let the initial time interval be [ , Let the start and end times be... = , = ;

[0059] Iterative initialization: Back-substitute the initial end time. = ;

[0060] Correlation coefficient calculation: using point m ( , ) and n( , Initial time interval for coordinate calculation [ , The decay time constant of the waveform and This generates a reproduced DC component waveform, specifically by substituting the coordinates of points m and n into the DC component waveform of the current attenuation. expression In the middle, get Solving the system of equations, we get... Substitute This allows us to obtain the initial recurrence time-domain waveform expression of the attenuated DC component in the short-circuit current, and calculate the correlation coefficient between the recurrence DC component waveform and the original waveform within the time interval [tm, tn]. ;

[0061] judge - Check if ≤0.02s is true. If true, output directly. and As a result; if not true, judge Does ≥cM hold true? If so, output the value. and As a result, if it is not true, calculate the interval [ , midpoint ,make = ,judge - Check if the condition ≤0.02s holds true. If it does, extend the interval to one power frequency cycle. = +0.02s, if - If ≤0.02s is not valid, return directly to the correlation coefficient calculation step and recalculate;

[0062] After iteration, the output is... and As a final result, the adjusted attenuated DC component is reproduced, thus obtaining the second target short-circuit characteristic quantity.

[0063] Step S105: Correct the initial short-circuit current time-domain expression based on the first target short-circuit characteristic quantity and the second target short-circuit characteristic quantity, and reconstruct the target short-circuit current time-domain waveform data based on the corrected initial short-circuit current time-domain expression.

[0064] In this step, the corrected time-domain expression for the initial short-circuit current is:

[0065] ,

[0066] In the formula, This is the short-circuit current. This is the initial phase. Angular frequency, The moment the short circuit occurs. For time, For the optimized amplitude, For the optimized initial phase, The optimized DC attenuation starting value, This is the optimized decay time constant.

[0067] Step S106: Determine the circuit breaker status channel in the target short-circuit current time-domain waveform data according to keyword vectorization technology, and detect the target circuit breaker with displacement in the circuit breaker status channel according to kurtosis algorithm.

[0068] In this step, after scanning the reproduced target short-circuit current time-domain waveform data, the platform extracts the digital channel information from the target short-circuit current time-domain waveform data, classifies the digital channel names, and uses keyword vectorization technology to filter out all digital channels with circuit breaker operation numbers and "opening," "closing," or other similar semantic keywords. A kurtosis algorithm is then used to determine whether there is displacement information in the digital channels. Finally, all circuit breakers that show displacement in the fault recording are selected.

[0069] Step S107: Calculate the attenuation time constant, fault current duration, and effective value of load current of the target circuit breaker, and determine whether the attenuation time constant, the fault current duration, and the effective value of load current are within the corresponding parameter threshold range.

[0070] In this step, the expression for calculating the duration of the fault current is:

[0071] ,

[0072] ,

[0073] In the formula, The duration of the fault current. The fault cutoff time, The time when the fault occurred;

[0074] The expression for calculating the effective value of the load current is:

[0075] ,

[0076] In the formula, This is the effective value of the current. This is the periodic component of the short-circuit current. The DC component with the shortest interruption time. This represents the actual shortest start-up time.

[0077] In summary, the method of this application first constructs a time-domain waveform expression for the short-circuit current. After acquiring the fault waveform, it maps the time-domain sampling points to the polar coordinate plane by defining reference points and sampling windows to form a phase-domain trajectory and draw it. Then, it performs waveform reproduction and similarity analysis, adjusts the initial phase of the sinusoidal AC component and the attenuated DC component, reproduces a high-precision time-domain waveform, and improves the time-domain waveform expression for the short-circuit current. Next, based on vectorized matching technology and kurtosis algorithm using digital channel names, it filters out associated circuit breakers with displacement in the fault waveform recording. Then, it calculates key parameters such as the DC time constant, fault current duration, and RMS value of the total current, and compares and verifies them with the rated parameters of the circuit breaker. This method solves the problems of inaccurate waveform data extraction and processing and low degree of automation in existing technologies, improves the accuracy and real-time performance of circuit breaker breaking capacity assessment, and provides an efficient and automated method for circuit breaker performance assessment and anomaly diagnosis after power grid faults.

[0078] Please see Figure 3 The diagram shows a structural block diagram of a circuit breaker breaking parameter analysis system based on phase domain trajectory analysis according to this application.

[0079] like Figure 3As shown, the circuit breaker breaking parameter analysis system 200 includes a construction module 210, a sampling module 220, a mapping module 230, an optimization module 240, a correction module 250, a determination module 260, and an analysis module 270.

[0080] The system comprises the following modules: a construction module 210, configured to construct an initial short-circuit current time-domain expression including a sinusoidal AC component and a decaying DC component; a sampling module 220, configured to acquire short-circuit current time-domain waveform data, and digitally sample the short-circuit current time-domain waveform data to obtain at least one discrete time-domain sampling point, wherein the time-domain sampling point is the first sampling point after the zero-crossing point of the sinusoidal AC component from negative to positive; a mapping module 230, configured to map the at least one time-domain sampling point to a polar coordinate plane to form a phase-domain trajectory, wherein the polar angle of the phase-domain trajectory corresponds to the phase of the short-circuit current time-domain waveform, and the polar radius of the phase-domain trajectory corresponds to the instantaneous value of the short-circuit current; and an optimization module 240, configured to extract a first short-circuit feature quantity under the sinusoidal AC component and a second short-circuit feature quantity under the decaying DC component from the phase-domain trajectory, and optimize the first short-circuit feature quantity and the second short-circuit feature quantity according to a preset iterative optimization strategy. The second feature quantity is optimized to obtain the first target short-circuit feature quantity and the second target short-circuit feature quantity; the correction module 250 is configured to correct the initial short-circuit current time-domain expression based on the first target short-circuit feature quantity and the second target short-circuit feature quantity, and reconstruct the target short-circuit current time-domain waveform data based on the corrected initial short-circuit current time-domain expression; the determination module 260 is configured to determine the circuit breaker state channel in the target short-circuit current time-domain waveform data based on keyword vectorization technology, and detect the target circuit breaker with displacement in the circuit breaker state channel based on kurtosis algorithm; the analysis module 270 is configured to calculate the attenuation time constant, fault current duration and load current effective value of the target circuit breaker, and determine whether the attenuation time constant, the fault current duration and the load current effective value are within the corresponding parameter threshold range.

[0081] It should be understood that Figure 3 The modules and references described in the document Figure 1 The steps described in the text correspond to those in the method described above. Therefore, the operations, features, and corresponding technical effects described above also apply to the method described in the text. Figure 3 The various modules in the document will not be described in detail here.

[0082] In other embodiments, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein when the program instructions are executed by a processor, the processor performs the circuit breaker breaking parameter analysis method based on phase domain trajectory analysis in any of the above method embodiments.

[0083] In one embodiment, the computer-readable storage medium of the present invention stores computer-executable instructions, which are configured as follows:

[0084] Construct a time-domain expression for the initial short-circuit current that includes a sinusoidal AC component and a decaying DC component;

[0085] Acquire short-circuit current time-domain waveform data, and digitally sample the short-circuit current time-domain waveform data to obtain at least one discrete time-domain sampling point, wherein the time-domain sampling point is the first sampling point after the zero-crossing point of the sinusoidal AC component from negative to positive.

[0086] The at least one time-domain sampling point is mapped to the polar coordinate plane to form a phase-domain trajectory. The polar angle of the phase-domain trajectory corresponds to the phase of the short-circuit current time-domain waveform, and the polar radius of the phase-domain trajectory corresponds to the instantaneous value of the short-circuit current.

[0087] The first short-circuit feature quantity under the sinusoidal AC component and the second short-circuit feature quantity under the attenuated DC component are extracted from the phase domain trajectory. The first short-circuit feature quantity and the second feature quantity are optimized according to the preset iterative optimization strategy to obtain the first target short-circuit feature quantity and the second target short-circuit feature quantity.

[0088] The initial short-circuit current time-domain expression is corrected based on the first target short-circuit characteristic quantity and the second target short-circuit characteristic quantity, and the target short-circuit current time-domain waveform data is reconstructed based on the corrected initial short-circuit current time-domain expression.

[0089] The circuit breaker status channel in the time-domain waveform data of the target short-circuit current is determined by keyword vectorization technology, and the target circuit breaker with displacement is detected in the circuit breaker status channel by kurtosis algorithm.

[0090] Calculate the attenuation time constant, fault current duration, and effective load current value of the target circuit breaker, and determine whether the attenuation time constant, fault current duration, and effective load current value are within the corresponding parameter threshold range.

[0091] Computer-readable storage media may include a stored program area and a stored data area, wherein the stored program area may store an operating system and an application program required for at least one function; the stored data area may store data created based on the use of the circuit breaker breaking parameter analysis system based on phase domain trajectory analysis. Furthermore, the computer-readable storage medium may include high-speed random access memory, and may also include memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, the computer-readable storage medium may optionally include memory remotely disposed relative to a processor, which can be connected to the circuit breaker breaking parameter analysis system based on phase domain trajectory analysis via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0092] Figure 4 This is a schematic diagram of the structure of the electronic device provided in the embodiment of the present invention, such as... Figure 4 As shown, the device includes a processor 310 and a memory 320. The electronic device may also include an input device 330 and an output device 340. The processor 310, memory 320, input device 330, and output device 340 can be connected via a bus or other means. Figure 4 Taking a bus connection as an example, the memory 320 is the computer-readable storage medium described above. The processor 310 executes various server functions and data processing by running non-volatile software programs, instructions, and modules stored in the memory 320, thereby implementing the circuit breaker breaking parameter analysis method based on phase domain trajectory analysis described in the above embodiment. The input device 330 can receive input digital or character information and generate key signal inputs related to user settings and function control of the circuit breaker breaking parameter analysis system based on phase domain trajectory analysis. The output device 340 may include a display screen or other display device.

[0093] The aforementioned electronic device can execute the method provided in the embodiments of the present invention, and has the corresponding functional modules and beneficial effects for executing the method. Technical details not described in detail in this embodiment can be found in the method provided in the embodiments of the present invention.

[0094] In one implementation, the above-described electronic device is applied in a circuit breaker breaking parameter analysis system based on phase domain trajectory analysis, for a client, and includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to:

[0095] Construct a time-domain expression for the initial short-circuit current that includes a sinusoidal AC component and a decaying DC component;

[0096] Acquire short-circuit current time-domain waveform data, and digitally sample the short-circuit current time-domain waveform data to obtain at least one discrete time-domain sampling point, wherein the time-domain sampling point is the first sampling point after the zero-crossing point of the sinusoidal AC component from negative to positive.

[0097] The at least one time-domain sampling point is mapped to the polar coordinate plane to form a phase-domain trajectory. The polar angle of the phase-domain trajectory corresponds to the phase of the short-circuit current time-domain waveform, and the polar radius of the phase-domain trajectory corresponds to the instantaneous value of the short-circuit current.

[0098] The first short-circuit feature quantity under the sinusoidal AC component and the second short-circuit feature quantity under the attenuated DC component are extracted from the phase domain trajectory. The first short-circuit feature quantity and the second feature quantity are optimized according to the preset iterative optimization strategy to obtain the first target short-circuit feature quantity and the second target short-circuit feature quantity.

[0099] The initial short-circuit current time-domain expression is corrected based on the first target short-circuit characteristic quantity and the second target short-circuit characteristic quantity, and the target short-circuit current time-domain waveform data is reconstructed based on the corrected initial short-circuit current time-domain expression.

[0100] The circuit breaker status channel in the time-domain waveform data of the target short-circuit current is determined by keyword vectorization technology, and the target circuit breaker with displacement is detected in the circuit breaker status channel by kurtosis algorithm.

[0101] Calculate the attenuation time constant, fault current duration, and effective load current value of the target circuit breaker, and determine whether the attenuation time constant, fault current duration, and effective load current value are within the corresponding parameter threshold range.

[0102] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of various embodiments or some parts of embodiments.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for analyzing circuit breaker breaking parameters based on phase domain trajectory analysis, characterized in that, include: Construct a time-domain expression for the initial short-circuit current that includes a sinusoidal AC component and a decaying DC component; Acquire short-circuit current time-domain waveform data, and digitally sample the short-circuit current time-domain waveform data to obtain at least one discrete time-domain sampling point, wherein the time-domain sampling point is the first sampling point after the zero-crossing point of the sinusoidal AC component from negative to positive. The at least one time-domain sampling point is mapped to the polar coordinate plane to form a phase-domain trajectory. The polar angle of the phase-domain trajectory corresponds to the phase of the short-circuit current time-domain waveform, and the polar radius of the phase-domain trajectory corresponds to the instantaneous value of the short-circuit current. The first short-circuit feature quantity under the sinusoidal AC component and the second short-circuit feature quantity under the attenuated DC component are extracted from the phase domain trajectory. The first short-circuit feature quantity and the second short-circuit feature quantity are optimized according to the preset iterative optimization strategy to obtain the first target short-circuit feature quantity and the second target short-circuit feature quantity. The initial short-circuit current time-domain expression is corrected based on the first target short-circuit characteristic quantity and the second target short-circuit characteristic quantity, and the target short-circuit current time-domain waveform data is reconstructed based on the corrected initial short-circuit current time-domain expression. The circuit breaker status channel in the time-domain waveform data of the target short-circuit current is determined by keyword vectorization technology, and the target circuit breaker with displacement is detected in the circuit breaker status channel by kurtosis algorithm. Calculate the attenuation time constant, fault current duration, and effective load current value of the target circuit breaker, and determine whether the attenuation time constant, fault current duration, and effective load current value are within the corresponding parameter threshold range.

2. The circuit breaker breaking parameter analysis method based on phase domain trajectory analysis according to claim 1, characterized in that, The time-domain expression for the initial short-circuit current is: ， ， ， In the formula, Let be the short-circuit current at time t. This represents the amplitude of the steady-state sinusoidal current before the short circuit. This represents the initial phase of the steady-state sinusoidal circuit before the short circuit. Angular frequency, The moment the short circuit occurs. Let be the sinusoidal AC component of the short-circuit current at time t. Let be the decaying DC component of the short-circuit current at time t. For the optimized amplitude, For the optimized initial phase, This is the initial value for attenuation. This is the decay time constant.

3. The method for analyzing circuit breaker breaking parameters based on phase domain trajectory analysis according to claim 1, characterized in that, in, The expression for calculating the polar angle of the phase domain trajectory is: ， ， In the formula, The polar angle of the nth sampling point index. For sampling window, For system frequency, The sampling frequency; The expression for calculating the polar radius of the phase domain trajectory is: ， In the formula, The polar radius of the nth sampling point is... The sampling current value is the number of the nth sampling point.

4. The circuit breaker breaking parameter analysis method based on phase domain trajectory analysis according to claim 1, characterized in that, The first target short-circuit characteristic includes amplitude and initial phase; the second target short-circuit characteristic includes attenuated DC initial value and attenuation time constant.

5. The circuit breaker breaking parameter analysis method based on phase domain trajectory analysis according to claim 4, characterized in that, in, The first short-circuit feature is optimized according to a preset iterative optimization strategy to obtain the first target short-circuit feature, specifically including: Set the precision cM, calculate the initial phase φ0, and the initial phase adjustment interval: [φ0-Δφ, φ0+Δφ]. Let the boundaries of the initial adjustment interval be: b1 = φ0-Δφ, b2 = φ0+Δφ. Calculate the midpoint a of the interval [b1, b2], and use the value of a to divide the interval [b1, b2] into [b1, a] and [a, b2]; Calculate the midpoints of the intervals [b1, a] and [a, b2], i.e. the initial phases: a1 and a2. When the initial phases are equal to a1 and a2, calculate the correlation coefficients c1 and c2 between the reproduced sine waveform and the original waveform. Determine whether c1≥cM and c2≥cM are true. If either one is true, the adjustment ends and the corresponding a1 or a2 is taken as the final initial phase. If both c1≥cM and c2≥cM are true, take the larger of c1 and c2, corresponding to a1 or a2, as the initial phase. If neither c1≥cM nor c2≥cM holds true, then determine whether c1≥c2 holds true. If c1≥c2 holds true, then let b2=a. If c1≥c2 does not hold true, then let b1=a and recalculate c1 and c2 until either c1≥cM or c2≥cM is satisfied, thus obtaining the first target short-circuit characteristic quantity.

6. The circuit breaker breaking parameter analysis method based on phase domain trajectory analysis according to claim 4, characterized in that, in, The second short-circuit feature is optimized according to a preset iterative optimization strategy to obtain the second target short-circuit feature, which specifically includes: Calculate the raw data of the DC component and find the initial value of attenuation. , Sampling time when =M Set the precision to cM; calculate =1%M, sampling time Let the initial time interval be [ , ]; Using point m ( , ) and n( , Initial time interval for coordinate calculation [ , The decay time constant of the waveform and And form a reproduced DC component waveform, specifically: Substitute the coordinates of points m and n into the DC component of the current attenuation. expression In the middle, get Solving the system of equations, we get... Substitute The initial recurrence time-domain waveform expression of the attenuated DC component in the short-circuit current is obtained, and the time period is calculated. , The correlation coefficient between the reproduced DC component waveform and the original waveform. ; judge - Check if ≤0.02s is true. If true, output directly. and As a result; if not true, judge Does ≥cM hold true? If so, output the value. and As a result, if it is not true, calculate the interval [ , midpoint ,make = ,judge - Check if the condition ≤0.02s holds true. If it does, extend the interval to one power frequency cycle. = +0.02s, if - If ≤0.02s is not valid, return directly to the correlation coefficient calculation step and recalculate; After iteration, the output is... and As a final result, the adjusted attenuated DC component is reproduced, thus obtaining the second target short-circuit characteristic quantity.

7. The method for analyzing circuit breaker breaking parameters based on phase domain trajectory analysis according to claim 1, characterized in that, in, The corrected time-domain expression for the initial short-circuit current is: ， In the formula, This is the short-circuit current. This is the initial phase. Angular frequency, The moment the short circuit occurs. For time, For the optimized amplitude, For the optimized initial phase, The optimized DC attenuation starting value, This is the optimized decay time constant.

8. The method for analyzing circuit breaker breaking parameters based on phase domain trajectory analysis according to claim 1, characterized in that, The expression for calculating the duration of the fault current is: ， ， In the formula, The duration of the fault current. The fault cutoff time, The time when the fault occurred; The expression for calculating the effective value of the load current is: ， In the formula, This is the effective value of the current. This is the periodic component of the short-circuit current. The DC component with the shortest interruption time. This represents the actual shortest start-up time.

9. A circuit breaker breaking parameter analysis system based on phase domain trajectory analysis, characterized in that, include: The module is configured to construct an initial short-circuit current time-domain expression that includes a sinusoidal AC component and a decaying DC component. The sampling module is configured to acquire short-circuit current time-domain waveform data, and to perform digital sampling on the short-circuit current time-domain waveform data to obtain at least one discrete time-domain sampling point, wherein the time-domain sampling point is the first sampling point after the zero-crossing point of the sinusoidal AC component from negative to positive. The mapping module is configured to map the at least one time-domain sampling point to a polar coordinate plane to form a phase-domain trajectory, wherein the polar angle of the phase-domain trajectory corresponds to the phase of the short-circuit current time-domain waveform, and the polar radius of the phase-domain trajectory corresponds to the instantaneous value of the short-circuit current. The optimization module is configured to extract a first short-circuit feature quantity under the sinusoidal AC component and a second short-circuit feature quantity under the attenuated DC component in the phase domain trajectory, and optimize the first short-circuit feature quantity and the second short-circuit feature quantity according to a preset iterative optimization strategy to obtain a first target short-circuit feature quantity and a second target short-circuit feature quantity. The correction module is configured to correct the initial short-circuit current time-domain expression based on the first target short-circuit characteristic quantity and the second target short-circuit characteristic quantity, and reconstruct the target short-circuit current time-domain waveform data based on the corrected initial short-circuit current time-domain expression. The determination module is configured to determine the circuit breaker state channel in the target short-circuit current time-domain waveform data based on keyword vectorization technology, and to detect the target circuit breaker with displacement in the circuit breaker state channel based on kurtosis algorithm. The analysis module is configured to calculate the attenuation time constant, fault current duration, and effective value of load current of the target circuit breaker, and determine whether the attenuation time constant, the fault current duration, and the effective value of load current are within the corresponding parameter threshold range.

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