Method and device for determining just closing point of circuit breaker

Abstract

The embodiment of the invention discloses a method and device for determining the just closing point of a circuit breaker, and the method comprises the steps: obtaining a speed time signal corresponding to a moving contact of the circuit breaker, and the speed time signal is used for indicating the speed change condition of the moving contact in the closing process of the circuit breaker; through a local mean decomposition algorithm, decomposing based on the speed time signal to obtain a plurality of product function components; calculating self-information corresponding to each of the multiple product function components; selecting the product function component with the minimum corresponding self-information from the plurality of product function components as a target product function component; and determining an instantaneous frequency curve corresponding to the target product function component, and determining a rigid closing point of the circuit breaker according to the instantaneous frequency curve. According to the method, the just-closed point of the circuit breaker can be accurately determined with low cost.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a method and device for determining a just-closed point of a circuit breaker. Background Art

[0002] Circuit breakers are one of the most widely used switchgear in power systems. They play a role in protecting and controlling power systems. Whether circuit breakers can operate reliably is related to whether power systems can operate stably. With the development of power systems and digital and intelligent power grids, the number of circuit breakers in operation has increased rapidly.

[0003] According to statistics, mechanical failures account for about 70% of high-voltage circuit breaker failures, of which operating mechanism failures account for about 40%. In the face of circuit breaker failures, it is very important to carry out online monitoring of the mechanical characteristics of circuit breakers. By online monitoring of the mechanical characteristics of circuit breakers, the working status of related operating equipment can be monitored in real time, thereby achieving targeted operation and maintenance of operating equipment and early warning of failures, thereby reducing the failure rate of the power system, improving the power quality of the power grid, and ensuring the safe and reliable operation of the power grid.

[0004] When monitoring the mechanical characteristics of a circuit breaker online, the opening and closing speed of the circuit breaker is one of the important parameters that need to be monitored. A faster opening and closing speed may cause a certain degree of mechanical damage to the circuit breaker, and a slower opening and closing speed may affect the overall arcing effect. The key to determining the opening and closing speed of the circuit breaker is to determine the just-closed point and just-opened point of the circuit breaker; however, the methods currently used to determine the just-closed point of the circuit breaker in the relevant technology generally have the problems of high cost and low accuracy. Summary of the invention

[0005] The embodiments of the present application provide a method and device for determining a circuit breaker rigid closing point, which can determine the circuit breaker rigid closing point more accurately at a lower cost.

[0006] In view of this, a first aspect of the present application provides a method for determining a circuit breaker just-closed point, the method comprising:

[0007] Acquire a speed time signal corresponding to a moving contact of a circuit breaker; the speed time signal is used to indicate a speed change of the moving contact during the closing process of the circuit breaker;

[0008] Decomposing the speed time signal to obtain a plurality of product function components by a local mean decomposition algorithm;

[0009] Calculating the self-information corresponding to each of the plurality of product function components;

[0010] Among the multiple product function components, select the product function component with the smallest corresponding self-information as the target product function component;

[0011] An instantaneous frequency curve corresponding to the target product function component is determined, and a rigid closing point of the circuit breaker is determined according to the instantaneous frequency curve.

[0012] Optionally, obtaining a speed time signal corresponding to a moving contact of a circuit breaker includes:

[0013] Obtaining a travel time signal corresponding to the moving contact during the closing process of the circuit breaker through a displacement sensor installed on the circuit breaker;

[0014] Based on the travel time signal, the speed time signal is converted.

[0015] Optionally, the decomposition of the speed time signal by a local mean decomposition algorithm to obtain a plurality of product function components includes:

[0016] By using the local mean decomposition algorithm, multiple rounds of signal decomposition processing are performed based on the speed time signal until a preset number of product function components are obtained;

[0017] Wherein, each round of signal decomposition processing includes:

[0018] Extracting multiple reference extreme value points from the original signal of the current round of signal decomposition processing; when the current round of signal decomposition processing is the first round of signal decomposition processing, the original signal is the speed time signal;

[0019] Using a sliding average method, a local mean function and an envelope estimation function are determined according to the multiple reference extreme value points;

[0020] Determining a reference frequency modulation function according to the original signal, the local mean function and the envelope estimation function;

[0021] If the reference frequency modulation function is a pure frequency modulation function, the product function component obtained by the current round of signal decomposition processing is determined according to the reference frequency modulation function and the envelope estimation function determined in the current round and the previous round of signal decomposition processing; the original signal of the next round of signal decomposition processing is obtained according to the original signal and the product function component;

[0022] If the reference frequency modulation function is not the pure frequency modulation function, the original signal for the next round of signal decomposition processing is determined according to the reference frequency modulation function.

[0023] Optionally, determining a reference frequency modulation function according to the original signal, the local mean function and the envelope estimation function includes:

[0024] Subtracting the local mean function from the original signal to obtain a difference function;

[0025] The reference frequency modulation function is obtained by dividing the difference function by the envelope estimation function.

[0026] Optionally, determining the product function component obtained by the current round of signal decomposition processing according to the reference frequency modulation function and the envelope estimation function determined in the current round and the previous round of signal decomposition processing includes:

[0027] Calculating the product of the envelope estimation function determined in the current round of the signal decomposition processing and the envelope estimation function determined in each previous round of the signal decomposition processing to obtain an envelope signal;

[0028] The product of the envelope signal and the reference frequency modulation function is calculated as the product function component.

[0029] Optionally, obtaining the original signal for the next round of signal decomposition processing according to the original signal and the product function component includes:

[0030] The product function component is subtracted from the original signal to obtain the original signal for the next round of signal decomposition processing.

[0031] Optionally, the calculating the self-information corresponding to each of the plurality of product function components includes:

[0032] For each of the product function components, performing an integration operation on the product function component to obtain an energy value corresponding to the product function component;

[0033] Calculating the sum of energy values ​​corresponding to the multiple product function components to obtain a total energy value;

[0034] For each of the product function components, the self-information corresponding to the product function component is calculated according to the energy value corresponding to the product function component and the total energy value.

[0035] Optionally, each of the product function components is the product of an envelope signal and a pure frequency modulation function; and determining the instantaneous frequency curve corresponding to the target product function component comprises:

[0036] Acquire a pure frequency modulation function in the target product function component as a target pure frequency modulation function;

[0037] By deriving the inverse function of the target pure frequency modulation function, an instantaneous frequency curve corresponding to the target product function component is obtained.

[0038] Optionally, determining the rigid closing point of the target circuit breaker according to the instantaneous frequency curve includes:

[0039] Extracting a maximum point from the instantaneous frequency curve;

[0040] The time corresponding to the maximum value point is determined as the just-closing point of the circuit breaker.

[0041] A second aspect of the present application provides a device for determining a circuit breaker just-closed point, the device comprising:

[0042] A signal acquisition module, used to acquire a speed time signal corresponding to a moving contact of a circuit breaker; the speed time signal is used to indicate a speed change of the moving contact during the closing process of the circuit breaker;

[0043] A signal decomposition module, used for obtaining a plurality of product function components based on the speed time signal decomposition by a local mean decomposition algorithm;

[0044] A self-information calculation module, used to calculate the self-information corresponding to each of the plurality of product function components;

[0045] A component selection module, used to select a product function component with the smallest corresponding self-information from the plurality of product function components as a target product function component;

[0046] The rigid closing point determination module is used to determine the instantaneous frequency curve corresponding to the target product function component, and determine the rigid closing point of the circuit breaker according to the instantaneous frequency curve.

[0047] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0048] An embodiment of the present application provides a method for determining a rigid closing point of a circuit breaker, the method comprising: obtaining a speed time signal corresponding to a moving contact of the circuit breaker, the speed time signal being used to indicate a speed change of the moving contact during the closing process of the circuit breaker; then, using a local mean decomposition algorithm, decomposing the speed time signal to obtain a plurality of product function components; then, calculating the self-information corresponding to each of the plurality of product function components; and selecting a product function component with the smallest corresponding self-information from the plurality of product function components as a target product function component; and then, determining an instantaneous frequency curve corresponding to the target product function component, and determining the rigid closing point of the circuit breaker according to the instantaneous frequency curve. In the above method, the local mean decomposition algorithm is used to decompose the speed time signal. On the one hand, the local mean decomposition algorithm can be used to fit the envelope calculation method using the sliding average method to avoid the phenomenon of over-envelope or under-envelope, thereby improving the accuracy of the product function components obtained by decomposition; on the other hand, through the local mean decomposition algorithm, the product function components can be obtained with fewer screening times, thereby reducing the degree of contamination of the entire data segment by the endpoint effect and improving the accuracy of the product function components obtained by decomposition; accordingly, subsequent processing is performed based on the product function components with higher accuracy obtained by the local mean decomposition algorithm, which can more efficiently and accurately determine the rigid closing point of the circuit breaker, that is, ensure that the rigid closing point of the circuit breaker determined has higher accuracy. In addition, the embodiment of the present application can directly obtain the speed time signal based on the sensor originally deployed on the circuit breaker without deploying additional sensors, thereby also reducing the cost required to determine the rigid closing point of the circuit breaker. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic flow chart of a method for determining a circuit breaker just-closed point provided in an embodiment of the present application;

[0050] Figure 2 A schematic diagram of an exemplary local mean function provided in an embodiment of the present application;

[0051] Figure 3 A schematic diagram of an exemplary envelope estimation function provided in an embodiment of the present application;

[0052] Figure 4 A schematic diagram of a flow chart of iteratively executing signal decomposition processing provided in an embodiment of the present application;

[0053] Figure 5 A schematic diagram of the structure of a device for determining a circuit breaker just-closed point provided in an embodiment of the present application. DETAILED DESCRIPTION

[0054] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0055] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0056] In the related art, a common method for determining the rigid closing point of a circuit breaker is a method for analyzing the rigid closing point of a circuit breaker based on the Hilbert-Huang Transform (HHT). In this method, a non-contact optical fiber displacement sensor can be used to collect the travel time signal of the circuit breaker and convert it into a speed time signal. Then, the speed time signal is decomposed using an empirical mode decomposition algorithm to obtain an intrinsic mode function component including local characteristics of the speed signal. Then, the intrinsic mode function component is selected using the variance contribution rate, and the instantaneous amplitude is obtained through the Hilbert transform. The characteristic point of the curve is the rigid closing point of the circuit breaker.

[0057] However, the above method has the following problems: On the one hand, the Hilbert-Huang transform algorithm uses cubic interpolation to fit the envelope in the empirical mode decomposition, and this envelope fitting method is prone to over-envelope or under-envelope, affecting the accuracy of the intrinsic mode function components obtained by decomposition, and thus affecting the accuracy of the final determination of the circuit breaker just-closed point. On the other hand, the number of screening times in the Hilbert-Huang transform algorithm is too large, which will cause the endpoint effect to pollute the entire data segment to a large extent.

[0058] In order to solve the above problems, an embodiment of the present application provides a method for determining a circuit breaker rigid closing point based on a local mean decomposition (LMD) algorithm, the method comprising: obtaining a speed time signal corresponding to a moving contact of the circuit breaker, the speed time signal being used to indicate a speed change of the moving contact during the closing process of the circuit breaker; then, using a local mean decomposition algorithm, decomposing the speed time signal to obtain a plurality of product function components; then, calculating the self-information corresponding to each of the plurality of product function components; and selecting a product function component with the smallest corresponding self-information from the plurality of product function components as a target product function component; and then, determining an instantaneous frequency curve corresponding to the target product function component, and determining the rigid closing point of the circuit breaker according to the instantaneous frequency curve.

[0059] The above method uses the local mean decomposition algorithm to decompose the speed time signal. On the one hand, the local mean decomposition algorithm can be used to adopt the sliding average method to fit the envelope calculation method to avoid the phenomenon of over-envelope or under-envelope, thereby improving the accuracy of the product function components obtained by decomposition; on the other hand, through the local mean decomposition algorithm, the product function components can be obtained with fewer screening times, thereby reducing the degree of contamination of the entire data segment by the endpoint effect and improving the accuracy of the product function components obtained by decomposition. Accordingly, subsequent processing is performed based on the product function components with higher accuracy obtained by the local mean decomposition algorithm, so that the rigid closing point of the circuit breaker can be determined more efficiently and accurately, that is, the rigid closing point of the circuit breaker determined can be ensured to have higher accuracy. In addition, the embodiment of the present application can directly obtain the speed time signal based on the sensor originally deployed on the circuit breaker without deploying additional sensors, thereby also reducing the cost required to determine the rigid closing point of the circuit breaker.

[0060] In order to facilitate further understanding of the method for determining the just-closing point of a circuit breaker provided in an embodiment of the present application, the method for determining the just-closing point of a circuit breaker is described in detail below through a method embodiment.

[0061] See also Figure 1 , Figure 1 A flow chart of a method for determining a circuit breaker just-closed point provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the method comprises the following steps:

[0062] Step 101: Acquire a speed time signal corresponding to a moving contact of a circuit breaker; the speed time signal is used to indicate a speed change of the moving contact during the closing process of the circuit breaker.

[0063] In the embodiment of the present application, when the just-closing point of the circuit breaker is monitored online, a speed time signal corresponding to the moving contact of the circuit breaker during the closing process of the circuit breaker can be obtained. The speed time signal is used to indicate the speed change of the moving contact during the closing process of the circuit breaker. The speed time signal can specifically be a change curve of the movement speed of the moving contact during the closing process of the circuit breaker, and the horizontal coordinate of the change curve is time, and the vertical coordinate is the movement speed of the moving contact.

[0064] In a possible implementation, the speed time signal corresponding to the moving contact can be obtained by transforming the travel time signal corresponding to the moving contact. That is, the "obtaining the speed time signal corresponding to the moving contact of the circuit breaker" in the above step 101 can specifically include the following steps 1011 and 1012 (not shown in the figure):

[0065] Step 1011: obtaining a travel time signal corresponding to the moving contact during the closing process of the circuit breaker through a displacement sensor installed on the circuit breaker.

[0066] In practical applications, a displacement sensor is usually installed on the circuit breaker, and the displacement sensor is used to detect the displacement of the moving contact of the circuit breaker, that is, the movement stroke. Exemplarily, the displacement sensor installed on the circuit breaker can be a magnetic grating displacement sensor, and the reader of the magnetic grating displacement sensor is closely connected to the moving part of the circuit breaker mechanism (such as the moving contact), and moves with the moving part of the mechanism; based on this, the magnetic grating displacement sensor can be directly used to collect the travel time signal of the moving contact, and the travel time signal is used to indicate the movement stroke of the moving contact during the closing process of the circuit breaker. The travel time signal can specifically be the movement stroke curve of the moving contact during the closing process of the circuit breaker, and the horizontal coordinate of the movement stroke curve is time, and the vertical coordinate is the movement stroke of the moving contact.

[0067] Assume that the signal sampling period of the magnetic grating displacement sensor installed on the circuit breaker is 0.1ms, the number of sampling points is 3000, the effective stroke is 300mm, and the displacement accuracy is 0.1mm; then when using the magnetic grating displacement sensor to collect the travel time signal corresponding to the moving contact, the current movement stroke of the moving contact can be collected every 0.1ms, for a total of 3000 times, and then based on the movement stroke of the moving contact collected 3000 times, the corresponding movement stroke curve is constructed to obtain the travel time signal corresponding to the moving contact.

[0068] It should be understood that in practical applications, in addition to the above-mentioned magnetic grating displacement sensor, other types of displacement sensors, such as optical fiber displacement sensors, may be used to collect the travel time signal corresponding to the moving contact. The embodiments of the present application do not impose any limitation on the type of displacement sensor used.

[0069] Step 1012: Based on the travel time signal, convert to obtain the speed time signal.

[0070] After the travel time signal corresponding to the moving contact is collected by the displacement sensor, the travel time signal can be converted into a corresponding speed time signal. Exemplarily, the travel curve corresponding to each time unit (such as 0.1ms) can be intercepted in the travel time signal, and then the speed corresponding to each time unit can be calculated based on the change of the travel of each time unit; that is, for each time unit, the travel corresponding to the end point of the time unit can be subtracted from the travel corresponding to the starting point of the time unit to obtain the change of the travel within the time unit, and then the change of the travel can be divided by the time length of the time unit to obtain the speed corresponding to the time unit; then, based on the speed corresponding to each time unit, the speed change curve can be constructed, that is, the speed time signal can be constructed.

[0071] Exemplarily, when a magnetic grating displacement sensor is used to collect travel time signals, since the adjacent magnetic grating pitches of the magnetic grating scale in the magnetic grating displacement sensor are very short, the average speed passing through the magnetic grating pitch can be used as the instantaneous speed passing through each magnetic grating pitch; that is, the change in travel collected in each signal sampling period (such as 0.1ms) is divided by the length of the signal sampling period to obtain the average speed corresponding to the signal sampling period. Since the signal sampling period is short, the average speed can be regarded as the instantaneous speed, and the speed time signal can be obtained using the average speed corresponding to each signal sampling period.

[0072] In this way, through the above method, the displacement sensor originally configured on the circuit breaker is used to collect the travel time signal corresponding to the moving contact, and the travel time signal is converted into a speed time signal. Without installing other sensors, reliable collection of the speed time signal corresponding to the moving contact can be achieved, thereby reducing the implementation cost of detecting the rigid closing point of the circuit breaker.

[0073] Step 102: Decomposing the speed time signal to obtain a plurality of product function components by using a local mean decomposition algorithm.

[0074] After obtaining the speed time signal corresponding to the moving contact of the circuit breaker, the LMD algorithm can be used to decompose the speed time signal into several product function (PF) components, each PF component can be specifically the product of a pure frequency modulation function and an envelope signal. The LMD algorithm can decompose the original speed time signal into PF components corresponding to different frequencies, and then the circuit breaker just-closed point can be detected based on the PF components.

[0075] In a possible implementation, the “decomposing the speed time signal to obtain a plurality of product function components by a local mean decomposition algorithm” in step 102 may specifically include:

[0076] By means of the local mean decomposition algorithm, multiple rounds of signal decomposition processing are performed based on the speed time signal until a preset number of product function components are obtained.

[0077] That is, the LMD algorithm can be used to iteratively perform several rounds of signal decomposition processing based on the speed time signal, and the signal decomposition processing is used to decompose the PF component from the speed time signal. When a preset number of PF components are obtained through each round of signal decomposition processing performed, it can be considered that all frequency components in the speed time signal have been extracted, and then the signal decomposition processing is stopped. Usually, the above-mentioned preset number can be set to 6, because the first 6 PF components extracted from the speed time signal almost contain all frequency components in the speed time signal.

[0078] It should be noted that in practical applications, it is possible that the PF component cannot be extracted through one round of signal decomposition processing, that is, among the multiple rounds of signal decomposition processing performed, there may be some rounds of signal decomposition processing that fail to extract effective PF components. Therefore, the number of rounds of signal component processing performed is usually greater than or equal to the above-mentioned preset number.

[0079] More specifically, each round of signal decomposition processing may include the following steps 1 to 5:

[0080] Step 1: extract multiple reference extreme value points from the original signal of the current round of signal decomposition processing; when the current round of signal decomposition processing is the first round of signal decomposition processing, the original signal is the speed time signal.

[0081] When executing this round of signal decomposition processing, it is necessary to first determine the original signal of this round of signal decomposition processing. If this round of signal decomposition processing is the first round of signal decomposition processing, that is, signal decomposition processing has not been performed based on the speed time signal corresponding to the moving contact before, then it can be determined that the original signal of this round of signal decomposition processing is the speed time signal corresponding to the moving contact. If this round of signal decomposition processing is not the first round of signal decomposition processing, that is, signal decomposition processing has been performed based on the speed time signal corresponding to the moving contact before, then the original signal of this round of signal decomposition processing can be determined based on the signal decomposition processing performed in the previous round, that is, when the previous round of signal decomposition processing is performed, the original signal of the next round (that is, this round) of signal decomposition processing will be determined.

[0082] Then, multiple reference extreme value points are extracted from the original signal of the current round of signal decomposition processing. Exemplarily, the original signal can be divided into several sub-signals, such as equally dividing the original signal into several sub-signals according to a preset time length, or unequally dividing the original signal into several sub-signals according to the change trend of the original signal, and then, the extreme value points (including maximum value points and minimum value points) are extracted from each sub-signal as reference extreme value points.

[0083] Step 2: Using the sliding average method, determine the local mean function and the envelope estimation function according to the multiple reference extreme points.

[0084] After extracting a plurality of reference extreme value points from the original signal of this round of signal decomposition processing, the local mean function and envelope estimation parameters can be determined based on the plurality of reference extreme value points.

[0085] When determining the local mean function, for each sub-signal in the original signal, the mean of two reference extreme value points (maximum point and minimum point) extracted from the sub-signal can be calculated, for example, the mean of the amplitude corresponding to the two reference extreme value points and the mean of the time corresponding to the two reference extreme value points can be calculated, thereby obtaining the local mean point corresponding to the sub-signal; then, the local mean points corresponding to each sub-signal are connected to obtain the corresponding local mean polyline; then, the five-point sliding average method is used to smooth the local mean polyline, thereby obtaining the local mean function. See Figure 2 , Figure 2 A schematic diagram of an exemplary local mean function provided for an embodiment of the present application, wherein m1, m2, m3 and m4 are the above-mentioned local mean points, line 201 is the original signal, line 202 is the local mean curve, and line 203 is the local mean function.

[0086] When determining the envelope estimation function, for each sub-signal in the original signal, the difference between two reference extreme points (maximum point and minimum point) extracted from the sub-signal can be calculated, for example, the difference between the amplitudes corresponding to the two reference extreme points and the difference between the times corresponding to the two reference extreme points can be calculated, thereby obtaining the difference line corresponding to the sub-signal; then, the difference lines corresponding to each sub-signal are connected, that is, for adjacent sub-signals, the end point of the difference line corresponding to the previous sub-signal is connected to the starting point of the difference line corresponding to the next sub-signal, thereby obtaining the corresponding envelope polyline; then, the five-point sliding average method is used to smooth the envelope polyline, thereby obtaining the envelope estimation function. See. Figure 3 , Figure 3 A schematic diagram of an exemplary envelope estimation function provided in an embodiment of the present application, wherein a1, a2, a3 and a4 are the above-mentioned difference lines, line 301 is the envelope broken line, and line 302 is the envelope estimation function.

[0087] It should be noted that the moving average method is a prediction method that shifts the time series period by period and uses the average as the prediction value. In the embodiment of the present application, the simple moving average method is used to average the five most recent groups of data as the prediction value of the next group.

[0088] Step 3: Determine a reference frequency modulation function according to the original signal, the local mean function and the envelope estimation function.

[0089] After determining the local mean function and envelope estimation function based on the reference extreme points extracted from the original signal, the reference frequency modulation function can be further determined based on the original signal of this round of signal decomposition processing and the determined local mean function and envelope estimation function; the reference frequency modulation function is the reference data for determining whether the PF component can be obtained through this round of signal decomposition processing.

[0090] As an example, the reference chirp function may be determined as follows:

[0091] The local mean function is subtracted from the original signal to obtain a difference function; and the reference frequency modulation function is obtained by dividing the difference function by the envelope estimation function.

[0092] Specifically, the difference function can be calculated by the following formula (1):

[0093] h=xq i (1)

[0094] Among them, h is the difference function, x is the original signal of this round of signal decomposition, q i is the local mean function obtained in step 2.

[0095] The reference frequency modulation function can be calculated by the following formula (2):

[0096] s i =h / a i (2)

[0097] Among them, s i is the reference frequency modulation function, h is the difference function, a i is the envelope estimation function.

[0098] Step 4: If the reference frequency modulation function is a pure frequency modulation function, then determine the product function component obtained by this round of signal decomposition processing based on the reference frequency modulation function and the envelope estimation function determined in this round and the previous round of signal decomposition processing; and obtain the original signal of the next round of signal decomposition processing based on the original signal and the product function component.

[0099] After obtaining the reference frequency modulation function, it is necessary to determine whether the reference frequency modulation function is a pure frequency modulation function. If the reference frequency modulation function is a pure frequency modulation function, it means that the PF component can be obtained through this round of signal decomposition processing, and the PF component obtained through this round of signal decomposition processing can be determined based on the reference frequency modulation function; specifically, the PF component obtained through this round of signal decomposition processing can be determined based on the reference frequency modulation function, the envelope estimation function obtained in this round of signal decomposition processing, and the envelope estimation function obtained in the previous round of signal decomposition processing (if this round of signal decomposition processing is the first round of signal decomposition processing, this part of the envelope estimation function is not needed).

[0100] As an example, the above PF component can be determined in the following way:

[0101] Calculate the product of the envelope estimation function determined in the current round of signal decomposition processing and the envelope estimation function determined in the previous rounds of signal decomposition processing to obtain an envelope signal; calculate the product of the envelope signal and the reference frequency modulation function as the product function component.

[0102] Specifically, the PF component obtained by this round of signal decomposition processing can be calculated by the following formula (3):

[0103] PF i =∏a i *s i (3)

[0104] Among them, PF i is the PF component obtained through the i-th round of signal decomposition processing; ∏a i is the envelope signal, which is the envelope function a obtained in the i-th round of signal decomposition processing i , and the envelope function obtained in the signal decomposition processing from the first round to the i-1th round; s i is the reference frequency modulation function obtained in the i-th round of signal decomposition processing, which is a pure frequency modulation function.

[0105] When the number of PF components obtained does not reach the preset number, in addition to calculating the PF components obtained by this round of signal decomposition processing in the above manner, it is also necessary to determine the original signal of the next round of signal decomposition processing based on the original signal of this round of signal decomposition processing and the PF components obtained by this round of signal decomposition processing.

[0106] As an example, the original signal for the next round of signal decomposition processing can be determined in the following way:

[0107] The product function component is subtracted from the original signal to obtain the original signal for the next round of signal decomposition processing.

[0108] Specifically, the original signal of the next round of signal decomposition processing can be calculated by the following formula (4):

[0109] u=x-PF i (4)

[0110] Among them, u represents the original signal of the next round of signal decomposition processing, x represents the original signal of the current round of signal decomposition processing, PF i is the PF component obtained through this round of signal decomposition processing.

[0111] It should be understood that if the number of PF components obtained after the current round of signal decomposition processing has reached a preset number, there is no need to determine the original signal for the next round of signal decomposition processing, and the subsequent signal decomposition processing can be stopped.

[0112] Step 5: If the reference frequency modulation function is not the pure frequency modulation function, then determine the original signal for the next round of signal decomposition processing according to the reference frequency modulation function.

[0113] If the reference frequency modulation function is not a pure frequency modulation function, it means that the PF component cannot be obtained through this round of signal decomposition processing. At this time, the original signal for the next round of signal decomposition processing can be directly determined based on the reference frequency modulation function obtained in step 3. For example, the reference frequency modulation function can be directly used as the original signal for the next round of signal decomposition processing.

[0114] See also Figure 4 , Figure 4 A schematic diagram of a flow chart of iteratively executing signal decomposition processing provided in an embodiment of the present application. Figure 4 As shown in the figure, in each round of signal decomposition processing, the original signal x(t) is first determined, and the reference extreme point is extracted from it; then, the local mean function q is determined based on the reference extreme point using the sliding average method. i and the envelope estimation function a i ; Then, through the above equations (1) and (2), according to the original signal x, the local mean function q i and the envelope estimation function a i , calculate the reference frequency modulation function s i ; Then, determine the reference frequency modulation function s i Is it a pure frequency modulation function? If the reference frequency modulation function s i If it is a pure frequency modulation function, the PF component obtained by the current round of signal decomposition processing is calculated by the above formula (3), and the original signal of the next round of signal decomposition processing is calculated by formula (4), and it is judged whether the current PF component has reached 6. If it has reached, the whole process is terminated. If not, the next round of signal decomposition processing is triggered. If the reference frequency modulation function s iIf it is not a pure frequency modulation function, the reference frequency modulation function is used as the original signal for the next round of signal decomposition processing and triggers the execution of the next round of signal decomposition processing.

[0115] Thus, through the above method, the LMD algorithm is used to decompose the velocity time signal to obtain multiple PF components. The LMD algorithm can be used to fit the envelope using the sliding average method to avoid the phenomenon of over-envelope and under-envelope, thereby ensuring the accuracy of the decomposed PF components. In addition, the LMD algorithm has fewer screening times, which can reduce the degree of contamination of the entire data segment by the endpoint effect.

[0116] Step 103: Calculate the self-information corresponding to each of the plurality of product function components.

[0117] After decomposing multiple PF components from the velocity time signal through the LMD algorithm, the corresponding self-information of each PF component can be determined respectively, so as to subsequently determine the PF component to which the coincidence point information belongs based on the self-information corresponding to each of the multiple PF components.

[0118] In a possible implementation, the above step 103 of "calculating the self-information corresponding to each of the plurality of product function components" may include the following steps 1031 to 1033 (not shown in the figure):

[0119] Step 1031: For each of the product function components, obtain an energy value corresponding to the product function component by performing an integration operation on the product function component.

[0120] Specifically, for each PF component, the energy value corresponding to the PF component can be calculated by the following formula (5):

[0121]

[0122] Among them, E i is the energy value corresponding to the i-th PF component, PF i (t) indicates the i-th PF component. When a total of 6 PF components are obtained through step 102, i can be equal to 1 to 6.

[0123] Step 1032: Calculate the sum of the energy values ​​corresponding to the multiple product function components to obtain a total energy value.

[0124] Without considering the residual energy, the total energy value of the original speed time signal is equal to the sum of the energy values ​​corresponding to each decomposed PF component. Based on this, the total energy value can be calculated by the following formula (6):

[0125]

[0126] Wherein, E is the total energy value, and 6 indicates that a total of 6 PF components are decomposed.

[0127] Step 1033: For each of the product function components, the self-information corresponding to the product function component is calculated according to the energy value corresponding to the product function component and the total energy value.

[0128] For each PF component, the self-information corresponding to the PF component can be calculated by the following formula (7):

[0129] I i =-lnP i i=1,2,……,6(7)

[0130] Among them, I i is the self-information corresponding to the i-th PF component, P i =E i / E, which is equal to the ratio of the energy value corresponding to the i-th PF component to the total energy value.

[0131] Step 104: Select the product function component with the smallest corresponding self-information from among the multiple product function components as the target product function component.

[0132] Since the moving contact of the circuit breaker will be subjected to the reaction force of the static contact of the circuit breaker when it moves to the just-closing point, a sudden change in speed will occur at this time. Therefore, it can be determined that the self-information of the PF component containing the just-closing point information is the smallest, that is, the corresponding PF component with the smallest self-information can be determined as the target PF component, and then, the just-closing point of the circuit breaker is determined based on the target PF component.

[0133] Step 105: Determine the instantaneous frequency curve corresponding to the target product function component, and determine the rigid closing point of the circuit breaker according to the instantaneous frequency curve.

[0134] When determining the rigid closing point of the circuit breaker based on the target PF component, the instantaneous frequency curve corresponding to the target PF component may be determined first, and then the rigid closing point of the circuit breaker may be determined based on the instantaneous frequency curve.

[0135] In a possible implementation, as described above, each PF component is the product of an envelope signal and a pure frequency modulation function. Therefore, the "determining the instantaneous frequency curve corresponding to the target product function component" in the above step 105 may specifically include steps 1051 and 1052:

[0136] Step 1051: Obtain the pure frequency modulation function in the target product function component as the target pure frequency modulation function.

[0137] Specifically, assuming that the target PF component is PF j =∏a j*s j , where ∏a j is the envelope signal, s j Therefore, the pure frequency modulation function s can be extracted from the target PF component. j , as the target pure frequency modulation function, the target pure frequency modulation function can be specifically expressed as

[0138] Step 1052: Obtain an instantaneous frequency curve corresponding to the target product function component by deriving the inverse function of the target pure frequency modulation function.

[0139] The instantaneous frequency can be determined by the target pure frequency modulation function s j The inverse function of (t) is derived, that is, the instantaneous frequency curve corresponding to the target PF component can be calculated by the following formula (8):

[0140]

[0141] Wherein, f(t) is the instantaneous frequency curve corresponding to the target PF component.

[0142] In a possible implementation, the step of “determining the rigid closing point of the circuit breaker according to the instantaneous frequency curve” in step 105 may specifically include steps 1053 and 1054:

[0143] Step 1053: extracting a maximum point from the instantaneous frequency curve.

[0144] Step 1054: Determine the time corresponding to the maximum value point as the just-closing point of the circuit breaker.

[0145] That is, after obtaining the corresponding instantaneous frequency curve based on the target PF component, a maximum point can be extracted from the instantaneous frequency curve, and then the moment corresponding to the maximum point is used as the just-closing point in the circuit breaker closing process.

[0146] The method for determining the rigid closing point of a circuit breaker provided in an embodiment of the present application includes: obtaining a speed time signal corresponding to a moving contact of the circuit breaker, the speed time signal being used to indicate a speed change of the moving contact during the closing process of the circuit breaker; then, using a local mean decomposition algorithm, decomposing the speed time signal to obtain a plurality of product function components; then, calculating the self-information corresponding to each of the plurality of product function components; and selecting the product function component with the smallest corresponding self-information from the plurality of product function components as a target product function component; and then, determining an instantaneous frequency curve corresponding to the target product function component, and determining the rigid closing point of the circuit breaker according to the instantaneous frequency curve. In the above method, the local mean decomposition algorithm is used to decompose the speed time signal. On the one hand, the local mean decomposition algorithm can be used to fit the envelope calculation method using the sliding average method to avoid the phenomenon of over-envelope or under-envelope, thereby improving the accuracy of the product function components obtained by decomposition; on the other hand, through the local mean decomposition algorithm, the product function components can be obtained with fewer screening times, thereby reducing the degree of contamination of the entire data segment by the endpoint effect and improving the accuracy of the product function components obtained by decomposition; accordingly, subsequent processing is performed based on the product function components with higher accuracy obtained by the local mean decomposition algorithm, which can more efficiently and accurately determine the rigid closing point of the circuit breaker, that is, ensure that the rigid closing point of the circuit breaker determined has higher accuracy. In addition, the embodiment of the present application can directly obtain the speed time signal based on the sensor originally deployed on the circuit breaker without deploying additional sensors, thereby also reducing the cost required to determine the rigid closing point of the circuit breaker.

[0147] The present application also provides a device for determining a circuit breaker just-closed point. Figure 5 , Figure 5 This is a schematic diagram of the structure of a device for determining a circuit breaker just-closed point provided in an embodiment of the present application. Figure 5 As shown, the device comprises:

[0148] The signal acquisition module 501 is used to acquire a speed time signal corresponding to a moving contact of a circuit breaker; the speed time signal is used to indicate a speed change of the moving contact during the closing process of the circuit breaker;

[0149] A signal decomposition module 502, configured to obtain a plurality of product function components based on the speed time signal decomposition by a local mean decomposition algorithm;

[0150] A self-information calculation module 503, used to calculate the self-information corresponding to each of the plurality of product function components;

[0151] A component selection module 504 is used to select a product function component with the smallest corresponding self-information from the plurality of product function components as a target product function component;

[0152] The rigid closing point determination module 505 is used to determine the instantaneous frequency curve corresponding to the target product function component, and determine the rigid closing point of the circuit breaker according to the instantaneous frequency curve.

[0153] Optionally, the signal acquisition module 501 is specifically used for:

[0154] Obtaining a travel time signal corresponding to the moving contact during the closing process of the circuit breaker through a displacement sensor installed on the circuit breaker;

[0155] Based on the travel time signal, the speed time signal is converted.

[0156] Optionally, the signal decomposition module 502 is specifically used for:

[0157] By using the local mean decomposition algorithm, multiple rounds of signal decomposition processing are performed based on the speed time signal until a preset number of product function components are obtained;

[0158] Wherein, each round of signal decomposition processing includes:

[0159] Extracting multiple reference extreme value points from the original signal of the current round of signal decomposition processing; when the current round of signal decomposition processing is the first round of signal decomposition processing, the original signal is the speed time signal;

[0160] Using a sliding average method, a local mean function and an envelope estimation function are determined according to the multiple reference extreme value points;

[0161] Determining a reference frequency modulation function according to the original signal, the local mean function and the envelope estimation function;

[0162] If the reference frequency modulation function is a pure frequency modulation function, the product function component obtained by the current round of signal decomposition processing is determined according to the reference frequency modulation function and the envelope estimation function determined in the current round and the previous round of signal decomposition processing; the original signal of the next round of signal decomposition processing is obtained according to the original signal and the product function component;

[0163] If the reference frequency modulation function is not the pure frequency modulation function, the original signal for the next round of signal decomposition processing is determined according to the reference frequency modulation function.

[0164] Optionally, the signal decomposition module 502 is specifically used for:

[0165] Subtracting the local mean function from the original signal to obtain a difference function;

[0166] The reference frequency modulation function is obtained by dividing the difference function by the envelope estimation function.

[0167] Optionally, the signal decomposition module 502 is specifically used for:

[0168] Calculating the product of the envelope estimation function determined in the current round of the signal decomposition processing and the envelope estimation function determined in each previous round of the signal decomposition processing to obtain an envelope signal;

[0169] The product of the envelope signal and the reference frequency modulation function is calculated as the product function component.

[0170] Optionally, the signal decomposition module 502 is specifically used for:

[0171] The product function component is subtracted from the original signal to obtain the original signal for the next round of signal decomposition processing.

[0172] Optionally, the self-information calculation module 503 is specifically used for:

[0173] For each of the product function components, performing an integration operation on the product function component to obtain an energy value corresponding to the product function component;

[0174] Calculating the sum of energy values ​​corresponding to the multiple product function components to obtain a total energy value;

[0175] For each of the product function components, the self-information corresponding to the product function component is calculated according to the energy value corresponding to the product function component and the total energy value.

[0176] Optionally, each of the product function components is the product of an envelope signal and a pure frequency modulation function; the rigid conjunction point determination module 505 is specifically used for:

[0177] Acquire a pure frequency modulation function in the target product function component as a target pure frequency modulation function;

[0178] By deriving the inverse function of the target pure frequency modulation function, an instantaneous frequency curve corresponding to the target product function component is obtained.

[0179] Optionally, the rigid junction determination module 505 is specifically used for:

[0180] Extracting a maximum point from the instantaneous frequency curve;

[0181] The time corresponding to the maximum value point is determined as the just-closing point of the circuit breaker.

[0182] The device for determining the rigid closing point of the circuit breaker provided in the embodiment of the present application uses the local mean decomposition algorithm to decompose the speed time signal. On the one hand, the sliding average method can be used to fit the envelope calculation method with the help of the local mean decomposition algorithm to avoid the phenomenon of over-envelope or under-envelope, thereby improving the accuracy of the product function component obtained by decomposition; on the other hand, through the local mean decomposition algorithm, the product function component can be obtained with fewer screening times, thereby reducing the degree of contamination of the entire data segment by the endpoint effect, and improving the accuracy of the product function component obtained by decomposition; accordingly, based on the product function component with high accuracy obtained by the local mean decomposition algorithm, subsequent processing can be performed to determine the rigid closing point of the circuit breaker more efficiently and accurately, that is, to ensure that the rigid closing point of the circuit breaker determined has high accuracy. In addition, the embodiment of the present application can directly obtain the speed time signal based on the sensor originally deployed on the circuit breaker without deploying additional sensors, so the cost required to determine the rigid closing point of the circuit breaker can also be reduced.

[0183] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0184] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0185] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0186] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0187] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (full name in English: Read-Only Memory, English abbreviation: ROM), random access memory (full name in English: Random Access Memory, English abbreviation: RAM), disk or optical disk and other media that can store computer programs.

[0188] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0189] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for determining a circuit breaker just-closed point, characterized in that: The method comprises: Acquire a speed time signal corresponding to a moving contact of a circuit breaker; the speed time signal is used to indicate a speed change of the moving contact during the closing process of the circuit breaker; Decomposing the speed time signal to obtain a plurality of product function components by a local mean decomposition algorithm; Calculating the self-information corresponding to each of the plurality of product function components; Among the multiple product function components, select the product function component with the smallest corresponding self-information as the target product function component; An instantaneous frequency curve corresponding to the target product function component is determined, and a rigid closing point of the circuit breaker is determined according to the instantaneous frequency curve.

2. The method according to claim 1, characterized in that The obtaining of the speed time signal corresponding to the moving contact of the circuit breaker comprises: Obtaining a travel time signal corresponding to the moving contact during the closing process of the circuit breaker through a displacement sensor installed on the circuit breaker; Based on the travel time signal, the speed time signal is converted.

3. The method according to claim 1, characterized in that The method of obtaining a plurality of product function components based on the speed time signal by using a local mean decomposition algorithm includes: By using the local mean decomposition algorithm, multiple rounds of signal decomposition processing are performed based on the speed time signal until a preset number of product function components are obtained; Wherein, each round of signal decomposition processing includes: Extracting multiple reference extreme value points from the original signal of the current round of signal decomposition processing; when the current round of signal decomposition processing is the first round of signal decomposition processing, the original signal is the speed time signal; Using a sliding average method, a local mean function and an envelope estimation function are determined according to the multiple reference extreme value points; Determining a reference frequency modulation function according to the original signal, the local mean function and the envelope estimation function; If the reference frequency modulation function is a pure frequency modulation function, the product function component obtained by the current round of signal decomposition processing is determined according to the reference frequency modulation function and the envelope estimation function determined in the current round and the previous round of signal decomposition processing; the original signal of the next round of signal decomposition processing is obtained according to the original signal and the product function component; If the reference frequency modulation function is not the pure frequency modulation function, the original signal for the next round of signal decomposition processing is determined according to the reference frequency modulation function.

4. The method according to claim 3, characterized in that The step of determining a reference frequency modulation function according to the original signal, the local mean function and the envelope estimation function comprises: Subtracting the local mean function from the original signal to obtain a difference function; The reference frequency modulation function is obtained by dividing the difference function by the envelope estimation function.

5. The method according to claim 3, characterized in that: Determining the product function component obtained by the current round of signal decomposition processing according to the reference frequency modulation function and the envelope estimation function determined in the current round and the previous round of signal decomposition processing comprises: Calculating the product of the envelope estimation function determined in the current round of the signal decomposition processing and the envelope estimation function determined in each previous round of the signal decomposition processing to obtain an envelope signal; The product of the envelope signal and the reference frequency modulation function is calculated as the product function component.

6. The method according to claim 3, characterized in that The step of obtaining the original signal of the next round of signal decomposition processing according to the original signal and the product function component comprises: The product function component is subtracted from the original signal to obtain the original signal for the next round of signal decomposition processing.

7. The method according to claim 1, characterized in that The calculating the self-information corresponding to each of the plurality of product function components comprises: For each of the product function components, performing an integration operation on the product function component to obtain an energy value corresponding to the product function component; Calculating the sum of energy values ​​corresponding to the multiple product function components to obtain a total energy value; For each of the product function components, the self-information corresponding to the product function component is calculated according to the energy value corresponding to the product function component and the total energy value.

8. The method according to claim 1, characterized in that Each of the product function components is the product of an envelope signal and a pure frequency modulation function; and determining the instantaneous frequency curve corresponding to the target product function component comprises: Acquire a pure frequency modulation function in the target product function component as a target pure frequency modulation function; By deriving the inverse function of the target pure frequency modulation function, an instantaneous frequency curve corresponding to the target product function component is obtained.

9. The method according to claim 1, characterized in that: The determining the rigid closing point of the target circuit breaker according to the instantaneous frequency curve comprises: Extracting a maximum point from the instantaneous frequency curve; The time corresponding to the maximum value point is determined as the just-closing point of the circuit breaker.

10. A device for determining a circuit breaker just-closed point, characterized in that: The device comprises: A signal acquisition module, used to acquire a speed time signal corresponding to a moving contact of a circuit breaker; the speed time signal is used to indicate a speed change of the moving contact during the closing process of the circuit breaker; A signal decomposition module, used for obtaining a plurality of product function components based on the speed time signal decomposition by a local mean decomposition algorithm; A self-information calculation module, used to calculate the self-information corresponding to each of the plurality of product function components; A component selection module, used to select a product function component with the smallest corresponding self-information from the plurality of product function components as a target product function component; The rigid closing point determination module is used to determine the instantaneous frequency curve corresponding to the target product function component, and determine the rigid closing point of the circuit breaker according to the instantaneous frequency curve.

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