Circuit breaker, short circuit fault identification method and device thereof, and readable storage medium

Abstract

The invention provides a circuit breaker, a short-circuit fault identification method and device thereof and a readable storage medium. The short-circuit fault identification method of the circuit breaker comprises the steps that under the condition that the circuit breaker is in a closed state, waveform data of M voltage sampling waveforms of the circuit breaker in a preset time period are acquired, and M is a positive integer larger than 1; acquiring a first voltage effective value of the circuit breaker under the condition that the circuit breaker is in the opening state; according to the waveform data of each voltage sampling waveform, determining a second voltage effective value corresponding to each voltage sampling waveform to obtain M second voltage effective values; according to the first voltage effective value and the M second voltage effective values, the cumulative drop percentage of the M voltage sampling waveforms is determined; and when the cumulative drop percentage is greater than or equal to a preset threshold value, determining that the circuit breaker has a short-circuit fault. Therefore, the short-circuit fault of the circuit breaker is identified based on voltage drop detection, and the accuracy of circuit breaker short-circuit fault identification is ensured.

Description

Technical Field

[0001] The present invention relates to the field of electric power technology, and in particular to a circuit breaker and a short-circuit fault identification method and device thereof, and a readable storage medium. Background Art

[0002] In modern power systems, circuit breakers are important devices for circuit protection. Their main function is to disconnect the power supply in time when a circuit is overloaded or short-circuited, to prevent equipment damage or fire and other safety accidents. With the complexity of power systems and the diversification of power-consuming equipment, intelligent circuit breakers can determine whether to disconnect the circuit in advance based on real-time power consumption, and generally require intelligent circuit breakers to identify 100% of circuit faults and save circuit fault records. In power systems, common faults include overvoltage faults, undervoltage faults, overtemperature faults, leakage faults, overcurrent faults, overpower faults, and short circuit faults.

[0003] Among them, when the circuit breaker identifies a short-circuit fault, the following problems exist: 1. When a short circuit occurs in the line, due to the tripping characteristics of the circuit breaker, the circuit breaker will complete the tripping process in a very short time. The short circuit exists for a short time, and the duration of the short circuit is generally 5-7ms. 2. The computing power of the circuit breaker is limited. The processor of the intelligent circuit breaker, such as MCU (MicroControl Unit), is generally an 8-bit and 16-bit single-chip microcomputer, which makes it difficult to achieve high-speed current sampling and related real-time data calculation, making it difficult to record current characteristic values ​​in advance and difficult to determine the short-circuit fault in advance before the circuit breaker trips. 3. The hardware design is difficult. The current sampling is to transmit the current signal to the metering module of the circuit breaker through a mutual inductor. It is difficult to perform short-circuit detection from the hardware aspect based on the current signal.

[0004] Therefore, existing circuit breakers have certain technical difficulties in identifying short-circuit faults, and the accuracy of short-circuit identification is low. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0006] To this end, a first aspect of the present invention is to provide a short-circuit fault identification method for a circuit breaker.

[0007] A second aspect of the present invention is to provide a short-circuit fault identification device for a circuit breaker.

[0008] A third aspect of the present invention is to provide a circuit breaker.

[0009] A fourth aspect of the present invention is to provide a readable storage medium.

[0010] In view of this, according to a first aspect of the present invention, a short-circuit fault identification method for a circuit breaker is proposed, the method comprising: when the circuit breaker is in a closed state, obtaining waveform data of M voltage sampling waveforms of the circuit breaker in a preset time period, where M is a positive integer greater than 1; when the circuit breaker is in an open state, obtaining a first voltage effective value of the circuit breaker; according to the waveform data of each voltage sampling waveform, determining a second voltage effective value corresponding to each voltage sampling waveform, and obtaining M second voltage effective values; according to the first voltage effective value and the M second voltage effective values, determining a cumulative drop percentage of the M voltage sampling waveforms; when the cumulative drop percentage is greater than or equal to a preset threshold, determining that a short-circuit fault has occurred in the circuit breaker.

[0011] Specifically, in the short-circuit fault identification method of the circuit breaker provided by the present invention, in the process of short-circuit fault identification, when the circuit breaker is in the closed state, the waveform data of M voltage sampling waveforms of the front-end voltage of the circuit breaker within a preset time period are recorded. Further, when the circuit breaker is in the open state, the first voltage effective value of the front-end voltage of the circuit breaker is recorded, and the above waveform data is stopped from being updated. Further, based on the algorithm of the microcomputer relay protection, the second voltage effective value corresponding to each voltage sampling waveform is calculated according to the waveform data of each voltage sampling waveform, thereby obtaining M second voltage effective values. Further, according to the first voltage effective value and the calculated M second voltage effective values, the cumulative drop percentage of the M voltage sampling waveforms is determined, and when the cumulative drop percentage is greater than or equal to the preset threshold value, it is determined that the circuit breaker has a voltage drop phenomenon, thereby determining that the circuit breaker has a short-circuit fault. In this way, the short-circuit fault of the circuit breaker is identified based on the voltage drop detection, which ensures the accuracy of the short-circuit fault identification of the circuit breaker.

[0012] The short-circuit fault identification method of the circuit breaker according to the present invention may also have the following additional technical features:

[0013] In some technical schemes, optionally, the second voltage effective value corresponding to each voltage sampling waveform is determined based on the waveform data of each voltage sampling waveform, including: determining the real part value and the imaginary part value of the voltage fundamental component of each voltage sampling waveform based on the waveform data of each voltage sampling waveform; determining the second voltage effective value corresponding to each voltage sampling waveform based on the real part value and the imaginary part value of the voltage fundamental component of each voltage sampling waveform.

[0014] In this technical solution, in the process of calculating the second voltage effective value corresponding to each voltage sampling waveform according to the waveform data of each voltage sampling waveform, the real value and imaginary value of the voltage fundamental component of each voltage sampling waveform can be determined according to the waveform data of each voltage sampling waveform based on the full-cycle Fourier algorithm, and then the second voltage effective value corresponding to each voltage sampling waveform can be determined according to the real value and imaginary value of the voltage fundamental component of each voltage sampling waveform. In this way, the accuracy of the determined second voltage effective value is guaranteed, and then the accuracy of short-circuit fault identification is guaranteed.

[0015] In some technical solutions, optionally, determining the real value and the imaginary value of the voltage fundamental component of each voltage sampling waveform according to the waveform data of each voltage sampling waveform includes: determining the real value of the voltage fundamental component of each voltage sampling waveform according to the following formula; According to the following formula, determine the imaginary value of the voltage fundamental component of each voltage sampling waveform; Determining the second voltage effective value corresponding to each voltage sampling waveform according to the real value and the imaginary value of the voltage fundamental component of each voltage sampling waveform, including: determining the second voltage effective value corresponding to each voltage sampling waveform according to the following formula; Among them, k represents the ordinal number of the voltage sampling waveform, a k represents the real value of the voltage fundamental component of the k-th voltage sampling waveform, N represents the total number of sampling points of the k-th voltage sampling waveform, j represents the ordinal number of the sampling point of the k-th voltage sampling waveform, i ... j represents the sampling value of the jth sampling point of the kth voltage sampling waveform, b k Represents the imaginary value of the voltage fundamental component of the kth voltage sampling waveform, V k Indicates the second voltage effective value corresponding to the kth voltage sampling waveform.

[0016] In this technical solution, in the process of determining the real value of the voltage fundamental component of each voltage sampling waveform, the real value of the voltage fundamental component of each voltage sampling waveform can be calculated according to the following formula (1):

[0017]

[0018] Among them, k represents the ordinal number of the voltage sampling waveform, a k represents the real value of the voltage fundamental component of the k-th voltage sampling waveform, N represents the total number of sampling points of the k-th voltage sampling waveform, i.e., the length of the data window, j represents the ordinal number of the sampling points of the k-th voltage sampling waveform, and i represents the real value of the voltage fundamental component of the k-th voltage sampling waveform. j represents the sampling value of the jth sampling point of the kth voltage sampling waveform, where 0≤k≤M, and M can be specifically 50.

[0019] Furthermore, in the process of determining the imaginary value of the voltage fundamental component of each voltage sampling waveform, the imaginary value of the voltage fundamental component of each voltage sampling waveform can be calculated according to the following formula (2):

[0020]

[0021] Among them, b k Represents the imaginary value of the voltage fundamental component of the kth voltage sampling waveform.

[0022] Furthermore, the second voltage effective value is the voltage amplitude effective value of the voltage fundamental component of each voltage sampling waveform. In the process of determining the second voltage effective value corresponding to each voltage sampling waveform, the second voltage effective value corresponding to each voltage sampling waveform can be calculated according to the following formula (3):

[0023]

[0024] Among them, V k Indicates the second voltage effective value corresponding to the kth voltage sampling waveform.

[0025] In some technical schemes, optionally, the cumulative drop percentage of M voltage sampling waveforms is determined based on the first voltage effective value and M second voltage effective values, including: determining the drop percentage of each voltage sampling waveform based on the first voltage effective value and each second voltage effective value; and accumulating the drop percentages greater than 0 to obtain the cumulative drop percentages of the M voltage sampling waveforms.

[0026] In this technical solution, in the process of determining the cumulative drop percentage of M voltage sampling waveforms according to the first voltage effective value and the calculated M second voltage effective values, the drop percentage of each voltage sampling waveform is determined according to the first voltage effective value and each second voltage effective value to obtain M drop percentages. Further, the drop percentages greater than 0 in the M drop percentages are accumulated and calculated to obtain the cumulative drop percentage of the M voltage sampling waveforms. In this way, the accuracy of the determined cumulative drop percentage is guaranteed, and then the accuracy of the subsequent short-circuit fault identification based on the cumulative drop percentage is guaranteed.

[0027] In some technical solutions, optionally, determining the drop percentage of each voltage sampling waveform according to the first voltage effective value and each second voltage effective value includes: calculating the drop percentage of each voltage sampling waveform according to the following formula; Among them, V Dk Indicates the drop percentage of the kth voltage sampling waveform, V off Represents the effective value of the first voltage, V kIndicates the second voltage effective value corresponding to the kth voltage sampling waveform.

[0028] In this technical solution, in the process of calculating the drop percentage of each voltage sampling waveform, it can be calculated specifically according to the following formula (4):

[0029]

[0030] Among them, V Dk Indicates the drop percentage of the kth voltage sampling waveform, V off Represents the effective value of the first voltage, V k Indicates the second voltage effective value corresponding to the kth voltage sampling waveform.

[0031] According to a second aspect of the present invention, a short-circuit fault identification device for a circuit breaker is proposed, and the device includes: an acquisition unit, which is used to acquire waveform data of M voltage sampling waveforms of the circuit breaker in a preset time period when the circuit breaker is in a closed state, where M is a positive integer greater than 1; the acquisition unit is also used to acquire a first voltage effective value of the circuit breaker when the circuit breaker is in an open state; a processing unit, which is used to determine a second voltage effective value corresponding to each voltage sampling waveform according to the waveform data of each voltage sampling waveform, and obtain M second voltage effective values; the processing unit is also used to determine a cumulative drop percentage of the M voltage sampling waveforms according to the first voltage effective value and the M second voltage effective values; and a judgment unit, which is used to determine that a short-circuit fault has occurred in the circuit breaker when the cumulative drop percentage is greater than or equal to a preset threshold.

[0032] The short-circuit fault identification device of the circuit breaker provided by the present invention comprises an acquisition unit, a processing unit and a judgment unit. In the process of short-circuit fault identification, when the circuit breaker is in the closed state, the acquisition unit records the waveform data of M voltage sampling waveforms of the front-end voltage of the circuit breaker within a preset time period. Further, when the circuit breaker is in the open state, the acquisition unit records the first voltage effective value of the front-end voltage of the circuit breaker and stops updating the above waveform data. Further, the processing unit calculates the second voltage effective value corresponding to each voltage sampling waveform according to the waveform data of each voltage sampling waveform based on the algorithm of the microcomputer relay protection, thereby obtaining M second voltage effective values. Further, the processing unit determines the cumulative drop percentage of the M voltage sampling waveforms according to the first voltage effective value and the calculated M second voltage effective values, and the judgment unit further determines that the circuit breaker has a voltage drop phenomenon when the cumulative drop percentage is greater than or equal to the preset threshold value, thereby determining that the circuit breaker has a short-circuit fault. In this way, the short-circuit fault of the circuit breaker is identified based on the voltage drop detection, which ensures the accuracy of the short-circuit fault identification of the circuit breaker.

[0033] According to the third aspect of the present invention, a circuit breaker is proposed, comprising a processor and a memory, wherein the memory stores a program or instruction that can be run on the processor, and when the program or instruction is executed by the processor, the steps of the short-circuit fault identification method of the circuit breaker in any of the above technical solutions are implemented. Therefore, the circuit breaker proposed in the third aspect of the present invention has all the beneficial effects of the short-circuit fault identification method of the circuit breaker in any of the above technical solutions in the first aspect, which will not be repeated here.

[0034] The circuit breaker according to the present invention may also have the following additional technical features:

[0035] In some technical solutions, optionally, the circuit breaker also includes: a metering module connected to the processor, used to read the waveform data of the voltage sampling waveform; a gate state identification device connected to the processor, used to indicate that the circuit breaker is in a closed state or an open state; a gate drive device connected to the processor, used to drive the circuit breaker to switch to a closed state or an open state.

[0036] In this technical solution, the circuit breaker may further specifically include a metering module, a gate state identification device and a gate driving device.

[0037] The metering module is connected to the processor, and is used to read waveform data of the voltage sampling waveform.

[0038] Furthermore, a switch state identification device is connected to the processor, and the switch state identification device is used to indicate whether the circuit breaker is in a closed state or an open state.

[0039] Furthermore, the gate drive device is connected to the processor, and the gate drive device is used to drive the circuit breaker to perform a closing action or an opening action to drive the circuit breaker to switch to a closing state or an opening state.

[0040] In some technical solutions, optionally, the circuit breaker also includes: a leakage protection device connected to the processor, the leakage protection device includes: a leakage detection device for detecting leakage current; a leakage protection drive device connected to the leakage detection device, for driving the gate drive device to perform a tripping action according to the leakage current.

[0041] In this technical solution, the circuit breaker also includes a leakage protection device.

[0042] Wherein, the leakage protection device is connected to the processor.

[0043] Furthermore, the leakage protection device may specifically include a leakage detection device and a leakage protection driving device.

[0044] Among them, the leakage detection device is used to detect the leakage current existing in the circuit in real time.

[0045] Furthermore, the leakage protection driving device is connected to the leakage detection device, and the leakage protection driving device is used to drive the gate driving device to perform a gate opening action according to the leakage current, thereby realizing the leakage protection function of the circuit breaker.

[0046] According to a fourth aspect of the present invention, a readable storage medium is provided, on which a program or instruction is stored, and when the program or instruction is executed by a processor, a short-circuit fault identification method of a circuit breaker as in any of the above technical solutions is implemented. Therefore, the readable storage medium provided in the fourth aspect of the present invention has all the beneficial effects of the short-circuit fault identification method of a circuit breaker in any of the above technical solutions in the first aspect, and will not be described in detail here.

[0047] Additional aspects and advantages of the present invention will become apparent from the following description or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0049] Figure 1 A schematic diagram of a flow chart of a short-circuit fault identification method of a circuit breaker according to an embodiment of the present invention is shown;

[0050] Figure 2 A second flow chart of a method for identifying a short-circuit fault of a circuit breaker according to an embodiment of the present invention is shown;

[0051] Figure 3 A third flow chart of a method for identifying a short-circuit fault of a circuit breaker according to an embodiment of the present invention is shown;

[0052] Figure 4 One of the voltage sampling waveform schematic diagrams of an embodiment of the present invention is shown;

[0053] Figure 5 The second schematic diagram of the voltage sampling waveform according to the embodiment of the present invention is shown;

[0054] Figure 6 The third schematic diagram of the voltage sampling waveform according to the embodiment of the present invention is shown;

[0055] Figure 7 A fourth schematic diagram of a voltage sampling waveform according to an embodiment of the present invention is shown;

[0056] Figure 8 A structural block diagram of a short-circuit fault identification device for a circuit breaker according to an embodiment of the present invention is shown;

[0057] Fig. 9 A structural block diagram of a circuit breaker according to an embodiment of the present invention is shown;

[0058] Fig.10 A schematic structural diagram of a circuit breaker according to an embodiment of the present invention is shown.

[0059] Reference numerals:

[0060] 400 circuit breaker, 402 memory, 404 processor, 406 metering module, 408 gate state identification device, 410 gate drive device, 412 leakage protection device, 414 leakage detection device, 416 leakage protection drive device, 418 indicator light, 420 function button, 422 gateway, 424 Internet access module. DETAILED DESCRIPTION

[0061] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0062] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0063] Combine the following Figures 1 to 10 , the circuit breaker and its short-circuit fault identification method and device, and readable storage medium provided in the embodiments of the present application are described in detail through specific embodiments and their application scenarios.

[0064] In one embodiment of the present invention, Figure 1 As shown, the short-circuit fault identification method of the circuit breaker may specifically include the following steps 102 to 110:

[0065] Step 102, when the circuit breaker is in a closed state, obtaining waveform data of M voltage sampling waveforms of the circuit breaker in a preset time period;

[0066] Step 104, when the circuit breaker is in an open state, obtaining a first voltage effective value of the circuit breaker;

[0067] Step 106, determining the second voltage effective value corresponding to each voltage sampling waveform according to the waveform data of each voltage sampling waveform, and obtaining M second voltage effective values;

[0068] Step 108, determining the cumulative drop percentage of the M voltage sampling waveforms according to the first voltage effective value and the M second voltage effective values;

[0069] Step 110, when the cumulative drop percentage is greater than or equal to a preset threshold, determining that a short circuit fault occurs in the circuit breaker;

[0070] Wherein, M is a positive integer greater than 1.

[0071] In the short-circuit fault identification method of the circuit breaker provided by the present invention, in the process of short-circuit fault identification, when the circuit breaker is in the closed state, the waveform data of M voltage sampling waveforms of the front-end voltage of the circuit breaker within a preset time period are recorded. Further, when the circuit breaker is in the open state, the first voltage effective value of the front-end voltage of the circuit breaker is recorded, and the above waveform data is stopped from being updated. Further, based on the algorithm of the microcomputer relay protection, the second voltage effective value corresponding to each voltage sampling waveform is calculated according to the waveform data of each voltage sampling waveform, thereby obtaining M second voltage effective values. Further, according to the first voltage effective value and the calculated M second voltage effective values, the cumulative drop percentage of the M voltage sampling waveforms is determined, and when the cumulative drop percentage is greater than or equal to the preset threshold value, it is determined that the circuit breaker has a voltage drop phenomenon, thereby determining that the circuit breaker has a short-circuit fault. In this way, the short-circuit fault of the circuit breaker is identified based on the voltage drop detection, which ensures the accuracy of the short-circuit fault identification of the circuit breaker.

[0072] Moreover, the above short-circuit fault identification method is simple to calculate and does not consume too much CPU (Central Processing Unit) computing resources. Under normal use, the processor in the circuit breaker only updates data to the waveform buffer when the circuit breaker is closed, and the processor will only calculate data when the circuit breaker is opened. The waveform data buffer does not update data when the circuit breaker is opened. In this way, the above short-circuit fault identification method can identify short-circuit faults even if it is applied to circuit breakers using processors with low computing power.

[0073] Wherein, M is a positive integer greater than 1, and M can be specifically 50, which is not specifically limited here.

[0074] Furthermore, the above-mentioned preset time period may specifically be 1 second before the current moment, and no specific limitation is made here.

[0075] Furthermore, in the process of recording the waveform data of the M voltage sampling waveforms of the front end voltage of the circuit breaker within the preset time period, the waveform data of the M voltage sampling waveforms of the front end voltage of the circuit breaker within the preset time period can be recorded cyclically according to a preset period. For example, the waveform data of 50 voltage sampling waveforms of the front end voltage of the circuit breaker within the last 1 second are recorded cyclically with a period of 2 ms to obtain 500 waveform data.

[0076] It is understandable that when a short circuit occurs, the current is almost infinite and the voltage is 0. When the current is very large, the metal sheet inside the circuit breaker will deform, causing the circuit breaker to trip and disconnect the line. Existing circuit breakers are difficult to identify short circuit faults in terms of current, but because the circuit breaker trips, the voltage will drop. By detecting the voltage drop phenomenon, the circuit breaker tripping behavior can be identified, thereby identifying the short circuit fault of the circuit breaker.

[0077] Among them, the preset threshold for judging whether the circuit breaker has voltage drop can be 15% or other values. The preset threshold is affected by the circuit breaker tripping time. Those skilled in the art can set the specific value of the preset threshold according to the actual situation, and no specific limitation is made here.

[0078] It is understandable that when the circuit breaker is operating normally, the voltage sampling waveform of the voltage at the front end of the circuit breaker is as follows: Figure 4 As shown in the figure, when a short circuit occurs in the circuit breaker, taking the circuit breaker opening time as 6ms as an example, the voltage sampling waveform of the front end voltage of the circuit breaker can be specifically as follows Figure 5 , Figure 6 as well as Figure 7 As shown. Figure 5 , Figure 6 as well as Figure 7 In the figure, the shaded area indicates that a short circuit has occurred, and the sampling value of the shaded area is 0; the integral area of ​​the shaded area indicates the magnitude of the voltage drop. Figure 5 , Figure 6 as well as Figure 7 It can be seen that when a short circuit fault occurs, the voltage sampling waveform is close to Figure 6 When the voltage drops, the amplitude is relatively small. When the short circuit fault occurs, the voltage sampling waveform is close to Figure 7 In actual application, the minimum voltage drop amplitude when a short circuit occurs in the circuit breaker can be calculated according to the actual opening time of the circuit breaker, and the preset threshold value can be determined based on the minimum voltage drop amplitude.

[0079] In some embodiments of the present invention, optionally, the step of determining the second voltage effective value corresponding to each voltage sampling waveform according to the waveform data of each voltage sampling waveform may specifically include the following steps 112 and 114:

[0080] Step 112, determining the real part value and the imaginary part value of the voltage fundamental component of each voltage sampling waveform according to the waveform data of each voltage sampling waveform;

[0081] Step 114, determining a second voltage effective value corresponding to each voltage sampling waveform according to the real value and the imaginary value of the voltage fundamental component of each voltage sampling waveform.

[0082] In this embodiment, in the process of calculating the second voltage effective value corresponding to each voltage sampling waveform according to the waveform data of each voltage sampling waveform, the real value and imaginary value of the voltage fundamental component of each voltage sampling waveform can be determined according to the waveform data of each voltage sampling waveform based on the full-cycle Fourier algorithm, and then the second voltage effective value corresponding to each voltage sampling waveform can be determined according to the real value and imaginary value of the voltage fundamental component of each voltage sampling waveform. In this way, the accuracy of the determined second voltage effective value is guaranteed, and the accuracy of short-circuit fault identification is guaranteed.

[0083] In some embodiments of the present invention, optionally, the above step 112 may specifically include the following steps 112a and 112b, and the above step 114 may specifically include the following step 114a:

[0084] Step 112a, according to the formula Determine the real value of the voltage fundamental component of each voltage sampling waveform;

[0085] Step 112b, according to the formula Determine the imaginary value of the voltage fundamental component of each voltage sampling waveform;

[0086] Step 114a, according to the formula A second voltage effective value corresponding to each voltage sampling waveform;

[0087] Among them, k represents the ordinal number of the voltage sampling waveform, a k represents the real value of the voltage fundamental component of the k-th voltage sampling waveform, N represents the total number of sampling points of the k-th voltage sampling waveform, j represents the ordinal number of the sampling point of the k-th voltage sampling waveform, i ... j represents the sampling value of the jth sampling point of the kth voltage sampling waveform, b k Represents the imaginary value of the voltage fundamental component of the kth voltage sampling waveform, V k Indicates the second voltage effective value corresponding to the kth voltage sampling waveform.

[0088] In this embodiment, in the process of determining the real value of the voltage fundamental component of each voltage sampling waveform, the real value of the voltage fundamental component of each voltage sampling waveform can be calculated according to the following formula (1):

[0089]

[0090] Among them, k represents the ordinal number of the voltage sampling waveform, a k represents the real value of the voltage fundamental component of the k-th voltage sampling waveform, N represents the total number of sampling points of the k-th voltage sampling waveform, j represents the ordinal number of the sampling point of the k-th voltage sampling waveform, i ...j Indicates the sampling value of the jth sampling point of the kth voltage sampling waveform. Wherein, N can be specifically taken as a value such as 10, 0≤k≤M, and M can be specifically 50.

[0091] Furthermore, in the process of determining the imaginary value of the voltage fundamental component of each voltage sampling waveform, the imaginary value of the voltage fundamental component of each voltage sampling waveform can be calculated according to the following formula (2):

[0092]

[0093] Among them, b k Represents the imaginary value of the voltage fundamental component of the kth voltage sampling waveform.

[0094] Furthermore, the second voltage effective value is the voltage amplitude effective value of the voltage fundamental component of each voltage sampling waveform. In the process of determining the second voltage effective value corresponding to each voltage sampling waveform, the second voltage effective value corresponding to each voltage sampling waveform can be calculated according to the following formula (3):

[0095]

[0096] Among them, V k Indicates the second voltage effective value corresponding to the kth voltage sampling waveform.

[0097] In some embodiments of the present invention, optionally, Figure 2 As shown, the above step 108 may specifically include the following steps 108a and 108b:

[0098] Step 108a, determining the drop percentage of each voltage sampling waveform according to the first voltage effective value and each second voltage effective value;

[0099] Step 108b, accumulating and calculating the drop percentages that are greater than 0 to obtain the cumulative drop percentages of the M voltage sampling waveforms.

[0100] In this embodiment, in the process of determining the cumulative drop percentage of M voltage sampling waveforms according to the first voltage effective value and the calculated M second voltage effective values, the drop percentage of each voltage sampling waveform is determined according to the first voltage effective value and each second voltage effective value to obtain M drop percentages. Further, the drop percentages greater than 0 in the M drop percentages are accumulated and calculated to obtain the cumulative drop percentage of the M voltage sampling waveforms. In this way, the accuracy of the determined cumulative drop percentage is guaranteed, and the accuracy of the subsequent short-circuit fault identification based on the cumulative drop percentage is guaranteed.

[0101] In some embodiments of the present invention, optionally, the above step 108a may specifically include the following step 116:

[0102] Step 116, according to the formula Calculate the drop percentage of each voltage sampling waveform;

[0103] Among them, V Dk Indicates the drop percentage of the kth voltage sampling waveform, V off Represents the effective value of the first voltage, V k Indicates the second voltage effective value corresponding to the kth voltage sampling waveform.

[0104] In this embodiment, in the process of calculating the drop percentage of each voltage sampling waveform, the calculation can be performed specifically according to the following formula (4):

[0105]

[0106] Among them, V Dk Indicates the drop percentage of the kth voltage sampling waveform, V off Represents the effective value of the first voltage, V k Indicates the second voltage effective value corresponding to the kth voltage sampling waveform.

[0107] In summary, if Figure 3 As shown, the short-circuit fault identification method of the circuit breaker provided in the embodiment of the present invention may specifically include the following steps 202 to 218:

[0108] Step 202, determine: the circuit breaker is in the closed state, if yes, execute step 204, if no, execute step 218;

[0109] Step 204, recording waveform data of the voltage sampling waveform;

[0110] Step 206, determine: the circuit breaker is tripped, if yes, execute step 208, if no, execute step 204;

[0111] Step 208, determine: the circuit breaker has a non-short circuit fault, if so, execute step 218, if not, execute step 210;

[0112] Step 210, calculating the cumulative drop percentage of the voltage sampling waveform;

[0113] Step 212, determine: the cumulative drop percentage ≥ the preset threshold, if yes, execute step 214, if no, execute step 216;

[0114] Step 214, determining that a short circuit fault occurs in the circuit breaker;

[0115] Step 216, determining that the circuit breaker has other faults;

[0116] Step 218, stop updating the waveform data.

[0117] After executing step 214, step 216 or step 218, the process ends.

[0118] In one embodiment of the present invention, a short-circuit fault identification device for a circuit breaker is also provided. Figure 8 As shown, Figure 8 The structure block diagram of the short-circuit fault identification device 300 of the circuit breaker according to the embodiment of the present invention is shown. The short-circuit fault identification device 300 of the circuit breaker may specifically include the following acquisition unit 302, processing unit 304 and judgment unit 306:

[0119] An acquisition unit 302 is used to acquire waveform data of M voltage sampling waveforms of the circuit breaker in a preset time period when the circuit breaker is in a closed state, where M is a positive integer greater than 1;

[0120] The acquisition unit 302 is further configured to acquire a first voltage effective value of the circuit breaker when the circuit breaker is in an open state;

[0121] The processing unit 304 is used to determine the second voltage effective value corresponding to each voltage sampling waveform according to the waveform data of each voltage sampling waveform, and obtain M second voltage effective values;

[0122] The processing unit 304 is further used to determine the cumulative drop percentage of the M voltage sampling waveforms according to the first voltage effective value and the M second voltage effective values;

[0123] The judgment unit 306 is used to determine that a short circuit fault occurs in the circuit breaker when the cumulative drop percentage is greater than or equal to a preset threshold.

[0124] The short-circuit fault identification device 300 of the circuit breaker provided in the embodiment of the present invention includes an acquisition unit 302, a processing unit 304 and a judgment unit 306. In the process of short-circuit fault identification, when the circuit breaker is in the closed state, the acquisition unit 302 records the waveform data of M voltage sampling waveforms of the front-end voltage of the circuit breaker within a preset time period. Further, when the circuit breaker is in the open state, the acquisition unit 302 records the first voltage effective value of the front-end voltage of the circuit breaker and stops updating the above waveform data. Further, the processing unit 304 calculates the second voltage effective value corresponding to each voltage sampling waveform according to the waveform data of each voltage sampling waveform based on the algorithm of the microcomputer relay protection, thereby obtaining M second voltage effective values. Further, the processing unit 304 determines the cumulative drop percentage of the M voltage sampling waveforms according to the first voltage effective value and the calculated M second voltage effective values, and the judgment unit 306 further determines that the circuit breaker has a voltage drop phenomenon when the cumulative drop percentage is greater than or equal to the preset threshold, thereby determining that the circuit breaker has a short-circuit fault. In this way, the short-circuit fault of the circuit breaker is identified based on the voltage drop detection, thereby ensuring the accuracy of the short-circuit fault identification of the circuit breaker.

[0125] Moreover, the above short-circuit fault identification method is simple to calculate and does not consume too much CPU computing resources. Under normal use, the processor in the circuit breaker only updates data to the waveform buffer when the circuit breaker is closed, and the processor will only calculate data when the circuit breaker is opened. The waveform data buffer does not update data when the circuit breaker is opened. In this way, the above short-circuit fault identification method can identify short-circuit faults even if it is applied to circuit breakers using processors with low computing power.

[0126] Wherein, M is a positive integer greater than 1, and M can be specifically 50, which is not specifically limited here.

[0127] Furthermore, the above-mentioned preset time period may specifically be 1 second before the current moment, and no specific limitation is made here.

[0128] Further, in the process of recording the waveform data of M voltage sampling waveforms of the front end voltage of the circuit breaker within the preset time period by the acquisition unit 302, the waveform data of M voltage sampling waveforms of the front end voltage of the circuit breaker within the preset time period can be recorded cyclically according to a preset period. For example, the waveform data of 50 voltage sampling waveforms of the front end voltage of the circuit breaker within the last 1 second is recorded cyclically with a period of 2 ms to obtain 500 waveform data.

[0129] It is understandable that when a short circuit occurs, the current is almost infinite and the voltage is 0. When the current is very large, the metal sheet inside the circuit breaker will deform, causing the circuit breaker to trip and disconnect the line. Existing circuit breakers are difficult to identify short circuit faults in terms of current, but because the circuit breaker trips, the voltage will drop. By detecting the voltage drop phenomenon, the circuit breaker tripping behavior can be identified, thereby identifying the short circuit fault of the circuit breaker.

[0130] Among them, the preset threshold for judging whether the circuit breaker has a voltage drop phenomenon can be specifically taken as 15% or other values. The preset threshold is affected by the circuit breaker tripping time. Those skilled in the art can set the specific value of the preset threshold according to actual conditions, and no specific limitation is made here.

[0131] In actual application, the minimum voltage drop amplitude when a short circuit fault occurs in the circuit breaker can be calculated according to the actual opening time of the circuit breaker, and the preset threshold value can be determined based on the minimum voltage drop amplitude.

[0132] In some embodiments of the present invention, optionally, the processing unit 304 is specifically used to: determine the real value and imaginary value of the voltage fundamental component of each voltage sampling waveform based on the waveform data of each voltage sampling waveform; determine the second voltage effective value corresponding to each voltage sampling waveform based on the real value and imaginary value of the voltage fundamental component of each voltage sampling waveform.

[0133] In some embodiments of the present invention, optionally, the processing unit 304 is specifically configured to: determine the real value of the voltage fundamental component of each voltage sampling waveform according to the following formula; According to the following formula, determine the imaginary value of the voltage fundamental component of each voltage sampling waveform; Determining the second voltage effective value corresponding to each voltage sampling waveform according to the real value and the imaginary value of the voltage fundamental component of each voltage sampling waveform, including: determining the second voltage effective value corresponding to each voltage sampling waveform according to the following formula; Among them, k represents the ordinal number of the voltage sampling waveform, a k represents the real value of the voltage fundamental component of the k-th voltage sampling waveform, N represents the total number of sampling points of the k-th voltage sampling waveform, j represents the ordinal number of the sampling point of the k-th voltage sampling waveform, i ... j represents the sampling value of the jth sampling point of the kth voltage sampling waveform, b k Represents the imaginary value of the voltage fundamental component of the kth voltage sampling waveform, V k Indicates the second voltage effective value corresponding to the kth voltage sampling waveform.

[0134] In some embodiments of the present invention, optionally, the processing unit 304 is specifically used to: determine the drop percentage of each voltage sampling waveform based on the first voltage effective value and each second voltage effective value; accumulate the drop percentages greater than 0 to obtain the cumulative drop percentages of M voltage sampling waveforms.

[0135] In some embodiments of the present invention, optionally, the processing unit 304 is specifically configured to: calculate the drop percentage of each voltage sampling waveform according to the following formula; Among them, V Dk Indicates the drop percentage of the kth voltage sampling waveform, V off Represents the effective value of the first voltage, V k Indicates the second voltage effective value corresponding to the kth voltage sampling waveform.

[0136] In one embodiment of the present invention, a circuit breaker is also provided. Fig. 9 As shown, Fig. 9 FIG. 4 is a block diagram of a circuit breaker 400 according to an embodiment of the present invention. The circuit breaker 400 includes:

[0137] Memory 402, where programs or instructions are stored;

[0138] Processor 404, when executing the above program or instruction, implements the steps of the short-circuit fault identification method of the circuit breaker in any of the above embodiments.

[0139] The circuit breaker 400 provided in this embodiment includes a memory 402 and a processor 404. When the program or instructions in the memory 402 are executed by the processor 404, the steps of the short-circuit fault identification method of the circuit breaker in any of the above embodiments are implemented. Therefore, the circuit breaker 400 has all the beneficial effects of the short-circuit fault identification method of the circuit breaker in any of the above embodiments, which will not be repeated here.

[0140] Specifically, the memory 402 and the processor 404 may be connected via a bus or other means. The processor 404 may include one or more processing units, and the processor 404 may be a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), and other chips.

[0141] In some embodiments of the present invention, optionally, Fig.10As shown, the circuit breaker 400 may further include a metering module 406 , a gate state identification device 408 and a gate driving device 410 .

[0142] The metering module 406 is connected to the processor 404 , and the metering module 406 is used to read waveform data of the voltage sampling waveform.

[0143] Furthermore, the switch state identification device 408 is connected to the processor 404, and the switch state identification device 408 is used to indicate whether the circuit breaker 400 is in a closed state or an open state.

[0144] Furthermore, the gate driving device 410 is connected to the processor 404, and the gate driving device 410 is used to drive the circuit breaker 400 to perform a closing action or an opening action, so as to drive the circuit breaker 400 to switch to a closing state or an opening state.

[0145] In actual application, the metering module 406 communicates with the processor 404 via SPI (Serial Peripheral Interface) or IIC (Inter-Integrated Circuit). If the processor 404 has a metering function, the metering module 406 in the circuit breaker 400 can also be removed.

[0146] Furthermore, the switch state identification device 408 may be specifically a switch-on / off state button. When the circuit breaker 400 is in the closed state, the switch-on / off state button is always in a pressed state. When the circuit breaker 400 is in the open state, the switch-on / off state button is always in a released state.

[0147] Furthermore, the gate driving device 410 may specifically communicate with the processor 404 via PWM (Pulse Width Modulation).

[0148] Furthermore, in actual application, the circuit breaker 400 may also include an indicator light 418 , a function button 420 , a gateway 422 and an Internet access module 424 .

[0149] The indicator light 418, the function button 420, the gateway 422 and the Internet access module 424 are all connected to the processor 404. The indicator light 418 and the function button 420 can communicate with the processor 404 through an IO (Input Output) interface, and the gateway 422 and the Internet access module 424 can communicate with the processor 404 through a UART (Universal Asynchronous Receiver / Transmitter).

[0150] Furthermore, the indicator light 418 is used to indicate whether the circuit breaker 400 is in a closed state or an open state. The indicator light 418 can also be used to alarm and indicate fault information of the circuit breaker 400.

[0151] Furthermore, the function button 420 is used to test whether the gate driving device 410 of the circuit breaker 400 works normally.

[0152] Furthermore, the gateway 422 is used to collect working data of different circuit breakers 400 and report the working data to the cloud platform, so that the working data of the circuit breaker 400 is presented on the platform for display.

[0153] Furthermore, the Internet access module 424 is used for the circuit breaker 400 to connect to a WIFI (Wireless Fidelity) module, so as to report the working data of a single circuit breaker 400 to the cloud platform separately.

[0154] Furthermore, the circuit breaker 400 can also receive control instructions from the gateway 422 or the cloud platform to perform closing and opening actions, thereby realizing the remote control function of the circuit breaker 400.

[0155] In some embodiments of the present invention, optionally, Fig.10 As shown, the circuit breaker 400 further includes a leakage protection device 412 .

[0156] The leakage protection device 412 is connected to the processor 404 .

[0157] Furthermore, the leakage protection device 412 may specifically include a leakage detection device 414 and a leakage protection driving device 416 .

[0158] The leakage detection device 414 is used to detect the leakage current in the circuit in real time.

[0159] Furthermore, the leakage protection driving device 416 is connected to the leakage detection device 414 , and the leakage protection driving device 416 is used to drive the gate driving device 410 to perform a gate opening action according to the leakage current, thereby realizing the leakage protection function of the circuit breaker 400 .

[0160] In actual application, the leakage protection device 412 can communicate with the processor 404 through an IO interface.

[0161] Furthermore, the leakage protection driving device 416 can be specifically a leakage protection test button, so that maintenance personnel can regularly check whether the leakage protection function of the circuit breaker 400 can operate normally. Specifically, when the leakage protection test button is pressed, the circuit breaker 400 will generate leakage, triggering the leakage protection circuit in the circuit breaker 400 to take effect, so that the circuit breaker 400 performs a tripping action.

[0162] Furthermore, the leakage detection device 414 can report the detection data to the cloud platform through interaction with the gateway 422 or the cloud platform, so that the detection data can be presented on the platform for display.

[0163] On this basis, if the leakage protection drive device 416 fails, when the leakage current is greater than 80% of the rated leakage current, the cloud platform will drive the circuit breaker 400 to perform the opening action to ensure the normal execution of the opening action and ensure the leakage protection function of the circuit breaker 400.

[0164] In one embodiment of the present invention, a readable storage medium is also provided, on which a program or instruction is stored, and when the program or instruction is executed by a processor, the steps of the short-circuit fault identification method of a circuit breaker in any of the above embodiments are implemented.

[0165] The readable storage medium provided by the embodiment of the present invention can implement the steps of the short-circuit fault identification method of the circuit breaker in any of the above embodiments when the program or instruction stored therein is executed by the processor. Therefore, the readable storage medium has all the beneficial effects of the short-circuit fault identification method of the circuit breaker in any of the above embodiments, which will not be described in detail here.

[0166] Specifically, the above-mentioned readable storage medium may include any medium capable of storing or transmitting information. Examples of readable storage media include electronic circuits, semiconductor memory devices, read-only memory (ROM), random access memory (RAM), compact disc read-only memory (CD-ROM), flash memory, erasable ROM (EROM), magnetic tape, floppy disk, optical disk, hard disk, optical fiber medium, radio frequency (RF) link, optical data storage device, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0167] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance unless otherwise clearly specified and limited; the terms "connection", "installation", "fixation" and the like should be understood in a broad sense, for example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0168] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0169] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0170] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A short-circuit fault identification method for a circuit breaker, characterized in that: include: When the circuit breaker is in a closed state, waveform data of M voltage sampling waveforms of the circuit breaker in a preset time period are obtained, where M is a positive integer greater than 1; When the circuit breaker is in an open state, obtaining a first voltage effective value of the circuit breaker; Determine, according to the waveform data of each of the voltage sampling waveforms, a second voltage effective value corresponding to each of the voltage sampling waveforms, to obtain M second voltage effective values; Determine the cumulative drop percentages of the M voltage sampling waveforms according to the first voltage effective value and the M second voltage effective values; When the cumulative drop percentage is greater than or equal to a preset threshold, it is determined that a short circuit fault occurs in the circuit breaker.

2. The short-circuit fault identification method of a circuit breaker according to claim 1, characterized in that: The step of determining the second voltage effective value corresponding to each of the voltage sampling waveforms according to the waveform data of each of the voltage sampling waveforms comprises: Determine the real value and the imaginary value of the voltage fundamental component of each of the voltage sampling waveforms according to the waveform data of each of the voltage sampling waveforms; The second voltage effective value corresponding to each of the voltage sampling waveforms is determined according to the real part value and the imaginary part value of the voltage fundamental wave component of each of the voltage sampling waveforms.

3. The short-circuit fault identification method of a circuit breaker according to claim 2, characterized in that: Determining the real value and the imaginary value of the voltage fundamental component of each voltage sampling waveform according to the waveform data of each voltage sampling waveform comprises: Determine the real value of the voltage fundamental component of each voltage sampling waveform according to the following formula; Determine the imaginary value of the voltage fundamental component of each voltage sampling waveform according to the following formula; Determining the second voltage effective value corresponding to each of the voltage sampling waveforms according to the real value and the imaginary value of the voltage fundamental component of each of the voltage sampling waveforms comprises: Determine the effective value of the second voltage corresponding to each of the voltage sampling waveforms according to the following formula; Where, k represents the ordinal number of the voltage sampling waveform, a k represents the real value of the voltage fundamental component of the k-th voltage sampling waveform, N represents the total number of sampling points of the k-th voltage sampling waveform, j represents the ordinal number of the sampling point of the k-th voltage sampling waveform, i ... j represents the sampling value of the jth sampling point of the kth voltage sampling waveform, b k Represents the imaginary value of the voltage fundamental component of the kth voltage sampling waveform, V k Indicates the second voltage effective value corresponding to the kth voltage sampling waveform.

4. The short-circuit fault identification method of a circuit breaker according to claim 1, characterized in that: Determining the cumulative drop percentages of the M voltage sampling waveforms according to the first voltage effective value and the M second voltage effective values ​​includes: Determining the drop percentage of each of the voltage sampling waveforms according to the first voltage effective value and each of the second voltage effective values; The drop percentages that are greater than 0 are cumulatively calculated to obtain the cumulative drop percentages of the M voltage sampling waveforms.

5. The short-circuit fault identification method of a circuit breaker according to claim 4, characterized in that: Determining the drop percentage of each of the voltage sampling waveforms according to the first voltage effective value and each of the second voltage effective values ​​includes: The drop percentage of each voltage sampling waveform is calculated according to the following formula; Among them, V Dk Indicates the drop percentage of the kth voltage sampling waveform, V off Represents the effective value of the first voltage, V k Indicates the second voltage effective value corresponding to the kth voltage sampling waveform.

6. A short-circuit fault identification device for a circuit breaker, characterized in that: include: An acquisition unit, configured to acquire waveform data of M voltage sampling waveforms of the circuit breaker in a preset time period when the circuit breaker is in a closed state, where M is a positive integer greater than 1; The acquisition unit is further configured to acquire a first voltage effective value of the circuit breaker when the circuit breaker is in an open state; A processing unit, configured to determine, according to the waveform data of each of the voltage sampling waveforms, a second voltage effective value corresponding to each of the voltage sampling waveforms, and obtain M second voltage effective values; The processing unit is further used to determine the cumulative drop percentages of the M voltage sampling waveforms according to the first voltage effective value and the M second voltage effective values; The judgment unit is used to determine that a short circuit fault occurs in the circuit breaker when the cumulative drop percentage is greater than or equal to a preset threshold.

7. A circuit breaker, characterized in that: The method comprises a processor and a memory, wherein the memory stores a program or instruction that can be run on the processor, and when the program or instruction is executed by the processor, the steps of the short-circuit fault identification method of a circuit breaker according to any one of claims 1 to 5 are implemented.

8. The circuit breaker according to claim 7, characterized in that: Also includes: A metering module, connected to the processor, for reading waveform data of a voltage sampling waveform; A switch state identification device, connected to the processor, for indicating whether the circuit breaker is in a closed state or an open state; A switch driving device is connected to the processor and is used to drive the circuit breaker to switch to a closed state or an open state.

9. The circuit breaker according to claim 8, characterized in that Also includes: A leakage protection device is connected to the processor, and the leakage protection device includes: A leakage detection device for detecting leakage current; The leakage protection driving device is connected to the leakage detection device and is used to drive the gate driving device to perform a gate opening action according to the leakage current.

10. A readable storage medium, characterized in that: The readable storage medium stores a program or an instruction, and when the program or the instruction is executed by the processor, the steps of the short-circuit fault identification method of the circuit breaker according to any one of claims 1 to 5 are implemented.

Images