A molded case circuit breaker and a method, medium and device for predicting the electrical life of the molded case circuit breaker

Abstract

The present invention provides a molded case circuit breaker and a method for predicting the electrical life of a molded case circuit breaker. When the circuit breaker is actuated once, the instantaneous voltage and instantaneous current of each phase input and output are sampled, arc power is calculated based on the instantaneous voltage and instantaneous current, the difference between the arc power of the input end and the arc power of the output end of the same phase is calculated, the difference is defined as the instantaneous arc power, and it is defined as the amount of electrical wear; the instantaneous arc power after each circuit breaker action is accumulated and calculated to obtain the accumulated arc energy, and the remaining electrical life of each phase contact is calculated based on the accumulated arc energy; the remaining electrical life of each phase contact is compared, and the remaining electrical life with the smallest value is selected as the remaining electrical life of the molded case circuit breaker. The present invention calculates the accumulated arc energy by using the arc power generated when each phase contact system of the circuit breaker is disconnected, and calculates the life of the circuit breaker based on the amount of electrical wear, thereby providing guidance for the inspection and maintenance time of the circuit breaker contacts.

Description

Technical Field

[0001] The present invention relates to the technical field of molded case circuit breakers, and in particular to a molded case circuit breaker and a method, a medium and a device for predicting the electrical life of the molded case circuit breaker. Background Art

[0002] The operational reliability of power equipment is an important guarantee for the safe, stable and economical operation of the power system. Circuit breakers are widely used in different locations of the power grid, playing a role of control and protection. Once a failure occurs, it will directly cause a power grid accident or further expand the accident, causing huge economic and social benefits.

[0003] When multiple moving contacts are used to form a moving contact in an existing molded case circuit breaker, arcs will occur between the moving contacts, thus affecting the use of the moving contacts. Secondly, when the contact system in the existing molded case circuit breaker is working, it will be subjected to various electromagnetic forces, mechanical forces and thermal stresses to produce electrical wear, which will cause the working performance of the circuit breaker to deteriorate. Summary of the invention

[0004] The object of the present invention is to provide a molded case circuit breaker and a method, medium and device for predicting the electrical life of the molded case circuit breaker to solve the above technical problems.

[0005] The present invention provides a molded case circuit breaker, characterized in that it includes a moving contact assembly arranged in each phase, the moving contact assembly includes a first moving contact piece and a second moving contact piece, a connecting piece is arranged between the first moving contact piece and the second moving contact piece, the connecting piece is arranged in a gap formed by the first moving contact piece and the second moving contact piece and respectively connects the first moving contact piece and the second moving contact piece, the first moving contact piece and the second moving contact piece are provided with a first connecting hole and a second connecting hole, and the corresponding connecting piece is formed with an arc guide hole arranged concentrically with the first connecting hole and a connecting column arranged concentrically with the second connecting hole, the connecting column is located on both sides of the connecting piece and extends into the second connecting hole and is respectively connected to the first moving contact piece and the second moving contact piece. The contacts are connected, the first connecting hole and the arc guide hole are close to one end of the contact, the second connecting hole and the connecting column are arranged away from one end of the contact, the two side surfaces of the connecting piece are recessed inward to form an arc guide cavity, and the connecting piece is also provided with an upper abutment plate and a lower abutment plate for limiting the rotation of the first moving contact piece and the second moving contact piece in the longitudinal direction, wherein an upper arc guide opening is formed between the upper abutment plate and the arc guide cavity, and a lower arc guide opening is formed between the lower abutment plate and the arc guide cavity, the upper abutment plate is located on the upper end surfaces of the first moving contact piece and the second moving contact piece and extends toward the first moving contact piece and the second moving contact piece respectively, and the lower abutment plate is located on the lower end surfaces of the first moving contact piece and the second moving contact piece and extends toward the first moving contact piece and the second moving contact piece respectively.

[0006] The present invention also provides a method for predicting the electrical life of a molded case circuit breaker, which is characterized by comprising the following steps:

[0007] S100, when obtaining a single action of the circuit breaker, the instantaneous voltage and instantaneous current of each phase input terminal and output terminal are sampled to obtain corresponding samples, the arc power is calculated according to the instantaneous voltage and instantaneous current, the difference between the arc power of the input terminal and the arc power of the output terminal of the same phase is calculated, the difference is defined as the instantaneous arc power, and it is defined as the electrical wear amount;

[0008] S200, after calculating the arc power, use a sliding average filter to process samples in the measured power, and obtain the filtered instantaneous arc power according to the output data sequence generated by the sliding average filter;

[0009] S300, accumulating and calculating the instantaneous arc power after each circuit breaker operation to obtain the accumulated arc energy, and calculating the remaining electrical life of each phase contact according to the accumulated arc energy;

[0010] S400, comparing the remaining electrical life of each phase contact, and selecting the remaining electrical life with the smallest value as the remaining electrical life of the molded case circuit breaker.

[0011] The present invention further arranges that the instantaneous arc power is calculated as follows: ;

[0012] Where s is the sampling index; T S is the sampling period; and are the instantaneous voltages at the input and output of the circuit breaker respectively; and is the instantaneous current at the input and output of the circuit breaker.

[0013] The present invention is further configured such that the output data sequence is as follows: In the above formula, is the input data sequence, representing the instantaneous arc power; is the output data sequence. It represents the sliding average value of the instantaneous arc power; j is the instantaneous arc power at the sampling moment; N is the length of the sliding average filter cycle.

[0014] The present invention is further configured to calculate the threshold value of the arc energy under the original life of the molded case circuit breaker when calculating the remaining electrical life, and the calculation method is as follows: In the above formula The number of interruptions allowed for the rated current of the circuit breaker specified by the manufacturer; n is the number of samples of the instantaneous arc power; is the instantaneous arc power related to the rated power of the circuit breaker; k is the interrupting current index, which is determined by the insulation dielectric strength of the circuit breaker.

[0015] The present invention further provides that the instantaneous arc power after each circuit breaker action is accumulated and calculated to obtain the cumulative arc energy calculation method as follows: In the formula, m is the number of actions.

[0016] The present invention further provides that the calculation formula for the remaining electrical life of each phase contact is: In the above formula, S is the remaining electrical life of each phase contact; S 0 is the initial electrical life, the default value is 1; E i is the accumulated arc energy of each phase contact during the i-th action.

[0017] The present invention further provides that the remaining electrical life of the circuit breaker is: S'=min[S 1 , S 2 , S 3 ]; In the above formula, S' is the remaining electrical life of the circuit breaker; S 1 , S 2 , S 3 They are the remaining electrical life of the molded case circuit breaker based on the electrical wear of the contacts of each phase.

[0018] The present invention also provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute the method for predicting the electrical life of a molded case circuit breaker.

[0019] The present invention also provides a readable storage medium on which a program is stored. When the program is executed by a processor, the method for predicting the electrical life of a molded case circuit breaker is implemented.

[0020] Beneficial effects of the present invention: Since there are differences in the electrical wear of the three-phase contacts of the molded case circuit breaker when it is disconnected, the power and energy of the arc generated when each phase contact system of the circuit breaker is disconnected are used to calculate the cumulative arc energy, and it is used as an evaluation index to evaluate the degradation level of the contact. The algorithm can effectively obtain the electrical wear of the circuit breaker contacts, and calculate the life of the circuit breaker based on the electrical wear, thereby providing guidance for the inspection and maintenance time of the circuit breaker contacts. In addition, the connecting piece used in the present invention firstly serves to connect the first moving contact piece and the second moving contact piece, which simplifies the operation of connecting the existing multiple contact pieces by bolts and is more conducive to assembly; through the arc guide cavity on both sides of the connecting piece, when the moving contact is in the open position, since the connecting piece is made of gas-generating material, when an arc is generated around the first moving contact piece and the second moving contact piece, the arc is extinguished; specifically as follows: first, part of the arc can flow along the edge contour of the connecting piece to the upper abutment plate and the lower abutment plate, and the upper abutment plate and the lower abutment plate can guide the arc to extinguish the arc due to the extended part, and the upper abutment plate and the lower abutment plate have the function of limiting the displacement of the first moving contact piece and the second moving contact piece during rotation, thereby improving the synchronization between the two; the second arc enters the arc guide hole from the first connecting hole, and the arc is guided and extinguished from the inside of the arc guide cavity, and a very small amount of arc is then produced from the upper abutment plate and the lower abutment plate through the upper arc guide port and the lower arc guide port, thereby greatly improving the self-capacity of the moving contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0022] Figure 1 This is a flowchart of Example 1 of the present invention.

[0023] Figure 2 It is a structural schematic diagram of a molded case circuit breaker according to embodiment 4 of the present invention.

[0024] Figure 3 It is a schematic structural diagram of the moving contact assembly of embodiment 4 of the present invention.

[0025] Figure 4 This is a schematic diagram of the structure of the moving contact assembly after removing the second moving contact piece according to embodiment 4 of the present invention.

[0026] Reference numerals: 10, moving contact assembly; 101, first moving contact piece; 102, second moving contact piece; 103, connecting piece; 1031, connecting column; 1032, arc guide hole; 1033, arc guide cavity; 1034, upper abutment plate; 1035, lower abutment plate; 1036, lower arc guide opening; 1037, upper arc guide opening; 20, first connecting hole; 30, second connecting hole; DETAILED DESCRIPTION

[0027] The following will describe the implementation methods of the present application in detail with the help of accompanying drawings and examples, so that the implementation process of how the present application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0028] Embodiment 1:

[0029] like Figure 1 As shown, this embodiment proposes a method for predicting the electrical life of a molded case circuit breaker, comprising the following steps:

[0030] S100, when obtaining a single action of the circuit breaker, the instantaneous voltage and instantaneous current of each phase input terminal and output terminal are sampled to obtain corresponding samples, the arc power is calculated according to the instantaneous voltage and instantaneous current, the difference between the arc power of the input terminal and the arc power of the output terminal of the same phase is calculated, the difference is defined as the instantaneous arc power, and it is defined as the electrical wear amount;

[0031] S200, after calculating the arc power, use a sliding average filter to process samples in the measured power, and obtain the filtered instantaneous arc power according to the output data sequence generated by the sliding average filter;

[0032] S300, accumulating and calculating the instantaneous arc power after each circuit breaker operation to obtain the accumulated arc energy, and calculating the remaining electrical life of each phase contact according to the accumulated arc energy;

[0033] S400, comparing the remaining electrical life of each phase contact, and selecting the remaining electrical life with the smallest value as the remaining electrical life of the molded case circuit breaker.

[0034] In this embodiment, the instantaneous arc power is calculated as follows: ;

[0035] Where s is the sampling index; T S is the sampling period; and are the instantaneous voltages at the input and output of the circuit breaker respectively; and is the instantaneous current at the input and output of the circuit breaker.

[0036] In addition, the instantaneous arc power can also be calculated as follows: in , They are the instantaneous values ​​of the circuit breaker terminal voltage and the current passing through the circuit breaker respectively.

[0037] After obtaining the instantaneous arc power, it is filtered through a sliding average filter to output a smooth arc power, effectively suppressing high-frequency oscillation. The output data sequence is shown in the following formula: In the above formula, is the input data sequence, representing the instantaneous arc power; is the output data sequence. It represents the sliding average value of the instantaneous arc power; j is the instantaneous arc power at the sampling moment; N is the length of the sliding average filter cycle.

[0038] In addition, in order to obtain the remaining electrical life, the original life needs to be calculated. The following method is used, that is, when calculating the remaining electrical life, the threshold value of the arc energy under the original life of the molded case circuit breaker is calculated. The calculation method is as follows: In the above formula The number of interruptions allowed for the rated current of the circuit breaker specified by the manufacturer; n is the number of samples of the instantaneous arc power; is the instantaneous arc power related to the rated power of the circuit breaker; k is the interrupting current index, which is determined by the insulation dielectric strength of the circuit breaker.

[0039] The instantaneous arc power after each circuit breaker action is accumulated to obtain the cumulative arc energy of each phase contact. The calculation method is as follows: In the formula, m is the number of actions.

[0040] The calculation formula for the remaining electrical life of each phase contact is: In the above formula, S is the remaining electrical life of each phase contact; S 0 is the initial electrical life, the default value is 1; E i is the accumulated arc energy of each phase contact during the i-th action.

[0041] The remaining electrical life of the circuit breaker is: S'=min[S 1 , S 2 , S 3 ]; In the above formula, S' is the remaining electrical life of the circuit breaker; S 1 , S 2 , S 3 They are the remaining electrical life of the molded case circuit breaker based on the electrical wear of the contacts of each phase.

[0042] In addition, the molded case circuit breaker includes a moving contact. The contact in this embodiment is a moving contact, wherein there may be multiple moving contact pieces in the moving contact of the same phase. In this embodiment, the current and voltage are used to ensure that the overall calculation can be achieved even when there are multiple moving contact pieces, thereby reducing the complexity of calculation based on multiple contact pieces.

[0043] In the present invention, the power and energy of the arc generated when each phase contact system of the circuit breaker is disconnected are used to calculate the cumulative arc energy, and it is used as an evaluation index to evaluate the degradation level of the contact. The algorithm can effectively obtain the electrical wear of the circuit breaker contacts and calculate the life of the circuit breaker based on the electrical wear, thereby providing guidance for the inspection and maintenance time of the circuit breaker contacts. Example

[0044] The present invention also provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute the method for predicting the electrical life of a molded case circuit breaker. Example

[0045] The present invention also provides a readable storage medium on which a program is stored. When the program is executed by a processor, the method for predicting the electrical life of a molded case circuit breaker is implemented. Example

[0046] like Figure 2-Figure 4 As shown, this embodiment provides a molded case circuit breaker, including a moving contact assembly 10 provided for each phase, wherein the moving contact assembly 10 includes a first moving contact piece 101 and a second moving contact piece 102, and the first moving contact piece 101 and the second moving contact piece 102 have the same structure.

[0047] A connecting member 103 is provided between the first moving contact piece 101 and the second moving contact piece 102. The connecting member 103 is provided in the gap formed by the first moving contact piece 101 and the second moving contact piece 102 and respectively connects the first moving contact piece 101 and the second moving contact piece 102. The first moving contact piece 101 and the second moving contact piece 102 are provided with a first connecting hole 20 and a second connecting hole 30. Correspondingly, the connecting member 103 is formed with an arc guide hole 1032 which is arranged concentrically with the first connecting hole 20 and a connecting column 1031 which is arranged concentrically with the second connecting hole 30. The connecting column 1031 is located on both sides of the connecting member 103 and extends into the second connecting hole 30 and is respectively connected to the first moving contact piece 101 and the second moving contact piece 102. The first connecting hole 20 and the arc guide hole 1032 are close to one end of the contact point, and the second connecting hole 30 and the connecting column 1 031 is arranged away from one end of the contact point, and both side surfaces of the connecting piece 103 are recessed inwardly to form an arc guide cavity 1033. The connecting piece 103 is also provided with an upper abutment plate 1034 and a lower abutment plate 1035, which are used to limit the rotation of the first moving contact piece 101 and the second moving contact piece 102 in the longitudinal direction, wherein an upper arc guide opening 1037 is formed between the upper abutment plate 1034 and the arc guide cavity 1033, and a lower arc guide opening 1036 is formed between the lower abutment plate 1035 and the arc guide cavity 1033, the upper abutment plate 1034 is located on the upper end surfaces of the first moving contact piece 101 and the second moving contact piece 102 and extends toward the first moving contact piece 101 and the second moving contact piece 102 respectively, and the lower abutment plate 1035 is located on the lower end surfaces of the first moving contact piece 101 and the second moving contact piece 102 and extends toward the first moving contact piece 101 and the second moving contact piece 102 respectively.

[0048] The connecting piece 103 used in this embodiment firstly serves to connect the first moving contact piece 101 and the second moving contact piece 102, which simplifies the operation of connecting multiple contacts by bolts, and is more convenient for assembly; through the arc guide cavity 1033 on both sides of the connecting piece 103, when the moving contact is in the open state, since the connecting piece 103 is made of gas-generating material, when an arc is generated around the first moving contact piece 101 and the second moving contact piece 102, the arc is extinguished; specifically as follows: first, part of the arc can flow along the edge contour of the connecting piece 103 to the upper abutment plate 1034 and the lower abutment plate 1035, and the upper abutment plate 1 034 and the lower abutment plate 1035 have an extended part, which can guide the arc to extinguish the arc. At the same time, the upper abutment plate 1034 and the lower abutment plate 1035 have the function of limiting the displacement of the first moving contact piece 101 and the second moving contact piece 102 during rotation, thereby improving the synchronization between the two; the second arc enters the arc guide hole 1032 from the first connecting hole 20, and realizes arc guiding and arc extinguishing from the inside of the arc guide cavity 1033. A very small amount of arc is then output from the upper abutment plate 1034 and the lower abutment plate 1035 through the upper arc guide port 1037 and the lower arc guide port 1036, thereby greatly improving the ability of the moving contact itself.

[0049] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve technical problems within a certain error range and basically achieve technical effects.

[0050] It should be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a product or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such product or system. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the product or system including the elements.

[0051] The above description shows and describes several preferred embodiments of the present invention, but as before, it should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the invention concept of this article through the above teachings or the technology or knowledge of the relevant field. And the changes and modifications made by those skilled in the art do not depart from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A molded case circuit breaker, characterized in that: The invention further comprises a moving contact assembly provided in each phase, wherein the moving contact assembly comprises a first moving contact piece and a second moving contact piece, a connecting piece is provided between the first moving contact piece and the second moving contact piece, the connecting piece is provided in a gap formed by the first moving contact piece and the second moving contact piece and respectively connects the first moving contact piece and the second moving contact piece, a first connecting hole and a second connecting hole are provided on the first moving contact piece and the second moving contact piece, and an arc guide hole and a connecting column which are arranged concentrically with the first connecting hole and the second connecting hole are formed on the corresponding connecting piece, the connecting column is located on two side surfaces of the connecting piece and extends into the second connecting hole to be connected to the first moving contact piece and the second moving contact piece respectively, the first connecting The connecting hole and the arc-guiding hole are close to one end of the contact, and the second connecting hole and the connecting column are arranged away from one end of the contact. The two side surfaces of the connecting piece are recessed inward to form an arc-guiding cavity. The connecting piece is also provided with an upper abutment plate and a lower abutment plate for limiting the rotation of the first moving contact piece and the second moving contact piece in the longitudinal direction, wherein an upper arc-guiding opening is formed between the upper abutment plate and the arc-guiding cavity, and a lower arc-guiding opening is formed between the lower abutment plate and the arc-guiding cavity, the upper abutment plate is located on the upper end surfaces of the first moving contact piece and the second moving contact piece and extends toward the first moving contact piece and the second moving contact piece respectively, and the lower abutment plate is located on the lower end surfaces of the first moving contact piece and the second moving contact piece and extends toward the first moving contact piece and the second moving contact piece respectively.

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