Method for evaluating electrical wear state of contact of high-voltage circuit breaker

Abstract

The invention discloses a high-voltage circuit breaker contact electrical wear state evaluation method, which comprises the following steps: S1, when a high-voltage circuit breaker acts, obtaining fault indicator information; s2, obtaining a current electrical parameter estimation value based on the correlation between a fault type and an open circuit electrical parameter and fault indicator information; and S3, obtaining a current high-voltage circuit breaker contact electrical wear state evaluation result according to the current electrical parameter estimation value, the electrical wear state and the circuit breaking electrical parameter correlation. The beneficial effects of the application are that no extra monitoring hardware needs to be added, the evaluation convenience is ensured, the circuit breaker short-circuit current estimation accuracy is ensured through the indication principle of the fault indicator, and the circuit breaker state evaluation accuracy and evaluation convenience are both considered.

Description

Technical Field

[0001] The present application relates to the field of electrical wear status assessment of high-voltage circuit breaker contacts, and more particularly to a method for assessing the electrical wear status of high-voltage circuit breaker contacts. Background Art

[0002] High-voltage circuit breakers are key components for energy transmission and distribution in power systems, and they play a dual role of protection and control in power grids. If high-voltage circuit breakers do not follow control instructions during operation, such as malfunction or refusal to operate, it may cause damage to power equipment and even cause a chain reaction in the system, resulting in a large-scale power outage. Therefore, timely and effective maintenance of the working status of circuit breakers is of great significance to ensure the reliable operation of high-voltage circuit breakers.

[0003] In the related technology, it is necessary to collect a variety of parameters, such as circuit breaker closing time, speed, acceleration, coil resistance, voltage / current mutation, breaking wear, etc., and then perform data analysis and processing to finally obtain the circuit breaker status evaluation. Although this method makes the evaluation factors considered more comprehensive and accurate, it is necessary to install corresponding sensors on the existing circuit breakers, that is, these methods can only be implemented on the basis of an online monitoring system for circuit breakers. However, not all high-voltage circuit breakers in the distribution network are equipped with an online monitoring system. If each circuit breaker is installed with an online monitoring system and then superimposed with a status evaluation algorithm, the cost is high and the scope of application is small.

[0004] In other methods, circuit breakers without online monitoring systems are often maintained and serviced based on work experience, and maintenance instructions are generally issued based on the circuit breaker's operating time, number of interruptions, brand, etc. This maintenance method lacks scientific basis and is time-consuming and labor-intensive.

[0005] When a high-voltage circuit breaker is disconnected, an arc will inevitably be generated between the moving and static contacts. The high temperature of the arc causes the contact surface to burn and the material to deform. Moreover, the greater the current flowing through the circuit breaker when it is disconnected, the greater the contact wear and the shorter the life of the circuit breaker. Therefore, the evaluation of the electrical wear state of the circuit breaker is the key to the inspection and maintenance of high-voltage circuit breakers. However, these data are often collected at regular intervals. For example, a set of data such as voltage, current, electric energy, and power is generally collected every 15 minutes. When the circuit breaker is disconnected, it is often impossible to detect and transmit the current and voltage values ​​to the power grid cloud platform in time. Although the circuit breaker with an online monitoring system can detect the current when the circuit breaker is disconnected in real time, since the data of the circuit breaker online monitoring system is not the power system assessment data, they will not be transmitted to the database of the power management department, and the operation and inspection department cannot obtain these data.

[0006] The patent "Circuit breaker state assessment method, device, storage medium and computer program product", publication number: CN118520230A, publication date: August 20, 2024, specifically discloses a method including: obtaining multimodal data corresponding to the target circuit breaker, wherein the multimodal data is collected by multiple sensors associated with the target circuit breaker; fusing and analyzing the multimodal data based on the target state assessment model to obtain the target state assessment result, wherein the target state assessment model is obtained by machine learning using multiple groups of sample data, and each group of sample data of the multiple groups of sample data includes: sample travel data corresponding to the sample circuit breaker, sample current data, sample speed data, sample acceleration data, sample pressure data, and sample state labeling results corresponding to the sample circuit breaker, and the target state assessment result is used to indicate the operating state of the target circuit breaker. This solution also requires an additional monitoring system. Summary of the invention

[0007] In view of the problem in the prior art that it is impossible to strike a balance between the accuracy and convenience of circuit breaker status assessment, the present application provides a method for assessing the electrical wear status of high-voltage circuit breaker contacts. The method estimates the short-circuit current of the circuit breaker based on the indication principle of a fault indicator, and obtains the electrical wear status assessment result of the circuit breaker contacts based on the correlation between the short-circuit current of the circuit breaker and the electrical wear of the circuit breaker. The method does not require the addition of additional monitoring hardware to ensure the convenience of assessment, and ensures the accuracy of the estimation of the short-circuit current of the circuit breaker through the indication principle of a fault indicator, thereby achieving a balance between the accuracy and convenience of circuit breaker status assessment.

[0008] To achieve the above technical objectives, the present application provides a technical solution, which is a method for evaluating the electrical wear status of high-voltage circuit breaker contacts, comprising the following steps: S1: when the high-voltage circuit breaker is actuated, obtaining fault indicator information; S2: obtaining current electrical parameter estimates based on the correlation between the fault type and the circuit-breaking electrical parameters and the fault indicator information; S3: obtaining current high-voltage circuit breaker contact electrical wear status evaluation results based on the current electrical parameter estimates, the electrical wear status and the circuit-breaking electrical parameter correlation.

[0009] Furthermore, it also includes: S0: obtaining line information, and determining the line connection relationship and line node data according to the line information.

[0010] Furthermore, determining the line connection relationship and line node data based on the line information includes: determining the line connection relationship based on the resource number of the substation start end and the resource number of the feeder start and end ends; obtaining the line node based on the line connection relationship, obtaining the node impedance data according to the distance from the substation start end to each line node, and outputting the line node data in the form of node impedance data and node position.

[0011] Furthermore, the S0 also includes: calculating the per-unit value of the line impedance corresponding to the node based on the node impedance data and the node position; and outputting the line node data based on the line node, the node impedance data and the per-unit value of the line impedance corresponding to the node.

[0012] Furthermore, the S1 includes: receiving a status evaluation signal, acquiring circuit breaker information according to the status evaluation signal, and acquiring fault indicator information according to the circuit breaker information and a line connection relationship.

[0013] Furthermore, the obtaining of fault indicator information according to the circuit breaker information and the line connection relationship includes: obtaining an actuated circuit breaker according to the circuit breaker information, searching for a fault indicator corresponding to the actuated circuit breaker along the line according to the line connection relationship, and searching for an unactuated circuit breaker in a normal operating state along the line with the fault indicator as the center, taking the line between the actuated circuit breaker and the unactuated circuit breaker as the fault occurrence area, and outputting the fault indicator number, fault type and fault occurrence area as the fault indicator information.

[0014] Furthermore, S2 also includes: obtaining a theoretical threshold range of electrical parameters based on data of operated circuit breakers, unoperated circuit breakers and line nodes; obtaining a current electrical parameter estimation value based on the theoretical threshold range of electrical parameters, correlation between fault type and circuit breaker electrical parameters, and fault type in fault indicator information.

[0015] Furthermore, the obtaining of the theoretical threshold range of electrical parameters based on the operated circuit breaker, the unoperated circuit breaker and the line node data includes: obtaining a first impedance according to the line node and the line node data corresponding to the operated circuit breaker; obtaining a second impedance according to the line node and the line node data corresponding to the unoperated circuit breaker; and outputting the theoretical threshold range of electrical parameters with the first impedance, the second impedance and the internal impedance of the substation output power supply.

[0016] Furthermore, obtaining the current electrical parameter estimate based on the electrical parameter theoretical threshold range, the fault type and the circuit breaker electrical parameter correlation, and the fault type in the fault indicator information includes: using the electrical parameter theoretical threshold range and the fault type in the fault indicator information to obtain the current electrical parameter actual threshold range as the current electrical parameter estimate according to the fault type and the circuit breaker electrical parameter correlation.

[0017] Furthermore, the method of obtaining the current electrical wear state evaluation result of the high-voltage circuit breaker contacts based on the current electrical parameter estimation value, the electrical wear state and the correlation between the electrical parameters of the circuit breaker includes: obtaining the minimum electrical wear cumulative value and the maximum electrical wear cumulative value based on the current electrical parameter estimation value, the electrical wear state and the correlation between the electrical parameters of the circuit breaker; and outputting the current high-voltage circuit breaker contact electrical wear state evaluation result based on the preset wear threshold, the minimum electrical wear cumulative value and the maximum electrical wear cumulative value.

[0018] The beneficial effects of the present application are as follows: the electrical parameters of the high-voltage circuit breaker are evaluated when the circuit is tripped through the fault indicator existing in the power grid system, and the current electrical parameter estimation value is obtained according to the fault type output by the fault indicator and the pre-constructed correlation between the fault type and the circuit breaker electrical parameters. The current high-voltage circuit breaker contact electrical wear state evaluation result is directly obtained by the correlation between the electrical wear state and the circuit breaker electrical parameters and the current electrical parameter estimation value, without the need to add other hardware, thus avoiding additional burden on the power grid system. At the same time, the fault indicator itself outputs faults based on the changes in electrical parameters, and the circuit breaker electrical parameters are estimated by its induction of the changes in electrical parameters, which can ensure the accuracy of the estimation range and thus ensure the accuracy of the electrical wear state evaluation result. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic flow chart of a method for evaluating the electrical wear status of high-voltage circuit breaker contacts according to the present application.

[0020] Figure 2 This is a diagram of the distribution network line structure in one embodiment of the present application. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application is further described in detail below in conjunction with the drawings and examples. It should be understood that the specific implementation method described here is only an optimal embodiment of the present application, which is only used to explain the present application and does not limit the scope of protection of the present application. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0022] like Figure 1 As shown, as the first embodiment of the present application, a method for evaluating the electrical wear state of high-voltage circuit breaker contacts includes the following steps: S1: Receive status evaluation signal and obtain fault indicator information; S2: obtaining current electrical parameter estimation values ​​based on the correlation between the fault type and the circuit breaker electrical parameters and the fault indicator information; S3: Obtain the current high-voltage circuit breaker contact electrical wear state assessment result based on the current electrical parameter estimation value, electrical wear state and circuit breaker electrical parameter correlation.

[0023] In this embodiment, the electrical parameters of the high-voltage circuit breaker are evaluated when the circuit is broken by using the fault indicator existing in the power grid system. The current electrical parameter estimation value is obtained according to the fault type output by the fault indicator and the pre-constructed correlation between the fault type and the electrical parameters of the circuit breaker. The current electrical wear state evaluation result of the high-voltage circuit breaker contacts is directly obtained by the correlation between the electrical wear state and the electrical parameters of the circuit breaker and the current electrical parameter estimation value, without adding any additional hardware, thus avoiding additional burden on the power grid system. At the same time, the fault indicator itself outputs faults based on the changes in the electrical parameters, and estimates the electrical parameters of the circuit breaker by sensing the changes in the electrical parameters, thereby ensuring the accuracy of the estimation range and further ensuring the accuracy of the electrical wear state evaluation result.

[0024] In another aspect, a method for assessing electrical wear status of contacts of a high voltage circuit breaker further includes: S0: Obtain line information, and determine line connection relationships and line node data based on the line information.

[0025] The line information includes at least the substation information and the feeder information. The substation information includes at least the substation start resource number, and the feeder information includes at least the feeder start and end resource numbers. The substation start resource number is the starting number of the electrical equipment or line in the substation, which is used to identify and distinguish different equipment and lines; the feeder start and end resource numbers are the corresponding numbers at the start and end of the feeder line, which are used to indicate the connection point and direction of the feeder line. Determining the line connection relationship and line node data based on the line information includes: Determine the line connection relationship based on the substation start resource number and the feeder start and end resource number; The line nodes are obtained based on the line connection relationship, the node impedance data is obtained according to the distance from the substation start to each line node, and the line node data is output as the node impedance data and the node position.

[0026] Read line information from the power grid cloud platform, obtain the substation starting resource number and the feeder starting and ending resource numbers, start from the substation starting resource number, determine the line connection relationship according to the feeder starting and ending resource numbers, calculate the distance from the substation output power supply to each node and the impedance data, and obtain the line node data.

[0027] Specifically, taking the substation as the starting point, according to the feeder head and end numbering, draw the line connection relationship diagram, identify the starting point and end point of each feeder, and the connection node between them, and obtain the line connection relationship and line node. It can be understood that here only provides a feasible way to determine the line connection relationship. In other cases, the connection node and the connection relationship can also be directly obtained according to the mutual correspondence between the substation starting resource number and the feeder head and end resource number, and the connection node is used as the line node. Of course, in the case where the line itself has special nodes, the line node also includes the corresponding special node.

[0028] Among them, in order to facilitate the calculation of the distance from the substation start to each line node and the node impedance data, the substation start information also includes the substation start location, and the feeder start and end information also includes the feeder length and feeder type. The node impedance data obtained according to the distance from the substation start to each line node includes: Calculate the distance from the substation start to each line node based on the substation start location and feeder length; The node impedance data is calculated based on the feeder type, preset impedance coefficient, and the distance from the substation start to each line node.

[0029] Different feeder types have different impedance coefficients. For example, in some cases, the impedance of overhead lines is 0.4Ω / km per kilometer, and the impedance of cable lines is 0.08Ω / km per kilometer, that is, the impedance coefficient corresponding to overhead lines is 0.4Ω / km, and the impedance coefficient corresponding to cable lines is 0.08Ω / km. After obtaining the node impedance data, the line impedance per unit value is calculated according to the line capacity and the voltage rating. At this time, the line information also includes the line capacity and the voltage rating. Assume that the line capacity is S, the voltage rating is UN, and the node impedance data is R. The line impedance per unit value is obtained according to R*S / UN2. Step S0 also includes: Calculate the per unit line impedance value corresponding to the node based on the node impedance data and node position; Output line node data in the form of line nodes, node impedance data, and per-unit line impedance values ​​corresponding to the nodes.

[0030] It is understandable that the line node at least includes the line node name and the end resource number corresponding to the line node. The line node data at least includes the line node name, the resource number corresponding to the line node, the node impedance data and the line impedance per unit value corresponding to the node.

[0031] In this embodiment, the state evaluation signal includes a circuit breaker action signal and / or a timing update signal. When the state evaluation signal is a circuit breaker action signal, the circuit breaker wear state evaluation is performed only when the high-voltage circuit breaker switch is actuated; when the state evaluation signal is a timing update signal, the circuit breaker wear state evaluation is performed only when the timing time is reached; when the state evaluation signal is a timing update signal and a circuit breaker action signal, the circuit breaker wear state evaluation is performed when the high-voltage circuit breaker switch is actuated or when the timing time is reached. The state evaluation signal is set according to actual needs. For example, when it is necessary to perform the wear state evaluation in a timely manner, the circuit breaker action signal is set as the state evaluation signal, and the wear state evaluation is updated when the circuit breaker is actuated. When it is not necessary to perform the wear state evaluation frequently, the timing update signal is set as the state evaluation signal. In other cases, a wear status assessment threshold can be set. When the wear status assessment result is less than the wear status assessment threshold, the timed update signal is set as the status assessment signal. When the wear status assessment result is greater than or equal to the wear status assessment threshold, the circuit breaker action signal is switched to the status assessment signal. When the circuit breaker is lightly worn, the frequency of assessment is reduced. When the circuit breaker is heavily worn but is in a normal operation stage, an assessment is triggered every time the circuit breaker is actuated, thereby ensuring that when the circuit breaker is in a dangerous state of wear, the operation and maintenance personnel can be reminded in time to perform maintenance.

[0032] At this time, step S1 includes: A state evaluation signal is received, circuit breaker information is acquired according to the state evaluation signal, and fault indicator information is acquired according to the circuit breaker information and a line connection relationship.

[0033] The circuit breaker information includes at least the circuit breaker resource number and the action time. When the circuit breaker is actuated or updated regularly, the circuit breaker switch in the line is actuated and the action reason is "fault", the number and action time of the circuit breaker are recorded, and each fault indicator is searched along the line according to the line connection relationship to see whether it sends fault indication information at the time of the circuit breaker action, and the fault indicator number and fault type of the fault indicator that sends fault indication information when the circuit breaker is actuated are recorded, and the circuit breaker of the line corresponding to the fault indicator is continued to be searched until the circuit breaker found is operating normally in the time period of the action time and there is no action information, and the resource number of the circuit breaker that is operating normally is recorded to determine the fault location. Obtaining fault indicator information according to the circuit breaker information and the line connection relationship includes: The actuated circuit breaker is obtained according to the circuit breaker information, and the fault indicator corresponding to the actuated circuit breaker is searched along the line according to the line connection relationship. The non-actuated circuit breaker in normal operation state is searched along the line with the fault indicator as the center. The line between the actuated circuit breaker and the non-actuated circuit breaker is taken as the fault occurrence area, and the fault indicator number, fault type and fault occurrence area are output as the fault indicator information.

[0034] In this embodiment, a fault indicator indicating an actuated circuit breaker is obtained through line connection relationships, and a circuit breaker in a normal operating state that has not been actuated is searched for with the fault indicator as the center to obtain the area where the fault point is located, thereby facilitating subsequent fault detection and maintenance.

[0035] Furthermore, step S2 comprises: Obtain historical fault data, and build a correlation between fault type and circuit breaker electrical parameters based on the historical fault data; The current electrical parameter estimation value is obtained based on the fault type in the fault indicator information and the correlation between the fault type and the circuit breaker electrical parameter.

[0036] The historical fault data at least includes historical fault indicator information and corresponding circuit breaker electrical parameters. The correlation between the fault type in the historical fault indicator information and the circuit breaker electrical parameters is obtained by regression analysis or neural network training. Then, the electrical parameter estimation value corresponding to the fault type in the current fault indicator information is obtained. Without the need to add additional electrical parameter detection devices, the indication principle of the fault indicator can still be used to obtain a relatively close or covered electrical parameter estimation value, thereby reducing the monitoring cost while ensuring a certain degree of wear assessment accuracy.

[0037] In the case where the fault indicator reflects the short-circuit current, the circuit breaker electrical parameter is the circuit breaker current parameter.

[0038] In some other embodiments, in order to ensure that the current estimated value of the electrical parameter covers the actual value of the electrical parameter, the estimated value of the electrical parameter is made into a range value. That is, step S2 further includes: Obtaining theoretical threshold ranges of electrical parameters based on data of operated circuit breakers, unoperated circuit breakers and line nodes; The current electrical parameter estimation value is obtained based on the electrical parameter theoretical threshold range, the correlation between the fault type and the circuit breaker electrical parameter, and the fault type in the fault indicator information.

[0039] Acquiring the theoretical threshold range of the electrical parameter based on the operated circuit breaker, the unoperated circuit breaker and the line node data includes: acquiring a first impedance according to the line node corresponding to the operated circuit breaker and the line node data; Obtaining a second impedance according to the line node corresponding to the unoperated circuit breaker and the line node data; The theoretical threshold range of the electrical parameter is outputted by the first impedance, the second impedance and the internal impedance of the substation output power supply.

[0040] According to the resource number of the operated circuit breaker, the distribution network pole node where it is located is obtained, and the per-unit value of the line impedance of the distribution network pole node is obtained as the first impedance; according to the resource number of the circuit breaker that operates normally after the line where the fault indicator is located, that is, the resource number of the unoperated circuit breaker, the distribution network pole node where it is located is obtained, and the per-unit value of the line impedance of the distribution network pole node is obtained as the second impedance. If there are other branches between the operated circuit breaker and the unoperated circuit breaker, the impedance between the branch end point and the substation output power supply is read, and the maximum impedance between the branch end point and the substation output power supply is taken as the second impedance. When the electrical parameter is a current parameter, the theoretical threshold range of the output current parameter is based on the first impedance, the second impedance and the internal impedance of the substation output power supply: Among them, I max is the maximum short-circuit current of the circuit breaker, I min is the minimum short-circuit current of the circuit breaker, Z0 is the internal impedance of the substation output power supply, Z1 is the first impedance, Z2 is the second impedance, S is the line capacity, and UN is the voltage rating.

[0041] The theoretical threshold range of the current parameter is obtained as follows: At this time, the correlation between the fault type and the circuit breaker electrical parameters is constructed based on the historical fault data, including: Calculate the theoretical threshold range of electrical parameters at historical moments based on historical fault data; Obtaining the actual threshold range of the electrical parameter at the historical moment based on the fault type at the historical moment; The correlation between the fault type and the circuit breaker electrical parameters is constructed based on the correspondence between the theoretical threshold range of the electrical parameters at the historical moment and the actual threshold range of the electrical parameters at the historical moment.

[0042] The actual threshold range of the electrical parameters under the historical conditions of each fault type and the theoretical threshold range of the electrical parameters of the circuit breaker are obtained, so as to calculate the ratio relationship between the actual threshold range of the electrical parameters and the theoretical threshold range of the electrical parameters of the circuit breaker, and construct the correlation between the fault type and the electrical parameters of the circuit breaker.

[0043] Obtaining the current electrical parameter estimation value based on the electrical parameter theoretical threshold range, the correlation between the fault type and the circuit breaker electrical parameter, and the fault type in the fault indicator information includes: The current electrical parameter actual threshold range is obtained as the current electrical parameter estimation value according to the correlation between the fault type and the circuit breaker electrical parameter by using the electrical parameter theoretical threshold range and the fault type in the fault indicator information.

[0044] For example, when the electrical parameter is a current parameter, the correlation between the fault type and the circuit breaker electrical parameter is constructed based on historical fault data: when the fault type of the fault indicator is "three-phase short circuit", then When the fault indicator fault type is "two-phase short circuit", When the fault indicator fault type is "single-phase grounding", And when the fault type of the fault indicator is "overcurrent",

[0045] The current electrical parameter estimate is When the corresponding fault type is obtained by the actual region where the historical electrical parameters fall, the electrical parameters are equivalent to the range of the current line data, ensuring that the actual electrical parameters fall within the range of the estimated values ​​of the electrical parameters, thereby ensuring the accuracy of the final assessment of circuit breaker wear.

[0046] Step S3 also includes: Obtain historical wear data, and build a correlation between electrical wear status and circuit breaker electrical parameters based on the historical wear data.

[0047] The historical wear data at least includes the electrical wear state of the circuit breaker contacts and the corresponding electrical parameters of the circuit breaker at the historical moment. In other cases, the correlation between the electrical wear state and the electrical parameters of the circuit breaker can also be obtained based on expert experience.

[0048] In this embodiment, the electrical parameter is a current parameter, and the correlation between the electrical wear state and the electrical parameter of the circuit breaker is: N is the number of times the circuit breaker is opened, I N is the rated current of the circuit breaker, Q M is the electrical wear value. When the current parameter is less than 0.35I N When, through Calculate the electrical wear value when the current parameter is greater than or equal to 0.35I N When, through Calculate the electrical wear value.

[0049] The single electrical wear value and the cumulative electrical wear value are calculated according to the current current estimation value, and the electrical wear state of the current high-voltage circuit breaker contacts is evaluated according to the cumulative electrical wear value. In this embodiment, the electrical wear value is calculated for the maximum value and the minimum value of the current electrical parameter estimation value, respectively, and the maximum electrical wear value and the minimum electrical wear value are obtained correspondingly. The maximum electrical wear value accumulated from the use of the circuit breaker to the current period is obtained by accumulating the maximum electrical wear value, and the minimum electrical wear value accumulated from the use of the circuit breaker to the current period is obtained by accumulating the minimum electrical wear value. At this time, the current electrical wear state evaluation result of the high-voltage circuit breaker contacts is obtained based on the correlation between the current electrical parameter estimation value, the electrical wear state and the circuit breaker electrical parameters, including: According to the current electrical parameter estimation value, the electrical wear state and the correlation between the electrical parameters of the circuit breaker, the minimum electrical wear accumulation value and the maximum electrical wear accumulation value are obtained; The current high-voltage circuit breaker contact electrical wear state evaluation result is output based on the preset wear threshold, the minimum electrical wear accumulation value and the maximum electrical wear accumulation value.

[0050] The preset wear threshold can be set according to the actual wear of the circuit breaker. For example, in this embodiment, the total amount of electrical wear allowed for a new high-voltage circuit breaker is set to 1, and the preset wear threshold is set according to the wear state and the corresponding degree of operational danger: When ΣQM-min≤0.3 and ΣQM-max≤0.3, the current evaluation result of the electrical wear state of the high-voltage circuit breaker contacts is "excellent"; When ΣQM-min≤0.5, and 0.3<ΣQM-max≤0.5, the current evaluation result of the electrical wear state of the high-voltage circuit breaker contacts is "good"; When 0.3<ΣQM-min≤0.5, and 0.5<ΣQM-max≤0.8, the current high-voltage circuit breaker contact electrical wear state assessment result is "normal"; When ΣQM-min≥0.5 and 0.5<ΣQM-max≤0.8, the current evaluation result of the electrical wear state of the high-voltage circuit breaker contacts is "poor"; When ΣQM-min≥0.5 and ΣQM-max≥0.8, the current high-voltage circuit breaker contact electrical wear status assessment result is "dangerous".

[0051] Based on the comparison results of the minimum electrical wear cumulative value and the maximum electrical wear cumulative value with the preset wear threshold, the electrical wear status evaluation result of the current high-voltage circuit breaker contact is obtained, so that the electrical wear status corresponding to the electrical wear amount represented by the actual electrical parameters must be included in the electrical wear status represented by the minimum electrical wear cumulative value and the maximum electrical wear cumulative value, thereby ensuring the accuracy of the evaluation without adding other monitoring devices.

[0052] As the second embodiment of the present application, a specific embodiment is provided for illustration. Figure 2The structure diagram of the overhead line distribution network is shown in the figure. In the figure, "Gaibian" represents a substation, line 192 represents a distribution line derived from the substation, 1#, 3#, etc. in the line represent overhead pole numbers, switches 1003, 1022 and 1063 represent high-voltage circuit breakers, A1, A2 and A3 represent line fault indicators, whose function is to record the fault information of the line, #5 to 100, #9 to 100, #10 to 160 and #16 to 400 represent transformers in the branches of the main line, which convert 10kV voltage into 400V for load use and can be considered as a load node. All data in the line can be transmitted to the cloud platform of the power grid data center. When the fault indicator in the line detects a line fault, it can not only flip or flash an alarm on the spot, but also transmit the fault information to the communication device through a short-distance wireless method. The communication device then sends the fault information to the cloud platform of the power grid data center through a wireless public network or optical fiber. The fault information includes "single-phase grounding", "phase-to-phase short circuit", "three-phase short circuit" and "overcurrent". Similarly, when the circuit breaker switch in the line is in action, it will send the action status and action reason to the power grid cloud platform. For example, when the high-voltage circuit breaker changes from state 1 (closed) to state (0), the reason is: maintenance or failure. Generally, when the reason is "maintenance", the current of the circuit breaker action is small, and the circuit breaker electrical wear assessment is negligible.

[0053] In this embodiment, the line information includes a device table and a feeder table, as shown in Table 1 and Table 2. The line information is also stored in the power grid cloud platform.

[0054] Table 1 Line equipment table

[0055] Table 2 Line feeder table

[0056] According to Table 1 and Table 2, the line connection relationship and line node data can be determined. For example, the number of pole 1# is VTLHTdCGoI6ucPOPHj6DTk, which is the starting point. The end number of this section of the line is kjjQ12yewYunPIxMkUNfpk, from which the line connection mode, the location of the fault indicator and the location information of the circuit breaker can be obtained. The line topology structure can be constructed to facilitate the retrieval and viewing of information.

[0057] Every time the high-voltage circuit breaker changes its action and the reason for the change, data will be sent to the cloud platform of the power grid data center. The reasons for the action change include "normal maintenance and power off" and "fault". After the fault indicator detects a line fault, it will also send data to the cloud platform of the power grid data center. The fault types include: "single-phase grounding", "two-phase short circuit", "three-phase short circuit" and "overcurrent". The data output by the high-voltage circuit breaker and the fault indicator can be processed and analyzed to obtain the wear status of the circuit breaker. In some cases, the circuit breaker electrical wear assessment processor can be constructed based on the communication equipment and data analysis equipment in the power grid system, and the assessment results can be output to the cloud platform. The power grid cloud platform is the data center of the State Grid Corporation, which contains the topology information of the distribution network line and receives various data uploaded by the line equipment; the circuit breaker electrical wear assessment processor module reads the data in the power grid cloud platform through a security protocol; the high-voltage circuit breaker is used to protect the line power supply. When the circuit breaker is activated, the action status information and the action reason will be sent to the power grid cloud platform; after the fault occurs, the fault indicator will indicate an alarm and upload the fault type to the cloud platform. Of course, if the cloud platform itself has data analysis capabilities, it can also directly analyze the data through the cloud platform to output the wear status assessment results of the circuit breaker.

[0058] When a high-voltage circuit breaker is in operation, an arc occurs. The contacts are subjected to the high-temperature arc, which causes a strong physical / chemical reaction. Under the strong gasification and electric field force, the metal of the contact material is liquefied, and the liquefied metal droplets are blown away, causing serious damage to the contacts. A large number of field tests have shown that the main factor causing the wear of circuit breaker contacts is the breaking arc. The size of the arc energy determines the degree of electrical wear of the contacts, and the size of the arc energy is related to the breaking current and the arc burning time.

[0059] When the fault occurs near 20#, the 1003 switch is activated and the A1 fault indication is displayed; when the fault occurs near 25#, the 1002 switch is activated and the A1 fault indication is displayed; when the fault occurs near 46#, 53# or 63#, the 1002 switch is activated and the A2 fault indication is displayed; when the fault occurs near 64#, the 1063 switch is activated and the A3 fault indication is displayed. After the device is activated, the relevant status information is sent to the power grid cloud platform.

[0060] Starting from the resource number at the beginning of the substation, according to the resource numbers at the beginning and end of the feeder, determine the connection relationship of the line, calculate the distance from the substation output power to the node, for the 10kv distribution network line, the impedance of the overhead line is 0.4Ω / km per kilometer, and the impedance of the cable line is 0.08Ω / km per kilometer, calculate the impedance R of the power output to each node of the line, assume that the line capacity is S, the voltage rating is UN, and the total impedance is calibrated according to the formula R*S / UN2, and the impedance calibrated value of the line and the node related information data are saved as line node data in the local data table, as shown in Table 3.

[0061] Table 3 Impedance from substation power supply to each node

[0062] If switch 1002 is actuated and A1 and A2 issue three-phase short-circuit fault indications, the system records that switch 1002 is actuated, and its number is eSCyS7w9W42U6pmtp6hczU. A1 and A2 issue fault indications, and their resource numbers are YvwRi5gHw4iUJbIH55RyQk and gFdIeyufBIuFKlV8xmyf6k, respectively. Switch 1063 operates normally and does not issue an action instruction, and its number is recorded as DwgdbBY9B4muLyOl4kIpjE. Obviously, the fault occurs between switches 1002 and 1063. At this time, the distribution network pole node where the 1002 switch is located is 22#, and the impedance from the power supply to 22# is Z1; the distribution network pole node where the 1063 switch is located is 63#, and the maximum impedance from the power supply to #10 transformer 160, 16 transformer 400 and 63# is Z2. The theoretical threshold range of the electrical parameters is calculated, and the current electrical parameter estimation value is obtained according to the fault type of the fault indicator. The current high-voltage circuit breaker contact electrical wear status assessment result is obtained by analysis.

[0063] This application is based on the data transmission from various intelligent devices in the distribution network to the power grid cloud platform, combined with the basic line topology data, circuit breaker action information and fault indicator fault information stored in the power grid cloud platform, to estimate the short-circuit current flowing through the circuit breaker, and use the circuit breaker relative wear method and fuzzy inference to evaluate the electrical wear state of the high-voltage circuit breaker. No additional hardware equipment is required, the data relied on is small, the cost is low, the implementation is convenient, and it is easy to promote and apply.

[0064] The specific implementation described above is a preferred implementation of a method for evaluating the electrical wear state of high-voltage circuit breaker contacts of the present application, and is not intended to limit the specific implementation scope of the present application. The scope of the present application includes but is not limited to the specific implementation embodiment. All equivalent changes made in accordance with the shape and structure of the present application are within the protection scope of the present application.

Claims

1. A method for evaluating the electrical wear state of high-voltage circuit breaker contacts, characterized in that: The steps include: S1: When the high voltage circuit breaker is actuated, the fault indicator information is obtained; S2: obtaining the estimated value of the current electrical parameter based on the correlation between the fault type and the circuit-breaking electrical parameter and the fault indicator information; S3: Obtain the current high-voltage circuit breaker contact electrical wear state assessment result based on the current electrical parameter estimation value, the electrical wear state and the circuit breaker electrical parameter correlation.

2. A method for evaluating the electrical wear state of high-voltage circuit breaker contacts according to claim 1, characterized in that: Also includes: S0: Obtain line information, and determine line connection relationships and line node data based on the line information.

3. A method for evaluating the electrical wear state of high-voltage circuit breaker contacts as claimed in claim 2, characterized in that: Determining the line connection relationship and line node data according to the line information includes: Determine the line connection relationship based on the substation start resource number and the feeder start and end resource number; The line nodes are obtained based on the line connection relationship, the node impedance data is obtained according to the distance from the substation start to each line node, and the line node data is output as the node impedance data and the node position.

4. A method for evaluating electrical wear status of high-voltage circuit breaker contacts as claimed in claim 3, characterized in that: The S0 further includes: Calculate the per unit line impedance value corresponding to the node based on the node impedance data and node position; Output line node data in the form of line nodes, node impedance data, and per-unit line impedance values ​​corresponding to the nodes.

5. A method for evaluating the electrical wear state of high-voltage circuit breaker contacts as claimed in claim 2, characterized in that: The S1 includes: A state evaluation signal is received, circuit breaker information is acquired according to the state evaluation signal, and fault indicator information is acquired according to the circuit breaker information and a line connection relationship.

6. A method for evaluating the electrical wear state of high-voltage circuit breaker contacts as claimed in claim 5, characterized in that: The acquiring of fault indicator information according to the circuit breaker information and the line connection relationship comprises: The actuated circuit breaker is obtained according to the circuit breaker information, and the fault indicator corresponding to the actuated circuit breaker is searched along the line according to the line connection relationship. The non-actuated circuit breaker in normal operation state is searched along the line with the fault indicator as the center. The line between the actuated circuit breaker and the non-actuated circuit breaker is taken as the fault occurrence area, and the fault indicator number, fault type and fault occurrence area are output as the fault indicator information.

7. A method for evaluating the electrical wear state of high-voltage circuit breaker contacts according to claim 6, characterized in that: The S2 further includes: Obtaining theoretical threshold ranges of electrical parameters based on data of operated circuit breakers, unoperated circuit breakers and line nodes; The current electrical parameter estimation value is obtained based on the electrical parameter theoretical threshold range, the correlation between the fault type and the circuit breaker electrical parameter, and the fault type in the fault indicator information.

8. A method for evaluating the electrical wear state of high-voltage circuit breaker contacts according to claim 7, characterized in that: The method for obtaining the theoretical threshold range of the electrical parameters based on the data of the operated circuit breaker, the unoperated circuit breaker and the line node includes: Obtaining a first impedance according to the line node corresponding to the actuated circuit breaker and line node data; Obtaining a second impedance according to the line node corresponding to the unoperated circuit breaker and the line node data; The theoretical threshold range of the electrical parameter is outputted by the first impedance, the second impedance and the internal impedance of the substation output power supply.

9. A method for evaluating electrical wear status of high-voltage circuit breaker contacts according to claim 7, characterized in that: The obtaining of the current electrical parameter estimation value based on the electrical parameter theoretical threshold range, the correlation between the fault type and the circuit breaker electrical parameter, and the fault type in the fault indicator information includes: The actual threshold range of the current electrical parameter is obtained as the current electrical parameter estimation value according to the correlation between the fault type and the electrical parameter of the circuit breaker by using the electrical parameter theoretical threshold range and the fault type in the fault indicator information.

10. A method for evaluating electrical wear status of high-voltage circuit breaker contacts according to claim 1, characterized in that: The method of obtaining the current electrical wear state evaluation result of the high-voltage circuit breaker contacts based on the current electrical parameter estimation value, the electrical wear state and the correlation between the electrical parameters of the circuit breaker comprises: According to the current electrical parameter estimation value, the electrical wear state and the correlation between the electrical parameters of the circuit breaker, the minimum electrical wear accumulation value and the maximum electrical wear accumulation value are obtained; The current high-voltage circuit breaker contact electrical wear state evaluation result is output based on the preset wear threshold, the minimum electrical wear accumulation value and the maximum electrical wear accumulation value.

Images