Method and system for evaluating reliability of relay protection device

Abstract

The invention discloses a method and a system for evaluating the reliability of a relay protection device. The method comprises the following steps: determining a sample space of the relay protection device needing to be analyzed; counting the device operation number and the defect occurrence frequency in the sample space according to time periods; calculating a defect frequency normalization value corresponding to each time period based on the device operation number and the defect occurrence frequency corresponding to each time period; calculating accumulated failure rates corresponding to different time periods based on the defect frequency normalization value corresponding to each time period; fitting is carried out based on the accumulated failure rates corresponding to the different time periods, so that fitting equations corresponding to the early failure stage, the accidental failure stage and the loss failure stage of the protection device are determined; and determining the reliability of the relay protection device based on the parameter values in the fitting equation corresponding to the early failure stage, the accidental failure stage and the loss failure stage of the protection device. The change trend of the reliability of the device in different stages can be accurately mastered, and technical support is provided for device maintenance.

Description

Technical Field

[0001] The present invention relates to the technical field of relay protection, and more particularly to a method and system for evaluating the reliability of a relay protection device. Background Art

[0002] The relay protection device is the first line of defense to ensure the safe operation of the power grid. The internal boards of the device include CPU board, power board, AD sampling board, communication board, I\O board, etc. Affected by the inherent life of various components in the board and the different welding and printing processes of the board, the protection device has a fixed design life. The protection device undergoes strict testing and system debugging before being put into operation on site. After being put into operation, the reliability of the device can be guaranteed to a certain extent, thereby ensuring the high reliability of the protection device. After the protection device is put into operation, its reliability is affected by the device body, the current and voltage secondary circuits, and the communication system. As the operating time of the device increases, the aging degree of the device gradually deepens, and the reliability of the device gradually decreases. The weak points caused by design, materials, production processes or other random factors will increase the possibility of their appearance as the aging degree deepens, thereby increasing the possibility of device defects.

[0003] Failure rate refers to the probability that a system or component that has not failed at any time t will fail in the next unit time. During the entire life cycle from the commissioning to the retirement of the device, the failure rate has the following characteristics: in the early life or "early failure period", the initial value of the failure rate is high, but as the operating years of the device increase, the failure rate also decreases rapidly, so the curve shows a rapid downward trend. The characteristics of this stage are mainly related to the cumulative effects of process volatility and uncertainty in material strength during the manufacturing process, but this stage is generally not considered for equipment put into use after leaving the factory; in the middle of the life or "accidental failure period", the failure rate of the device drops to the lowest level. During this period, the causes of device failure are mostly human error or sudden changes in environmental conditions; in the late life or "wear and tear failure period", the failure rate of the device shows an upward trend with the increase in service years. This feature is usually caused by aging, moisture, product degradation, strength degradation, etc. due to the long service life of the equipment. Since the overall shape of the above-mentioned "failure rate-time" curve resembles a bathtub, it is called a "bathtub" curve, such as Figure 1 As shown. The bathtub curve can be represented by a Weibull function with adjustable shape parameters and scale parameters. Accurately analyzing the changing law and trend of device failure rate is of great significance to evaluating the reliability and life of the device.

[0004] The Duane model is an important method for analyzing device reliability test data in the product development stage. A single device or multiple devices that can be repaired are put into reliability tests at the same time. During the test, hidden dangers and defects found are repaired in a timely manner. At the same time, the product design plan, production process, and equipment maintenance plan are improved based on the causes of the defects. The repaired devices are then put back into reliability tests. The Duane model is used to calculate the changing trend of the cumulative failure rate of the product, and the experiment is stopped until the failure rate of the device is significantly reduced or reduced to the predetermined target, and the product design plan, production process, or equipment maintenance plan are finally determined.

[0005] The Duane model can effectively analyze the reliability test data of the device in the product development stage or the data in the operation and maintenance process of a certain (multiple) complex system, and determine the advantages and disadvantages of the improved design scheme, production process or equipment maintenance scheme. However, the Duane model requires that the number of products analyzed remains unchanged, and the product should be repaired in time after a defect occurs and put into test or operation again. The relay protection device is a high-reliability device, and its operating life is required to be no less than 12 years. According to statistics, the overall defect rate of 220kV and above voltage level protection, that is, related equipment, in 2018 was 1.260 times / 100 units / year. The defect rate of the protection device is very low, and most devices have no defects from commissioning to retirement. By the end of 2018, the number of 220kV and above system protection devices within the scope of State Grid Corporation of China reached 182,000. The scale of the device is huge, and the commissioning date and retirement date of each device are different. It is impossible to directly use the traditional Duane model to analyze the defect data occurring during the operation of the device. In order to accurately calculate the changes in the cumulative failure rate of the relay protection device.

[0006] Therefore, the Duane model algorithm needs to be improved, and a method for evaluating the reliability of relay protection devices using operating data is needed. Summary of the invention

[0007] The present invention provides a method and system for evaluating the reliability of a relay protection device, so as to solve the problem of how to determine the reliability of the relay protection device.

[0008] In order to solve the above problem, according to one aspect of the present invention, a method for evaluating the reliability of a relay protection device is provided, the method comprising:

[0009] Determine the sample space of relay protection devices that need to be analyzed;

[0010] Counting the number of device operations and the number of defect occurrences in the sample space according to time periods;

[0011] Calculate a normalized value of the number of defects corresponding to each time period based on the number of device operations and the number of defect occurrences corresponding to each time period;

[0012] Calculate the cumulative failure rate corresponding to different time periods based on the normalized value of the number of defects corresponding to each time period;

[0013] Fitting is performed based on the cumulative failure rates corresponding to different time periods to determine the fitting equations corresponding to the early failure stage, accidental failure stage and loss failure stage of the protection device respectively;

[0014] The reliability of the relay protection device is determined based on the parameter values ​​in the fitting equations corresponding to the early failure stage, accidental failure stage and loss failure stage of the protection device.

[0015] Preferably, counting the number of device operations and the number of defect occurrences in the sample space according to time periods includes:

[0016] Divide the sample space into K groups and set The number of protection devices M(kΔt) whose operating time in the statistical sample space is greater than kΔt (k=1,2,3…K), and the total number of defects N(kΔt) of protection devices whose defect occurrence time since commissioning is less than kΔt (k=1,2,3…K) and greater than (k-1)Δt (k=1,2,3…K); where T is the total data analysis time.

[0017] Preferably, the step of calculating a normalized value of the number of defects corresponding to each time period based on the number of device operations and the number of defect occurrences corresponding to each time period includes:

[0018] n kΔt =N(kΔt) / M(kΔt),

[0019] Among them, n kΔt is the normalized value of the number of defects corresponding to the kth time period; N(kΔt) is the total number of defects of the protection device whose defect occurrence time is less than kΔt (k=1,2,3…K) and greater than (k-1)Δt (k=1,2,3…K) since the commissioning; M(kΔt) is the number of devices whose operating time is greater than kΔt (k=1,2,3…K).

[0020] Preferably, the calculating of the cumulative failure rates corresponding to different time periods based on the normalized value of the number of defects corresponding to each time period includes:

[0021]

[0022] Among them, λ pΔt is the cumulative failure rate in the pΔt period; T is the total time of data analysis, K is the number of groups into which the sample space is divided; n kΔt is the normalized value of the number of defects corresponding to the kth time period.

[0023] Preferably, the fitting equation is:

[0024] lnλ pΔt =lna-mlnt,

[0025] Among them, λ pΔt is the cumulative failure rate in the time period pΔt; a is the scale parameter; m is the growth rate.

[0026] Preferably, the step of determining the reliability of the relay protection device based on the parameter values ​​in the fitting equations corresponding to the early failure stage, the accidental failure stage and the loss failure stage of the protection device comprises:

[0027] For the fitting equation corresponding to any one of the early failure stage, accidental failure stage and wear failure stage, if m>0, it is determined that the cumulative failure rate of the device in any one of the stages is reduced and the device reliability is high; if m<0, it is determined that the cumulative failure rate of the device in any one of the stages is increased and the device reliability is low.

[0028] According to another aspect of the present invention, there is provided a system for evaluating the reliability of a relay protection device, the system comprising:

[0029] A sample space determination unit, used for determining a sample space of a relay protection device to be analyzed;

[0030] A statistical unit, used to count the number of device operations and the number of defect occurrences in the sample space according to time periods;

[0031] A normalization unit, used to calculate a normalized value of the number of defects corresponding to each time period based on the number of device operations and the number of defect occurrences corresponding to each time period;

[0032] A cumulative failure rate calculation unit, used to calculate the cumulative failure rates corresponding to different time periods based on the normalized value of the number of defects corresponding to each time period;

[0033] A fitting unit, used for performing fittings based on the cumulative failure rates corresponding to different time periods, so as to respectively determine fitting equations corresponding to the early failure stage, the accidental failure stage and the loss failure stage of the protection device;

[0034] The reliability determination unit is used to determine the reliability of the relay protection device based on the parameter values ​​in the fitting equations corresponding to the early failure stage, accidental failure stage and loss failure stage of the protection device.

[0035] Preferably, the statistical unit counts the number of device operations and the number of defect occurrences in the sample space according to time periods, including:

[0036] Divide the sample space into K groups and set The number of protection devices M(kΔt) whose operating time in the statistical sample space is greater than kΔt (k=1,2,3…K), and the total number of defects N(kΔt) of protection devices whose defect occurrence time since commissioning is less than kΔt (k=1,2,3…K) and greater than (k-1)Δt (k=1,2,3…K); where T is the total data analysis time.

[0037] Preferably, the normalization unit calculates a normalized value of the number of defects corresponding to each time period based on the number of device operations and the number of defect occurrences corresponding to each time period, including:

[0038] n kΔt =N(kΔt) / M(kΔt),

[0039] Among them, n kΔt is the normalized value of the number of defects corresponding to the kth time period; N(kΔt) is the total number of defects of the protection device whose defect occurrence time is less than kΔt (k=1,2,3…K) and greater than (k-1)Δt (k=1,2,3…K) since the commissioning; M(kΔt) is the number of devices whose operating time is greater than kΔt (k=1,2,3…K).

[0040] Preferably, the cumulative failure rate calculation unit calculates the cumulative failure rate λ corresponding to different time periods based on the normalized value of the number of defects corresponding to each time period. pΔt ,include:

[0041]

[0042] Among them, λ pΔt is the cumulative failure rate in the pΔt period; T is the total time of data analysis, K is the number of groups into which the sample space is divided; n kΔt is the normalized value of the number of defects corresponding to the kth time period.

[0043] Preferably, the fitting equation is:

[0044] lnλ pΔt =lna-mlnt,

[0045] Among them, λ pΔt is the cumulative failure rate in the time period pΔt; a is the scale parameter; m is the growth rate.

[0046] Preferably, the reliability determination unit determines the reliability of the relay protection device based on parameter values ​​in the fitting equations corresponding to the early failure stage, accidental failure stage and loss failure stage of the protection device, including:

[0047] For the fitting equation corresponding to any one of the early failure stage, accidental failure stage and wear failure stage, if m>0, it is determined that the cumulative failure rate of the device in any one of the stages is reduced and the device reliability is high; if m<0, it is determined that the cumulative failure rate of the device in any one of the stages is increased and the device reliability is low.

[0048] According to yet another aspect of the present invention, the present invention provides a computer device, comprising: one or more processors;

[0049] The processor is used to store one or more programs;

[0050] When the one or more programs are executed by the one or more processors, any step of a method for evaluating the reliability of a relay protection device is implemented.

[0051] According to another invention of the present invention, there is provided a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed, any step in the method for evaluating the reliability of a relay protection device is implemented.

[0052] The present invention provides a method and system for evaluating the reliability of a relay protection device, including: determining a sample space of a relay protection device to be analyzed; counting the number of device operations and the number of defect occurrences in the sample space according to time periods; calculating a normalized value of the number of defect occurrences corresponding to each time period based on the number of device operations and the number of defect occurrences corresponding to each time period; calculating the cumulative failure rate corresponding to different time periods based on the normalized value of the number of defect occurrences corresponding to each time period; fitting based on the cumulative failure rates corresponding to different time periods to respectively determine the fitting equations corresponding to the early failure stage, the accidental failure stage, and the loss failure stage of the protection device; determining the reliability of the relay protection device based on the parameter values ​​in the fitting equations corresponding to the early failure stage, the accidental failure stage, and the loss failure stage of the protection device. The present invention evaluates the reliability of the relay protection device based on the improved Duane model, and the evaluation results are concise and intuitive, which is convenient for the professional management department and personnel of the relay protection to accurately grasp the changing trend of the reliability of the device at different stages by analyzing the changes in the failure rate of the device at different stages, and provide technical support for the technical transformation, maintenance, and inspection of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0054] Figure 1 is a schematic diagram of a bathtub-type failure rate curve;

[0055] Figure 2 is a flow chart of a method 200 for evaluating the reliability of a relay protection device according to an embodiment of the present invention;

[0056] Figure 3 A schematic diagram of the cumulative failure rate of a relay protection device of a certain manufacturer according to an embodiment of the present invention;

[0057] Figure 4 4 is a schematic diagram of the structure of a system 400 for evaluating the reliability of a relay protection device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0058] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0059] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0060] Figure 2 FIG. 2 is a flow chart of a method 200 for evaluating the reliability of a relay protection device according to an embodiment of the present invention. Figure 2 As shown, the method for evaluating the reliability of a relay protection device provided by an embodiment of the present invention is based on the improved Duane model to evaluate the reliability of the relay protection device. The evaluation result is concise and intuitive, which is convenient for the relay protection professional management department and personnel to analyze the changes in the failure rate of the device at different stages, accurately grasp the changing trend of the reliability of the device at different stages, and provide technical support for the technical transformation, maintenance and inspection of the device. The method 200 for evaluating the reliability of a relay protection device provided by an embodiment of the present invention starts from step 201. In step 201, the sample space of the relay protection device to be analyzed is determined.

[0061] In the present invention, when determining the sample space to be analyzed, the protection device can be selected according to the model, manufacturer, type, etc., and the sample space is determined. The selected sample space is set as D, the total number of protection devices is M, the commissioning date of all protection devices is set as t=0, and the operation time of the i-th protection device is t i ,i=1,2,3…M.

[0062] In step 202, the number of device operations and the number of defect occurrences in the sample space are counted according to time periods.

[0063] Preferably, counting the number of device operations and the number of defect occurrences in the sample space according to time periods includes:

[0064] Divide the sample space into K groups and set The number of protection devices M(kΔt) whose operating time in the statistical sample space is greater than kΔt (k=1,2,3…K), and the total number of defects N(kΔt) of protection devices whose defect occurrence time since commissioning is less than kΔt (k=1,2,3…K) and greater than (k-1)Δt (k=1,2,3…K); where T is the total data analysis time.

[0065] In the present invention, the number of devices and the number of defect occurrences are counted in sections. Specifically, the sample space is divided into K groups, and T is the total time of data analysis, and the operating time of the protection device in the sample space is t i The number of devices with a defect greater than kΔt (k=1,2,3…K) is M(kΔt), and the total number of defects of the protection device that have occurred less than kΔt (k=1,2,3…K) and greater than (k-1)Δt (k=1,2,3…K) since it was put into operation is N(kΔt).

[0066] In step 203, a normalized value of the number of defects corresponding to each time period is calculated based on the number of device operations and the number of defect occurrences corresponding to each time period.

[0067] Preferably, the step of calculating a normalized value of the number of defects corresponding to each time period based on the number of device operations and the number of defect occurrences corresponding to each time period includes:

[0068] n kΔt =N(kΔt) / M(kΔt),

[0069] Among them, n kΔt is the normalized value of the number of defects corresponding to the kth time period; N(kΔt) is the total number of defects of the protection device whose defect occurrence time is less than kΔt (k=1,2,3…K) and greater than (k-1)Δt (k=1,2,3…K) since the commissioning; M(kΔt) is the number of devices whose operating time is greater than kΔt (k=1,2,3…K).

[0070] In step 204, the cumulative failure rates corresponding to different time periods are calculated based on the normalized value of the number of defects corresponding to each time period.

[0071] Preferably, the calculating of the cumulative failure rates corresponding to different time periods based on the normalized value of the number of defects corresponding to each time period includes:

[0072]

[0073] Among them, λ pΔt is the cumulative failure rate in the pΔt period; T is the total time of data analysis, K is the number of groups into which the sample space is divided; n kΔt is the normalized value of the number of defects corresponding to the kth time period.

[0074] Since the number of protection devices in operation varies in different time periods, the present invention normalizes the number of defects. The specific calculation formula is:

[0075] n kΔt =N(kΔt) / M(kΔt),

[0076] Then calculate the cumulative failure rate:

[0077]

[0078] Among them, n kΔt is the normalized value of the number of defects corresponding to the kth time period; N(kΔt) is the total number of defects of the protection device whose defect occurrence time is less than kΔt (k=1,2,3…K) and greater than (k-1)Δt (k=1,2,3…K) since the commissioning; M(kΔt) is the number of devices with an operating time greater than kΔt (k=1,2,3…K); λ pΔt is the cumulative failure rate in the time period pΔt.

[0079] In step 205, fitting is performed based on the cumulative failure rates corresponding to different time periods to respectively determine fitting equations corresponding to the early failure stage, the accidental failure stage and the wear failure stage of the protection device.

[0080] Preferably, the fitting equation is:

[0081] lnλ pΔt =lna-mlnt,

[0082] Among them, λ pΔt is the cumulative failure rate in the time period pΔt; a is the scale parameter; m is the growth rate.

[0083] In step 206, the reliability of the relay protection device is determined based on the parameter values ​​in the fitting equations corresponding to the early failure stage, the accidental failure stage and the loss failure stage of the protection device.

[0084] Preferably, the step of determining the reliability of the relay protection device based on the parameter values ​​in the fitting equations corresponding to the early failure stage, the accidental failure stage and the loss failure stage of the protection device comprises:

[0085] For the fitting equation corresponding to any one of the early failure stage, accidental failure stage and wear failure stage, if m>0, it is determined that the cumulative failure rate of the device in any one of the stages is reduced and the device reliability is high; if m<0, it is determined that the cumulative failure rate of the device in any one of the stages is increased and the device reliability is low.

[0086] Research has found that about 14% of protection devices have an operating time of more than 12 years, and the maximum operating time can reach 20 years. The failure mode of the protection device goes through three stages: early failure, accidental failure, and loss failure. Therefore, in the present invention, the parameter form of the cumulative failure rate in the three stages is defined as λ c (t) = at -m , t is the device operation time. Expressed in logarithmic form as lnλ c (t) = lna-mlnt, where a is the scale parameter, a>0; m is the growth rate.

[0087] In the present invention, the cumulative failure rate of the protection device at different time points is calculated and the least squares method is used to fit the equation lnλ c (t) = lna-mlnt, to obtain the model parameters of the early failure stage, accidental failure stage and loss failure stage of the protection device respectively a and parameters m The estimated value of m is used to make a reliability judgment. When m>0, the cumulative failure rate of the device decreases and the reliability of the device is improved; when m<0, the cumulative failure rate of the device increases and the reliability of the device decreases. m The larger the absolute value, the lower the reliability of the device. Such devices should be inspected and repaired more frequently, and new protective devices should be replaced when necessary.

[0088] The present invention introduces the number of devices in different operation stages into the Duane model, which solves the problem that the original Duane model is only applicable to the test samples put into the test at the same time, and the total number of samples remains unchanged during the test. It proposes a cumulative failure rate algorithm that adapts to the random mode of commissioning and decommissioning time of the protection device, and proposes to apply the improved Duane model to the early failure, accidental failure and loss failure stages to analyze the cumulative failure rate of the protection device, and quantitatively analyze the changes in the reliability of the protection device at different stages. The algorithm proposed by the present invention is of great significance to support the relay protection management department to accurately grasp the reliability of the protection device, and supports the relay protection management department to timely adjust the inspection and patrol cycle, maintenance and inspection items of the protection device, etc., to avoid a significant reduction in the reliability of the protection device.

[0089] The following specifically illustrates the embodiments of the present invention.

[0090] The present invention selects the operating data of some protection devices of a certain manufacturer as of July 2023, and Table 1 is a specific data table. The data analysis period is selected as 20 years, K=40, Δt=0.5 years for analysis.

[0091] Table 1 Partial data of the operation of a manufacturer's device

[0092]

[0093]

[0094] The analysis results are as follows Figure 3 As shown in the figure, the cumulative failure rate of a manufacturer's protection device is directly revealed. When the device is just put into operation, the cumulative failure rate of the device is equal to the instantaneous failure rate, and the failure rate is relatively high. With the development of different types of maintenance and inspection of the device, the cumulative failure rate of the protection device shows a downward trend in the first three years (early failure period, growth rate m = 0.1121), reaching the lowest in the third year; in the following seven years, the cumulative failure rate of the protection device increases year by year (accidental failure period, growth rate is negative, m = -0.1406); after 10 years of operation, the cumulative failure rate of the protection device increases rapidly (loss failure period, growth rate is negative, m = -4.043). From the analysis conclusion, the loss failure period of the protection device of this manufacturer occurs around the 10th year. The protection device operation and maintenance unit should focus on strengthening the inspection and patrol of protection equipment that has been in operation for more than 10 years, timely grasp the operation status of the device, and avoid the occurrence of power grid safety incidents caused by the unreliable operation of the protection device.

[0095] Figure 4 FIG. 4 is a schematic diagram of a system 400 for evaluating the reliability of a relay protection device according to an embodiment of the present invention. Figure 4 As shown, the system 400 for evaluating the reliability of a relay protection device provided by an embodiment of the present invention includes: a sample space determination unit 401, a statistical unit 402, a normalization unit 403, a cumulative failure rate calculation unit 404, a fitting unit 405 and a reliability determination unit 406.

[0096] Preferably, the sample space determining unit 401 is used to determine the sample space of the relay protection device that needs to be analyzed.

[0097] Preferably, the statistical unit 402 is used to count the number of device operations and the number of defect occurrences in the sample space according to time periods. Preferably, the statistical unit 402, which counts the number of device operations and the number of defect occurrences in the sample space according to time periods, includes:

[0098] Divide the sample space into K groups and set The number of protection devices M(kΔt) whose operating time in the statistical sample space is greater than kΔt (k=1,2,3…K), and the total number of defects N(kΔt) of protection devices whose defect occurrence time since commissioning is less than kΔt (k=1,2,3…K) and greater than (k-1)Δt (k=1,2,3…K); where T is the total data analysis time.

[0099] Preferably, the normalization unit 403 is used to calculate a normalized value of the number of defects corresponding to each time period based on the number of device operations and the number of defect occurrences corresponding to each time period.

[0100] Preferably, the normalization unit 403 calculates a normalized value of the number of defects corresponding to each time period based on the number of device operations and the number of defect occurrences corresponding to each time period, including:

[0101] n kΔt =N(kΔt) / M(kΔt),

[0102] Among them, n kΔt is the normalized value of the number of defects corresponding to the kth time period; N(kΔt) is the total number of defects of the protection device whose defect occurrence time is less than kΔt (k=1,2,3…K) and greater than (k-1)Δt (k=1,2,3…K) since the commissioning; M(kΔt) is the number of devices whose operating time is greater than kΔt (k=1,2,3…K).

[0103] Preferably, the cumulative failure rate calculation unit 404 is used to calculate the cumulative failure rates corresponding to different time periods based on the normalized value of the number of defects corresponding to each time period.

[0104] Preferably, the cumulative failure rate calculation unit 404 calculates the cumulative failure rates corresponding to different time periods based on the normalized value of the number of defects corresponding to each time period, including:

[0105]

[0106] Among them, λ pΔt is the cumulative failure rate in the pΔt period; T is the total time of data analysis, K is the number of groups into which the sample space is divided; n kΔt is the normalized value of the number of defects corresponding to the kth time period.

[0107] Preferably, the fitting unit 405 is used to perform fitting based on the cumulative failure rates corresponding to different time periods, so as to respectively determine fitting equations corresponding to the early failure stage, accidental failure stage and wear failure stage of the protection device.

[0108] Preferably, the fitting equation is:

[0109] lnλ pΔt =lna-mlnt,

[0110] Among them, λ pΔt is the cumulative failure rate in the time period pΔt; a is the scale parameter; m is the growth rate.

[0111] Preferably, the reliability determination unit 406 is used to determine the reliability of the relay protection device based on parameter values ​​in the fitting equations corresponding to the early failure stage, accidental failure stage and wear failure stage of the protection device.

[0112] Preferably, the reliability determination unit 406 determines the reliability of the relay protection device based on the parameter values ​​in the fitting equations corresponding to the early failure stage, the accidental failure stage and the loss failure stage of the protection device, including:

[0113] For the fitting equation corresponding to any one of the early failure stage, accidental failure stage and wear failure stage, if m>0, it is determined that the cumulative failure rate of the device in any one of the stages is reduced and the device reliability is high; if m<0, it is determined that the cumulative failure rate of the device in any one of the stages is increased and the device reliability is low.

[0114] The system 400 for evaluating the reliability of a relay protection device according to an embodiment of the present invention corresponds to the method 100 for evaluating the reliability of a relay protection device according to another embodiment of the present invention, and will not be described in detail herein.

[0115] Based on another aspect of the present invention, the present invention provides a computer device, comprising: one or more processors; the processor is used to store one or more programs; when the one or more programs are executed by the one or more processors, any step of a method for evaluating the reliability of a relay protection device is implemented.

[0116] Based on another invention of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed, any step in the method for evaluating the reliability of a relay protection device is implemented.

[0117] The invention has been described above with reference to a few embodiments. However, it is readily apparent to a person skilled in the art that other embodiments than the ones disclosed above are equally within the scope of the invention, as defined by the appended patent claims.

[0118] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise therein. All references to "a / said / the [means, components, etc.]" are to be openly interpreted as at least one instance of said means, components, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not necessarily have to be performed in the exact order disclosed, unless explicitly stated otherwise.

[0119] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0120] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0121] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0122] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for evaluating the reliability of a relay protection device, characterized in that: The method comprises: Determine the sample space of relay protection devices that need to be analyzed; Counting the number of device operations and the number of defect occurrences in the sample space according to time periods; Calculate a normalized value of the number of defects corresponding to each time period based on the number of device operations and the number of defect occurrences corresponding to each time period; Calculate the cumulative failure rate corresponding to different time periods based on the normalized value of the number of defects corresponding to each time period; Fitting is performed based on the cumulative failure rates corresponding to different time periods to determine the fitting equations corresponding to the early failure stage, accidental failure stage and loss failure stage of the protection device respectively; The reliability of the relay protection device is determined based on the parameter values ​​in the fitting equations corresponding to the early failure stage, accidental failure stage and loss failure stage of the protection device.

2. The method according to claim 1, characterized in that The number of device operations and the number of defect occurrences in the sample space are counted according to the time period, including: Divide the sample space into K groups and set The number of protection devices M(kΔt) whose operating time in the statistical sample space is greater than kΔt (k=1,2,3…K), and the total number of defects N(kΔt) of protection devices whose defect occurrence time since commissioning is less than kΔt (k=1,2,3…K) and greater than (k-1)Δt (k=1,2,3…K); where T is the total data analysis time.

3. The method according to claim 1, characterized in that The calculating of the normalized value of the number of defects corresponding to each time period based on the number of device operations and the number of defect occurrences corresponding to each time period includes: n kΔt =N(kΔt) / M(kΔt), Among them, n kΔt is the normalized value of the number of defects corresponding to the kth time period; N(kΔt) is the total number of defects of the protection device whose defect occurrence time is less than kΔt (k=1,2,3…K) and greater than (k-1)Δt (k=1,2,3…K) since the commissioning; M(kΔt) is the number of devices whose operating time is greater than kΔt (k=1,2,3…K).

4. The method according to claim 1, characterized in that: The calculating the cumulative failure rate corresponding to different time periods based on the normalized value of the number of defects corresponding to each time period includes: Among them, λ pΔt is the cumulative failure rate in the pΔt period; T is the total time of data analysis, K is the number of groups divided into sample space; n kΔt is the normalized value of the number of defects corresponding to the kth time period.

5. The method according to claim 1, characterized in that The fitting equation is: lnλ pΔt =lna-mlnt, Among them, λ pΔt is the cumulative failure rate in the time period pΔt; a is the scale parameter; m is the growth rate.

6. The method according to claim 5, characterized in that The reliability of the relay protection device is determined based on parameter values ​​in the fitting equations corresponding to the early failure stage, the accidental failure stage and the loss failure stage of the protection device, including: For the fitting equation corresponding to any one of the early failure stage, accidental failure stage and wear failure stage, if m>0, it is determined that the cumulative failure rate of the device in any one of the stages is reduced and the device reliability is high; if m<0, it is determined that the cumulative failure rate of the device in any one of the stages is increased and the device reliability is low.

7. A system for evaluating the reliability of a relay protection device, characterized in that: The system comprises: A sample space determination unit, used for determining a sample space of a relay protection device to be analyzed; A statistical unit, used to count the number of device operations and the number of defect occurrences in the sample space according to time periods; A normalization unit, used to calculate a normalized value of the number of defects corresponding to each time period based on the number of device operations and the number of defect occurrences corresponding to each time period; A cumulative failure rate calculation unit, used to calculate the cumulative failure rates corresponding to different time periods based on the normalized value of the number of defects corresponding to each time period; A fitting unit, used for performing fittings based on the cumulative failure rates corresponding to different time periods, so as to respectively determine fitting equations corresponding to the early failure stage, the accidental failure stage and the loss failure stage of the protection device; The reliability determination unit is used to determine the reliability of the relay protection device based on the parameter values ​​in the fitting equations corresponding to the early failure stage, accidental failure stage and loss failure stage of the protection device.

8. The system according to claim 7, characterized in that The statistical unit counts the number of device operations and the number of defect occurrences in the sample space according to time periods, including: Divide the sample space into K groups and set The number of protection devices M(kΔt) whose operating time in the statistical sample space is greater than kΔt (k=1,2,3…K), and the total number of defects N(kΔt) of protection devices whose defect occurrence time since commissioning is less than kΔt (k=1,2,3…K) and greater than (k-1)Δt (k=1,2,3…K); where T is the total data analysis time.

9. The system according to claim 7, characterized in that The normalization unit calculates a normalized value of the number of defects corresponding to each time period based on the number of device operations and the number of defect occurrences corresponding to each time period, including: n kΔt =N(kΔt) / M(kΔt), Among them, n kΔt is the normalized value of the number of defects corresponding to the kth time period; N(kΔt) is the total number of defects of the protection device whose defect occurrence time is less than kΔt (k=1,2,3…K) and greater than (k-1)Δt (k=1,2,3…K) since the commissioning; M(kΔt) is the number of devices whose operating time is greater than kΔt (k=1,2,3…K).

10. The system according to claim 7, characterized in that The cumulative failure rate calculation unit calculates the cumulative failure rates corresponding to different time periods based on the normalized value of the number of defects corresponding to each time period, including: Among them, λ pΔt is the cumulative failure rate in the pΔt period; T is the total time of data analysis, K is the number of groups divided into sample space; n kΔt is the normalized value of the number of defects corresponding to the kth time period.

11. The system according to claim 7, characterized in that: The fitting equation is: lnλ pΔt =lna-mlnt, Among them, λ pΔt is the cumulative failure rate in the time period pΔt; a is the scale parameter; m is the growth rate.

12. The system according to claim 11, characterized in that The reliability determination unit determines the reliability of the relay protection device based on parameter values ​​in the fitting equation corresponding to the early failure stage, the accidental failure stage and the loss failure stage of the protection device, including: For the fitting equation corresponding to any one of the early failure stage, accidental failure stage and wear failure stage, if m>0, it is determined that the cumulative failure rate of the device in any one of the stages is reduced and the device reliability is high; if m<0, it is determined that the cumulative failure rate of the device in any one of the stages is increased and the device reliability is low.

13. A computer device, characterized in that: include: one or more processors; The processor is used to store one or more programs; When the one or more programs are executed by the one or more processors, the method for evaluating the reliability of a relay protection device according to any one of claims 1 to 6 is implemented.

14. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, the method for evaluating the reliability of a relay protection device as claimed in any one of claims 1 to 6 is implemented.

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