Fault positioning method for equipment wire clamp
By establishing a total fault scoring formula for equipment clamps and using multiple parameter scoring methods to locate faults, the problem of inaccurate fault location of equipment clamps in existing technologies has been solved, and accurate and reliable fault location has been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-19
- Publication Date
- 2026-04-07
AI Technical Summary
Existing methods for locating faults in equipment clamps lack quantitative results, resulting in poor reliability and inconsistent locating conclusions from the same technician or at different times.
Electrical parameters, non-electrical parameters, environmental parameters, and operation and maintenance parameters are used as the scoring parameters in the overall fault scoring formula. Sub-fault scoring formulas are established through sub-scoring parameters such as kurtosis, skewness, impulse factor, margin factor, contact resistance degradation rate, thermal residual value, air quality, relative humidity, consumed life rate, and maintenance quality coefficient. Finally, the overall fault score is calculated to locate the fault.
It achieves accurate and reliable location of equipment clamp faults, and improves the reliability and consistency of fault location through quantitative calculation results.
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Figure CN121805902A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of power transmission and distribution equipment technology, specifically, it relates to a fault location method for equipment clamps. Background Technology
[0002] Equipment clamps are crucial connecting hardware in power systems, primarily used in substations or converter stations to electrically and mechanically connect busbars, down conductors, and the outgoing terminals of electrical equipment such as transformers, circuit breakers, disconnect switches, and instrument transformers. During power grid operation, equipment clamps not only need to withstand the mechanical tension of conductors, wind loads, and mechanical stresses such as aerobatic vibrations, but also need to withstand high-load operating currents and short-circuit current surges over long periods.
[0003] Equipment clamps are commonly used in three-phase power systems. When a power system is about to fail or has already failed, if the cause of the failure may be related to the equipment clamps, then the most important thing for those skilled in the art is to locate the fault in the equipment clamps, that is, to determine which phase's equipment clamps have failed, so that maintenance personnel can carry out subsequent testing and maintenance work.
[0004] Currently, most fault location for equipment clamps is determined by technicians who collect multiple physical parameter values from the clamps on each phase during operation and then compare the current values with normal values. This method is relatively simple and fast, but it relies heavily on the experience of technicians and lacks quantifiable results. Different technicians at different times, or different technicians at the same time, may arrive at different fault location conclusions, making it unreliable. Summary of the Invention
[0005] Existing methods for fault location of equipment clamps lack quantitative results and have poor overall reliability. To address this issue, the following invention is proposed: A fault diagnosis method for a device wire clamp includes the following steps: Step S1: Select electrical parameters, non-electrical parameters, environmental parameters, and operation and maintenance parameters as the scoring parameters of the total fault scoring formula. Each scoring parameter includes multiple sub-scoring parameters. Step S2: Select kurtosis, skewness, impulse factor, and margin factor as sub-scoring parameters of electrical parameters to establish the fault scoring formula of electrical parameters and obtain the fault scores of electrical parameters. Step S3: Select the contact resistance degradation ratio and thermal residual value as sub-scoring parameters of non-electrical parameters to establish the sub-fault scoring formula of non-electrical parameters and obtain the sub-fault score of non-electrical parameters. Step S4: Select air quality and relative humidity as sub-scoring parameters of environmental parameters to establish the sub-fault scoring formula of environmental parameters and obtain the sub-fault scores of environmental parameters. Step S5: Select the consumed life rate and maintenance quality coefficient as sub-scoring parameters of the operation and maintenance parameters to establish the sub-fault scoring formula of the operation and maintenance parameters and obtain the sub-fault scores of the operation and maintenance parameters. Step S6: Based on the comprehensive fault scores of electrical parameters, non-electrical parameters, environmental parameters, and operation and maintenance parameters, obtain the total fault score formula. According to the total fault score formula, calculate the total fault score of each phase equipment clamp in the three-phase power system. Based on the magnitude of the total fault score, locate the fault in the equipment clamp.
[0006] Furthermore, in step S2, the electrical parameter is a current parameter, and the raw current signal generated by the equipment clamp during operation is collected. From the original current signal Extracting residual signals From the residual signal Extracting kurtosis F 11 skewness F 12 Pulse factor F 13 Margin factor F 14 .
[0007] Furthermore, in step S2, the formula for calculating the fault score based on electrical parameters is as follows: ,in Fault scoring for electrical parameters. Sub-scoring parameters The standard sub-rating parameters obtained after parameter normalization for The sub-scoring parameter weights.
[0008] Furthermore, in step S3, the contact resistance degradation rate F 21 The calculation formula is as follows: ,in for Standard contact resistance converted to 20°C The initial contact resistance, For the equipment clamp at the current operating temperature The actual contact resistance is as follows. The temperature coefficient of resistance of the material; the thermal residual value F 22 The calculation formula is , To determine the current theoretical operating temperature of the equipment clamp, solve the equation. Where m is mass, Represents specific heat capacity. Represents the heating rate, For heat-generating items, For the sunlit item, To satisfy the convection heat dissipation requirement, This is a radiation heat dissipation item.
[0009] Furthermore, in step S3, the formula for calculating the fault score for non-electrical parameters is as follows: ,in Fault scoring for non-electrical parameters. Sub-scoring parameters The standard sub-rating parameters obtained after parameter normalization for The sub-scoring parameter weights.
[0010] Furthermore, in step S4, the formula for calculating the fault score of environmental parameters is as follows: ,in Fault scoring for environmental parameters. The pollution coefficient is calculated using the following formula: , Here F 31 This refers to air quality, where 'a' is the basic pollution coefficient and 'b' is the highest pollution coefficient. The first air quality threshold, This is the second air quality threshold. The humidity coefficient is calculated using the following formula: , where F 32 For ambient humidity, This represents the critical value for ambient humidity.
[0011] Furthermore, in step S5, the consumed lifetime rate F 41 The calculation formula is as follows: ,in This indicates the service life of the equipment's wire clamps. Represents the theoretical maximum service life; maintenance quality factor F 42 The calculation formula is as follows: ,in The level is the same as the last maintenance. This is the time since the last maintenance.
[0012] Furthermore, in step S5, the formula for calculating the fault score of the operation and maintenance parameters is as follows: ,in Fault scoring for electrical parameters. Sub-scoring parameters The standard sub-rating parameters obtained after parameter normalization for The sub-scoring parameter weights.
[0013] Further, in step S6, the total fault score formula is: Where HI is the total fault score, and W i For the scoring parameter F i The corresponding weight, Z i Fault rating Y i Standardized fault score after normalization.
[0014] Furthermore, the weights corresponding to all scoring parameters or sub-scoring parameters are obtained through the analytic hierarchy process (AHP).
[0015] This invention proposes a fault diagnosis method for equipment clamps, which establishes a total fault score formula for equipment clamps. Based on the total fault score formula, the total fault score of any equipment clamp can be calculated. Based on the total fault score, the current fault status of the equipment clamp can be measured, thereby enabling fault location of the faulty equipment clamp in a three-phase power system. The beneficial effect of this invention is that by quantifying the current fault status of the equipment clamp and then locating the fault based on the quantification calculation results, the fault location of the equipment clamp is more accurate and reliable. Attached Figure Description
[0016] Figure 1 This is a flowchart of the fault diagnosis method in this invention. Detailed Implementation
[0017] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments.
[0018] like Figure 1 As shown, this is a preferred embodiment of the present invention, a fault diagnosis method for a device clamp, which includes the following steps.
[0019] Step S1: Select the scoring parameters for the total fault score formula. In a three-phase power system, in order to accurately determine which phase clamp has failed, it is necessary to establish a total fault scoring formula for the clamp. Ultimately, the degree of fault of the clamp can be determined based on the total fault score output by the total fault scoring formula.
[0020] Before establishing the total fault rating formula, it is necessary to select multiple rating parameters that affect the total fault rating formula during the actual use of the equipment clamp. In this embodiment, the following four types of rating parameters are mainly selected: (1) Electrical parameters, which are used to reflect the status of the electrical signal on the equipment clamp during operation. The specific method for obtaining the parameter value is to collect the electrical signal generated by the equipment clamp according to the time during operation, and then substitute the electrical signal into the relevant electrical parameter formula to calculate it; (2) Non-electrical parameters, which include the physical parameters of the equipment clamp itself in the operation process other than electrical parameters. They are usually not easy to collect directly and need to be indirectly calculated through the relevant non-electrical parameter formula; (3) Environmental parameters, which are mainly used to reflect the external environmental conditions. They usually depend on the subjective evaluation of technicians; (4) Operation and maintenance parameters, which are used to reflect the current life cycle status of the equipment clamp and the quality of its current maintenance.
[0021] These four types of scoring parameters can fully reflect the degree of fault of the equipment clamps. Each of these four types of scoring parameters also contains multiple sub-scoring parameters, which belong to different categories of sub-scoring parameters. Direct comparison is difficult. Therefore, it is necessary to establish sub-fault scoring formulas for each of these four types of scoring parameters. Finally, the total fault scoring formula is obtained by merging all the sub-fault scoring formulas.
[0022] To eliminate the influence of different rating parameters and the dimensions between different sub-rating parameters, the following parameter normalization method is given. Let X be a rating parameter or sub-rating parameter, then its normalization result is Y, and it satisfies... or H represents the set of historical values for X. If the corresponding historical data is missing, the upper limit of the value of X can be used instead. Use the lower limit of the value of X to replace .
[0023] In the subsequent process of establishing the sub-fault scoring formula and the total fault scoring formula, since quantitative calculation results are required, it is necessary to determine the weights between each scoring parameter or sub-scoring parameter. In this embodiment, the analytic hierarchy process is used to determine the weights between each scoring parameter and sub-scoring parameter. The advantage of this method is that technicians can incorporate some subjective factors to improve the adaptability of the subsequent formulas in actual use.
[0024] The steps are as follows: (1) For any two parameters a i and a j Construct a judgment matrix S for both, satisfying:
[0025] a ij Representative auxiliary parameter ai Relative total auxiliary parameter a j The importance of a ij and a ji They are reciprocals of each other, where n is the number of parameters; (2) Solve To obtain the largest eigenvalue And its corresponding feature vector w, normalize the feature vector w, and each element inside it corresponds to the weight of each parameter; (3) In order to ensure that the weights are meaningful, when n is not less than 3, a consistency check is also required. The formula for the consistency ratio CR is:
[0026] CI is the consistency index, and RI is the average consistency index, which is a fixed value related to n and can be obtained from a table. When CR < 0.1, it is generally considered to have passed the consistency test.
[0027] Step S2: Establish fault scoring formulas for electrical parameters. In practical applications, electrical parameters are usually divided into current parameters and voltage parameters, which reflect the current status of current signals and voltage signals respectively. Since the voltage signal is an external input in the power system, it usually remains stable. When the equipment clamp fails, it is generally reflected in the change of the current signal. Therefore, this embodiment selects the current parameter as the electrical parameter. During the operation of the equipment clamp, the current signal on it is collected sequentially according to time. The current signal is discrete.
[0028] This embodiment uses a Rogowski coil or a high-frequency Hall sensor to collect the current signal generated by the equipment clamp during operation. The sampling frequency is set to no less than 200kHz. Let the collected original current signal be... , It forms a discrete sequence itself, and when n takes a specific positive integer, The original current signal value obtained from the nth sampling is mainly composed of the power frequency fundamental wave. Fault characteristic noise Background white noise And satisfy: .
[0029] It is necessary to obtain the original current signal Extracting residual signals containing fault information Soon, the power frequency fundamental wave Removed due to fault signal It typically exhibits randomness and transientity, and tends to zero after multiple averagings. Therefore, the fundamental waveform template obtained by the multi-period synchronous averaging method can be used. Approximate replacement of the fundamental frequency of the power line The specific steps are as follows: Using zero-crossing detection technology, the number of sampling points N corresponding to a single period T is accurately locked, and a sliding window with a length of M periods is constructed. The larger M is, the stronger the ability to suppress fault characteristic noise, but the slower the response to signal changes. Given the following fundamental waveform template, the calculation is performed. The formula:
[0030] Then the residual signal satisfy, .
[0031] The residual signal mentioned above already contains fault characteristic noise. To extract the fault characteristics of this fault characteristic noise, this embodiment selects four sub-scoring parameters—kurtosis, impulse factor, margin factor, and skewness—to establish a sub-fault scoring formula for current parameters. Let F1 be an electrical parameter, and let F... 1i Let be the i-th sub-score parameter of the electrical parameters. Then, these four sub-score parameters are as follows: kurtosis F 11 Kurtosis is a fourth-order statistic characterizing the "thickness" or "sharpness" of a signal distribution's tail. Background white noise typically follows a Gaussian distribution. The stronger the fault-specific noise in the residual signal, the more sparse but extremely large-amplitude pulses will appear in the current waveform, leading to a longer tail in the probability distribution and ultimately a higher kurtosis. Its calculation formula is:
[0032] N represents the number of sequences in the residual signal. The mean of the residual signal is represented. This represents the mean of the residual signal.
[0033] Skewness F 12 Skewness primarily reflects the overall asymmetry of the signal. The stronger the fault-characteristic noise in the residual signal, the greater the skewness typically is. Its calculation formula is: .
[0034] Pulse factor F 13 The impulse factor is obtained by dividing the peak value of the signal by the rectified average value. The impulse factor is highly sensitive to impulsive pulses; the larger the peak value of fault-characteristic noise in the residual signal, the larger the impulse factor. Its calculation formula is: .
[0035] Margin factor F 14 The margin factor is obtained by dividing the signal peak value by the square of the signal root amplitude. Similarly, the larger the peak value of the fault-characteristic noise in the residual signal, the larger the margin factor. Unlike the impulse factor, the margin factor's upward trend occurs earlier than the impulse factor when a fault occurs in the initial stage of the equipment clamp. Its calculation formula is: .
[0036] After obtaining all the sub-scoring parameters for the electrical parameters, they are normalized using the parameters in step S1 to eliminate the differences between the sub-scoring parameters.
[0037] The following fault rating calculation formulas are given directly regarding electrical parameters:
[0038] in Fault scoring for electrical parameters. Sub-scoring parameters The standard sub-rating parameters obtained after parameter normalization for The weights of the sub-scoring parameters can be determined by the analytic hierarchy process. Since four sub-scoring parameters are involved, consistency checks are required.
[0039] Step S3: Establish fault scoring formulas for non-electrical parameters. During the operation of the equipment clamps, in addition to electrical parameters, non-electrical parameters are also involved. Electrical parameters directly carry real-time fault signals and are used to score the equipment clamps in real time. Non-electrical parameters do not directly carry real-time fault signals, but they can be used to reflect the aging of the equipment clamps during long-term use and are used to score the equipment clamps during long-term use. In this embodiment, the contact resistance degradation rate and thermal residual difference are selected as sub-scoring parameters of the non-electrical parameters. F2 is defined as a non-electrical parameter, and F... 2i Let be the i-th sub-score parameter of the electrical parameter. Then, these two sub-score parameters are: Contact resistance degradation rate F 21 As the equipment clamps age, their contact resistance gradually increases, raising the likelihood of clamp failure. To eliminate the difference in initial contact resistance, the contact resistance degradation rate is used instead of the contact resistance itself. The calculation formula is as follows:
[0040] here for Standard contact resistance converted to 20°C The initial contact resistance, For the equipment clamp at the current operating temperature The actual contact resistance is as follows. is the temperature coefficient of resistance of the material, where This can be obtained by direct measurement in offline mode when the device clamp is at 20°C. Obtained periodically using an electrical contact resistance tester or wireless sensors. Measured using an infrared temperature sensor.
[0041] Thermal residual difference F 22 As the equipment clamps age, their overall heat generation increases during operation. Higher heat generation indicates a higher likelihood of clamp failure. The heat generation of the clamps can be measured by their operating temperature. By comparing the current operating temperature with the theoretical operating temperature under healthy conditions, the degree of aging of the clamps can be determined. The theoretical operating temperature under healthy conditions can be calculated using the following formula:
[0042] The details are as follows, including the change in thermal reserves. In this context, m represents the mass of the equipment clamp. The specific heat capacity of the wire clamp in the device. Represents the heating rate, where This refers to the current theoretical operating temperature of the equipment clamp. (Heat generation item) satisfy: ,in The original current signal The effective value, The theoretical contact resistance is a value related to the current theoretical operating temperature. functions, and The difference is that, This describes the contact resistance of the equipment wire clamp in a healthy state; Sunlight item satisfy: , Represents the heat absorption rate. Represents the average daily sunshine area. Represents average solar radiation intensity; convective heat dissipation. satisfy: , The convective heat transfer coefficient is affected by wind speed. The total surface area Represents ambient temperature; radiative heat dissipation item satisfy: , The blackness represents the ability of a device's cable clamp to radiate energy outwards. Let be the Stefan-Boltzmann constant. Solving the above formula yields the theoretical operating temperature. Compare it with the current operating temperature In comparison, the greater the difference between the current operating temperature and the theoretical operating temperature, the greater the additional heat generated by the equipment clamps, and the closer it is to a fault state. The final formula for calculating the residual heat difference is: .
[0043] Similarly, after obtaining all the sub-scoring parameters for non-electrical parameters, they are normalized using the parameters in step S1 to eliminate the differences between the sub-scoring parameters.
[0044] The following fault scoring formulas for non-electrical parameters are given directly:
[0045] in Fault scoring for non-electrical parameters. Sub-scoring parameters The standard sub-rating parameters obtained after parameter normalization for The weights of the sub-scoring parameters can be determined by the analytic hierarchy process (AHP) without the need for consistency testing. Unlike the fault scoring formula for electrical parameters given in step S2, the sub-scoring parameters for non-electrical parameters fluctuate less, but as their values increase, the aging degree of the equipment clamps will increase exponentially.
[0046] Step S4: Establish the fault scoring formula for environmental parameters. The environmental parameters are not related to the equipment clamp itself, but rather quantify the severity of the environment in which the equipment clamp is currently located. When other parameters are the same, the more severe the environmental parameters, the more serious the external corrosion of the equipment clamp, which in turn makes the equipment clamp more likely to fail. This is equivalent to introducing an external risk correction factor.
[0047] In this embodiment, air quality F is selected. 31 and relative humidity F 32 These are two sub-scoring parameters of environmental parameter F3.
[0048] Air quality F 31 It is usually expressed using the AQI value, which represents the current concentration of particulate matter in the air. The higher the value, the more severe the environment in which the equipment clamp is located. Unlike electrical and non-electrical parameters, the sub-score parameters within environmental parameters are directly interrelated. For example, when the relative humidity F... 32At lower relative humidity levels, even if the AQI value is high, the external corrosion rate of the equipment clamp is also low. However, if the relative humidity reaches a critical value at the same time, a water film forms on the surface of the equipment clamp. Acidic gases and salt particles carried in the air dissolve in the water film to form an electrolyte, causing a huge corrosion effect on the surface of the equipment clamp. Conversely, if the AQI value is low, even if the relative humidity is high, it will not produce a strong corrosion effect on the outside of the equipment clamp.
[0049] The following environmental parameters are directly given as the formula for calculating the fault score.
[0050] in Fault scoring for environmental parameters. The pollution coefficient is a factor relating to air quality F. 31 The piecewise function is as follows:
[0051] Here F 31 This refers to the AQI value, where 'a' is the basic pollution factor, usually set to 1, and 'b' is the highest pollution factor. The first air quality threshold, The second air quality threshold is represented by this formula, which indicates that the pollution coefficient initially has a base pollution coefficient, and only when F... 31 After exceeding the first air quality threshold, the pollution coefficient begins to change linearly and reaches its highest level after exceeding the second air quality threshold. This can be considered as follows: even if F... 31 Even if it continues to increase, it will not continue to increase the corrosion on the outside of the equipment clamps; The humidity coefficient (F) is related to the ambient humidity. 32 The piecewise function is as follows:
[0052] Where F 32 The ambient humidity is measured by an ambient humidity sensor. This is the critical value for ambient humidity, typically set at 60%. When the ambient humidity exceeds this critical value, the humidity coefficient increases significantly. This indicates the formation of a complete water film on the surface of the equipment clamps, thereby greatly accelerating the corrosion rate. The growth rate represents the rate at which the humidity coefficient increases after the ambient humidity exceeds a critical value.
[0053] Step S5: Establish fault scoring formulas for operation and maintenance parameters. Maintenance parameters are used to reflect the current lifecycle status of the equipment clamps and the quality of current maintenance. In this embodiment, the consumed lifespan rate F is selected. 41 and maintenance quality coefficient F 42It is used as a sub-scoring parameter of operation and maintenance parameter F4.
[0054] Among them, the consumed lifespan rate F 41 Calculated using the following formula: ,in This indicates the service life of the equipment's wire clamps. Represents the theoretical maximum service life; maintenance quality factor F 42 Then it is calculated using the following formula: ,in The level of maintenance needs to be subjectively determined by technicians; the worse the maintenance level, the more accurate the assessment. The larger, A maximum maintenance interval is typically set to reflect the time elapsed since the last maintenance. When the maintenance time exceeds the maximum maintenance time After that, only take .
[0055] After obtaining the two sub-scoring parameters of the operation and maintenance parameters, the parameters are also normalized using the parameters in step S1 to eliminate the differences between the sub-scoring parameters.
[0056] The following formulas for calculating fault scores based on operational parameters can be provided directly: in Fault scoring for electrical parameters. Sub-scoring parameters The standard sub-rating parameters obtained after parameter normalization for The weights of the sub-score parameters can be determined by the analytic hierarchy process (AHP) without the need for consistency checks.
[0057] Step S6: Establish the overall fault score formula and fault location. After obtaining the sub-fault scores for electrical parameters, non-electrical parameters, environmental parameters, and operation and maintenance parameters through steps S2-S5, the following total fault score HI for the equipment clamp can be established, with the following calculation formula: Among them W i For the scoring parameter F i The corresponding weights are obtained using the analytic hierarchy process (AHP) in step S1, and a consistency check is required. i Fault rating Y i The standard fault score is processed by the normalization method in step S1.
[0058] The higher the total fault score HI, the higher the degree of fault of the equipment clamp. When the total fault score HI exceeds a certain fault threshold, the equipment clamp is considered to have entered a fault state. This threshold can be set based on the historical data of equipment clamps that have already failed.
[0059] In a three-phase power system, phases A, B, and C are each connected to a device clamp. Based on the relevant parameter values sampled from these clamps, the total fault scores for phases A, B, and C can be calculated respectively, in the following order: , 、.
[0060] If a fault has occurred in the power system, the total fault scores of the three phases are arranged in descending order. If the total fault score of any phase does not exceed the fault threshold, it is considered that the fault does not occur on the equipment clamp. Otherwise, the corresponding phases are inspected in descending order of total fault score to achieve the purpose of fault location of the equipment clamp.
[0061] If no fault occurs in the power system, the total fault scores of the three phases are still arranged in descending order. At this time, the total fault score represents the probability of the equipment clamps of that phase failing in the future. When performing fault repair on the power system, the equipment clamps of the phase with the higher total fault score are repaired first, thereby achieving the purpose of pre-locating the faults of the equipment clamps.
[0062] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A method for diagnosing faults in equipment clamps, characterized in that, Includes the following steps: Step S1: Select electrical parameters, non-electrical parameters, environmental parameters, and operation and maintenance parameters as the scoring parameters of the total fault scoring formula. Each scoring parameter includes multiple sub-scoring parameters. Step S2: Select kurtosis, skewness, impulse factor, and margin factor as sub-scoring parameters of electrical parameters to establish the fault scoring formula of electrical parameters and obtain the fault scores of electrical parameters. Step S3: Select the contact resistance degradation ratio and thermal residual value as sub-scoring parameters of non-electrical parameters to establish the sub-fault scoring formula of non-electrical parameters and obtain the sub-fault score of non-electrical parameters. Step S4: Select air quality and relative humidity as sub-scoring parameters of environmental parameters to establish the sub-fault scoring formula of environmental parameters and obtain the sub-fault scores of environmental parameters. Step S5: Select the consumed life rate and maintenance quality coefficient as sub-scoring parameters of the operation and maintenance parameters to establish the sub-fault scoring formula of the operation and maintenance parameters and obtain the sub-fault scores of the operation and maintenance parameters. Step S6: Based on the comprehensive fault scores of electrical parameters, non-electrical parameters, environmental parameters, and operation and maintenance parameters, obtain the total fault score formula. According to the total fault score formula, calculate the total fault score of each phase equipment clamp in the three-phase power system. Based on the magnitude of the total fault score, locate the fault in the equipment clamp.
2. The fault diagnosis method according to claim 1, characterized in that: In step S2, the electrical parameter is the current parameter, and the raw current signal generated by the equipment clamp during operation is collected. From the original current signal Extracting residual signals From the residual signal Extracting kurtosis F 11 skewness F 12 Pulse factor F 13 Margin factor F 14 .
3. The fault diagnosis method according to claim 2, characterized in that: In step S2, the formula for calculating the fault score based on electrical parameters is as follows: ,in Fault scoring for electrical parameters. Sub-scoring parameters The standard sub-rating parameters obtained after parameter normalization for The sub-scoring parameter weights.
4. The fault diagnosis method according to claim 3, characterized in that: In step S3, the contact resistance degradation rate F 21 The calculation formula is as follows: ,in for Standard contact resistance converted to 20°C The initial contact resistance, For the equipment clamp at the current operating temperature The actual contact resistance is as follows. The temperature coefficient of resistance of the material; the thermal residual value F 22 The calculation formula is , To determine the current theoretical operating temperature of the equipment clamp, solve the equation. Where m is mass, Represents specific heat capacity. Represents the heating rate, For heat-generating items, For the sunlit item, To satisfy the convection heat dissipation requirement, This is a radiation heat dissipation item.
5. The fault diagnosis method according to claim 4, characterized in that: In step S3, the fault score calculation formula for non-electrical parameters is as follows: ,in Fault scoring for non-electrical parameters. Sub-scoring parameters The standard sub-rating parameters obtained after parameter normalization for The sub-scoring parameter weights.
6. The fault diagnosis method according to claim 5, characterized in that: In step S4, the formula for calculating the fault score of environmental parameters is as follows: ,in Fault scoring for environmental parameters. The pollution coefficient is calculated using the following formula: ， Here F 31 This refers to air quality, where 'a' is the basic pollution coefficient and 'b' is the highest pollution coefficient. The first air quality threshold, This is the second air quality threshold. The humidity coefficient is calculated using the following formula: F 32 For ambient humidity, This represents the critical value for ambient humidity.
7. The fault diagnosis method according to claim 6, characterized in that: In step S5, the consumed lifespan rate F 41 The calculation formula is as follows: ,in This indicates the service life of the equipment's wire clamps. Represents the theoretical maximum service life; maintenance quality factor F 42 The calculation formula is as follows: ,in The level is the same as the last maintenance. This is the time since the last maintenance.
8. The fault diagnosis method according to claim 7, characterized in that: In step S5, the formula for calculating the fault score of the operation and maintenance parameters is as follows: ,in Fault scoring for electrical parameters. Sub-scoring parameters The standard sub-rating parameters obtained after parameter normalization for The sub-scoring parameter weights.
9. The fault diagnosis method according to claim 8, characterized in that: In step S6, the total fault score formula is: Where HI is the total fault score, and W i For the scoring parameter F i The corresponding weight, Z i Fault rating Y i Standardized fault score after normalization.
10. The fault diagnosis method according to claim 9, characterized in that: The weights of all rating parameters or sub-rating parameters are obtained using the analytic hierarchy process (AHP).