Method for overall evaluation and fault judgment of a wobbler contact and measuring system thereof

Abstract

The application relates to a method for overall evaluation and fault judgment of a star contact and a measuring system thereof, and the method specifically comprises the following steps: S1, collecting resistance values and pressure values of each contact finger piece in the star contact, and respectively obtaining a resistance data set and a pressure data set; S2, pre-processing and checking the resistance data set and the pressure data set to obtain an effective resistance data set and an effective pressure data set; S3, traversing the effective resistance data set and the effective pressure data set, judging the state type of each contact finger according to the effective resistance data set, and calculating the resistance average value, the resistance standard deviation and the resistance range of the star contact; S4, judging the overall state of the star contact according to the state of each contact finger, the resistance average value, the resistance standard deviation and the resistance range, and judging the fault type of the star contact according to the effective resistance data set and the effective pressure data set. The resistance values and the pressure values of each contact finger piece of the star contact can be collected, so that it can be accurately evaluated that which contact finger piece of the star contact has a problem, the overall state of the star contact can be judged according to the condition of each contact finger, and the fault type of the star contact can be judged.

Description

Technical Field

[0001] This invention relates to the field of fault diagnosis technology for plum blossom contacts, and in particular to a method and measurement system for the overall evaluation and fault diagnosis of plum blossom contacts. Background Technology

[0002] As a critical moving and stationary connection component in high-voltage switchgear, the reliability of the plum blossom contact's conductivity directly affects the safe and stable operation of the entire power system. The contact consists of multiple independent arc-shaped contact fingers arranged circumferentially, with contact springs providing contact pressure. During operation, the moving contact rod inserts into it, simultaneously contacting all the contact fingers to form a conductive circuit. The advantages of this structure are numerous contact points, good heat dissipation, and strong self-cleaning ability; however, the stability of its contact resistance also depends on the uniformity of the contact state of each contact finger.

[0003] Loop resistance is a core indicator for evaluating the conductivity of spline contacts. An abnormally high resistance value will cause overheating at the connection point during current flow, accelerating oxidation of the contact surface and creating a vicious cycle that may ultimately lead to equipment burnout or even power outages. Therefore, regularly testing the loop resistance of spline contacts is an important part of preventative testing for power equipment.

[0004] Currently, the most commonly used measurement method in the industry is the overall loop resistance test based on the DC voltage drop method. This method uses a high-current loop resistance tester (micro-ohmmeter) to apply a constant high DC current (usually 50A, 100A or higher) between the Phillips head contact base and the moving contact rod (or test simulation rod), and measures the voltage drop between them to calculate the total loop resistance of the entire contact system.

[0005] Chinese patent application CN120403450A discloses an intelligent detection method and system for the contact stroke of a circuit breaker's pentagonal contact. The method includes: a configuration step, in which a fiber optic sensor array, an image acquisition module, and a supplementary lighting module are configured on the stationary contact. The fiber optic sensor array includes a fiber optic sensor, which includes a fiber optic probe, a matching fiber optic cable, and a fiber optic amplifier. The image acquisition module includes an industrial camera. A dynamic detection step involves coordinating the fiber optic sensor and the industrial camera to collect real-time displacement data of the moving contact piece and the connection status data of the moving and stationary contacts after closure. A data processing step involves fusing the displacement data from the fiber optic sensor and the image data from the industrial camera to evaluate the contact status and surface defects of the stationary and moving contacts. A lightweight AI inference chip is embedded for localized real-time processing. A contact wear compensation algorithm is used to dynamically adjust the detection threshold of the fiber optic probe and the parameters of the contact status evaluation model based on the number of contact closures and historical wear data. This method does not rely on resistance and pressure to determine the state of the pentagonal contact.

[0006] Therefore, how to determine the state of the plum blossom contact through resistance and pressure is an urgent problem to be solved. Summary of the Invention

[0007] The purpose of this invention is to overcome the defects of the prior art by providing a method and measurement system for the overall evaluation and fault diagnosis of plum blossom contacts.

[0008] The objective of this invention can be achieved through the following technical solutions: According to one aspect of the present invention, a method for overall evaluation and fault diagnosis of a plum blossom contact is provided, the method specifically comprising: S1. Collect the resistance and pressure values ​​of each contact finger in the plum blossom contact, and obtain the resistance dataset and pressure dataset respectively; S2. Preprocess and verify the resistance dataset and pressure dataset to obtain the effective resistance dataset and effective pressure dataset. S3. Traverse the effective resistance dataset and the effective pressure dataset, determine the state type of each contact finger based on the effective resistance dataset, and calculate the mean resistance, standard deviation of resistance, and range of resistance of the clover contact. S4. Determine the overall condition of the plum blossom contact based on the state of each contact finger, the average resistance, the standard deviation of resistance, and the range of resistance; and determine the fault type of the plum blossom contact based on the effective resistance dataset and the effective pressure dataset.

[0009] As a preferred technical solution, the preprocessing and verification include: The resistance dataset and pressure dataset are collected synchronously with the corresponding contact finger. The resistance of any contact finger is matched with the pressure of that contact finger, and there are no missing, misaligned, or out-of-range abnormal values.

[0010] As a preferred technical solution, the preprocessing and verification further include: Remove sensor fault spurious data from the resistance and pressure datasets.

[0011] As a preferred technical solution, the sensor fault pseudo data includes infinite resistance or 0, pressure of 0 or exceeding the range.

[0012] As a preferred technical solution, the state type of the contact finger is determined and marked based on the resistance of any contact finger.

[0013] As a preferred technical solution, the overall state judgment process of the plum blossom contact includes: like ,and , , If so, the plum blossom contact head is generally qualified; like but ,or or Then the plum blossom tip will trigger an overall warning; like or If so, the entire plum blossom contact head is defective; like or If this happens, the entire plum blossom contactor will become disabled and cannot be used. in, This represents the number of defective contact finger pieces. The average resistance; S represents the upper limit of acceptable average resistance; S represents the standard deviation of resistance. The upper limit of the standard deviation of resistance; This represents the resistance range; The resistance range threshold; The number of warnings for the touch screen; Let be the resistance of the i-th contact finger; This is the failure threshold for a single-chip resistor. The percentage of defective or failed contact lenses; This represents the percentage of defective or failed contact lenses, which is the threshold value.

[0014] As a preferred technical solution, the fault type determination process of the plum blossom contact includes: If the resistance of fewer than the first preset number of contact fingers is greater than the upper limit of single-finger qualification and the pressure of the corresponding contact finger is greater than or equal to the lower limit of pressure qualification, or the average pressure and dispersion of the plum blossom contact are normal, then it is a partial contact finger fault. If the resistance of at least a first preset number of contact fingers is greater than the upper limit of single-finger qualification and the pressure of the corresponding contact fingers is less than the lower limit of pressure qualification, or the average pressure of the plum blossom contact is less than the lower limit of pressure qualification and the dispersion is normal, or the proportion of unqualified contact fingers is greater than the threshold of the proportion of unqualified contact fingers, then the ring spring will be fatigued or fail as a whole. If the resistance of consecutive adjacent contact fingers is greater than the upper limit of single-finger acceptance, and the pressure of the corresponding contact fingers is less than the lower limit of pressure acceptance while the pressure of the other contact fingers is acceptable, or if the resistance range is greater than the resistance range threshold and the resistance standard deviation is greater than the upper limit of the resistance standard deviation, then the spring is partially broken or the assembly is stuck. If the resistance of any contact finger is greater than the single-piece resistor failure threshold and the resistance of any contact finger is greater than the single-piece resistor warning threshold and the pressure of the corresponding contact finger is qualified, or the average resistance, the dispersion of resistance and pressure are all qualified, then it is a contact finger assembly misalignment or uneven stress. If the resistance of fewer than the first preset number of contact fingers is less than the low resistance value and the pressure of the corresponding contact finger is greater than or equal to the upper limit of the pressure qualification, and the resistance and pressure of the remaining contact fingers are qualified, then it is a contact finger insertion interference or foreign object jamming. If the pressure of any contact finger is less than the lower limit of the qualified pressure and the resistance of the corresponding contact finger is greater than the upper limit of the qualified resistance of a single piece, or if the pressure of any contact finger is qualified but the resistance of the contact finger is unqualified, then it is a combined fault of resistance and voltage degradation.

[0015] According to another aspect of the present invention, a measurement system based on the overall evaluation and fault judgment method of the plum blossom contact as described above is provided, characterized in that it includes a processing module, a four-terminal measurement unit, a constant current source, a voltage acquisition module and a synchronous acquisition instrument, wherein the four-terminal measurement unit is mounted on the contact finger and is respectively connected to the constant current source and the voltage acquisition module, and the synchronous acquisition instrument is communicatively connected to the processing module, the constant current source and the voltage acquisition module respectively, and the processing module processes the resistance and voltage data of each contact finger in real time.

[0016] As a preferred technical solution, the four-terminal measurement unit includes current leads and voltage leads. The current leads are communicatively connected to a constant current source and a contact finger, respectively, and the voltage leads are communicatively connected to the contact finger and a voltage acquisition module, respectively.

[0017] As a preferred technical solution, the finger pad and the four-terminal measurement unit are arranged in a one-to-one correspondence.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention can collect the resistance and pressure values ​​of each contact finger of a plum blossom contact to accurately assess which contact finger of the plum blossom contact has a problem, and judge the overall condition of the plum blossom contact and the type of fault based on the condition of each finger.

[0019] 2. The present invention presets a resistance range, and calibrates the state of any contact finger based on the real-time measured resistance value, and marks the contact finger as the corresponding type.

[0020] 3. This invention accurately identifies different faults in the Phillips-shaped contact by judging the resistance and voltage of the contact finger, and can accurately determine the fault type.

[0021] 4. This invention employs a four-terminal measurement method, completely separating the current loop from the voltage acquisition loop. The lead resistance generated by the current leads and the contact resistance between the current terminals and the contact fingers are all located in the current loop and do not participate in voltage acquisition. The voltage leads only acquire the pure voltage drop at the contact interface, and the voltage leads use high-precision shielded wires, which can effectively suppress environmental electromagnetic interference and vibration interference, ensuring the accuracy of the acquired voltage drop data, and ultimately achieving accurate measurement of micro-ohm level contact resistance. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the judgment process of the present invention; Figure 2 This is a schematic diagram of the cable connection of the present invention; Figure 3 This is a schematic diagram of the power transmission structure of the present invention; Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0024] Example 1 like Figure 1 As shown, a method for overall evaluation and fault diagnosis of a plum blossom contact is provided, the method specifically including: S1. Collect the resistance and pressure values ​​of each contact finger in the plum blossom contact, and obtain the resistance dataset and pressure dataset respectively; S2. Preprocess and verify the resistance dataset and pressure dataset to obtain the effective resistance dataset and effective pressure dataset. S3. Traverse the effective resistance dataset and the effective pressure dataset, determine the state type of each contact finger based on the effective resistance dataset, and calculate the mean resistance, standard deviation of resistance, and range of resistance of the clover contact. S4. Determine the overall condition of the plum blossom contact based on the state of each contact finger, the average resistance, the standard deviation of resistance, and the range of resistance; and determine the fault type of the plum blossom contact based on the effective resistance dataset and the effective pressure dataset.

[0025] In this embodiment, the plum blossom contact includes multiple contact fingers, which are typically arranged in a ring and numbered sequentially in a certain direction. The real-time resistance and pressure values ​​of each contact finger are collected in real time, forming a resistance dataset and a pressure dataset. The resistance dataset R = {r1, r2, ..., r_N} (where N is the total number of contact fingers, r...). i The data set includes the synchronous measured contact resistance of the i-th contact finger, and the pressure dataset P = {p1, p2, ..., p_N} (where N is the total number of contact fingers, P...). i (This refers to the synchronous measured contact resistance of the i-th contact finger).

[0026] The preprocessing and verification include: The resistance dataset and pressure dataset are collected synchronously with the corresponding contact finger. The resistance of any contact finger is matched with the pressure of that contact finger, and there are no missing, misaligned, or out-of-range abnormal values.

[0027] The preprocessing and verification also include: Remove sensor fault spurious data from the resistance and pressure datasets.

[0028] The sensor fault pseudo data includes infinite resistance or 0, pressure of 0 or exceeding the range.

[0029] In this embodiment, it is confirmed that the contact resistance dataset R and the positive pressure dataset P are synchronously collected corresponding to the same contact finger. i With p i One-to-one matching means that for any contact finger, the resistance and pressure values ​​must be obtained simultaneously, and the resistance and pressure values ​​of the same contact finger must correspond, with no missing, misaligned, or out-of-range abnormal values. In addition, false data of sensor faults (such as resistance being infinite or 0, or pressure being 0 or out of range) are removed to obtain effective resistance datasets and effective pressure datasets. Subsequent processes will use data from the effective resistance datasets and effective pressure datasets.

[0030] The state type of any contact finger is determined and marked based on its resistance.

[0031] In this embodiment, each finger is traversed. The calibration status is classified according to resistance value as shown in Table 1: Table 1 Among them, the upper limit of acceptable single resistor is: (The maximum permissible contact resistance that meets the national / industry standards and the requirements for temperature rise at rated current is calibrated according to the contact type and rated current.) Single-chip resistor warning threshold: ( Upon reaching the degradation warning line, it is recommended to take... ); Single-chip resistor failure threshold: (The critical resistance at which the finger contacts fail and are nearly disconnected) ).

[0032] The overall state determination process of the plum blossom contact includes: like ,and , , If so, the plum blossom contact head is generally qualified; like but ,or or Then the plum blossom tip will trigger an overall warning; like or If so, the entire plum blossom contact head is defective; like or If this happens, the entire plum blossom contactor will become disabled and cannot be used. in, This represents the number of defective contact finger pieces. The average resistance; S represents the upper limit of acceptable average resistance; S represents the standard deviation of resistance. The upper limit of the standard deviation of resistance; This represents the resistance range; The resistance range threshold; The number of warnings for the touch screen; Let be the resistance of the i-th contact finger; This is the failure threshold for a single-chip resistor. The percentage of defective or failed contact lenses; This represents the percentage of defective or failed contact lenses, which is the threshold value.

[0033] In this embodiment, in, This is the number of high-resistance non-conforming items (i.e., U1); This represents the number of defective contact finger pieces. U2 is the number of single-chip failures. This represents the number of defective contact finger pieces. This represents the percentage of defective or failed contact lenses.

[0034] average resistance Resistance standard deviation Resistance range Where N is the number of finger pieces; Let i be the resistance of the i-th contact finger; This is a valid resistance dataset.

[0035] In addition, the upper limit of acceptable average resistance is: ; Resistance dispersion threshold: (Upper limit of resistance standard deviation, characterizing contact uniformity); Resistance range threshold: (Maximum resistance difference between the fingers); Threshold for the percentage of defective contact pads: (High resistance non-compliance rate warning line, recommended ≤5%) The corresponding indicators are calculated based on the resistance of each contact finger, and the overall condition of the plum blossom contact is judged based on the overall judgment rules of the plum blossom contact.

[0036] The fault type determination process for the plum blossom contact includes: If the resistance of fewer than the first preset number of contact fingers is greater than the upper limit of single-finger qualification and the pressure of the corresponding contact finger is greater than or equal to the lower limit of pressure qualification, or the average pressure and dispersion of the plum blossom contact are normal, then it is a partial contact finger fault. If the resistance of at least a first preset number of contact fingers is greater than the upper limit of single-finger qualification and the pressure of the corresponding contact fingers is less than the lower limit of pressure qualification, or the average pressure of the plum blossom contact is less than the lower limit of pressure qualification and the dispersion is normal, or the proportion of unqualified contact fingers is greater than the threshold of the proportion of unqualified contact fingers, then the ring spring will be fatigued or fail as a whole. If the resistance of consecutive adjacent contact fingers is greater than the upper limit of single-finger qualification and the pressure of the corresponding contact finger is less than the lower limit of pressure qualification and the pressure of the other contact fingers is qualified, or if the resistance range is greater than the resistance range threshold and the resistance standard deviation is greater than the upper limit of the resistance standard deviation, then the spring is partially broken or the assembly is stuck. If the resistance of any contact finger is greater than the single-piece resistor failure threshold, and at the same time the resistance of any contact finger is greater than the single-piece resistor warning threshold and the pressure of the corresponding contact finger is qualified, or the average resistance, the dispersion of resistance and pressure are all qualified, then it is a contact finger assembly misalignment or uneven stress. If the resistance of fewer than the first preset number of contact fingers is less than the low resistance value and the pressure of the corresponding contact finger is greater than or equal to the upper limit of the pressure qualification, and the resistance and pressure of the remaining contact fingers are qualified, then it is a contact finger insertion interference or foreign object jamming. If the pressure of any contact finger is less than the lower limit of the qualified pressure and the resistance of the corresponding contact finger is greater than the upper limit of the qualified resistance of a single piece, or if the pressure of any contact finger is qualified but the resistance of the contact finger is unqualified, then it is a combined fault of resistance and voltage degradation.

[0037] In this embodiment, the fault determination process based on resistance and pressure is shown in Table 2: Table 2 The first preset quantity, m, is typically a few pieces and can be set as needed. Finally, a standardized report is output, including resistance dataset, pressure dataset, individual contact status table, overall pass / warning / failure judgment results, and resistance statistical characteristics + resistance-voltage correlation fault conclusions. If the overall performance is passable, normal operation is implemented with periodic spot checks; if there is an overall warning, operation is monitored and repaired during the next inspection; if the overall performance is passable or fails and the system is disabled, replacement is performed according to the fault type.

[0038] Example 2 A measurement system based on the overall evaluation and fault diagnosis method of plum blossom contacts includes a processing module, a four-terminal measurement unit, a constant current source, a voltage acquisition module, and a synchronous acquisition instrument. The four-terminal measurement unit is installed on the contact finger and connected to the constant current source and the voltage acquisition module respectively. The synchronous acquisition instrument is communicatively connected to the processing module, the constant current source, and the voltage acquisition module respectively. The processing module processes the resistance and voltage data of each contact finger in real time.

[0039] The four-terminal measurement unit includes current leads and voltage leads. The current leads are communicatively connected to a constant current source and a contact finger, respectively, and the voltage leads are communicatively connected to the contact finger and a voltage acquisition module, respectively.

[0040] The finger contact and the four-terminal measurement unit are configured in a one-to-one correspondence.

[0041] In this embodiment, considering that the number of contacts in the plum blossom contact is large (uniformly distributed in a ring) and the contact resistance is extremely small (usually in the micro-ohm range), the traditional two-terminal measurement method is affected by the resistance of the lead wires and the contact resistance between the contact terminals and the contacts, resulting in excessive measurement errors and failing to meet the requirements for accurate detection. Therefore, a four-terminal measurement method is adopted. The core purpose is to eliminate the interference of lead wire resistance and terminal contact resistance and ensure measurement accuracy. The specific principle is as follows: Measurement system configuration: Each set of contact points corresponds to a four-terminal measurement unit, including two current leads and two voltage leads, which are respectively connected to a constant current source, a voltage acquisition module, and a synchronous acquisition instrument. The specific connection method is as follows: Current leads: One end is connected to a constant current source, and the other end is attached to the outer side of the contact finger and the conductor end of the mating plum blossom contact, respectively. It is used to pass a constant small test current (usually 1~10A) into the closed loop of the contact finger-matting conductor to avoid the contact finger from overheating, changing the contact interface state, and affecting the measurement accuracy. Voltage lead: One end connects to the high-precision voltage acquisition module, and the other end is precisely fitted to the inner contact surface of the contact finger and the contact surface of the mating conductor (staggered from the current lead to avoid the thermal effect of the current lead), used to synchronously acquire the voltage drop at both ends of the contact interface between the contact finger and the mating conductor.

[0042] Measurement and calculation principle: based on Ohm's law A preset constant test current is output through a constant current source. The voltage acquisition module synchronously acquires the voltage drop at the contact interface. The ratio of the two is the contact resistance of the contact finger. .

[0043] Anti-interference principle: The four-terminal measurement method completely separates the current loop from the voltage acquisition loop. The lead resistance generated by the current lead and the contact resistance between the current terminal and the contact finger are all located in the current loop and do not participate in voltage acquisition. The voltage lead only acquires the pure voltage drop at the contact interface, and the voltage lead uses a high-precision shielded wire, which can effectively suppress environmental electromagnetic interference and vibration interference, ensuring the accuracy of the acquired voltage drop data, and ultimately achieving accurate measurement of micro-ohm level contact resistance.

[0044] Furthermore, since the plum blossom contactor is composed of multiple sets of contact fingers, with each set of contact fingers corresponding to a set of measurement units, it is necessary to collect data from the contact fingers in an orderly manner. Therefore, a data selector (such as...) is also included. Figure 2 As shown in the figure, a single output is achieved, sequentially outputting the data of each group of touch pads to avoid data confusion caused by multiple groups of data.

[0045] Example 3 The pressure of the contact finger pieces can be acquired using pressure sensors, with a set of pressure sensors set for each contact finger piece. During detection, the detection device contacts the contact finger piece, and simultaneously, the pressure sensors contact the contact finger piece to detect the pressure. Figure 3 As shown, the detection device may include: a housing, a pressure sensor 4, a motor 1, a slider 2, etc. The pressure sensor 4 is mounted on the housing, the motor 1 causes the slider 2 to move back and forth in the housing, and the slider 2 pushes the pressure sensor 4 close to the contact finger for detection. The movement of the slider 2 can be achieved by using a screw 3 to move the motor 1 and the slider 2.

[0046] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for overall evaluation and fault diagnosis of a plum blossom contact, characterized in that, The method includes: S1. Collect the resistance and pressure values ​​of each contact finger in the plum blossom contact, and obtain the resistance dataset and pressure dataset respectively; S2. Preprocess and verify the resistance dataset and pressure dataset to obtain the effective resistance dataset and effective pressure dataset. S3. Traverse the effective resistance dataset and the effective pressure dataset, determine the state type of each contact finger based on the effective resistance dataset, and calculate the mean resistance, standard deviation of resistance, and range of resistance of the clover contact. S4. Determine the overall condition of the plum blossom contact based on the state of each contact finger, the average resistance, the standard deviation of resistance, and the range of resistance; and determine the fault type of the plum blossom contact based on the effective resistance dataset and the effective pressure dataset.

2. The method for overall evaluation and fault diagnosis of a plum blossom contact as described in claim 1, characterized in that, The preprocessing and verification include: The resistance dataset and pressure dataset are collected synchronously with the corresponding contact finger. The resistance of any contact finger is matched with the pressure of that contact finger, and there are no missing, misaligned, or out-of-range abnormal values.

3. The method for overall evaluation and fault diagnosis of a plum blossom contact as described in claim 1, characterized in that, The preprocessing and verification also include: Remove sensor fault spurious data from the resistance and pressure datasets.

4. The method for overall evaluation and fault diagnosis of a plum blossom contact as described in claim 3, characterized in that, The sensor fault pseudo data includes infinite resistance or 0, pressure of 0 or exceeding the range.

5. The method for overall evaluation and fault diagnosis of a plum blossom contact as described in claim 1, characterized in that, The state type of any contact finger is determined and marked based on its resistance.

6. The method for overall evaluation and fault diagnosis of a plum blossom contact as described in claim 1, characterized in that, The overall state determination process of the plum blossom contact includes: like ,and , , If so, the plum blossom contact head is generally qualified; like but ,or or Then the plum blossom tip will trigger an overall warning; like or If so, the entire plum blossom contact head is defective; like or If this happens, the entire plum blossom contactor will become disabled and cannot be used. in, This represents the number of defective contact finger pieces. The average resistance; S represents the upper limit of acceptable average resistance; S represents the standard deviation of resistance. The upper limit of the standard deviation of resistance; This represents the resistance range; The resistance range threshold; The number of warnings for the touch screen; Let be the resistance of the i-th contact finger; This is the failure threshold for a single-chip resistor. The percentage of defective or failed contact lenses; This represents the percentage of defective or failed contact lenses, which is the threshold value.

7. The method for overall evaluation and fault diagnosis of a plum blossom contact as described in claim 1, characterized in that, The fault type determination process for the plum blossom contact includes: If the resistance of fewer than the first preset number of contact fingers is greater than the upper limit of single-finger qualification and the pressure of the corresponding contact finger is greater than or equal to the lower limit of pressure qualification, or the average pressure and dispersion of the plum blossom contact are normal, then it is a partial contact finger fault. If the resistance of at least a first preset number of contact fingers is greater than the upper limit of single-finger qualification and the pressure of the corresponding contact fingers is less than the lower limit of pressure qualification, or the average pressure of the plum blossom contact is less than the lower limit of pressure qualification and the dispersion is normal, or the proportion of unqualified contact fingers is greater than the threshold of the proportion of unqualified contact fingers, then the ring spring will be fatigued or fail as a whole. If the resistance of consecutive adjacent contact fingers is greater than the upper limit of single-finger acceptance, and the pressure of the corresponding contact fingers is less than the lower limit of pressure acceptance while the pressure of the other contact fingers is acceptable, or if the resistance range is greater than the resistance range threshold and the resistance standard deviation is greater than the upper limit of the resistance standard deviation, then the spring is partially broken or the assembly is stuck. If the resistance of any contact finger is greater than the single-piece resistor failure threshold and the resistance of any contact finger is greater than the single-piece resistor warning threshold and the pressure of the corresponding contact finger is qualified, or the average resistance, the dispersion of resistance and pressure are all qualified, then it is a contact finger assembly misalignment or uneven stress. If the resistance of fewer than the first preset number of contact fingers is less than the low resistance value and the pressure of the corresponding contact finger is greater than or equal to the upper limit of the pressure qualification, and the resistance and pressure of the remaining contact fingers are qualified, then it is a contact finger insertion interference or foreign object jamming. If the pressure of any contact finger is less than the lower limit of the qualified pressure and the resistance of the corresponding contact finger is greater than the upper limit of the qualified resistance of a single piece, or if the pressure of any contact finger is qualified but the resistance of the contact finger is unqualified, then it is a combined fault of resistance and voltage degradation.

8. A measurement system based on the overall evaluation and fault judgment method of the plum blossom contact as described in any one of claims 1-7, characterized in that, It includes a processing module, a four-terminal measurement unit, a constant current source, a voltage acquisition module, and a synchronous acquisition device. The four-terminal measurement unit is installed on the contact finger and is connected to the constant current source and the voltage acquisition module respectively. The synchronous acquisition device is communicatively connected to the processing module, the constant current source, and the voltage acquisition module respectively. The processing module processes the resistance and voltage data of each contact finger in real time.

9. The measurement system according to claim 8, characterized in that, The four-terminal measurement unit includes current leads and voltage leads. The current leads are communicatively connected to a constant current source and a contact finger, respectively, and the voltage leads are communicatively connected to the contact finger and a voltage acquisition module, respectively.

10. The measurement system according to claim 8, characterized in that, The finger contact and the four-terminal measurement unit are configured in a one-to-one correspondence.

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