Relay fault identification method considering contact quality

Abstract

The invention discloses a relay fault identification method considering contact quality, relates to the technical field of relay fault identification, and solves the problem that the relay fault identification result is inaccurate due to the fact that the contact quality of a relay is not considered in the relay fault identification process in the prior art. According to the method, a multi-parameter weighted comprehensive evaluation system with the contact quality as the core is constructed, the contact resistance value, the fluctuation standard deviation of the contact resistance value and the pull-in and release time characteristics of the contact resistance value are synchronously considered, the contact quality is improved from single parameter judgment to quantifiable comprehensive scoring, a state grading and fault recognition linkage mechanism is established, and the contact quality evaluation accuracy is improved. The defect of insufficient identification accuracy caused by neglecting the contact quality in the prior art is effectively overcome, and the relay fault identification precision and the intelligent level of power grid equipment state maintenance are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of relay fault identification technology, and in particular to a relay fault identification method that takes into account contact quality. Background Technology

[0002] With the deepening of smart grid construction, relays, as core actuators in power system protection, control, and automation devices, directly impact the safety and stability of the entire power grid due to their operational reliability. In critical scenarios such as substation automation systems, distribution network protection devices, and power quality monitoring equipment, relays perform vital functions including precise circuit switching, rapid fault isolation, and reliable transmission of control signals. During long-term operation, relay contacts experience increased contact resistance and deteriorated operating characteristics due to mechanical wear, arc erosion, surface oxidation, and environmental pollution. This leads to latent faults such as malfunctions, failure to operate, or poor contact, posing a significant threat to the safe operation of the power grid. Therefore, accurate assessment and fault identification of relay contact quality are crucial technical aspects for ensuring the healthy operation of power equipment and improving the reliability of power grid supply.

[0003] However, existing relay fault identification technologies have significant shortcomings. The core problem lies in the failure to incorporate contact quality as a key consideration in the evaluation system, leading to insufficient accuracy in the identification results. Traditional methods often employ a single-parameter threshold judgment mode, which only measures the static contact resistance value or simply records the action time parameter. When the parameter exceeds a preset threshold, it is judged as a fault. This evaluation method essentially severs the intrinsic relationship between contact quality and fault type, ignoring the dynamic fluctuation characteristics of contact resistance, the comprehensive manifestation of the physical and chemical state of the contact surface, and the coupling effect of multiple characteristic parameters. In engineering practice, contact quality deterioration is a gradual process, involving multiple dimensions of characteristics such as drift in the mean of contact resistance, increased fluctuation, increased energy loss during engagement, and prolonged duration of the arc release. Because existing technologies have not established a quantitative evaluation model for contact quality, they cannot comprehensively capture these characteristic information, resulting in a large deviation between the evaluation results and the actual contact state, which easily leads to false alarms or missed alarms, making it difficult to meet the urgent needs of power grid equipment for high-precision fault early warning and condition-based maintenance.

[0004] Therefore, a relay fault identification method that takes into account contact quality is needed. Summary of the Invention

[0005] To address the problem that existing technologies fail to consider relay contact quality during relay fault identification, leading to inaccurate results, this invention provides a relay fault identification method that considers contact quality. This method constructs a multi-parameter weighted comprehensive evaluation system centered on contact quality, simultaneously considering contact resistance value and its fluctuation standard deviation, as well as pull-in and release time characteristics. This elevates contact quality from a single-parameter judgment to a quantifiable comprehensive score. Furthermore, it establishes a linkage mechanism between state classification and fault identification, effectively overcoming the shortcomings of existing technologies that neglect contact quality, thus significantly improving the accuracy of relay fault identification and the intelligent level of condition-based maintenance of power grid equipment. The specific technical solution is as follows: A relay fault identification method considering contact quality includes the following steps: Step 1: Apply a constant test current during the relay contact test. Collect the voltage across the contact points The time from when the relay coil is energized to when the contacts first conduct. Release transient time ; Step 2: Within a fixed time window T, sample the contact resistance to obtain a sequence. Calculate the standard deviation ; Step 3: Based on , , , A weighted comprehensive evaluation method is used to construct a contact quality evaluation function, obtain a comprehensive score, and then classify the relay contact status into multiple levels based on the comprehensive score; Step 4: If the relay contact status is within the set level, proceed to Step 5; otherwise, output a relay contact fault signal and the relay contact status level. Step 5: Identify relay faults based on characteristic fault parameters. When a relay fault is identified, output the relay fault type and relay contact status level.

[0006] Preferably, the contact resistance is calculated using the following formula: in, For constant test current, The voltage across the contact; Standard deviation The calculation process is as follows: in, For sequence The contact resistance at a certain moment. For sequence The average contact resistance at all times. For sequence The total number of elements in the text.

[0007] The preferred method for calculating the overall score is as follows: in, For comprehensive scoring, These are the weighting coefficients for each feature parameter. , is the normalization function for each feature parameter, used to map parameters of different dimensions to the interval [0,1].

[0008] Preferably, the relay contact status levels are divided into the following levels: Level 1: Output: "Contact status is good"; Level Two: Output: "Slight contact degradation, please pay attention"; Level 3: Output: "Contacts are severely degraded; replacement recommended." in, , This is the level threshold.

[0009] Preferably, step five is as follows: S1: Constructing the feature vector: in: Indicates the coil resistance; Indicates the coil operating current; Indicates the contact resistance of the contact point; This indicates the fluctuation value of contact resistance; Indicates the adsorption and release time; S2: Primary fault detection is performed based on threshold rules, as follows: Coil open circuit fault: Coil short circuit or aging fault: Contact adhesion fault: or And cannot be disconnected Poor contact fault: S3: When a relay fault is detected, output the relay fault type and the relay contact status level.

[0010] Preferably, step five also introduces a comprehensive fault discrimination function, as follows: in, Comprehensive fault discrimination value; Feature weight coefficients; Feature mapping function; Based on the range of values ​​for F, the fault type is finally determined, the fault identification type is obtained, and the relay fault type, fault identification type, and relay contact status level are finally output.

[0011] Preferably, the fault type is finally determined based on the range of values ​​for F, as follows: The fault type is "normal"; The fault type is "performance degradation"; The fault identification type is "fault status".

[0012] A computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device in which the computer-readable storage medium is located to perform the relay fault identification method considering contact quality as described above.

[0013] A processor for running a program, wherein the program, when running, executes the relay fault identification method considering contact quality as described above.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The relay fault identification method proposed in this invention, which considers contact quality, fundamentally solves the problem of insufficient identification accuracy caused by neglecting contact quality in existing technologies by constructing a multi-parameter weighted comprehensive evaluation system with contact quality as the core. This method achieves precise quantification of relay contact status and scientific identification of fault types, with specific advantages reflected in the following three aspects: First, this scheme establishes a comprehensive quantitative characterization mechanism for contact quality, transforming it from an abstract concept into a calculable comprehensive indicator. By simultaneously acquiring the contact resistance sequence Rc and its standard deviation σR, not only are the static values ​​of the contact resistance obtained, but also the degree of its dynamic fluctuation is precisely quantified, effectively capturing contact instability caused by microscopic unevenness of the contact surface and inhomogeneity of the oxide film. Simultaneously, the scheme introduces the relay coil energization time to the first contact conduction time ton and the release transient time tooff, organically integrating mechanical action characteristics with the electrical contact process. This multi-physical quantity collaborative monitoring mechanism breaks through the limitations of traditional methods that only focus on a single electrical or time parameter, achieving comprehensive quantification of contact quality's "steady-state characteristics—dynamic fluctuations—time response." This allows the evaluation results to more comprehensively and realistically reflect the comprehensive performance degradation trajectory of the contact under actual working conditions, significantly improving the information completeness and diagnostic accuracy of the condition assessment.

[0015] Secondly, this scheme employs a weighted comprehensive evaluation method to construct a contact quality evaluation function, achieving both scientific rigor and adaptability in the assessment model. Addressing the varying degrees of influence of different parameters on contact quality under different operating conditions, a quantitative scoring system consistent with relay failure mechanisms is established by assigning different weight coefficients to the mean contact resistance, standard deviation of fluctuation, pull-in time, and release time. This weighted mechanism fully considers the correlation and sensitivity differences of various characteristic parameters during contact quality deterioration. For example, contact resistance fluctuation is more sensitive to early contact failures, while time parameters are more indicative of mechanical fatigue. By dynamically adjusting the weights, the assessment model can adapt to complex factors such as power system vibration environment, load fluctuation characteristics, and climate changes, making the scoring results more closely match the actual operating scenarios of power grid equipment. This effectively overcomes the rigidity and susceptibility to environmental interference inherent in traditional threshold judgments, significantly improving the robustness and accuracy of fault identification.

[0016] Finally, this solution implements a closed-loop fault identification mechanism based on contact quality grading, forming a progressive diagnostic architecture of "state assessment—gradual early warning—type identification". Through comprehensive scoring, the contact state is finely divided into multiple levels, establishing a progressive characterization system of "health—degradation—fault". When the contact quality level enters the early warning range, a secondary identification process of model characteristic fault parameters is automatically triggered, realizing cascaded diagnosis of state assessment and fault classification. This graded linkage mechanism, with contact quality at its core, can not only detect potential defects early, avoiding sudden failures that could lead to power grid outages, but also accurately locate fault types (such as contact erosion, spring fatigue, coil aging, etc.), providing clear guidance for maintenance personnel to formulate targeted maintenance strategies. It truly regards contact quality as the decisive factor throughout the entire fault identification process, fundamentally solving the core problem of inaccurate identification results in existing technologies, and effectively improving the efficiency of power equipment operation and maintenance and the safety margin of the power grid. Attached Figure Description (none). Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 are within the scope of protection of the present invention.

[0018] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0019] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0020] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0021] In one embodiment of the present invention, a relay fault identification method considering contact quality is provided, characterized by comprising the following steps: Step 1: Apply a constant test current during the relay contact test. Collect the voltage across the contact points The time from when the relay coil is energized to when the contacts first conduct. Release transient time ; Step 2: Within a fixed time window T, sample the contact resistance to obtain a sequence. Calculate the standard deviation ; Step 3: Based on , , , A weighted comprehensive evaluation method is used to construct a contact quality evaluation function, obtain a comprehensive score, and then classify the relay contact status into multiple levels based on the comprehensive score; Step 4: If the relay contact status is within the set level, proceed to Step 5; otherwise, output a relay contact fault signal and the relay contact status level. Step 5: Identify relay faults based on characteristic fault parameters. When a relay fault is identified, output the relay fault type and relay contact status level.

[0022] The following section details the contact quality assessment and fault identification steps mentioned above.

[0023] 1. Contact Quality Assessment Model 1.1 Technical Objectives of Contact Quality Assessment During long-term operation of a relay, due to contact oxidation, ablation, contamination, or spring fatigue, although the relay contacts can still perform the action of engaging or disengaging, their contact resistance, conduction stability, and transient characteristics will deteriorate significantly. Traditional "on / off" detection methods are difficult to identify such hidden faults.

[0024] Therefore, this invention introduces a Contact Quality Evaluation Model (CQEM) into the rapid relay detection process to quantitatively evaluate the conduction performance of relay contacts, thereby enabling early identification of relays in a "sub-healthy state".

[0025] 1.2 Acquisition of Multimodal Contact Characteristic Parameters This invention, based on the concept of multimodal detection, synchronously collects multiple key parameters of relay contacts during the testing process, mainly including: Steady-state contact resistance parameters After the relay contacts have stabilized, a constant test current is applied. Real-time acquisition of voltage across the contact points Calculate the contact resistance: Contact resistance fluctuation parameters Within a fixed time window T, the contact resistance is sampled multiple times to obtain a sequence: Calculate its standard deviation to reflect the stability of the contact: Pull-in transient time parameters Record the time from when the relay coil is energized to when the contacts first close: Release transient time parameters: 1.3 Comprehensive Evaluation Model for Contact Quality To provide a unified and quantitative assessment of relay contact conditions, this invention employs a weighted comprehensive evaluation method to construct a contact quality evaluation function: in: Overall contact quality score; The weight coefficients of each feature parameter satisfy: A normalization function is used to map parameters of different dimensions to the interval [0,1]. An example of normalization is shown below (using contact resistance as an example): 1.4 Determination of Contact Quality Level Based on the comprehensive score Q, the relay contact status is divided into multiple levels: The contacts are in good condition. The contacts show slight deterioration; monitoring is recommended. The contacts are severely degraded; replacement is recommended.

[0026] This model can identify potential failure risks in advance while the relay is still in normal operation, thereby improving the safety of equipment operation.

[0027] 2. Fault Identification Algorithm 2.1 Technical Objectives of Fault Identification To address issues such as coil failure, contact abnormalities, and delayed operation that may occur in relays during practical applications, this invention proposes a relay fault identification algorithm based on rule and feature fusion, which enables automatic identification and classification of various fault types.

[0028] 2.2 Construction of Fault Characteristic Parameter Set During relay detection, a feature vector is constructed: in: : Coil resistance; : Coil operating current; Contact resistance at the contact point; Contact resistance fluctuation value; : Adsorption and release time.

[0029] 2.3 Primary Fault Judgment Based on Threshold Rules First, a preliminary classification is performed using rule-based judgment: Coil open circuit fault: Coil short circuit or aging fault: Contact adhesion fault: or And cannot be disconnected Poor contact fault: 2.4 Comprehensive Fault Discrimination Function For relays in complex or boundary states, a comprehensive fault discrimination function is introduced: Comprehensive fault discrimination value; Feature weight coefficients; : Feature mapping function.

[0030] Based on the range of values ​​for F, the fault type is finally determined: :normal; Performance degradation; Fault status.

[0031] 2.5 Fault Result Output and Report Generation Fault identification results are output in the following manner: The display screen provides real-time feedback on the fault type. Automatically writes test reports, including test parameters, fault types, and handling suggestions.

[0032] The fault identification algorithm works in conjunction with the aforementioned contact quality assessment model to achieve integrated detection capabilities for relay status assessment, fault diagnosis, and maintenance decision support, thereby significantly improving the intelligence level and engineering practical value of the device of this invention.

[0033] In summary, this invention can improve contact quality from a single-parameter judgment to a quantifiable comprehensive score by constructing a multi-parameter weighted comprehensive evaluation system with contact quality as the core, simultaneously considering contact resistance value and its fluctuation standard deviation, and pull-in and release time characteristics. Furthermore, it establishes a linkage mechanism between state classification and fault identification, effectively overcoming the shortcomings of existing technologies that suffer from insufficient identification accuracy due to neglecting contact quality. This significantly improves the accuracy of relay fault identification and the level of intelligence in condition-based maintenance of power grid equipment.

[0034] Those skilled in the art will recognize that the units of the various examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the invention.

[0035] In the embodiments provided by the present invention, it should be understood that the division of units is only a logical functional division. In actual implementation, there may be other division methods, such as multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored.

[0036] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0037] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A relay fault identification method considering contact quality, characterized in that, Includes the following steps: Step 1: Apply a constant test current during the relay contact test. Collect the voltage across the contact points The time from when the relay coil is energized to when the contacts first conduct. Release transient time ; Step 2: Within a fixed time window T, sample the contact resistance to obtain a sequence. Calculate the standard deviation ; Step 3: Based on , , , A weighted comprehensive evaluation method is used to construct a contact quality evaluation function, obtain a comprehensive score, and then classify the relay contact status into multiple levels based on the comprehensive score; Step 4: If the relay contact status is within the set level, proceed to Step 5; otherwise, output a relay contact fault signal and the relay contact status level. Step 5: Identify relay faults based on characteristic fault parameters. When a relay fault is identified, output the relay fault type and relay contact status level.

2. The relay fault identification method considering contact quality according to claim 1, characterized in that, Contact resistance is calculated using the following formula: in, For constant test current, The voltage across the contact; Standard deviation The calculation process is as follows: in, For sequence The contact resistance at a certain moment. For sequence The average contact resistance at all times. For sequence The total number of elements in the text.

3. The relay fault identification method considering contact quality according to claim 1, characterized in that, The overall score is calculated as follows: in, For comprehensive scoring, These are the weighting coefficients for each feature parameter. , is the normalization function for each feature parameter, used to map parameters of different dimensions to the interval [0,1].

4. The relay fault identification method considering contact quality according to claim 1, characterized in that, Relay contact status levels are classified into the following levels: Level 1: Output: "Contact status is good"; Level Two: The output message reads: "Slight contact degradation, please pay attention." Level 3: The output message reads: "Contacts are severely degraded; replacement is recommended." in, , This is the level threshold.

5. The relay fault identification method considering contact quality according to claim 1, characterized in that, Step five is as follows: S1: Constructing the feature vector: in: Indicates the coil resistance; Indicates the coil operating current; Indicates the contact resistance of the contact point; This indicates the fluctuation value of contact resistance; Indicates the adsorption and release time; S2: Primary fault detection is performed based on threshold rules, as follows: Coil open circuit fault: Coil short circuit or aging fault: Contact adhesion fault: or And cannot be disconnected Poor contact fault: S3: When a relay fault is detected, output the relay fault type and the relay contact status level.

6. The relay fault identification method considering contact quality according to claim 5, characterized in that, Step five also introduces a comprehensive fault discrimination function, as follows: in, Comprehensive fault discrimination value; Feature weight coefficients; Feature mapping function; Based on the range of values ​​for F, the fault type is finally determined, the fault identification type is obtained, and the relay fault type, fault identification type, and relay contact status level are finally output.

7. A relay fault identification method considering contact quality according to claim 6, characterized in that, Based on the range of values ​​for F, the fault type is finally determined as follows: The fault type is "normal"; The fault type is "performance degradation"; The fault identification type is "fault status".

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device in which the computer-readable storage medium is located to perform the relay fault identification method considering contact quality as described in any one of claims 1 to 7.

9. A processor, characterized in that, The processor is used to run a program, wherein the program executes the relay fault identification method considering contact quality as described in any one of claims 1 to 7.

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