Circuit breaker control loop disconnection fault positioning method and system applied to transformer substation

Abstract

The application relates to the technical field of substation operation and maintenance, in particular to a circuit breaker control loop disconnection fault positioning method and system applied to a substation, which comprises the following steps: in response to a disconnection fault signal of a circuit breaker control loop, acquiring a real-time state spectrum of the loop, the real-time state spectrum being obtained by injecting a composite detection signal into the loop and synchronously collecting electrical response data of a plurality of preset nodes; the composite detection signal comprises a wideband signal with a plurality of frequency components; according to the real-time state spectrum and a pre-stored reference state spectrum, the comprehensive deviation degree score of real-time data of each preset node relative to reference data is calculated; according to a loop logical function area defined by the comprehensive deviation degree score and an actual opening / closing position of the circuit breaker, a function area associated with a node group with the highest score is determined as a primary fault area; and the characteristic change of the electrical response data in the frequency domain in the primary fault area is analyzed. Through the application, data collection is completed while operation and maintenance continuity is ensured, and positioning accuracy is improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of substation operation and maintenance, and in particular to a circuit breaker control loop disconnection fault positioning method and system applied to a substation. BACKGROUND

[0002] In substation operation and maintenance, as a key device for realizing circuit on-off and fault removal in a substation, the reliability of the control loop of a circuit breaker directly determines the operation response capability of the circuit breaker. The control loop of the circuit breaker is responsible for transmitting the on-off operation instruction, and if the loop has disconnection faults such as broken connection terminals and oxidized virtual connection, the circuit breaker will not be able to normally receive or execute the operation instruction, and in an extreme case, the fault line cannot be isolated in time, which may cause the accident range to expand and seriously affect the stability of power supply of the power grid.

[0003] The existing positioning method for disconnection faults of the control loop of the circuit breaker mainly relies on voltage measurement, resistance testing or single frequency signal detection: among them, the voltage measurement and resistance testing methods require power-off operation, which not only affects the normal operation and maintenance efficiency of the substation, but also is difficult to accurately locate the hidden contact fault; although the single frequency signal detection method can realize live detection, it is limited by the single frequency of the signal, and cannot comprehensively reflect the electrical characteristics of different frequency bands of the loop, resulting in weak fault nature distinguishing ability, low positioning accuracy and high fault misjudgment rate. SUMMARY

[0004] The application provides a circuit breaker control loop disconnection fault positioning method and system applied to a substation, which can effectively solve the problems in the background art.

[0005] In order to achieve the above purpose, the technical scheme adopted by the application is:

[0006] The circuit breaker control loop disconnection fault positioning method applied to a substation comprises:

[0007] In response to the disconnection fault signal of the control loop of the circuit breaker, the real-time state spectrum of the loop is obtained, the real-time state spectrum is obtained by injecting a composite detection signal into the loop and synchronously collecting electrical response data of a plurality of preset nodes; the composite detection signal comprises a wideband signal with a plurality of frequency components;

[0008] According to the real-time state spectrum and the pre-stored reference state spectrum, the comprehensive deviation degree score of the real-time data of each preset node relative to the reference data is calculated;

[0009] According to the comprehensive deviation degree score and the loop logical function area defined by the actual on-off position of the circuit breaker, the function area associated with the node group with the highest score is determined as the primary fault area;

[0010] Analyze the characteristic change of the electrical response data in the primary fault area in the frequency domain, and distinguish the fault nature and locate the fault point according to different characteristic change modes.

[0011] Further, the electrical response data includes time domain response collected from the preset node and frequency domain response converted.

[0012] Further, the reference state spectrum and the real-time state spectrum at least include impedance frequency characteristics based on the frequency domain response;

[0013] The reference state spectrum is established in the loop health state in the same way as obtaining the real-time state spectrum.

[0014] Further, the distinguishing of the fault nature according to different characteristic change modes comprises:

[0015] If the impedance frequency characteristics present open circuit characteristics in the first preset frequency band, it is determined as hard open circuit fault;

[0016] If the impedance frequency characteristics only occur distortion in the second preset frequency band, it is determined as poor contact fault.

[0017] Further, in response to the determination of hard open circuit fault, the fault point is located to the component or the wiring terminal in combination with the interruption point in the preset signal transmission delay matrix;

[0018] In response to the determination of poor contact fault, the fault point is located to the contact interface by comparing the signal attenuation gradient of the upstream and downstream of the fault node.

[0019] Further, the comprehensive deviation score is calculated based on the time domain response deviation, the frequency domain response deviation and the impedance deviation.

[0020] The impedance deviation is given the highest weight, the frequency domain deviation is given the second weight, and the time domain deviation is given the lowest weight.

[0021] Further, the signal transmission delay matrix is constructed synchronously when the real-time state spectrum is obtained, and the signal transmission delay matrix includes the time difference of the composite detection signal from the injection end to each preset node.

[0022] Further, for poor contact fault, the fault point is located by comparing the signal attenuation gradient of the upstream and downstream of the fault node, and the signal attenuation gradient is calculated based on the frequency domain amplitude data.

[0023] Further, the loop logic function area includes a protection screen instruction output area, a coil driving area and an auxiliary switch area.

[0024] In another aspect, the application also provides a circuit breaker control loop disconnection fault positioning system applied to a substation, comprising:

[0025] a state spectrum acquisition module, configured to inject a broadband composite detection signal comprising a plurality of frequency components into the circuit in response to a disconnection fault signal of the circuit breaker control loop, and synchronously acquire electrical response data of a plurality of preset nodes to obtain a real-time state spectrum of the circuit;

[0026] a data analysis module, configured to calculate a comprehensive deviation score of real-time data of each preset node relative to reference data according to the real-time state spectrum and a pre-stored reference state spectrum;

[0027] a region determination module, configured to determine a functional region associated with a node group with the highest score as a primary fault region according to the comprehensive deviation score and a functional region defined by an actual opening / closing position of the circuit breaker;

[0028] a fault diagnosis module, configured to analyze characteristic changes of the electrical response data in the frequency domain in the primary fault region, and distinguish fault properties and locate fault points according to different characteristic change modes.

[0029] The technical scheme of the application can achieve the following technical effects:

[0030] The application adopts a broadband composite detection signal comprising a plurality of frequency components to realize live detection, complete data acquisition without interrupting normal operation of the substation, and ensure operation and maintenance continuity; the use of the multi-frequency coverage feature to obtain electrical responses of the control loop in different frequency bands is conducive to distinguishing different fault properties; comparison of the reference state spectrum in the healthy state with the real-time state spectrum in the fault state, combined with the comprehensive deviation algorithm to quantify data differences, and determination of the fault region based on the functional region logic defined by the opening / closing position of the circuit breaker can improve positioning accuracy.

[0031] The above description is only a summary of the technical scheme of the application, in order to more clearly understand the technical means of the application, which can be implemented according to the content of the specification, and in order to make the above and other purposes, features and advantages of the application more obvious and easy to understand, the following specific embodiments of the application are described. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical scheme in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments described in the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0033] Figure 1A flowchart of a circuit breaker control loop disconnection fault positioning method applied to a substation in the present application is shown in the figure.

[0034] Figure 2 A structure block diagram of a circuit breaker control loop disconnection fault positioning system applied to a substation in the present application is shown in the figure. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described in the present application with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this description, the singular forms "a", "an" and "the" include plural references unless the context clearly dictates otherwise.

[0037] As shown in the figure, the circuit breaker control loop disconnection fault positioning method applied to a substation in the present application specifically includes the following steps: Figure 1

[0038] Step S1, in response to a disconnection fault signal of a circuit breaker control loop, acquiring a real-time state spectrum of the loop, the real-time state spectrum being obtained by injecting a composite detection signal into the loop and synchronously collecting electrical response data of a plurality of preset nodes; the composite detection signal including a wideband signal of a plurality of frequency components; the electrical response data including time domain responses collected from the preset nodes and frequency domain responses obtained by conversion;

[0039] Step S2, according to the real-time state spectrum and a pre-stored reference state spectrum, calculating a comprehensive deviation score of real-time data of each preset node relative to reference data; the reference state spectrum and the real-time state spectrum at least including impedance frequency characteristics based on the frequency domain responses; the reference state spectrum being established in a healthy state of the loop in the same way as acquiring the real-time state spectrum;

[0040] Step S3, according to the comprehensive deviation score and a loop logical function area defined by an actual opening / closing position of the circuit breaker, determining a function area associated with a node group with the highest score as a primary fault area;

[0041] Step S4, analyzing characteristic changes of electrical response data in the frequency domain in the primary fault area, and distinguishing fault properties and locating fault points according to different characteristic change modes.

[0042] ​In the embodiment, by adopting a wideband composite detection signal including multiple frequency components, live detection is realized, data acquisition is completed while ensuring the continuity of operation and maintenance without interrupting the normal operation of the substation; by utilizing the characteristics of multi-frequency coverage, the electrical response of the control loop at different frequency bands is obtained, which is conducive to distinguishing different fault properties; by comparing the reference state spectrum under the healthy state with the real-time state spectrum at the time of fault, combining the comprehensive deviation degree algorithm to quantify the data difference, and determining the fault area based on the function area logic defined by the on-off position of the circuit breaker, the positioning accuracy is improved.

[0043] The comparison of the multi-frequency signal and the spectrum can make the characteristic differences of different fault types more obvious. For example, the high-frequency open-circuit characteristics of hard breaking and the low-frequency amplitude attenuation characteristics of poor contact form unique identification marks in a wide frequency band. The fault types that originally need to be distinguished by multiple measurements can be determined by a spectrum comparison once, improving the fault classification efficiency. The comprehensive deviation degree algorithm cooperates with the function area logic to form a double check of data deviation and operation logic, effectively filtering single-point interference and invalid areas, and improving the preliminary fault area positioning accuracy.

[0044] In some embodiments of the present application, in order to obtain multi-dimensional data that can fully reflect the fault characteristics without affecting the normal operation of the control loop, step S1 injects a wideband signal including multiple frequency components, which can cover the sensitive frequency band of different faults, collect time domain and frequency domain responses, and retain signal transient change information while quantifying loop parameter abnormalities through frequency domain analysis; the specific implementation is as follows:

[0045] Step S11, install a fault signal detection unit at the power supply input terminal or protection screen output node of the circuit breaker control loop, and set the trigger condition; when it is detected that the loop current is continuously lower than a certain proportion of the rated working current, or the node voltage fluctuation amplitude exceeds a certain range of the rated control voltage, it is determined as a broken line fault signal; after the fault signal is triggered, the detection unit immediately sends a synchronous start instruction to the signal generation module and the data acquisition module, and sends a fault warning information to the substation operation and maintenance background;

[0046] Step S12, the signal generation module generates a composite detection signal using a programmable signal generator, the frequency range needs to cover the fault sensitive frequency band of the control loop coil, wiring, contact and other elements, including multiple discrete frequency components. The amplitude of each frequency component needs to consider the following two aspects: one is to avoid high amplitude interference with normal elements of the loop, and the other is to prevent low amplitude from causing weak response signals difficult to collect; the composite detection signal is injected into the protection screen output terminal of the control loop through a coupling module with bidirectional electrical isolation function. The isolation module needs to have a certain impulse voltage withstand capability to prevent the original voltage of the loop from damaging the signal generator in reverse.

[0047] Step S13, according to the control loop topology and the high-fault position, select the key preset nodes, the preset nodes need to cover the full link from the instruction output to the execution element, including the protection screen output terminal, the mechanism box input terminal, the two ends of the opening coil, the two ends of the closing coil, the auxiliary switch moving contact point end, the auxiliary switch static contact point end, etc.; install a high-frequency response voltage probe at each preset node, connect to a multi-channel synchronous acquisition module, the sampling rate of the acquisition module needs to meet the sampling requirements of the highest frequency of the signal; the acquisition module and the signal generator realize synchronization through the same clock signal, ensure that the time deviation of signal injection and data acquisition is controlled in a very small range, each node continuously collects for a sufficient time to include a complete composite signal period, and acquires time domain response data;

[0048] Step S14, import the time domain response data of each preset node into the embedded data processing unit, convert the time domain data into frequency domain data through fast Fourier transform, extract the voltage amplitude and phase information under each discrete frequency component; combined with the current signal obtained through the micro current sensor connected in series in the loop, calculate the impedance value of each node at different frequencies using Ohm's law, and form the impedance frequency characteristic curve; finally, integrate the time domain response curve, frequency domain amplitude and phase curve, and impedance frequency characteristic curve of each node to generate a real-time state spectrum including multi-dimensional data.

[0049] It should be noted that in the above specific implementation method, the frequency range of the composite detection signal can be adjusted according to the voltage level or element parameters of the circuit breaker control loop, the lower limit of the frequency can be appropriately reduced for low-voltage control loops, and the upper limit of the frequency can be appropriately increased for high-voltage loops; the number and position of the preset nodes can be increased or decreased according to the complexity of the loop topology, the loop with multiple auxiliary switches can increase the contact node, and the simplified loop can reduce the number of nodes; the fault signal triggering condition can be customized according to the operation and maintenance standards of different substations, the amplitude output range of the signal generator can be adjusted through software to adapt to the insulation level and load characteristics of different loops; the trigger source of the fault signal can include not only the alarm signal of the substation monitoring system or the protection device, but also the detection instruction manually triggered by the operation and maintenance personnel through the detection terminal, the automatic triggering instruction during regular inspection, etc. Any implementation method that injects a detection signal including multiple frequency components into the circuit breaker control loop, acquires the time domain and frequency domain response of the preset nodes to obtain a real-time state spectrum, belongs to the protection scope of the method.

[0050] In the embodiment, a low-amplitude and wide-band composite signal is injected through the isolation coupling module, and the signal frequency avoids the normal operating frequency of the circuit, so as to not interfere with the on-off command transmission, complete data acquisition without power-off, and avoid the substation operation and maintenance stagnation problem caused by power-off detection. The composite signal covers multiple frequency bands, and can simultaneously capture the characteristics of hard circuit breaking and implicit contact failure, solving the limitation of single frequency signal that can only identify a certain type of fault. The combination of time domain and frequency domain data retains the intermittent on-off transient information of virtual contact, and can also quantify the impedance abnormality of the circuit parameters. The synchronous acquisition module ensures the time synchronization of signal injection and data acquisition, avoiding the frequency domain analysis error caused by time deviation. The preset nodes cover the entire link of the circuit, and the collected data can reflect the state of each section, avoiding the omission of fault characteristics caused by insufficient node selection.

[0051] In a specific implementation, as an embodiment, in order to quantify the difference between the real-time state and the health state of the control circuit, the embodiment integrates the multi-dimensional data of the real-time state spectrum and the reference state spectrum, and gives different weights to different dimensional parameters, so that the quantization result can truly reflect the parameter abnormality caused by faults.

[0052] Specifically, the method for obtaining the reference state spectrum comprises the following steps: first, when the circuit breaker control circuit is in a healthy state, using the same composite detection signal, the same preset node, and the same acquisition parameter as in step S1, respectively collecting multiple state spectrum data at the opening and closing positions to form multiple healthy samples according to the same method as in step S1; then, removing abnormal data points in each sample caused by transient electromagnetic interference, and calculating the average value and the standard deviation of the parameters corresponding to each sample; finally, combining the average value and the standard deviation to determine the health threshold range of the parameter, integrating the health threshold ranges of all parameters to form two reference state spectra corresponding to the opening and closing positions, storing them in the local database and synchronously uploading them to the reference library of the substation operation and maintenance background; at the same time, periodically re-collecting and updating the reference state spectrum according to the health state after circuit maintenance to avoid the reference deviation caused by component aging.

[0053] More specifically, according to the real-time state spectrum and the pre-stored reference state spectrum, the comprehensive deviation score of the real-time data of each preset node relative to the reference data is calculated, comprising:

[0054] Step S21, after obtaining the real-time state spectrum, first, according to the current actual opening / closing position of the circuit breaker, the corresponding reference state spectrum is called from the reference library to ensure the consistency of the working conditions of the comparison objects; then, for the time domain response data, the starting injection time of the composite detection signal is taken as the reference to synchronize the time axis of the real-time time domain curve and the reference time domain curve, ensuring that the signal data at the same time point are one-to-one corresponding; for the frequency domain data and the impedance frequency characteristic curve, they are matched one by one according to the discrete frequency components, ensuring that the real-time data and the reference data are compared at the same frequency point, avoiding comparison errors caused by frequency misalignment.

[0055] Step S22, for each set of aligned parameters, the deviation of the real-time data relative to the reference data is calculated respectively:

[0056] The time domain response deviation is calculated, three characteristic parameters of the peak value, the rising edge time and the falling edge time of the time domain curve are selected, the absolute difference between the real-time value and the reference average value of each characteristic parameter is calculated, and then divided by the reference standard deviation to obtain the time domain deviation of a single characteristic parameter; if the real-time value is within the healthy threshold range, the time domain deviation is recorded as 0, and finally the average value of the time domain deviation of the three characteristic parameters is taken as the total time domain deviation of the node;

[0057] The frequency domain response deviation is calculated, for each discrete frequency component, the absolute difference between the real-time frequency domain amplitude and the reference amplitude is calculated, and then divided by the reference amplitude to obtain the amplitude deviation at the frequency point, and the maximum value of the amplitude deviation of all frequency points is taken as the total frequency domain deviation of the node; if all the real-time amplitudes of the frequency points are within the healthy threshold range, the frequency domain deviation is recorded as 0;

[0058] The impedance deviation is calculated, for each discrete frequency component, the absolute difference between the real-time impedance value and the reference impedance value is calculated, and then divided by the reference impedance value to obtain the impedance deviation at the frequency point, and the average value of the impedance deviation of all frequency points is taken as the total impedance deviation of the node; if all the real-time impedance values of the frequency points are within the healthy threshold range, the impedance deviation is recorded as 0.

[0059] Step S23, according to the sensitivity of different parameters to faults, different weights are given; among them, since the impedance change is the main feature of the broken line fault, the impedance deviation weight is the highest; the frequency domain deviation weight is the second, the frequency domain amplitude change can reflect the signal transmission loss and indirectly reflect the fault influence; the time domain deviation weight is the lowest, the time domain feature mainly reflects the signal instantaneous change and is sensitive to intermittent faults; the total time domain deviation, the total frequency domain deviation and the total impedance deviation of each node are multiplied by the corresponding weight respectively, and then summed to obtain the comprehensive deviation score of the node, the higher the score, the more significant the parameter anomaly of the node.

[0060] It should be noted that the calculation dimension of the parameter deviation degree can be adjusted according to the loop characteristics, for example, for a control loop containing a capacitive element, the deviation degree calculation of the capacitive reactance parameter can be increased; the weight distribution can be optimized according to the actual fault statistical data, if the time domain signal anomaly in a certain type of substation is more significant in indicating faults, the weight of the time domain deviation degree can be increased; the update period of the reference state spectrum can be customized according to the operation and maintenance frequency of the substation, the operation and maintenance frequency of the substation can be shortened, and the operation and maintenance period of the substation can be appropriately extended; the parameter alignment method can be adapted to different types of composite detection signals, if the composite signal is a continuous frequency sweeping signal, the frequency axis can be segmented and matched according to the frequency sweeping interval, and then compared; any method that calculates the deviation degree by weighting multiple dimensions of parameters and realizes quantitative comparison with the reference state spectrum in real time belongs to the protection scope of the present method.

[0061] In the present embodiment, by aligning the working conditions and parameters, the comparison errors caused by working condition differences and data misalignment are eliminated; the reference standard deviation is introduced to participate in the deviation degree calculation, which can effectively distinguish between normal fluctuations caused by environmental interference and abnormal deviations caused by faults, and avoid misjudgment; by giving the highest weight to the impedance parameter, the time domain and frequency domain parameters are considered, which can represent parameter abnormalities of different types of faults and avoid fault omission caused by single parameter comparison; the comprehensive deviation degree score converts multi-dimensional parameter abnormalities into intuitive numerical values, which can determine whether there is an abnormality and reflect the abnormality degree, reducing the interference of manual subjective judgment.

[0062] In specific implementation, as an embodiment, when the circuit breaker is in the open and closed positions, the on-off logic and current flow direction of the control loop are different, and the working states of different functional areas are completely different, and single node anomaly may only be a partial manifestation of overall functional area failure; if the functional area logical association is ignored, isolated node misjudgment or fault range expansion problems may occur, resulting in low subsequent troubleshooting efficiency; step S3 filters high abnormal node groups through the comprehensive deviation degree score, and then divides the specific functional area according to the functional area corresponding to the open / closed position, so as to converge the scattered node anomalies to the specific functional area, ensuring that the primary fault area positioning is accurate and consistent with the actual working logic of the loop; the specific implementation is as follows:

[0063] Step S31, according to the electrical schematic diagram of the circuit breaker control circuit and the closing / opening working logic, combined with the preset node distribution, the circuit logic function area corresponding to the closing / opening position is divided in advance; wherein, under the closing position, the protection screen instruction output area, the closing coil driving area, and the closing auxiliary switch area are divided; under the opening position, the protection screen instruction output area, the opening coil driving area, and the opening auxiliary switch area are divided; wherein, the protection screen instruction output area includes the protection screen output terminal node; the closing coil driving area includes the mechanism box input terminal and the closing coil two-end node; the closing auxiliary switch area includes the auxiliary switch moving contact end and the static contact end node; the opening coil driving area includes the mechanism box input terminal and the opening coil two-end node; the opening auxiliary switch area includes the auxiliary switch moving contact end and the static contact end node; each function area is bound with the corresponding preset node group to form a mapping relationship table of position, function area, and node group, and is stored in the logic partition library of the operation and maintenance background.

[0064] Step S32, after obtaining the comprehensive deviation score of all preset nodes, an abnormal threshold is set, which is determined according to historical fault data and a health threshold range; nodes with scores exceeding the abnormal threshold are screened out and recorded as abnormal nodes; then, according to the position, function area, and node group mapping relationship table, the abnormal nodes are classified into the node group of the corresponding function area according to the actual closing / opening position of the circuit breaker, and the proportion of the number of abnormal nodes in each node group and the average comprehensive deviation score of the abnormal nodes are counted; the proportion of the number of abnormal nodes is the ratio of the number of abnormal nodes to the total number of nodes in the node group; if the proportion of the number of abnormal nodes in a node group reaches a set proportion and the average comprehensive deviation score is the highest among all node groups, the node group is determined as a high abnormal node group.

[0065] Step S33, according to the function area corresponding to the high abnormal node group, further verification is made combined with the circuit working logic; if the current is the closing position, the high abnormal node group corresponds to the closing coil driving area, the circuit on-off logic of the function area is checked, the function area should form a complete path when the closing instruction is issued, if the abnormal characteristics of the high abnormal node group are consistent with the path interruption logic, the function area is confirmed as a primary fault area; if the current is the opening position, the high abnormal node group corresponds to the opening auxiliary switch area, the switch switching logic of the function area is verified, the auxiliary switch should be in the open state when opening, if the abnormal characteristics of the high abnormal node group are consistent with the switch not normally open logic, the function area is confirmed as a primary fault area; finally, the confirmed function area is marked as a primary fault area.

[0066] In the embodiment, the collective abnormal characteristics of the functional area node group are screened instead of the single node abnormality determination, which can exclude the false abnormality of a single node caused by transient interference and ensure the reliability of the fault area positioning; for example, if the abnormality proportion of the node group in which a certain node is located is low, the node will not be misjudged as a fault area due to temporary high score caused by electromagnetic interference, thereby reducing the misjudgment rate; the circuit breaker opening / closing position is used to divide the functional area, so that the primary fault area matches the actual working state of the circuit and invalid investigation across the functional area is avoided; for example, under the closing position, the possibility of fault in the opening coil driving area is directly excluded, thereby reducing a large amount of investigation range and improving the positioning efficiency.

[0067] In the specific implementation, as an embodiment, in order to accurately locate a specific component, a terminal or a contact interface, the step S4 uses the frequency domain characteristic difference of the electrical response in the primary fault area to establish a corresponding relationship between the fault property and the frequency domain mode, and then combines the signal transmission delay or attenuation gradient to realize accurate positioning of the fault point; the specific implementation is as follows:

[0068] In step S41, the impedance frequency characteristic curve and the frequency domain amplitude data of all preset nodes in the primary fault area are extracted from the real-time state spectrum obtained in step S1, and the characteristic changes of the first preset frequency band and the second preset frequency band are analyzed, the first preset frequency band is a high frequency band, and the second preset frequency band is a medium-low frequency band; wherein the high frequency band signal has strong penetration and is sensitive to the continuity of the conductor, and the medium-low frequency band signal is easily affected by the contact resistance;

[0069] If the impedance frequency characteristic curve shows a sharp rise in impedance value in the high frequency band and is stable, showing an open circuit characteristic, and the impedance in the medium-low frequency band has no obvious abnormality, it is determined as a hard open circuit fault.

[0070] If the impedance frequency characteristic curve shows a sharp rise in impedance value in the high frequency band and is stable, showing an open circuit characteristic, and the impedance in the medium-low frequency band has no obvious abnormality, it is determined as a hard open circuit fault.

[0071] In step S42, the signal transmission delay matrix needs to be constructed at the same time when the real-time state spectrum is obtained in step S1. Specifically, when the composite detection signal is injected into the control circuit, the time difference of the composite detection signal from the injection end to each preset node in the primary fault area is recorded to form matrix data including the transmission time between the injection end and the node and between the nodes. The signal transmission delay matrix can reflect the propagation efficiency of the signal in each section of the circuit, and the transmission time between the nodes is stable under normal working conditions. If there is an open circuit, the signal cannot be normally transmitted, which will cause abnormal transmission time of the corresponding node.

[0072] When locating the hard breaking fault point, the signal transmission delay matrix constructed synchronously is called to analyze the breaking point in the signal transmission delay matrix. If the signal transmission time of a node is far more than the benchmark transmission time, and the transmission time of the upstream adjacent node of the node is normal, and the downstream adjacent node has no signal response, then the connection path between the node and the downstream adjacent node has a break. In combination with the loop topology, the fault point is located to a specific component or terminal. For example, the primary fault area is the closing coil driving area, if the transmission time of one end node of the closing coil is normal, and the other end node has no transmission signal record, then the fault point is the terminal or internal broken wire of the other end of the closing coil. The benchmark transmission time is obtained from the benchmark state spectrum in the healthy state.

[0073] In step S43, the signal attenuation gradient of the upstream and downstream of the fault node in the primary fault area is calculated; 1-2 adjacent nodes of the fault node and its upstream and downstream are selected, and the frequency domain amplitude data of the adjacent nodes in the medium and low frequency band is extracted; the signal attenuation gradient calculation method is that the difference between the amplitude of the upstream node and the current node is divided by the distance between the two nodes to obtain the attenuation gradient from the upstream node to the current node; the difference between the amplitude of the current node and the downstream node is divided by the distance between the two nodes to obtain the attenuation gradient from the current node to the downstream node; if the upstream attenuation gradient of the current node is normal, and the downstream attenuation gradient suddenly increases, then the contact interface at the current node is the fault point; if the upstream and downstream attenuation gradients of the current node are both abnormal, and the current node is a component connection point, then the connection point is the poor contact fault point; wherein the benchmark attenuation gradient is obtained from the benchmark state spectrum in the healthy state, and the normal upstream attenuation gradient means that the deviation from the benchmark attenuation gradient is within a reasonable range.

[0074] It should be noted that the specific range of the first preset frequency band and the second preset frequency band can be adjusted according to the element parameters of the control loop. For loops with different wire cross-sectional areas, distributed capacitances, and inductance element quantities, the upper and lower limits of the frequency band can be flexibly adjusted; the construction of the signal transmission delay matrix can record the node and node transmission time pairs according to the increase and decrease of the loop node quantity, and the node distance parameter can also be customized according to the actual wiring length of the loop; the benchmark deviation threshold and the growth threshold of the signal attenuation gradient can be iteratively optimized in combination with factors such as the aging degree of the loop and the environmental humidity of different substations; any implementation method that distinguishes the fault nature through the frequency domain characteristics and locates the fault point in combination with the synchronously constructed signal transmission delay matrix or attenuation gradient belongs to the protection scope of the method.

[0075] In the embodiment, the difference between the high frequency band and the low frequency band is used to establish a fault property determination standard, avoid misjudgment of hard circuit breaking and poor contact, and ensure the accuracy of the maintenance direction; the synchronous construction logic of the signal transmission delay matrix is used to ensure the reliability of the data source, and the breakpoint is used to quickly lock the hard circuit breaking position; the poor contact is locked by comparing the attenuation gradient of the contact interface, and there is no need to traverse all elements in the primary fault area, so that the positioning accuracy is improved from the functional area to the specific element, terminal or interface, and the troubleshooting efficiency is improved.

[0076] Based on the same inventive concept as the circuit breaker control loop disconnection fault positioning method applied to a substation in the foregoing embodiment, the application also provides a circuit breaker control loop disconnection fault positioning system applied to a substation, as shown in the accompanying drawings, the system comprises: Figure 2

[0077] A state spectrum acquisition module is configured to inject a broadband composite detection signal comprising a plurality of frequency components into the circuit breaker control loop in response to a disconnection fault signal of the circuit, and synchronously acquire electrical response data of a plurality of preset nodes to obtain a real-time state spectrum of the circuit;

[0078] A data analysis module is configured to calculate a comprehensive deviation score of real-time data of each preset node relative to reference data according to the real-time state spectrum and a pre-stored reference state spectrum;

[0079] A region determination module is configured to determine a functional area associated with a node group with the highest score as a primary fault area according to the comprehensive deviation score and a functional area defined by an actual opening / closing position of the circuit breaker;

[0080] A fault diagnosis module is configured to analyze characteristic changes of the electrical response data in the primary fault area in the frequency domain, and distinguish fault properties and locate fault points according to different characteristic change modes.

[0081] The system in the application can effectively realize the circuit breaker control loop disconnection fault positioning system applied to a substation, and the technical effects are as described in the foregoing embodiments, which will not be described here.

[0082] Although the application is described in combination with specific features and embodiments, it is obvious that various modifications and combinations can be made without departing from the spirit and scope of the application. Accordingly, the specification and drawings are merely illustrative of the application defined in the appended claims, and any and all modifications, variations, combinations or equivalents that are within the scope of the application are intended to be covered. Obviously, those skilled in the art can make various modifications and variations to the application without departing from the scope of the application. Thus, if these modifications and variations of the application belong to the scope of the application and its equivalents, the application intends to include these modifications and variations.​

Claims

1. A method for locating open-circuit faults in the control circuit of a circuit breaker in a substation, characterized in that, include: In response to a circuit breaker control circuit open fault signal, the real-time state spectrum of the circuit is obtained. The real-time state spectrum is obtained by injecting a composite detection signal into the circuit and simultaneously collecting electrical response data of multiple preset nodes. The composite detection signal includes a broadband signal with multiple frequency components; Based on the real-time state spectrum and the pre-stored reference state spectrum, calculate the comprehensive deviation score of the real-time data of each preset node relative to the reference data; the comprehensive deviation score is calculated based on the time domain response deviation, frequency domain response deviation and impedance deviation; the impedance deviation is given the highest weight, the frequency domain deviation is given the second highest weight, and the time domain deviation is given the lowest weight. Multiply the total time-domain deviation, total frequency-domain deviation, and total impedance deviation of each node by their respective weights, and then sum them to obtain the overall deviation score of that node. Based on the comprehensive deviation score and the circuit logic functional area defined by the actual opening / closing position of the circuit breaker, the functional area associated with the node group with the highest score is determined as the primary fault area. This includes: obtaining the comprehensive deviation score of all preset nodes, setting an abnormal threshold, which is determined based on historical fault data and the range of health thresholds; filtering out nodes with scores exceeding the abnormal threshold and recording them as abnormal nodes; according to the mapping relationship table of position, functional area, and node group, classifying abnormal nodes into the node groups of the corresponding functional areas according to the current actual opening / closing position of the circuit breaker, and calculating the proportion of abnormal nodes in each node group and the average comprehensive deviation score of abnormal nodes, where the proportion of abnormal nodes is the ratio of the number of abnormal nodes to the total number of nodes in the node group; if the proportion of abnormal nodes in a node group reaches a set ratio and the average comprehensive deviation score is the highest among all node groups, then the node group is determined as a high-abnormal node group. The frequency domain characteristics of electrical response data within the primary fault region are analyzed, and the fault nature and fault location are distinguished based on different characteristic change patterns.

2. The method for locating open-circuit faults in circuit breaker control circuits of substations according to claim 1, characterized in that, The electrical response data includes the time-domain response collected from the preset node and the frequency-domain response obtained after conversion.

3. The method for locating open-circuit faults in circuit breaker control circuits of substations according to claim 2, characterized in that, The reference state spectrum and the real-time state spectrum include at least the impedance-frequency characteristics obtained based on the frequency domain response; The baseline state spectrum is established under the loop health state in the same manner as the real-time state spectrum is acquired.

4. The method for locating open-circuit faults in circuit breaker control circuits of substations according to claim 3, characterized in that, The method of distinguishing fault nature based on different characteristic change patterns includes: If the impedance frequency characteristic exhibits open-circuit characteristics in the first preset frequency band, it is determined to be a hard open-circuit fault. If the impedance frequency characteristic is distorted only in the second preset frequency band, it is determined to be a poor contact fault.

5. The method for locating open-circuit faults in circuit breaker control circuits of substations according to claim 4, characterized in that, In response to the determination of a hard open circuit fault, the fault point is located to the component or terminal by combining the interruption point in the preset signal transmission delay matrix. In response to the determination of a poor contact fault, the fault point is located at the contact interface by comparing the signal attenuation gradient upstream and downstream of the fault node.

6. The method for locating open-circuit faults in circuit breaker control circuits of substations according to claim 5, characterized in that, The signal transmission delay matrix is ​​constructed synchronously when the real-time state spectrum is acquired. The signal transmission delay matrix includes the time difference between the transmission of the composite detection signal from the injection end to each preset node.

7. The method for locating open-circuit faults in circuit breaker control circuits of substations according to claim 5, characterized in that, For poor contact faults, the fault point is located by comparing the signal attenuation gradients upstream and downstream of the fault node. The signal attenuation gradients are calculated based on frequency domain amplitude data.

8. The method for locating open-circuit faults in the control circuit of a circuit breaker in a substation according to any one of claims 1-7, characterized in that, The circuit logic functional area includes a protection panel instruction output area, a coil drive area, and an auxiliary switch area.

9. A fault location system for a circuit breaker control circuit in a substation, wherein the system is applied to the fault location method for a circuit breaker control circuit in a substation as described in claim 1, characterized in that, The system includes: The state spectrum acquisition module is used to respond to the open circuit fault signal of the circuit breaker control circuit, inject a broadband composite detection signal including multiple frequency components into the circuit, and simultaneously acquire electrical response data of multiple preset nodes to obtain the real-time state spectrum of the circuit. The data analysis module is used to calculate the comprehensive deviation score of the real-time data of each preset node relative to the reference data based on the real-time state spectrum and the pre-stored reference state spectrum. The area determination module is used to determine the functional area associated with the node group with the highest score as the primary fault area based on the circuit logic functional area defined by the comprehensive deviation score and the actual opening / closing position of the circuit breaker. The fault diagnosis module is used to analyze the characteristic changes of electrical response data in the frequency domain within the primary fault area, distinguish the nature of the fault and locate the fault point based on different characteristic change patterns.

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