CN112103911A - Hidden fault discrimination method and device for relay protection system - Google Patents
Hidden fault discrimination method and device for relay protection system Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/26—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents
- H02H3/28—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at two spaced portions of a single system, e.g. at opposite ends of one line, at input and output of apparatus
- H02H3/30—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at two spaced portions of a single system, e.g. at opposite ends of one line, at input and output of apparatus using pilot wires or other signalling channel
- H02H3/305—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at two spaced portions of a single system, e.g. at opposite ends of one line, at input and output of apparatus using pilot wires or other signalling channel involving current comparison
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0092—Details of emergency protective circuit arrangements concerning the data processing means, e.g. expert systems, neural networks
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Abstract
The invention discloses a hidden fault judgment method and a hidden fault judgment device for a relay protection system, wherein the method comprises the following steps: weighting and summing the temperature difference of the key links based on the weight of the temperature difference of the key links of at least one mutual inductor on the influence of the relay protection current difference of the system to obtain the generalized temperature difference of a certain line; establishing a relation model of the generalized temperature difference of each line and the current difference of the relay protection system; judging whether the current difference output by the relation model is larger than a preset threshold boundary or not and whether the number of points exceeding the threshold boundary is larger than a preset threshold or not; and if the current difference is greater than a preset threshold boundary and the number of points exceeding the threshold boundary is greater than a preset threshold, outputting alarm information with hidden faults. And establishing a corresponding relation between the generalized temperature difference and the current difference, so that the hidden fault of the existing line longitudinal current differential protection system is conveniently searched.
Description
Technical Field
The invention belongs to the technical field of relay protection of power systems, and particularly relates to a hidden fault judgment method and device for a relay protection system.
Background
The relay protection is an important guarantee for the safe operation of the power system, and is required to have good adaptability when a primary system is in any state, and to be capable of rapidly and reliably removing faults or sending signals according to a preset protection range when the primary system is in fault or abnormal. The relay protection device is a component of a relay protection system. In order for a relay protection system to function correctly, each link must be ensured to be in a normal working state. However, until now, relay protection systems have not been able to do a completely reliable correct action.
The hidden relay protection fault is a defect hidden in a protection system, and can cause the relay protection device to malfunction or refuse to malfunction under the triggering of a certain condition, and the direct result is that a protected element is mistakenly disconnected or a fault element cannot be isolated from the system for a long time, so that the fault power failure area is enlarged. The relay protection hidden fault has the characteristics of high threat, high concealment and the like, namely, immeasurable loss is brought although the fault is not easy to be found in daily operation.
At present, the main protection of the circuit is mostly the pilot current differential protection of the circuit, the current difference of the mutual inductor of the same circuit can approach to zero when the relay protection system works normally, the temperature influence can be mutually offset to a certain degree, but if the system has some hidden faults, the current difference can be reflected on the change of the current difference.
Disclosure of Invention
The embodiment of the invention provides a hidden fault judgment method and a hidden fault judgment device for a relay protection system, which are used for solving at least one of the technical problems.
In a first aspect, an embodiment of the present invention provides a hidden fault determination method for a relay protection system, including: based on the weight of the influence of the temperature difference of a key link of at least one mutual inductor on the relay protection current difference of the system, carrying out weighted sum on the temperature difference of the key link to obtain the generalized temperature difference of a certain line; analyzing current difference data of the relay protection system corresponding to the generalized temperature difference to obtain a curve of the generalized temperature difference corresponding to the current difference, wherein the current difference data of the relay protection system are delivery current difference data and/or actual operation historical current difference data; performing data fitting on a curve of the generalized temperature difference corresponding to the current difference to obtain a relation model of the generalized temperature difference of each line and the current difference of the relay protection system; judging whether the current difference output by the relation model is larger than a preset threshold boundary or not and whether the number of points exceeding the threshold boundary is larger than a preset threshold or not, wherein the threshold boundary is an upper boundary curve and a lower boundary curve of which the current difference is influenced by the generalized temperature difference under the normal working state; and if the current difference is larger than a preset threshold boundary and the number of points exceeding the threshold boundary is larger than a preset threshold, outputting alarm information of hidden faults of the relay protection system.
In a second aspect, an embodiment of the present invention provides a hidden fault determining device for a relay protection system, including: the calculation module is configured to perform weighted sum on the temperature difference of the key link based on the weight of the temperature difference of the key link of at least one transformer on the influence of the current difference of the relay protection system to obtain the generalized temperature difference of a certain line; the analysis module is configured to analyze current difference data of the relay protection system corresponding to the generalized temperature difference to obtain a curve of the generalized temperature difference corresponding to the current difference, wherein the current difference data of the relay protection system is factory current difference data and/or actual operation historical current difference data; the establishing module is configured to perform data fitting on a curve of the generalized temperature difference corresponding to the current difference so as to obtain a relation model of the generalized temperature difference of each line and the current difference of the relay protection system; the judging module is configured to judge whether the current difference output by the relation model is larger than a preset threshold boundary and whether the number of points exceeding the threshold boundary is larger than a preset threshold, wherein the threshold boundary is an upper boundary curve and a lower boundary curve of which the current difference is influenced by the generalized temperature difference in a normal working state; and the output module is configured to output alarm information of hidden faults of the relay protection system if the current difference is larger than a preset threshold boundary and the number of points exceeding the threshold boundary is larger than a preset threshold.
In a third aspect, an electronic device is provided, comprising: the relay protection system comprises at least one processor and a memory which is in communication connection with the at least one processor, wherein the memory stores instructions which can be executed by the at least one processor, and the instructions are executed by the at least one processor, so that the at least one processor can execute the steps of the hidden fault judging method for the relay protection system according to any embodiment of the invention.
In a fourth aspect, an embodiment of the present invention further provides a computer program product, where the computer program product includes a computer program stored on a non-volatile computer-readable storage medium, where the computer program includes program instructions, and when the program instructions are executed by a computer, the computer is caused to execute the steps of the hidden fault determination method for a relay protection system according to any embodiment of the present invention.
The method and the device have the following beneficial effects:
1. and establishing a corresponding relation between the generalized temperature difference and the current difference, clearing the influence of the generalized temperature difference on the differential protection current error of the line longitudinal current, and facilitating the hidden fault finding of the existing line longitudinal current differential protection system.
2. The method can provide a referee evaluation index for the state evaluation research of the intelligent substation relay protection system.
3. After the rule of influence of temperature on the error is found out, the error can be compensated correspondingly, or the current difference threshold value can be set more accurately, so that the misoperation rate of the relay protection device is reduced, and the reliability of the relay protection device is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
Fig. 1 is a flowchart of a hidden fault determination method for a relay protection system according to an embodiment of the present invention;
fig. 2 is a flowchart of a hidden fault determination method for a relay protection system according to another embodiment of the present invention;
fig. 3 is a flowchart of a hidden fault determination method for a relay protection system according to another embodiment of the present invention;
FIG. 4 is a block diagram of one embodiment of the present invention;
FIG. 5 is a schematic diagram of an embodiment of the present invention;
FIG. 6 is a flow chart of an embodiment of the present invention;
fig. 7 is a block diagram of a hidden fault determination apparatus for a relay protection system according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, a flowchart of an embodiment of a hidden fault determination method for a relay protection system according to the present application is shown, where the hidden fault determination for the relay protection system according to the present embodiment may be applied to a terminal for data processing.
As shown in fig. 1, in S101, based on a weight of a temperature difference of a key link of at least one transformer on an influence of a current difference of a system, a weighted sum is performed on the temperature difference of the key link to obtain a generalized temperature difference of a certain line;
in S102, establishing a relation model of the generalized temperature difference of each line and the current difference of the relay protection system;
in S103, it is determined whether the current difference output via the relationship model is greater than a preset threshold boundary and whether the number of points exceeding the threshold boundary is greater than a preset threshold, where the threshold boundary is an upper and lower boundary curve where the current difference is affected by a generalized temperature difference in a normal operating state;
in S104, if the current difference is greater than the preset threshold boundary and the number of points exceeding the threshold boundary is greater than the preset threshold, outputting an alarm message indicating that a hidden fault exists in the relay protection system.
In this embodiment, for S101, the hidden fault determination apparatus performs weighted sum on the temperature difference of the key link based on the weight of the temperature difference of the key link of at least one transformer on the current difference influence of the relay protection system, so as to obtain the generalized temperature difference of a certain line. Then, for S102, the hidden fault determination device establishes a relational model between the generalized temperature difference of each line and the current difference of the relay protection system. Then, for S103, the hidden fault determining device determines whether the current difference output via the relationship model is greater than a preset threshold boundary and whether the number of points exceeding the threshold boundary is greater than a preset threshold, where the threshold boundary is an upper and lower boundary curve where the current difference is affected by the generalized temperature difference in the normal operating state. Then, for S104, if the current difference is greater than the preset threshold boundary and the number of points exceeding the threshold boundary is greater than the preset threshold, the hidden fault determination device outputs alarm information that the relay protection system has a hidden fault. If the current difference is smaller than the preset threshold boundary or the number of points exceeding the threshold boundary is smaller than the preset threshold, the hidden fault judgment device does not output alarm information.
The scheme provided by the embodiment adopts the steps of determining the weight of the temperature difference of the key link to the current difference of the relay protection system, calculating to obtain the generalized temperature difference of a certain line, and establishing a relation model of the generalized temperature difference and the current difference of the relay protection system, so that after the generalized temperature difference of each line is input into the relation model, the changed current difference can be obtained, and whether the current difference output by the relation model is greater than a preset threshold boundary or not and whether the number of points exceeding the threshold boundary is greater than a preset threshold or not is judged, so that the influence of the generalized temperature difference on the line pilot current differential protection current error is visually embodied, and the hidden fault finding of the existing line pilot current differential protection system is facilitated.
In some alternative embodiments, the weights are calculated by an analytic hierarchy process.
In some optional embodiments, thermistor sensors are used to collect the temperature of each link of at least one transformer.
Referring to fig. 2, a flowchart of another hidden fault determination method for a relay protection system according to an embodiment of the present application is shown. The flowchart mainly includes steps defined further in S102 "a relational model between the generalized temperature difference of each line and the current difference of the relay protection system" is established.
As shown in fig. 2, in S201, current difference data of the relay protection system corresponding to the generalized temperature difference is analyzed based on a data clustering algorithm to obtain a current difference curve corresponding to the generalized temperature difference, where the current difference data of the relay protection system is factory current difference data and/or actual operation historical current difference data;
in S202, data fitting is performed on the curve of the generalized temperature difference corresponding to the current difference to obtain an expression of the relational model:
wherein, in the step (A),
in the case of a generalized temperature difference,
is the current difference.
In this embodiment, for S201, the hidden fault determining device analyzes current difference data of the relay protection system corresponding to the generalized temperature difference based on a data clustering algorithm to obtain a current difference curve corresponding to the generalized temperature difference, where the current difference data of the relay protection system is factory current difference data and/or actual operation historical current difference data. Then, for S202, data fitting is performed on the curve of the generalized temperature difference corresponding to the current difference to obtain an expression of the relational model:
wherein, in the step (A),
in the case of a generalized temperature difference,
is the current difference.
The method of the embodiment considers the influence of the temperature change of each key link of different transformers on the current difference of the line longitudinal current differential protection, carries out data clustering fitting and other processing on factory data and actual operation data of the transformers over the years, introduces the temperature difference weighted sum of each main influence link as a generalized temperature difference, establishes a relation model of the generalized temperature difference of each line longitudinal current differential protection system and the longitudinal differential current collected by a relay protection device, carries out verification and model threshold correction through different differential protection systems of the same line and differential protection systems among different lines, and is applied to hidden fault judgment of the line longitudinal current differential protection system.
Referring to fig. 3, a flowchart of another hidden fault determination method for a relay protection system according to an embodiment of the present application is shown. The flow chart is mainly a flow chart of a further limited step of S101 'weighting the influence of the temperature difference of the key link of at least one transformer on the current difference of the relay protection system, and carrying out weighted sum on the temperature difference of the key link to obtain the generalized temperature difference of a certain line'.
As shown in fig. 3, in S301, nine-level judgment scales are constructed;
in S302, based on a subjective weighting method and correlation coefficients of each link and current difference, the temperature difference of each link of a certain transformer is scored to obtain
Judging a matrix by a criterion layer;
in S303, consistency check is carried out on the judgment matrix, wherein the consistency index
In the formula (I), wherein,
is the maximum characteristic root of N-order positive and negative matrix (judgment matrix), N is the only non-zero characteristic root of N-order consistent matrix, and consistency ratio
In the formula, RI is a random consistency index,CIis a consistency index;
in S304, if the matrix consistency is qualified, calculating a weight based on a eigenvalue method, where the corresponding eigenvector is N when the eigenvalue is N
，
Normalizing the feature vector to obtain the weight for the score value of the temperature difference of a certain link:
，
，
……，
；
in S305, a generalized temperature difference is calculated based on each link temperature difference of a certain transformer and a weight of each link temperature difference affecting a current difference.
In the present embodiment, for S301, nine-level judgment scales are constructed, wherein the nine-level judgment scales are 9 points which are very important, 7 points which are very important, 5 points which are very important, 3 points which are slightly important, 1 point which is also important, 1/3 points which are slightly less important, 1/5 points which are not important, 1/7 points which are less important, and 1/9 points which are very important. Then, for S302, based on the subjective weighting method and the correlation coefficient of each link and the current difference, the temperature difference of each link of a certain transformer is scored to obtain
Criterion layer judgment matrix
. Then, for S303, the hidden fault discrimination device performs consistency check on the judgment matrix, wherein the consistency index
In the formula (I), wherein,
is the maximum characteristic root of N-order positive and negative matrix (judgment matrix), N is the only non-zero characteristic root of N-order consistent matrix, and consistency ratio
In the formula, RI is a random consistency index,CIis a consistency index. Then, for S304, if the matrix consistency is judged to be qualified, calculating the weight based on a characteristic value method, wherein when the characteristic value is N, the corresponding characteristic vector is
And normalizing the feature vectors to obtain weights:
，
，
……，
. And then, for S304, calculating the generalized temperature difference based on the temperature difference of each link of a certain transformer and the weight of the temperature difference of each link influencing the current difference.
It should be noted that the above method steps are not intended to limit the execution order of the steps, and in fact, some steps may be executed simultaneously or in the reverse order of the steps, which is not limited herein.
The following description is provided to enable those skilled in the art to better understand the present disclosure by describing some of the problems encountered by the inventors in implementing the present disclosure and by describing one particular embodiment of the finally identified solution.
The inventor finds that: and selecting each key link in the pilot current differential protection of the circuit, and researching the influence of the temperature change on the current difference. Most of the existing methods are used for analyzing errors of the current transformer, and are mostly based on data driving, but the existing methods lack consideration of current differences of a line longitudinal current differential protection system, also lack methods for hiding faults of the line longitudinal current differential protection system through temperature redundancy, and lack related deep research on influences of temperature on differential protection current.
Referring to fig. 4, the left-most side of fig. 4 is a transmission line, the main protection of the transmission line adopts differential protection, electronic current transformers are arranged at two ends of the transmission line, the collected current information is transmitted to an exchanger through optical fibers, then the current value is collected to a relay protection device through the exchanger, under normal conditions, the currents at the two ends are equal,
if there is temperature or other hidden fault influence, the current at two ends will be different, thereby causing the difference
Further causing malfunction of the relay protection device, wherein,
in the line longitudinal differential protection, the current of one end of a certain line,
in the line longitudinal differential protection, the current of the other end of a certain line,I setis the set current difference threshold.
Referring to fig. 5-6, the solution of the present application is designed and optimized to solve the hidden fault problem associated with the lack of temperature and error in the prior art mainly from the following aspects:
the method comprises the steps of firstly, acquiring temperature difference information of key links of different transformers in the relay protection system of the intelligent substation according to categories, and acquiring actual working temperature of a transformer coil of the electromagnetic current transformer
Actual operating temperature of current transducer
Actual operating temperature of filter
Actual operating temperature of sample and hold circuit
Actual operating temperature of A/D conversion circuit
And differed from the respective ideal working temperature to obtain respective temperature difference
、
、
、
、
. For an optical electronic current transformer, the actual working temperature of the shell part is collected
Collecting the actual working temperature of the optical fiber part of the sensing sensitive ring
Collecting the actual operating temperature of the light source part
Collecting the actual working temperature of the A/D conversion circuit
And differed from the respective ideal working temperature to obtain respective temperature difference
、
、
、
. For the Rogowski coil electronic current transformer, the actual working temperature of the Rogowski coil is collected
Actual operating temperature of integral amplifier circuit
Actual operating temperature of filter circuit
Actual operating temperature of A/D conversion circuit
Actual operating temperature of the electro-optical conversion circuit
And differed from the respective ideal working temperature to obtain respective temperature difference
、
、
、
、
。
And step two, respectively calculating the influence weight of the temperature difference of each link on the current difference. The weight of the temperature difference of each link influencing the current difference is respectively
(different according to the types of the mutual inductors), determining the weight of the current difference influenced by the temperature difference of each link based on an analytic hierarchy process, and further obtaining the generalized temperature difference
。
And thirdly, collecting data of the current difference of the pilot protection system and the corresponding generalized temperature difference, wherein the data comprises factory data and actual operation historical data. Analyzing current difference data corresponding to the generalized temperature difference by using a data clustering algorithm to obtain an error current curve corresponding to the temperature difference, and obtaining an expression by using a data fitting algorithm
。
And step four, setting a threshold value. In the above steps S101 to S103, after collecting the line temperature difference and the current difference in normal operation, two ideas are provided for setting the threshold, one is to make a scatter diagram envelope (boundary line) of the temperature difference and the current difference, and if the current difference in actual operation is within the normal operation current difference envelope, it indicates that the relay protection system is operating normally, and if the current difference exceeds the range, it indicates that there is an abnormal condition. And secondly, setting the out-of-range abnormal frequency, and when the inside and outside faults do not occur, indicating that the hidden fault exists when the current difference exceeds N times.
And step five, establishing a model, and carrying out hidden fault diagnosis on each line protection. And after the threshold value is set in the step S104, obtaining a criterion, establishing a correlation model, verifying and correcting the model through partial lines, bringing the relevant parameters of the rest lines into the correlation model, and judging whether the line has a hidden fault according to the comparison between the obtained prediction range and the actual threshold value.
Specifically, in the step one, a thermistor sensor can be used for acquiring the temperature, the measurement precision is high (can reach +/-0.1 ℃), the measurement range is wide (can be measured between-90 ℃ and 130 ℃), the size is small, the cost is low, the thermistor sensor can be widely applied to electronic components at present, the thermistor sensor can be arranged in different circuits of different transformers in the step S101, the temperature is acquired, and temperature difference data of each link is obtained
。
Specifically, in the second step, since the influence degrees of the temperature differences of the links on the current difference of the transformer displayed by the intelligent terminal are different, the objective influence is determined, and the influence of the temperature differences of the links needs to be weighted
(different depending on the kind of the transformer). The invention adopts an analytic hierarchy process (AHP algorithm) to determine the weight of the influence of each factor.
Taking the electromagnetic current transformer as an example, the temperature influence link, namely the criterion layer of the analytic hierarchy process, comprises the acquisition of the actual working temperature of the transformer coil
Actual operating temperature of current transducer
Actual operating temperature of filter
Actual operating temperature of sample and hold circuit
Actual operating temperature of A/D conversion circuit
They can be scored by constructing a nine-level scale of judgment, which is most important 9 points, most important 7 points, most important 5 points, somewhat important 3 points, also most important 1 point, somewhat less important 1/3 points, less important 1/5 points, less important 1/7 points, and very less important 1/9 points. Scoring the current difference on the basis of an expert subjective weighting method and solving the correlation coefficient of each link and the current difference to obtain
The criterion layer determines the matrix a.
Then, consistency judgment matrix inspection is carried out, and weight vectors are obtained
。
When consistency check is carried out, consistency indexes are calculated according to a formula:
wherein the content of the first and second substances,
is the maximum characteristic root of an N-order positive and inverse matrix (judgment matrix), and N is the only nonzero characteristic root of an N-order consistent matrix.
A consistency ratio of
In the formula, RI is a random consistency index, and CI is a consistency index.
Wherein RI is a random consistency index which can be calculated by Monte Carlo simulation, and a large number of random sample matrixes are constructed and calculated
Wherein N is the only nonzero characteristic root of the N-order coherent array,
the average value of the maximum characteristic root of the random construction matrix is a value based on statistics, and is irrelevant to a specific matrix and can be understood as a fixed value.
The RI value can also be determined according to an average random consistency RI index table corresponding to N.
The comparison table is as follows:
further obtain the generalized temperature difference
Specifically, in step three, data collection is performed on the pilot protection system current difference and the corresponding generalized temperature difference, including factory data and actual operation history data. Analyzing current difference data corresponding to the generalized temperature difference by using a data clustering algorithm to obtain an error current curve corresponding to the temperature difference, and obtaining an expression by using a data fitting algorithm
。
Processing factory temperature test data, historical operating temperature data and normal working current difference data, obtaining generalized temperature difference according to the method in the step two, making a generalized temperature difference and current difference scatter point relation diagram, and selecting
Theoretically, the step length is more accurate as the step length is smaller, but the calculation amount is also increased, so that the proper step length needs to be selected according to the scatter plot, and the step length is selected to be 0.01 ℃. And then processing the data: from
And starting from 0, clustering the corresponding current difference under each step length to obtain a corresponding clustering center. Since the cluster center has been specified, the most common K-Means clustering algorithm can be used.
The evaluation index of the clustering algorithm is usually based on a least square method, and for a single cluster center, a clustering error S can be used for measuring:
wherein k is the cluster center coordinate,
is composed of
The corresponding current difference data area values show that the smaller the S, the better the corresponding clustering effect, so that each clustering center can be found by using a K-Means algorithm to obtain
And
the relationship scatter plot of (1). Finally, the cftool box in the SPSS or matlab is used for fitting the cftool box to obtain the cftool
And (4) a relational expression.
Specifically, in step four, step three, obtain
And in the relational expression, a judgment threshold value needs to be set when the hidden fault of the line longitudinal current differential protection influenced by the generalized temperature difference is judged. Because different temperature differences have different influences on the current difference and the threshold value does not simply exceed a certain fixed value, the envelope curve of the current difference temperature difference relation scatter diagram for protecting the normal operation of the system is obtained through calculation, an area formed by the envelope curve is called a normal operation temperature influence change zone, and the exceeding part is abnormal.
The envelope curve of the scatter diagram is processed, if the extreme value is simply solved for the scatter diagram and the scatter diagram is fitted, the obtained envelope curve is not smooth and has burrs, and the obtained envelope curve is obviously not attractive and meets the actual working requirement, so that the envelope curve can be solved through matlab writing algorithm: in order to reduce excessive compactness (passing through full scattered points) of envelope lines and scattered point data and avoid excessive envelope (similar to convhull), concave and convex points are considered, the scattered point data are firstly sequenced according to the walking direction, the concave and convex of the points are judged, a threshold value is added aiming at the concave points, partial concave points are removed through included angle judgment, and then the cyclic judgment is continued until all the concave points meet the requirements. And then smoothing the obtained envelope line, wherein during smoothing, an interp1 interpolation function in matlab is adopted to perform spherical linear difference processing on the obtained polygonal line envelope line, and finally, an upper boundary curve and a lower boundary curve of which the current difference is influenced by the generalized temperature difference under the normal working state are obtained, namely the obtained threshold boundary.
The number of boundary points beyond the threshold may then be tuned. If the number of times of exceeding the certain number is more than or equal to M, an alarm needs to be sent out and is used as a criterion for judging whether the line pilot current differential protection system has hidden faults or not.
Specifically, in the fifth step, based on the foregoing steps, association models can be respectively established for the mutual inductor protection systems of different types, and it is considered that the equipment has not failed in the statistical period, so that the association model is a normal state model, a part of line protection can be selected to verify and correct the model frequency threshold M, the model can distinguish hidden failures in a certain line protection, specifically, in a normal working state, temperature difference data in a certain time scale range is input, a point exceeding the temperature difference threshold boundary is observed, the abnormal point Un is defined, and when the temperature difference data is greater than the set threshold, an alarm is given, so that hidden failures in the line longitudinal current differential protection of the mutual inductors of different principles are distinguished.
The method comprises the steps of considering the influence of temperature changes of various key links of different transformers on the current difference of the line longitudinal current differential protection on the premise of normal operation of a protection system, carrying out data clustering fitting and other processing on factory data and actual operation data of the transformer in the past year, introducing the weighted sum of the temperature differences of various main influencing links as a generalized temperature difference, establishing a relation model of the generalized temperature difference of the line longitudinal current differential protection system and the longitudinal differential current collected by a relay protection device, carrying out verification and model threshold correction through different differential protection systems of the same line and differential protection systems among different lines, and applying the relation model to hidden fault judgment of the line longitudinal current differential protection system.
Referring to fig. 7, a block diagram of a hidden fault determination apparatus for a relay protection system according to an embodiment of the present invention is shown.
As shown in fig. 7, the hidden fault determining apparatus 400 includes a calculating module 410, an establishing module 420, a determining module 430, and an outputting module 440.
The calculating module 410 is configured to perform weighted sum on the temperature difference of the key link based on the weight of the temperature difference of the key link of at least one transformer on the influence of the current difference of the relay protection system, so as to obtain the generalized temperature difference of a certain line; the establishing module 420 is configured to establish a relation model between the generalized temperature difference of each line and the current difference of the relay protection system; a determining module 430 configured to determine whether the current difference output via the relationship model is greater than a preset threshold boundary and whether the number of points exceeding the threshold boundary is greater than a preset threshold, where the threshold boundary is an upper and lower boundary curve where the current difference is affected by the generalized temperature difference in a normal operating state; the output module 440 is configured to output warning information that the relay protection system has a hidden fault if the current difference is greater than a preset threshold boundary and the number of points exceeding the threshold boundary is greater than a preset threshold.
It should be understood that the modules recited in fig. 7 correspond to various steps in the methods described with reference to fig. 1, 2, and 3. Thus, the operations and features described above for the method and the corresponding technical effects are also applicable to the modules in fig. 7, and are not described again here.
In other embodiments, an embodiment of the present invention further provides a non-volatile computer storage medium, where the computer storage medium stores computer-executable instructions, and the computer-executable instructions may execute the hidden fault determination method for a relay protection system in any of the above method embodiments;
as one embodiment, a non-volatile computer storage medium of the present invention stores computer-executable instructions configured to:
weighting and summing the temperature difference of the key links based on the weight of the temperature difference of the key links of at least one mutual inductor on the influence of the current difference of the relay protection system to obtain the generalized temperature difference of a certain line;
establishing a relation model of the generalized temperature difference of each line and the current difference of the relay protection system;
judging whether the current difference output by the relation model is larger than a preset threshold boundary or not and whether the number of points exceeding the threshold boundary is larger than a preset threshold or not, wherein the threshold boundary is an upper boundary curve and a lower boundary curve of which the current difference is influenced by the generalized temperature difference under the normal working state;
and if the current difference is greater than a preset threshold boundary and the number of points exceeding the threshold boundary is greater than a preset threshold, outputting alarm information of hidden faults of the relay protection system.
The non-volatile computer-readable storage medium may include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function; the storage data area may store data created from use of a hidden fault discrimination device for a relay protection system, and the like. Further, the non-volatile computer-readable storage medium may include high speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid state storage device. In some embodiments, the non-volatile computer readable storage medium optionally includes memory remotely located from the processor, and these remote memories may be connected to the hidden fault discrimination apparatus for the relay protection system via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
An embodiment of the present invention further provides a computer program product, where the computer program product includes a computer program stored on a non-volatile computer-readable storage medium, and the computer program includes program instructions, and when the program instructions are executed by a computer, the computer executes any one of the hidden fault determination methods for a relay protection system.
Fig. 8 is a schematic structural diagram of an electronic device according to an embodiment of the present invention, and as shown in fig. 8, the electronic device includes: one or more processors 510 and memory 520, with one processor 510 being an example in fig. 8. The apparatus for the hidden fault discrimination method of the relay protection system may further include: an input device 530 and an output device 540. The processor 510, the memory 520, the input device 530, and the output device 540 may be connected by a bus or other means, and fig. 8 illustrates an example of a connection by a bus. The memory 520 is a non-volatile computer-readable storage medium as described above. The processor 510 executes various functional applications and data processing of the server by running the nonvolatile software program, instructions and modules stored in the memory 520, that is, implements the hidden fault determination method for the relay protection system in the above method embodiment. The input device 530 may receive input numeric or character information and generate key signal inputs related to user settings and function control of the hidden fault discrimination device for the relay protection system. The output device 540 may include a display device such as a display screen.
The product can execute the method provided by the embodiment of the invention, and has corresponding functional modules and beneficial effects of the execution method. For technical details that are not described in detail in this embodiment, reference may be made to the method provided by the embodiment of the present invention.
As an embodiment, the electronic device is applied to a hidden fault determination device for a relay protection system, and is used for a client, and includes: at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor to cause the at least one processor to:
weighting and summing the temperature difference of the key links based on the weight of the temperature difference of the key links of at least one mutual inductor on the influence of the current difference of the relay protection system to obtain the generalized temperature difference of a certain line;
establishing a relation model of the generalized temperature difference of each line and the current difference of the relay protection system;
judging whether the current difference output by the relation model is larger than a preset threshold boundary or not and whether the number of points exceeding the threshold boundary is larger than a preset threshold or not, wherein the threshold boundary is an upper boundary curve and a lower boundary curve of which the current difference is influenced by the generalized temperature difference under the normal working state;
and if the current difference is greater than a preset threshold boundary and the number of points exceeding the threshold boundary is greater than a preset threshold, outputting alarm information of hidden faults of the relay protection system.
The electronic device of the embodiments of the present application exists in various forms, including but not limited to:
(1) a mobile communication device: such devices are characterized by mobile communications capabilities and are primarily targeted at providing voice, data communications. Such terminals include smart phones (e.g., iphones), multimedia phones, functional phones, and low-end phones, among others.
(2) Ultra mobile personal computer device: the equipment belongs to the category of personal computers, has calculation and processing functions and generally has the characteristic of mobile internet access. Such terminals include: PDA, MID, and UMPC devices, etc., such as ipads.
(3) A portable entertainment device: such devices can display and play multimedia content. Such devices include audio and video players (e.g., ipods), handheld game consoles, electronic books, as well as smart toys and portable car navigation devices.
(4) The server is similar to a general computer architecture, but has higher requirements on processing capability, stability, reliability, safety, expandability, manageability and the like because of the need of providing highly reliable services.
(5) And other electronic devices with data interaction functions.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods of the various embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (8)
1. A hidden fault discrimination method for a relay protection system is characterized by comprising the following steps:
based on the weight of the influence of the temperature difference of the key link of at least one mutual inductor on the current difference of the relay protection system, carrying out weighted sum on the temperature difference of the key link to obtain the generalized temperature difference of a certain line;
analyzing current difference data of the relay protection system corresponding to the generalized temperature difference to obtain a curve of the generalized temperature difference corresponding to the current difference, wherein the current difference data of the relay protection system are delivery current difference data and/or actual operation historical current difference data;
performing data fitting on a curve of the generalized temperature difference corresponding to the current difference to obtain a relation model of the generalized temperature difference of each line and the current difference of the relay protection system;
judging whether the current difference output by the relation model is larger than a preset threshold boundary or not and whether the number of points exceeding the threshold boundary is larger than a preset threshold or not, wherein the threshold boundary is an upper boundary curve and a lower boundary curve of which the current difference is influenced by the generalized temperature difference under the normal working state;
and if the current difference is larger than a preset threshold boundary and the number of points exceeding the threshold boundary is larger than a preset threshold, outputting alarm information of hidden faults of the relay protection system.
2. The hidden fault discrimination method for the relay protection system according to claim 1, wherein the expression of the relational model is as follows:
wherein, in the step (A),
in the case of a generalized temperature difference,
is the current difference.
3. The hidden fault discrimination method for the relay protection system according to claim 1, wherein the weight is calculated by an analytic hierarchy process.
4. The hidden fault discrimination method for the relay protection system according to claim 1, wherein the weighting the influence of the temperature difference of the key link of at least one transformer on the current difference of the system to obtain the generalized temperature difference of a certain line by performing a weighted sum on the temperature difference of the key link comprises:
constructing a nine-level judgment scale;
based on subjective weighting method and correlation coefficient of each link and current difference, each ring of a certain mutual inductorThe difference in temperature is scored to obtain
Judging a matrix by a criterion layer;
carrying out consistency check on the judgment matrix, wherein the consistency index
In the formula (I), wherein,
is the maximum characteristic root of N-order positive and negative matrix, N is the only non-zero characteristic root of N-order uniform matrix, and the uniformity ratio
In the formula, RI is a random consistency index,CIis a consistency index;
if the consistency of the judgment matrix is qualified through inspection, calculating the weight based on a characteristic value method, wherein when the characteristic value is N, the corresponding characteristic vector is
， 
Normalizing the feature vector to obtain a weight for the value of the score of the temperature difference of a certain link:
，
；
and calculating the generalized temperature difference based on the temperature difference of each link of a certain mutual inductor and the weight of the temperature difference of each link influencing the current difference.
5. The hidden fault discrimination method for the relay protection system according to claim 1, wherein a thermistor sensor is used to collect the temperature of each link of at least one transformer.
6. A hidden fault discrimination device for a relay protection system, comprising:
the calculation module is configured to perform weighted sum on the temperature difference of the key link based on the weight of the temperature difference of the key link of at least one transformer on the influence of the current difference of the relay protection system to obtain the generalized temperature difference of a certain line;
the analysis module is configured to analyze current difference data of the relay protection system corresponding to the generalized temperature difference to obtain a curve of the generalized temperature difference corresponding to the current difference, wherein the current difference data of the relay protection system is factory current difference data and/or actual operation historical current difference data;
the establishing module is configured to perform data fitting on a curve of the generalized temperature difference corresponding to the current difference so as to obtain a relation model of the generalized temperature difference of each line and the current difference of the relay protection system;
the judging module is configured to judge whether the current difference output by the relation model is larger than a preset threshold boundary and whether the number of points exceeding the threshold boundary is larger than a preset threshold, wherein the threshold boundary is an upper boundary curve and a lower boundary curve of which the current difference is influenced by the generalized temperature difference in a normal working state;
and the output module is configured to output alarm information of hidden faults of the relay protection system if the current difference is larger than a preset threshold boundary and the number of points exceeding the threshold boundary is larger than a preset threshold.
7. An electronic device, comprising: at least one processor, and a memory communicatively coupled to the at least one processor, wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the steps of the method of any one of claims 1 to 4.
8. A storage medium having stored thereon a computer program, characterized in that the program, when being executed by a processor, is adapted to carry out the steps of the method of any one of claims 1 to 4.
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