CN116090613A - Insulation degradation evaluation method and system for alternating current power supply system for station - Google Patents
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Abstract
The invention relates to the technical field of power equipment evaluation, in particular to a method and a system for evaluating insulation degradation of an alternating current power supply system for a station, wherein the method firstly acquires abrupt waveform of residual current of the alternating current power supply system; then, carrying out signal processing on the abrupt waveform, and determining a plurality of signal characteristic values representing amplitude-frequency characteristics; then determining a plurality of abnormal characteristic values representing the abnormality in the abrupt waveform according to the plurality of signal characteristic values; and finally, inputting the plurality of influence factor data and the plurality of abnormal characteristic values into an evaluation model to obtain an evaluation result of insulation degradation. According to the embodiment of the invention, the amplitude values of different frequencies in the abrupt waveform are extracted, so that the data quantity of data analysis is reduced; the content of the residual current mutation sample is extracted through the signal characteristic value so as to represent the abnormality degree of the mutation waveform, and the abnormal degree is input into an evaluation model constructed by insulating degradation samples of the alternating current power supply system for the station, so that the degradation evaluation result is obtained, the reliability of the evaluation result is high, and the evaluation result is accurate.
Description
Technical Field
The invention relates to the technical field of power equipment evaluation, in particular to a method and a system for evaluating insulation degradation of a station alternating current power supply system.
Background
The station AC power supply is used as an important working power supply of the transformer substation, and directly provides working power supply for a main transformer cooling device, a fire protection device, a DC charger, communication equipment, a DC system, a UPS (Uninterruptible Power Supply ), heating, moisture removal, air exhaust, illumination, power distribution maintenance, domestic electricity utilization and the like. The station AC power supply system generally comprises a station transformer, a 380V low-voltage distribution panel, a protection measurement and control system, an AC power supply network and the like, wherein the power supply is generally taken from the transformer used under different buses or an external standby power supply in a transformer substation, and when one power supply loses power, the operation mode of the other power supply is automatically switched to ensure the reliability of power supply. The station power buses generally adopt sectional wiring divided by station transformers, namely each station power transformer is provided with a section of bus, and an automatic transfer switch device is arranged, so that when the power connected with any bus exits, the adjacent bus can still acquire power, and the continuity of power supply is maintained.
Therefore, the reliability of the station alternating current power supply directly influences the safe and stable operation of the transformer substation. The problems of complicated wiring of the AC power supply on the site of the transformer substation, quality of electric equipment, aging of the circuit and the like cause the circuit to fail, so that not only can the tripping of an AC feed switch and the power loss of the electric equipment be caused, but also serious accidents such as fire disaster, total station AC power loss, shutdown of the transformer substation and the like are caused.
Aiming at the problems, each alternating current power supply system starts to strengthen management and control from the aspects of the design, the construction, the acceptance and the operation and maintenance management of the alternating current power supply for the station, emphasizes the configuration principle, the level difference matching, the fixed value management, the safety protection and the like of the alternating current power supply for the station, and has important significance for ensuring the safe operation of the alternating current power supply for the station. In addition, the conventional operation and maintenance of the station alternating current power supply further strengthens the daily measures of voltage and current monitoring, overvoltage and undervoltage warning, ATS switching (Automatic Transfer Switch, dual power supply automatic switching) test and the like.
However, aiming at the problem of insulation reduction of an alternating current power supply, part of units only carry out a voltage withstand test on an alternating current feed network before a transformer substation is put into operation, and no feasible on-line monitoring means exists after the transformer substation is put into operation. The early insulation abnormality cannot pay enough attention until the long-term insulation abnormality develops to insulation breakdown, arc discharge, direct grounding and even causes short circuit and fire accident, and then the tripping station is started to be used by virtue of overcurrent or zero sequence protection, so that the total station alternating current is out of voltage, the accident range is expanded virtually, and the operation safety of a transformer substation is even threatened.
Based on this, it is necessary to develop and design a method for evaluating insulation degradation of a station ac power supply system.
Disclosure of Invention
The embodiment of the invention provides a method and a system for evaluating insulation degradation of an alternating current power supply system for a station, which are used for solving the problems that the insulation degradation defect of the alternating current power supply system for the station is strong in concealment and difficult to find in the prior art.
In a first aspect, an embodiment of the present invention provides a method for evaluating insulation degradation of an ac power supply system for a station, including:
obtaining a sudden change waveform of the residual current of an alternating current power supply system;
performing signal processing on the abrupt waveform, and determining a plurality of signal characteristic values representing amplitude-frequency characteristics of the abrupt waveform;
determining a plurality of outlier features characterizing an anomaly in the abrupt waveform according to the plurality of signal feature values;
and inputting the plurality of influence factor data and the plurality of abnormal characteristic values into an evaluation model to obtain an evaluation result of insulation degradation, wherein the influence factor characterizes factors influencing the abnormal characteristic values, the evaluation model is constructed based on a plurality of sample data sets, and the sample data sets comprise insulation degradation degree data of a station alternating current power supply system and a plurality of factor data influencing the insulation degradation degree of the station alternating current power supply system.
In one possible implementation manner, the capturing the abrupt waveform through a mixed waveform generated by mixing with an intermediate frequency waveform, and the obtaining the abrupt waveform of the residual current of the ac power supply system includes:
Obtaining a mixed waveform, wherein the waveform length of the mixed waveform is an integer multiple of the period length of an intermediate frequency waveform;
waveform extraction is carried out on the mixed waveform according to a first formula, and a waveform coefficient corresponding to an intermediate frequency waveform is obtained, wherein the first formula is as follows:
wherein a is a first waveform coefficient, b is a second waveform coefficient, mwave (t) is a mixed waveform, ω0 is the angular frequency of an intermediate frequency waveform, n is the multiple of the length of the mixed waveform relative to the length of the intermediate frequency period, sin () is a sine function, cos () is a cosine function;
determining a sudden change waveform for obtaining the residual current of the alternating current power supply system according to a second formula, a mixing waveform and the waveform coefficient, wherein the second formula is as follows:
in the formula, PDwave (T) is a sudden change waveform, and T is the period of an intermediate frequency waveform.
In one possible implementation manner, the performing signal processing on the abrupt waveform to determine a plurality of signal feature values that characterize an amplitude-frequency feature of the abrupt waveform includes:
sampling the abrupt waveform according to a preset sampling interval to obtain an abrupt waveform array;
determining a plurality of signal characteristic values of the amplitude-frequency characteristic of the abrupt waveform according to a third formula and the abrupt waveform data, wherein the third formula is as follows:
Wherein AFC (m) is the m-th signal eigenvalue, v 0 is the fundamental frequency, N is the total number of data in the abrupt waveform sequence, PDwave (N) is the N-th data in the abrupt waveform sequence, j is the imaginary unit, pi is the circumference ratio, and pi is a natural constant.
In one possible implementation, the determining, from the plurality of signal eigenvalues, a plurality of outlier eigenvalues characterizing an anomaly in the abrupt waveform includes:
acquiring a plurality of sample signal feature sets, wherein the sample signal feature sets comprise a plurality of signal feature values of residual current abrupt changes and/or interference samples;
constructing a signal characteristic row matrix according to the plurality of signal characteristic values;
constructing a sample matrix according to the plurality of sample signal feature sets, wherein the sample matrix comprises a plurality of sample rows, and the sample rows are constructed by a plurality of signal feature values of the sample signal feature sets;
constructing an abnormal characteristic row matrix;
constructing a fourth formula about the abnormal feature line matrix according to the abnormal feature line matrix, the signal feature line matrix and the sample matrix, wherein the fourth formula is as follows:
wherein, AFC is signal characteristic line matrix, WEF is abnormal characteristic line matrix, SPL is sample matrix, WEFM is M element of abnormal characteristic line matrix, M is total number of sample signal characteristic sets, SPLMS is M element of S column of sample matrix, S is total number of elements of signal characteristic line matrix;
According to the fourth formula, solving the abnormal feature matrix, and determining values of a plurality of elements in the abnormal feature matrix;
and taking a plurality of elements of the abnormal characteristic matrix as a plurality of abnormal characteristic values.
In one possible implementation, the evaluation model is constructed based on a plurality of sample data sets, including:
obtaining an initial model, wherein the initial model comprises a plurality of inputs which are the same as the plurality of influencing factors and the plurality of abnormal characteristic values, the initial model indicates an evaluation result of insulation degradation degree according to the plurality of inputs and outputs, and the initial model is as follows:
wherein Mfa () is the a-th transfer function of the 1 st column, AFunc is an intermediate function, wa1 () is the M-th receiving coefficient of the a-th transfer function of the 1 st column, M is the total number of INPUTs, INPUT (M) is the M-th INPUT, OUTPUT () is the OUTPUT function, woutput (B) is the xB-th receiving coefficient of the OUTPUT function, xB is the total number of transfer functions of the last column, B is the total number of transfer function columns, mfxBB () is the xB-th transfer function of the last column, and e is a natural constant;
acquiring a plurality of sample data sets, wherein the sample data sets comprise data of insulation degradation degree of a station alternating current power supply system and a plurality of factor data influencing the insulation degradation degree of the station alternating current power supply system, and the factor data comprise abnormal characteristics;
Solving a plurality of receiving coefficients of the initial model according to the plurality of sample data sets, and verifying the accuracy of an output result of the initial model;
and if the accuracy of the output result of the initial model reaches a preset target, taking the initial model as the evaluation model.
In one possible implementation manner, the solving the plurality of receiving coefficients of the initial model according to the plurality of sample data sets and verifying accuracy of the output result of the initial model includes:
dividing the plurality of sample data sets into a solution group and a verification group, wherein the solution group and the verification group respectively comprise the plurality of sample data sets;
model adjustment: adjusting the total number of receiving coefficients in the initial model so that the total number of receiving coefficients in the initial model is the same as the total number of sample data sets in the solution set
Inputting a plurality of sample data sets in the solution set to the initial model respectively, and obtaining a plurality of equations about a plurality of receiving coefficients;
solving the plurality of equations to determine values of the plurality of receiving coefficients;
substituting values of the plurality of receiving coefficients into the initial model;
Inputting a plurality of factor data of each sample data set of the verification group into the initial model, and obtaining a plurality of results of the initial model corresponding to the plurality of sample data sets in the verification group;
determining the accuracy of the output result of the initial model according to the plurality of results and the insulation degradation degree data of the station alternating current power supply system of the plurality of sample data sets in the verification group;
and if the accuracy is lower than a threshold value, adjusting the total number of transfer function sequences, and returning to the model adjustment step.
In a second aspect, an embodiment of the present invention provides an insulation degradation evaluation system for a station ac power supply system, including:
the device comprises a mutation current acquisition module, an intermediate frequency module, a frequency mixing module and a signal processing module;
the intermediate frequency module generates an intermediate frequency waveform based on waveform frequency multiplication of the power frequency voltage, and the abrupt current acquisition module is used for acquiring the residual current waveform of the alternating current feeder line;
the frequency mixing module is used for converting the current waveform into a voltage waveform and mixing the voltage waveform with the intermediate frequency waveform to generate a mixed waveform;
the signal processing module is used for determining a period of generating a sudden change waveform according to the mixed waveform, obtaining the sudden change waveform by extracting the mixed waveform, and determining the insulation degradation degree of the alternating current power supply system for the station according to the sudden change waveform and a plurality of influence factor data.
In a third aspect, an embodiment of the present invention provides an ac power supply system insulation degradation evaluation device for a station, for implementing the ac power supply system insulation degradation evaluation method for a station according to the first aspect or any one of the possible implementation manners of the first aspect, the ac power supply system insulation degradation evaluation device for a station includes:
the abrupt waveform acquisition module is used for acquiring an abrupt waveform of the residual current of the alternating current power supply system;
the amplitude-frequency characteristic extraction module is used for carrying out signal processing on the abrupt waveform and determining a plurality of signal characteristic values representing amplitude-frequency characteristics of the abrupt waveform;
the abnormal characteristic extraction module is used for determining a plurality of abnormal characteristic values representing the abnormality in the abrupt waveform according to the plurality of signal characteristic values;
the method comprises the steps of,
the insulation degradation evaluation module is used for inputting a plurality of influence factor data and the plurality of abnormal characteristic values into the evaluation model to obtain an evaluation result of insulation degradation, wherein the influence factor characterizes factors influencing the abnormal characteristic values, the evaluation model is constructed based on a plurality of sample data sets, and the sample data sets comprise insulation degradation degree data of the alternating current power supply system for the station and a plurality of factor data influencing the insulation degradation degree of the alternating current power supply system for the station.
In a fourth aspect, embodiments of the present invention provide an electronic device comprising a memory and a processor, the memory having stored therein a computer program executable on the processor, the processor implementing the steps of the method as described above in the first aspect or any one of the possible implementations of the first aspect when the computer program is executed.
In a fifth aspect, embodiments of the present invention provide a computer readable storage medium storing a computer program which, when executed by a processor, implements the steps of the method as described above in the first aspect or any one of the possible implementations of the first aspect.
Compared with the prior art, the embodiment of the invention has the beneficial effects that:
the embodiment of the invention discloses a method for evaluating insulation degradation of an alternating-current power supply system for a station, which comprises the steps of firstly obtaining abrupt waveform of residual current of the alternating-current power supply system; then, carrying out signal processing on the abrupt waveform, and determining a plurality of signal characteristic values representing amplitude-frequency characteristics of the abrupt waveform; then, determining a plurality of abnormal characteristic values representing the abnormality in the abrupt waveform according to the plurality of signal characteristic values; and finally, inputting a plurality of influence factor data and the plurality of abnormal characteristic values into an evaluation model to obtain an evaluation result of insulation degradation, wherein the influence factor characterizes factors influencing the abnormal characteristic values, the evaluation model is constructed based on a plurality of sample data sets, and the sample data sets comprise insulation degradation degree data of a station alternating current power supply system and a plurality of factor data influencing the insulation degradation degree of the station alternating current power supply system. According to the embodiment of the invention, the possible abrupt waveform is mixed with the intermediate frequency signal in a mixing mode, so that the occurrence period of the abrupt waveform and the phase of the corresponding voltage waveform can be positioned, and the abnormal analysis is convenient. According to the embodiment of the invention, the signal characteristic value and the characteristic value of the residual current abrupt sample change and/or the interference sample are calculated, the content of the residual current abrupt sample change and/or the interference sample in the abrupt waveform is extracted as the abnormal characteristic value so as to represent the abnormal degree of different abnormalities in the abrupt waveform, the abnormal characteristic and the environmental factor when the residual current abrupt sample are input into an evaluation model constructed by insulating degradation samples of the alternating current power supply system for the station, and the degradation evaluation result is obtained.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a flowchart of a method for evaluating insulation degradation of a station ac power supply system according to an embodiment of the present invention;
fig. 2 is a schematic diagram of an insulation degradation evaluation system of the ac power supply system for a station according to the embodiment of the present invention;
fig. 3 is a functional block diagram of an insulation degradation evaluation device for a station ac power supply system according to an embodiment of the present invention;
fig. 4 is a functional block diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth such as the particular system architecture, techniques, etc., in order to provide a thorough understanding of the embodiments of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the following description will be made with reference to the accompanying drawings.
The following describes in detail the embodiments of the present invention, and the present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation procedure are given, but the protection scope of the present invention is not limited to the following embodiments.
Fig. 1 is a flowchart of a method for evaluating insulation degradation of a station ac power supply system according to an embodiment of the present invention.
As shown in fig. 1, a flowchart of an implementation of the insulation degradation evaluation method of a station ac power supply system according to an embodiment of the present invention is shown, and is described in detail as follows:
in step 101, a sudden change waveform of the residual current of the ac power supply system is acquired.
In some embodiments, the abrupt waveform is captured by a mixed waveform generated by mixing with an intermediate frequency waveform, and the step 101 includes:
obtaining a mixed waveform, wherein the waveform length of the mixed waveform is an integer multiple of the period length of an intermediate frequency waveform;
waveform extraction is carried out on the mixed waveform according to a first formula, and a waveform coefficient corresponding to an intermediate frequency waveform is obtained, wherein the first formula is as follows:
Wherein a is a first waveform coefficient, b is a second waveform coefficient, mwave (t) is a mixed waveform, ω0 is the angular frequency of an intermediate frequency waveform, n is the multiple of the length of the mixed waveform relative to the length of the intermediate frequency period, sin () is a sine function, cos () is a cosine function;
determining a sudden change waveform for obtaining the residual current of the alternating current power supply system according to a second formula, a mixing waveform and the waveform coefficient, wherein the second formula is as follows:
wherein PDwave (T) is a sudden change waveform, T is the period of the intermediate frequency waveform
Illustratively, as shown in fig. 2, the system includes an intermediate frequency module 203, a sudden-change current collection module 202, a frequency mixing module 204 and a signal processing module 205, the intermediate frequency module 203 generates an intermediate frequency waveform based on a voltage waveform signal of the power system through frequency multiplication, the sudden-change current collection module 202 obtains a current waveform of the sudden-change waveform through three phase lines and a neutral line 201, the current waveform is converted into a voltage waveform by sampling resistors in the frequency mixing module 204, and a mixing waveform is generated by mixing with the intermediate frequency waveform.
The mixed waveform comprises an intermediate frequency waveform and a possibly generated abrupt waveform, if the abrupt waveform does not occur, the mixed waveform is integrated in a voltage waveform, and the obtained integrated value is lower than a threshold value; when the mixing waveform is integrated in a voltage waveform, a value larger than a threshold value is obtained, and at this time, the time when the abrupt waveform is generated and the phase of the abrupt waveform corresponding to the voltage waveform can be determined by gradually reducing the length of the mixing waveform involved in the integration.
When the specific moment of the abrupt change waveform is determined, the abrupt change waveform can be extracted according to the mixed waveform of the corresponding abrupt change waveform, specifically, the coefficient of the intermediate frequency waveform is firstly extracted through a first formula, and the first formula is as follows:
where a is a first waveform coefficient, b is a second waveform coefficient, mwave (t) is a mixed waveform, ω0 is an angular frequency of an intermediate frequency waveform, n is a multiple of a length of the mixed waveform relative to a length of an intermediate frequency period, sin () is a sine function, and cos () is a cosine function.
The abrupt waveform can be determined according to the obtained first waveform coefficient, second waveform coefficient and second formula, wherein the second formula is:
in the formula, PDwave (T) is a sudden change waveform, and T is the period of an intermediate frequency waveform.
In step 102, the abrupt waveform is subjected to signal processing, and a plurality of signal characteristic values characterizing the amplitude-frequency characteristic of the abrupt waveform are determined.
In some embodiments, the step 102 includes:
sampling the abrupt waveform according to a preset sampling interval to obtain an abrupt waveform array;
determining a plurality of signal characteristic values of the amplitude-frequency characteristic of the abrupt waveform according to a third formula and the abrupt waveform data, wherein the third formula is as follows:
Where AFC (m) is an mth signal eigenvalue, v0 is a fundamental frequency, N is a total number of data in the abrupt waveform sequence, PDwave (N) is an nth data in the abrupt waveform sequence, j is an imaginary unit, pi is a circumferential rate, and pi is a natural constant.
For example, since the waveform analysis is directly performed by the waveform, the data involved in the calculation and analysis is large and the calculation amount is large, the embodiment of the present invention extracts a plurality of frequency amplitudes of the abrupt waveform as the characteristics of the waveform thereof by means of transformation.
Firstly, sampling the abrupt waveform to perform serialization, then, transforming the sequence according to a third formula, and extracting a plurality of characteristic values, wherein the third formula is as follows:
wherein AFC (m) is the m-th signal eigenvalue, v0 is the fundamental frequency, N is the total number of data in the abrupt waveform sequence, PDwave (N) is the N-th data in the abrupt waveform sequence, j is the imaginary unit, pi is the circumference ratio, and pi is a natural constant.
After the mutation waveform is characterized, the finally obtained data volume is small, so that the proportion of abnormal mutation waveforms contained in the mutation waveform can be conveniently analyzed.
In step 103, a plurality of outlier features characterizing an anomaly in the abrupt waveform is determined from the plurality of signal features.
In some embodiments, the step 103 includes:
acquiring a plurality of sample signal feature sets, wherein the sample signal feature sets comprise a plurality of signal feature values of residual current abrupt changes and/or interference samples;
constructing a signal characteristic row matrix according to the plurality of signal characteristic values;
constructing a sample matrix according to the plurality of sample signal feature sets, wherein the sample matrix comprises a plurality of sample rows, and the sample rows are constructed by a plurality of signal feature values of the sample signal feature sets;
constructing an abnormal characteristic row matrix;
constructing a fourth formula about the abnormal feature line matrix according to the abnormal feature line matrix, the signal feature line matrix and the sample matrix, wherein the fourth formula is as follows:
wherein, AFC is signal characteristic line matrix, WEF is abnormal characteristic line matrix, SPL is sample matrix, WEFM is M element of abnormal characteristic line matrix, M is total number of sample signal characteristic sets, SPLMS is M element of S column of sample matrix, S is total number of elements of signal characteristic line matrix;
according to the fourth formula, solving the abnormal feature matrix, and determining values of a plurality of elements in the abnormal feature matrix;
And taking a plurality of elements of the abnormal characteristic matrix as a plurality of abnormal characteristic values.
Illustratively, different forms of the abrupt waveform indicate different defect forms. However, one abrupt waveform may include a plurality of different abrupt waveforms, or, since the abrupt waveforms are intermittent, several dense, continuous abrupt waveforms often occur when the abrupt waveforms are generated, and thus, it is necessary to extract characteristics of the different forms of abrupt waveforms from one abrupt waveform or several dense, continuous abrupt waveforms to indicate defects of the ac power supply system for a station and the extent to which the defects are present.
For example, when an electric shock occurs in an ac power supply system, a sudden change waveform of the residual current caused by the electric shock generally resembles a step change, and the residual current is maintained for a certain period of time after rising. When some large negative load is put into or cut out, the generated arc discharge phenomenon can generate peak current abrupt change waveform; for capacitive load and inductive load, different residual current abrupt waveforms can be displayed at the starting time and the stopping time, and the abrupt waveforms show different amplitude-frequency characteristics after transformation.
The method can be used for manufacturing different defect samples, capturing current abrupt change waveforms under different defect forms in an experimental mode, recognizing that a plurality of amplitude-frequency characteristics of each defect sample are extracted through an amplitude-frequency conversion method of the abrupt change waveforms to form a sample signal characteristic set, and in addition, signals (mistakenly regarded as signals of the abrupt change waveforms) which are easily interfered by the abrupt change current acquisition module can be converted, and the plurality of amplitude-frequency characteristics are extracted to manufacture the interference sample signal characteristic set.
By comparing the plurality of signal characteristic values obtained in the previous step with a plurality of sample signal characteristic sets, the abnormal characteristics existing in the mutation can be resolved, and the embodiment of the invention adopts a fourth formula for resolving, wherein the fourth formula is as follows:
in the formula, AFC is a signal characteristic line matrix, WEF is an abnormal characteristic line matrix, SPL is a sample matrix, WEF M M is the M-th element of the abnormal feature row matrix, M is the total number of sample signal feature sets, SPL MS S is the total number of elements in the signal characteristic row matrix;
and solving the abnormal characteristic row matrix in the process of the formula, wherein the content of a plurality of elements in the solved row matrix, namely a plurality of sample signals, is solved.
Therefore, the content of the abnormal abrupt waveform in the abrupt waveform can be extracted by this step, and the degree of insulation degradation of the ac power supply system for the station can be easily determined by the content.
In step 104, a plurality of influencing factor data and the plurality of abnormal characteristic values are input into an evaluation model, and an evaluation result of insulation degradation is obtained, wherein the influencing factor characterizes factors influencing the abnormal characteristic values, the evaluation model is constructed based on a plurality of sample data sets, and the sample data sets comprise insulation degradation degree data of a station alternating current power supply system and a plurality of factor data influencing the insulation degradation degree of the station alternating current power supply system.
In some embodiments, the evaluation model is constructed based on a plurality of sample data sets, comprising:
obtaining an initial model, wherein the initial model comprises a plurality of inputs which are the same as the plurality of influencing factors and the plurality of abnormal characteristic values, the initial model indicates an evaluation result of insulation degradation degree according to the plurality of inputs and outputs, and the initial model is as follows:
wherein Mfa () is the a-th transfer function of the 1 st column, AFunc is an intermediate function, wa1 () is the M-th receiving coefficient of the a-th transfer function of the 1 st column, M is the total number of INPUTs, INPUT (M) is the M-th INPUT, OUTPUT () is the OUTPUT function, woutput (B) is the xB-th receiving coefficient of the OUTPUT function, xB is the total number of transfer functions of the last column, B is the total number of transfer function columns, mfxBB () is the xB-th transfer function of the last column, and e is a natural constant;
Acquiring a plurality of sample data sets, wherein the sample data sets comprise data of insulation degradation degree of a station alternating current power supply system and a plurality of factor data influencing the insulation degradation degree of the station alternating current power supply system, and the factor data comprise abnormal characteristics;
solving a plurality of receiving coefficients of the initial model according to the plurality of sample data sets, and verifying the accuracy of an output result of the initial model;
and if the accuracy of the output result of the initial model reaches a preset target, taking the initial model as the evaluation model.
In some embodiments, the solving the plurality of receiving coefficients of the initial model according to the plurality of sample data sets and verifying the accuracy of the output result of the initial model includes:
dividing the plurality of sample data sets into a solution group and a verification group, wherein the solution group and the verification group respectively comprise the plurality of sample data sets;
model adjustment: adjusting the total number of receiving coefficients in the initial model so that the total number of receiving coefficients in the initial model is the same as the total number of sample data sets in the solution set
Inputting a plurality of sample data sets in the solution set to the initial model respectively, and obtaining a plurality of equations about a plurality of receiving coefficients;
Solving the plurality of equations to determine values of the plurality of receiving coefficients;
substituting values of the plurality of receiving coefficients into the initial model;
inputting a plurality of factor data of each sample data set of the verification group into the initial model, and obtaining a plurality of results of the initial model corresponding to the plurality of sample data sets in the verification group;
determining the accuracy of the output result of the initial model according to the plurality of results and the insulation degradation degree data of the station alternating current power supply system of the plurality of sample data sets in the verification group;
and if the accuracy is lower than a threshold value, adjusting the total number of transfer function sequences, and returning to the model adjustment step.
Illustratively, the abnormal characteristic value obtained in step 103 and a plurality of influence factor data are input into an evaluation model, and an evaluation result of insulation degradation of the ac power supply system for a station can be obtained.
The influencing factors are factors that indicate influence on the abrupt waveform, such as temperature, humidity, etc., among environmental factors. The evaluation model is constructed based on the abnormal characteristic value of the insulation degradation sample of the ac power supply system for the station and the environmental factor data.
Specifically, an initial model is firstly established, wherein the initial model has abnormal characteristic value input, environment factor data input and evaluation result output, and the initial model is as follows:
where Mfa () is the a-th transfer function of the 1 st column, AFunc is an intermediate function, wa1 () is the M-th receiving coefficient of the a-th transfer function of the 1 st column, M is the total number of INPUTs, INPUT (M) is the M-th INPUT, OUTPUT () is the OUTPUT function, woutput (B) is the xB-th receiving coefficient of the OUTPUT function, xB is the total number of transfer functions of the last column, B is the total number of transfer function columns, mfxBB () is the xB-th transfer function of the last column, and e is a natural constant.
The reception coefficient in the model can be determined based on a plurality of samples of the current insulation degradation, thereby determining the initial model.
One way of determining is to divide the insulating degradation samples of the ac power supply system for a plurality of stations into two groups, which are respectively a solving group for solving the transfer function of the initial model and a verification group for verifying the accuracy of the initial model.
And inputting a plurality of data sets in the solving group into the model to obtain a plurality of equations taking the receiving coefficients as the quantity to be solved, wherein the total number of the receiving coefficients in the model is the same as the total number of the data sets in the solving group, so that a unique solution of each receiving coefficient can be solved.
The solutions are further substituted back into the initial model to obtain a model constructed by solving the set.
At this time, the abnormal characteristic value and the environmental factor data in the data set in the verification group are input into the model, so that an evaluation result of the model is obtained, the insulation degradation degree of the alternating current power supply system for the sample station in the verification group of the evaluation result is compared, if the deviation is large, the fact that the initial model is over-fitted is indicated, the number of columns in the model is adjusted (generally, the number of columns is reduced), and a plurality of receiving coefficients of the model are solved through the solving group again, otherwise, the model is fixed and used as the evaluation model.
The invention station is with the insulating degradation evaluation method implementation mode of the alternating-current power supply system, it obtains the sudden change waveform of the residual current of the alternating-current power supply system at first; then, carrying out signal processing on the abrupt waveform, and determining a plurality of signal characteristic values representing amplitude-frequency characteristics of the abrupt waveform; then, determining a plurality of abnormal characteristic values representing the abnormality in the abrupt waveform according to the plurality of signal characteristic values; and finally, inputting a plurality of influence factor data and the plurality of abnormal characteristic values into an evaluation model to obtain an evaluation result of insulation degradation, wherein the influence factor characterizes factors influencing the abnormal characteristic values, the evaluation model is constructed based on a plurality of sample data sets, and the sample data sets comprise insulation degradation degree data of a station alternating current power supply system and a plurality of factor data influencing the insulation degradation degree of the station alternating current power supply system. According to the embodiment of the invention, the possible abrupt waveform is mixed with the intermediate frequency signal in a mixing mode, so that the occurrence period of the abrupt waveform and the phase of the corresponding voltage waveform can be positioned, and the abnormal analysis is convenient. According to the embodiment of the invention, the signal characteristic value and the characteristic value of the residual current abrupt sample change and/or the interference sample are calculated, the content of the residual current abrupt sample change and/or the interference sample in the abrupt waveform is extracted as the abnormal characteristic value so as to represent the abnormal degree of different abnormalities in the abrupt waveform, the abnormal characteristic and the environmental factor when the residual current abrupt sample are input into an evaluation model constructed by insulating degradation samples of the alternating current power supply system for the station, and the degradation evaluation result is obtained.
It should be understood that the sequence number of each step in the foregoing embodiment does not mean that the execution sequence of each process should be determined by the function and the internal logic, and should not limit the implementation process of the embodiment of the present invention.
The following are device embodiments of the invention, for details not described in detail therein, reference may be made to the corresponding method embodiments described above.
Fig. 3 is a functional block diagram of an ac power supply system insulation degradation evaluation device for a station according to an embodiment of the present invention, and referring to fig. 3, the ac power supply system insulation degradation evaluation device 3 for a station includes: a sudden-change waveform acquisition module 301, a frequency-amplitude feature extraction module 302, an abnormal feature extraction module 303, and an insulation degradation evaluation module 304, wherein:
the abrupt waveform acquisition module 301 is configured to acquire an abrupt waveform of a residual current of the ac power supply system;
the amplitude-frequency characteristic extraction module 302 is configured to perform signal processing on the abrupt waveform, and determine a plurality of signal characteristic values that characterize amplitude-frequency characteristics of the abrupt waveform;
an abnormal feature extraction module 303, configured to determine a plurality of abnormal feature values that characterize an abnormality in the abrupt waveform according to the plurality of signal feature values;
And an insulation degradation evaluation module 304, configured to input a plurality of influencing factor data and the plurality of abnormal characteristic values into an evaluation model, and obtain an evaluation result of insulation degradation, where the influencing factor characterizes a factor influencing the abnormal characteristic value, and the evaluation model is constructed based on a plurality of sample data sets, and the sample data sets include insulation degradation degree data of the ac power supply system for the station and a plurality of factor data influencing the insulation degradation degree of the ac power supply system for the station.
Fig. 4 is a functional block diagram of an electronic device provided by an embodiment of the present invention. As shown in fig. 4, the electronic apparatus 4 of this embodiment includes: a processor 400 and a memory 401, said memory 401 having stored therein a computer program 402 executable on said processor 400. The processor 400 executes the computer program 402 to implement the steps in the above-described method and embodiment for evaluating insulation degradation of the ac power supply system for each station, for example, steps 101 to 104 shown in fig. 1.
By way of example, the computer program 402 may be partitioned into one or more modules/units that are stored in the memory 401 and executed by the processor 400 to accomplish the present invention.
The electronic device 4 may be a computing device such as a desktop computer, a notebook computer, a palm computer, a cloud server, etc. The electronic device 4 may include, but is not limited to, a processor 400, a memory 401. It will be appreciated by those skilled in the art that fig. 4 is merely an example of the electronic device 4 and is not meant to be limiting of the electronic device 4, and may include more or fewer components than shown, or may combine certain components, or different components, e.g., the electronic device 4 may further include input-output devices, network access devices, buses, etc.
The processor 400 may be a central processing unit (Central Processing Unit, CPU), but may also be other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), field programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory 401 may be an internal storage unit of the electronic device 4, such as a hard disk or a memory of the electronic device 4. The memory 401 may also be an external storage device of the electronic device 4, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card) or the like, which are provided on the electronic device 4. Further, the memory 401 may also include both an internal storage unit and an external storage device of the electronic device 4. The memory 401 is used for storing the computer program 402 and other programs and data required by the electronic device 4. The memory 401 may also be used to temporarily store data that has been output or is to be output.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional units and modules is illustrated, and in practical application, the above-described functional distribution may be performed by different functional units and modules according to needs, i.e. the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-described functions. The functional units and modules in the embodiment may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit, where the integrated units may be implemented in a form of hardware or a form of a software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working process of the units and modules in the above system may refer to the corresponding process in the foregoing method embodiment, and will not be described herein again.
In the foregoing embodiments, the descriptions of the embodiments are focused on, and the details or descriptions of other embodiments may be referred to for those parts of an embodiment that are not described in detail or are described in detail.
Those of ordinary skill in the art will appreciate that the elements and algorithm steps described in connection with the embodiments disclosed herein can be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
In the embodiments provided in the present invention, it should be understood that the disclosed apparatus/electronic device and method may be implemented in other manners. For example, the apparatus/electronic device embodiments described above are merely illustrative, e.g., the division of the modules or units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection via interfaces, devices or units, which may be in electrical, mechanical or other forms.
The units described as separate units may or may not be physically separate, and units shown 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 units may be selected according to actual needs to achieve the purpose of the embodiment.
In addition, each functional unit in each embodiment of the present invention may be integrated in one processing unit, each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.
The integrated modules/units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on this understanding, the present invention may also be implemented by implementing all or part of the procedures in the methods of the above embodiments, or by instructing the relevant hardware by a computer program, where the computer program may be stored in a computer readable storage medium, and the computer program may be implemented by implementing the steps of the embodiments of the methods and apparatuses described above when executed by a processor. Wherein the computer program comprises computer program code which may be in source code form, object code form, executable file or some intermediate form etc. The computer readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer Memory, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), an electrical carrier signal, a telecommunications signal, a software distribution medium, and so forth.
The above embodiments are only for illustrating the technical solution of the present invention, and are not limited thereto; although the 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 scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention, and they should be included in the protection scope of the present invention.
Claims (10)
1. A method for evaluating insulation degradation of an ac power supply system for a station, comprising:
obtaining a sudden change waveform of the residual current of an alternating current power supply system;
performing signal processing on the abrupt waveform, and determining a plurality of signal characteristic values representing amplitude-frequency characteristics of the abrupt waveform;
determining a plurality of outlier features characterizing an anomaly in the abrupt waveform according to the plurality of signal feature values;
and inputting the plurality of influence factor data and the plurality of abnormal characteristic values into an evaluation model to obtain an evaluation result of insulation degradation, wherein the influence factor characterizes factors influencing the abnormal characteristic values, the evaluation model is constructed based on a plurality of sample data sets, and the sample data sets comprise insulation degradation degree data of a station alternating current power supply system and a plurality of factor data influencing the insulation degradation degree of the station alternating current power supply system.
2. The method for evaluating insulation degradation of an ac power supply system for a station according to claim 1, wherein the abrupt waveform is captured by a mixed waveform generated by mixing with an intermediate frequency waveform, and the acquiring of the abrupt waveform of the residual current of the ac power supply system comprises:
obtaining a mixed waveform, wherein the waveform length of the mixed waveform is an integer multiple of the period length of an intermediate frequency waveform;
waveform extraction is carried out on the mixed waveform according to a first formula, and a waveform coefficient corresponding to an intermediate frequency waveform is obtained, wherein the first formula is as follows:
wherein a is a first waveform coefficient, b is a second waveform coefficient, mwave (t) is a mixed waveform, ω 0 For the angular frequency of the intermediate frequency waveform, n is the multiple of the length of the mixed waveform relative to the length of the intermediate frequency period, sin () is a sine function, cos () is a cosine function;
determining a sudden change waveform for obtaining the residual current of the alternating current power supply system according to a second formula, a mixing waveform and the waveform coefficient, wherein the second formula is as follows:
in the formula, PDwave (T) is a sudden change waveform, and T is the period of an intermediate frequency waveform.
3. The method for evaluating insulation degradation of a station ac power system according to claim 1, wherein said performing signal processing on said abrupt waveform to determine a plurality of signal characteristic values characterizing amplitude-frequency characteristics of said abrupt waveform, comprises:
Sampling the abrupt waveform according to a preset sampling interval to obtain an abrupt waveform array;
determining a plurality of signal characteristic values of the amplitude-frequency characteristic of the abrupt waveform according to a third formula and the abrupt waveform data, wherein the third formula is as follows:
wherein AFC (m) is the mth signal characteristic value, v 0 For the fundamental frequency, N is the total number of data in the abrupt waveform array, PDwave (N) is the nth data of the abrupt waveform array, j is the imaginary unit, and pi is the circumference ratioIs a natural constant.
4. The method of evaluating insulation deterioration of a station ac power supply system according to claim 3, wherein determining a plurality of abnormality characteristic values that characterize an abnormality in the abrupt waveform from the plurality of signal characteristic values comprises:
acquiring a plurality of sample signal feature sets, wherein the sample signal feature sets comprise a plurality of signal feature values of residual current abrupt changes and/or interference samples;
constructing a signal characteristic row matrix according to the plurality of signal characteristic values;
constructing a sample matrix according to the plurality of sample signal feature sets, wherein the sample matrix comprises a plurality of sample rows, and the sample rows are constructed by a plurality of signal feature values of the sample signal feature sets;
Constructing an abnormal characteristic row matrix;
constructing a fourth formula about the abnormal feature line matrix according to the abnormal feature line matrix, the signal feature line matrix and the sample matrix, wherein the fourth formula is as follows:
in the formula, AFC is a signal characteristic line matrix, WEF is an abnormal characteristic line matrix, SPL is a sample matrix, WEF M M is the M-th element of the abnormal feature row matrix, M is the total number of sample signal feature sets, SPL MS S is the total number of elements in the signal characteristic row matrix;
according to the fourth formula, solving the abnormal feature matrix, and determining values of a plurality of elements in the abnormal feature matrix;
and taking a plurality of elements of the abnormal characteristic matrix as a plurality of abnormal characteristic values.
5. The method for evaluating insulation degradation of an ac power supply system for a station according to any one of claims 1 to 4, wherein the evaluation model is constructed based on a plurality of sample data sets, comprising:
obtaining an initial model, wherein the initial model comprises a plurality of inputs which are the same as the plurality of influencing factors and the plurality of abnormal characteristic values, the initial model indicates an evaluation result of insulation degradation degree according to the plurality of inputs and outputs, and the initial model is as follows:
Wherein Mf a1 () A transfer function of column 1, AFunc is an intermediate function, w a1 (M) the mth reception coefficient of the a-th transfer function of column 1, M is the total number of the plurality of INPUTs, INPUT (M) the mth INPUT, OUTPUT () the OUTPUT function, w output (x B ) The x-th of the output function B Receiving coefficient X B For the total number of transfer functions of the last column, B is the total number of transfer function columns, mf xB B () is the xB transfer function of the last column, e is a natural constant;
acquiring a plurality of sample data sets, wherein the sample data sets comprise data of insulation degradation degree of a station alternating current power supply system and a plurality of factor data influencing the insulation degradation degree of the station alternating current power supply system, and the factor data comprise abnormal characteristics;
solving a plurality of receiving coefficients of the initial model according to the plurality of sample data sets, and verifying the accuracy of an output result of the initial model;
and if the accuracy of the output result of the initial model reaches a preset target, taking the initial model as the evaluation model.
6. The method for evaluating insulation degradation of a station ac power system according to claim 5, wherein said solving a plurality of reception coefficients of said initial model from said plurality of sample data sets and verifying accuracy of an output result of said initial model comprises:
Dividing the plurality of sample data sets into a solution group and a verification group, wherein the solution group and the verification group respectively comprise the plurality of sample data sets;
model adjustment: adjusting the total number of receiving coefficients in the initial model so that the total number of receiving coefficients in the initial model is the same as the total number of sample data sets in the solution set
Inputting a plurality of sample data sets in the solution set to the initial model respectively, and obtaining a plurality of equations about a plurality of receiving coefficients;
solving the plurality of equations to determine values of the plurality of receiving coefficients;
substituting values of the plurality of receiving coefficients into the initial model;
inputting a plurality of factor data of each sample data set of the verification group into the initial model, and obtaining a plurality of results of the initial model corresponding to the plurality of sample data sets in the verification group;
determining the accuracy of the output result of the initial model according to the plurality of results and the insulation degradation degree data of the station alternating current power supply system of the plurality of sample data sets in the verification group;
and if the accuracy is lower than a threshold value, adjusting the total number of transfer function sequences, and returning to the model adjustment step.
7. An insulation degradation evaluation system for a station ac power supply system, comprising:
the device comprises a mutation current acquisition module, an intermediate frequency module, a frequency mixing module and a signal processing module;
the intermediate frequency module generates an intermediate frequency waveform based on waveform frequency multiplication of the power frequency voltage, and the abrupt current acquisition module is used for acquiring the residual current waveform of the alternating current feeder line;
the frequency mixing module is used for converting the current waveform into a voltage waveform and mixing the voltage waveform with the intermediate frequency waveform to generate a mixed waveform;
the signal processing module is used for determining a period of generating a sudden change waveform according to the mixed waveform, obtaining the sudden change waveform by extracting the mixed waveform, and determining the insulation degradation degree of the alternating current power supply system for the station according to the sudden change waveform and a plurality of influence factor data.
8. An ac power system insulation degradation evaluation device for a station, for realizing the ac power system insulation degradation evaluation method for a station according to any one of claims 1 to 6, comprising:
the abrupt waveform acquisition module is used for acquiring an abrupt waveform of the residual current of the alternating current power supply system;
The amplitude-frequency characteristic extraction module is used for carrying out signal processing on the abrupt waveform and determining a plurality of signal characteristic values representing amplitude-frequency characteristics of the abrupt waveform;
the abnormal characteristic extraction module is used for determining a plurality of abnormal characteristic values representing the abnormality in the abrupt waveform according to the plurality of signal characteristic values;
the method comprises the steps of,
the insulation degradation evaluation module is used for inputting a plurality of influence factor data and the plurality of abnormal characteristic values into the evaluation model to obtain an evaluation result of insulation degradation, wherein the influence factor characterizes factors influencing the abnormal characteristic values, the evaluation model is constructed based on a plurality of sample data sets, and the sample data sets comprise insulation degradation degree data of the alternating current power supply system for the station and a plurality of factor data influencing the insulation degradation degree of the alternating current power supply system for the station.
9. An electronic device comprising a memory and a processor, the memory having stored therein a computer program executable on the processor, characterized in that the processor, when executing the computer program, implements the steps of the method according to any of the preceding claims 1 to 6.
10. A computer readable storage medium storing a computer program, characterized in that the computer program when executed by a processor implements the steps of the method according to any of the preceding claims 1 to 6.
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| CN108255132A (en) * | 2016-12-28 | 2018-07-06 | 浙江科技学院 | A kind of method for waveform identification based on wire cutting power curve mutation waveform database |
| CN113075577A (en) * | 2021-02-18 | 2021-07-06 | 国家电网有限公司 | Residual current monitoring system and method for low-voltage alternating-current power supply system |
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