CN116577594A - Fault monitoring method and system of relay protection device - Google Patents
Fault monitoring method and system of relay protection device Download PDFInfo
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Abstract
The application discloses a fault monitoring method and a fault monitoring system of a relay protection device, wherein when a signal to be analyzed acquired by the relay protection device is received, discrete sampling point data of the signal to be analyzed is extracted according to a preset period, discrete Fourier transform is carried out, transformed output phasor data is generated, discrete sampling point number values in the transformed output phasor data and the discrete sampling point data are input into a preset intermediate parameter analysis function, intermediate data is generated, the discrete sampling point number values and the intermediate data are input into a preset attenuation direct current influence function, attenuation direct current influence data is generated, power frequency alternating current phasor is generated according to the attenuation direct current influence data, the transformed output phasor data and the discrete sampling point data, and a comparison result of the power frequency alternating current phasor and a preset current threshold value is judged whether the signal to be analyzed is a fault signal or not. The method solves the technical problems that the attenuation direct current component which cannot be filtered by the discrete Fourier algorithm exists in the existing fault current signal, and the operation reliability of the relay protection device is reduced.
Description
Technical Field
The application relates to the technical field of power systems, in particular to a fault monitoring method and system of a relay protection device.
Background
In an alternating current power system, a relay protection device is secondary side equipment which can timely send a warning to an operator on duty or directly control a breaker to trip to terminate fault development when a power element in the alternating current power system or the alternating current power system itself breaks down and endanger the safe operation of the alternating current power system, plays a vital role in the safe operation of the alternating current power system and directly influences the safety of the system and the stable operation of the system, and mainly judges whether the alternating current power system or the power element breaks down according to the extracted power frequency alternating current phasors, so that the reliable operation of the relay protection device is ensured, and the extraction of the power frequency alternating current phasors is an indispensable work.
At present, the power frequency alternating current phasors are extracted from fault signals mainly through a discrete Fourier algorithm, but when a short circuit fault occurs in an alternating current power system, attenuation direct current components which cannot be filtered by the discrete Fourier algorithm are generated in the fault current signals, so that the accuracy of the power frequency phasor extraction is greatly influenced, and the operation reliability of a relay protection device is reduced.
Disclosure of Invention
The application provides a fault monitoring method and a fault monitoring system of a relay protection device, which solve the technical problems that when a short circuit fault occurs in an alternating current power system, an attenuated direct current component which cannot be filtered by a discrete Fourier algorithm is generated in a fault current signal, the precision of power frequency phasor extraction is greatly influenced, and the operation reliability of the relay protection device is reduced.
The fault monitoring method for the relay protection device provided by the first aspect of the application is applied to the relay protection device and comprises the following steps:
when a signal to be analyzed acquired by the relay protection device is received, discrete sampling point data of the signal to be analyzed are extracted according to a preset period;
performing discrete Fourier transform on the discrete sampling point data to generate transformed output phasor data;
inputting the discrete sampling point number values in the transformation output phasor data and the discrete sampling point data into a preset intermediate parameter analysis function, and determining corresponding intermediate data;
inputting the discrete sampling point number value and the intermediate data into a preset attenuation direct current influence function, and determining corresponding attenuation direct current influence data;
determining a power frequency alternating current phasor corresponding to the signal to be analyzed according to the attenuation direct current influence data, the transformation output phasor data and the discrete sampling point data;
and judging whether the signal to be analyzed is a fault signal or not according to the comparison result of the power frequency alternating current phasor and a preset current threshold value.
Optionally, the intermediate parameter analysis function is specifically:
；
；
wherein ,outputting the real part value of the phasor value for the first transformation, +.>The real part value of the phasor value is output for the second transformation,outputting the real part value of the phasor value for the third transformation, +.>Outputting the real part value of the phasor value for the fourth transformation, +.>Outputting the real part value of the phasor value for the fifth transformation, +.>For discrete sample point number value, < >>Is the first intermediate parameter value,/->Is the second intermediate parameter value,/->Is the third intermediate parameter value,/->Is the fourth intermediate parameter value, +.>Is the fifth intermediate parameter value,/->Is the sixth intermediate parameter value.
Optionally, the attenuation direct current influence function is specifically:
；
；
wherein ,to attenuate the DC influence value, < >>Is an imaginary factor, is->For the first intermediate variable value,/>For the second intermediate variable value,/>For the third intermediate variable value,/->For the fourth intermediate variable value,/->Discrete sample points are numbered values.
Optionally, the step of determining the power frequency ac phasor corresponding to the signal to be analyzed according to the attenuation dc impact data, the transformation output phasor data and the discrete sampling point data includes
Selecting a corresponding attenuation direct current influence value from the attenuation direct current influence data according to the discrete sampling point number value in the discrete sampling point data;
adding the attenuation direct current influence values to generate a first sum value;
performing multiplication operation on the first sum value and a preset influence threshold value to generate a first multiplication value;
performing ratio processing on the first multiplication value and the discrete sampling point number value to generate a first ratio value;
and performing difference processing on a first transformation output phasor value in the transformation output phasor data and the first ratio value to generate the power frequency alternating current phasor corresponding to the signal to be analyzed.
Optionally, the step of determining whether the signal to be analyzed is a fault signal according to a comparison result of the power frequency ac phasor and a preset current threshold value includes:
judging whether the power frequency alternating current phasor is larger than a preset current threshold value;
if the power frequency alternating current phasor is larger than the current threshold value, judging that the signal to be analyzed is a fault signal;
and if the power frequency alternating current phasor is smaller than or equal to the current threshold value, judging that the signal to be analyzed is a normal signal.
The fault monitoring system of the relay protection device provided in the second aspect of the present application is applied to the relay protection device, and includes:
the discrete sampling point data module is used for extracting discrete sampling point data of the signal to be analyzed according to a preset period when the signal to be analyzed acquired by the relay protection device is received;
the transformation output phasor data module is used for carrying out discrete Fourier transformation on the discrete sampling point data to generate transformation output phasor data;
the intermediate data module is used for inputting the discrete sampling point number values in the transformation output phasor data and the discrete sampling point data into a preset intermediate parameter analysis function and determining corresponding intermediate data;
the attenuation direct current influence analysis module is used for inputting the discrete sampling point number value and the intermediate data into a preset attenuation direct current influence function and determining corresponding attenuation direct current influence data;
the extraction module is used for determining the power frequency alternating current phasor corresponding to the signal to be analyzed according to the attenuation direct current influence data, the transformation output phasor data and the discrete sampling point data;
and the judging and analyzing module is used for judging whether the signal to be analyzed is a fault signal or not according to the comparison result of the power frequency alternating-current phasor and a preset current threshold value.
Optionally, the intermediate parameter analysis function is specifically:
；
；
wherein ,outputting the real part value of the phasor value for the first transformation, +.>The real part value of the phasor value is output for the second transformation,outputting the real part value of the phasor value for the third transformation, +.>Outputting the real part value of the phasor value for the fourth transformation, +.>Outputting the real part value of the phasor value for the fifth transformation, +.>For discrete sample point number value, < >>Is the first intermediate parameter value,/->Is the second intermediate parameter value,/->Is the third intermediate parameter value,/->Is the fourth intermediate parameter value, +.>Is the fifth intermediate parameter value,/->Is the sixth intermediate parameter value.
Optionally, the attenuation direct current influence function is specifically:
；
；
wherein ,to attenuate the DC influence value, < >>Is an imaginary factor, is->For the first intermediate variable value,/>For the second intermediate variable value,/>For the third intermediate variable value,/->For the fourth intermediate variable value,/->Discrete sample points are numbered values.
Optionally, the extraction module includes:
the selecting submodule is used for selecting a corresponding attenuation direct current influence value from the attenuation direct current influence data according to the discrete sampling point number value in the discrete sampling point data;
the first sum value calculation submodule is used for carrying out addition processing on a plurality of attenuation direct current influence values to generate a first sum value;
the first multiplication value calculation sub-module is used for carrying out multiplication value calculation on the first sum value and a preset influence threshold value to generate a first multiplication value;
the first ratio calculation sub-module is used for carrying out ratio processing on the first multiplied value and the discrete sampling point number value to generate a first ratio;
and the power frequency alternating current phasor extraction sub-module is used for performing difference processing on the first conversion output phasor value in the conversion output phasor data and the first ratio value to generate the power frequency alternating current phasor corresponding to the signal to be analyzed.
Optionally, the judgment analysis module includes:
the first judging and analyzing sub-module is used for judging whether the power frequency alternating current phasor is larger than a preset current threshold value or not;
the second judging and analyzing sub-module is used for judging that the signal to be analyzed is a fault signal if the power frequency alternating current phasor is larger than the current threshold value;
and the third judging and analyzing sub-module is used for judging that the signal to be analyzed is a normal signal if the power frequency alternating current phasor is smaller than or equal to the current threshold value.
From the above technical scheme, the application has the following advantages:
when a signal to be analyzed acquired by the relay protection device is received, discrete sampling point data of the signal to be analyzed are extracted according to a preset power frequency period, discrete Fourier transform is carried out on the discrete sampling point data, 5 continuous discrete Fourier output phasors are generated, discrete sampling point quantity values in the 5 continuous discrete Fourier output phasors and the discrete sampling point data are input into a preset intermediate parameter analysis function, corresponding intermediate data are determined, the discrete sampling point quantity values and the intermediate data are input into a preset attenuation direct current influence function, corresponding attenuation direct current influence data are determined, power frequency alternating current phasors corresponding to the signal to be analyzed are determined according to the attenuation direct current influence data, transformation output phasor data and the discrete sampling point data, whether the signal to be analyzed is a fault signal is judged according to the comparison result of the power frequency alternating current phasors and a preset current threshold value, and if the signal to be analyzed is the fault signal, the relay protection device is controlled to act. The method solves the technical problems that when the existing alternating current power system has a short circuit fault, an attenuated direct current component which cannot be filtered by a discrete Fourier algorithm is generated in a fault current signal, the accuracy of power frequency phasor extraction is greatly influenced, and the operation reliability of the relay protection device is reduced.
Drawings
In order to more clearly illustrate the embodiments of the application or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the application, and that other drawings can be obtained from these drawings without inventive faculty for a person skilled in the art.
Fig. 1 is a flowchart of steps of a fault monitoring method of a relay protection device according to a first embodiment of the present application;
fig. 2 is a flowchart of a fault monitoring method of a relay protection device according to a second embodiment of the present application;
fig. 3 is a block diagram of a fault monitoring system of a relay protection device according to a third embodiment of the present application.
Detailed Description
The embodiment of the application provides a fault monitoring method and a fault monitoring system for a relay protection device, which are used for solving the technical problems that when a short circuit fault occurs in an existing alternating current power system, an attenuated direct current component which cannot be filtered by a discrete Fourier algorithm is generated in a fault current signal, the precision of power frequency phasor extraction is greatly influenced, and the operation reliability of the relay protection device is reduced.
In order to make the objects, features and advantages of the present application more comprehensible, the technical solutions in the embodiments of the present application are described in detail below with reference to the accompanying drawings, and it is apparent that the embodiments described below are only some embodiments of the present application, but not all embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
Referring to fig. 1, fig. 1 is a flowchart illustrating a fault monitoring method of a relay protection device according to an embodiment of the present application.
The application provides a fault monitoring method of a relay protection device, which is applied to the relay protection device and comprises the following steps:
and 101, when a signal to be analyzed acquired by the relay protection device is received, extracting discrete sampling point data of the signal to be analyzed according to a preset period.
The signal to be analyzed refers to the current signal to be analyzed of the secondary side of the current transformer collected by the relay protection device or the fault recorder.
Discrete sampling point data refers to a data set of sequentially extracting N sampling data from a first sampling point to an nth sampling point within a preset power frequency period.
In the embodiment of the application, after receiving the current signal to be analyzed collected by the relay protection device or the fault recorder, discrete sampling point data of the current signal to be analyzed are extracted according to a preset power frequency period.
The signal to be analyzed includes the amplitude of the dc constant component, the amplitude of each integer harmonic, the angular velocity, the time, the initial phase angle of each integer harmonic, the initial value of the initial attenuated dc component, the attenuation time constant of the initial attenuated dc component, the initial value of the second attenuated dc component, and the attenuation time constant of the second attenuated dc component.
And 102, performing discrete Fourier transform on the discrete sampling point data to generate transformed output phasor data.
Transforming the output phasor data refers to performing discrete fourier transform on the discrete sampling point data to obtain 5 continuous discrete fourier output phasors.
In the embodiment of the application, discrete sampling point data are input into a preset discrete Fourier function to carry out discrete Fourier transform, and transformed output phasor data are generated.
And 103, inputting discrete sampling point number values in the transformation output phasor data and the discrete sampling point data into a preset intermediate parameter analysis function, and determining corresponding intermediate data.
The intermediate data refers to six intermediate parameter values generated by inputting 5 continuous discrete Fourier output phasors and discrete sampling point number values into a preset intermediate parameter analysis function.
In the embodiment of the application, the discrete sampling point number values in the 5 continuous discrete Fourier output phasors and the discrete sampling point data are input into a preset intermediate parameter analysis function to determine corresponding intermediate data.
And 104, inputting the discrete sampling point number value and the intermediate data into a preset attenuation direct current influence function, and determining corresponding attenuation direct current influence data.
In the embodiment of the application, the discrete sampling point number value and the intermediate data are input into a preset attenuation direct current influence function to generate a plurality of attenuation direct current influence values.
The attenuation dc influence value indicates the influence of two attenuation dc components on the instantaneous sampling amount of each fault signal.
And 105, determining the power frequency alternating current phasors corresponding to the signals to be analyzed according to the attenuation direct current influence data, the transformation output phasor data and the discrete sampling point data.
In the embodiment of the application, according to a plurality of attenuation direct current influence values and discrete sampling point number values in discrete sampling point data, an attenuation direct current phasor corresponding to a first conversion output phasor value is determined, a first difference value between the first conversion output phasor value and the attenuation direct current phasor is calculated, and the first difference value is determined as a power frequency alternating current phasor corresponding to a signal to be analyzed.
And step 106, judging whether the signal to be analyzed is a fault signal or not according to the comparison result of the power frequency alternating-current phasor and the preset current threshold value.
In the embodiment of the application, whether the signal to be analyzed is a fault signal is judged according to the comparison result of the power frequency alternating-current phasor and the preset current threshold value, and if the signal is the fault signal, the relay protection device is controlled to act.
In the embodiment of the application, when a signal to be analyzed acquired by a relay protection device is received, discrete sampling point data of the signal to be analyzed is extracted according to a preset power frequency period, discrete Fourier transform is carried out on the discrete sampling point data, 5 continuous discrete Fourier output phasors are generated, discrete sampling point quantity values in the 5 continuous discrete Fourier output phasors and the discrete sampling point data are input into a preset intermediate parameter analysis function, corresponding intermediate data is determined, the discrete sampling point quantity values and the intermediate data are input into a preset attenuation direct current influence function, corresponding attenuation direct current influence data is determined, a power frequency alternating current phasor corresponding to the signal to be analyzed is determined according to the attenuation direct current influence data, the transformation output phasor data and the discrete sampling point data, whether the signal to be analyzed is a fault signal is judged according to the comparison result of the power frequency alternating current phasors and a preset current threshold value, and if the signal to be analyzed is the fault signal, the relay protection device is controlled to act. The method solves the technical problems that when the existing alternating current power system has a short circuit fault, an attenuated direct current component which cannot be filtered by a discrete Fourier algorithm is generated in a fault current signal, the accuracy of power frequency phasor extraction is greatly influenced, and the operation reliability of the relay protection device is reduced.
Referring to fig. 2, fig. 2 is a flowchart illustrating a fault monitoring method of a relay protection device according to a second embodiment of the present application.
The application provides a fault monitoring method of a relay protection device, which is applied to the relay protection device and comprises the following steps:
step 201, when a signal to be analyzed collected by the relay protection device is received, discrete sampling point data of the signal to be analyzed are extracted according to a preset period.
The signals to be analyzed are represented as follows:
；
wherein ,for the signal to be analyzed, +.>Is the magnitude of the DC constant component, +.>Is the magnitude of the DC constant component, +.>For angular velocity +.>For time (I)>For each integer order of harmonic initial phase angle, +.>For initial attenuation of the DC component initial value, +.>Decay time constant for initially decaying the DC component, < +.>For the second attenuated DC component initial value, +.>A decay time constant for the second decaying dc component, is->For the frequency number of the components, +.>Is the highest frequency harmonic order contained in the signal.
In the embodiment of the application, when the signal to be analyzed acquired by the relay protection device is received, the signal to be analyzed containing n+4 sampling points is sampled in sequence according to a preset power frequency period, and N discrete sampling points are extracted as discrete sampling point data.
When the following is performedWhen =1, the power frequency component is the same as +.>If the value is greater than 1, the harmonic component is an integer.
And 202, performing discrete Fourier transform on the discrete sampling point data to generate transformed output phasor data.
Discrete fourier transform（/>=0, 1,2,3, 4) is expressed as follows:
；
wherein ,output phasor values for discrete fourier transform, +.>Is->The exact power frequency phasors contained in +.>Is->In the decaying DC phasor caused by the decaying DC component,>for the sampling interval +.>，/>Is->Discrete fourier transform output phasors of time, +.>Is->The exact power frequency phasors contained in +.>Is->In the initial decaying DC phasor caused by the initial decaying DC component,/DC component>Is->A second attenuated DC phasor caused by a second attenuated DC component,/or->For the magnitude of the exact fundamental frequency phasor, +.>For the initial phase angle of accurate fundamental frequency phasors, +.>For what phasor->In imaginary units.
Transforming output phasor data, referred to as by a plurality ofThe discrete fourier transform outputs a dataset of phasor values.
In the embodiment of the application, discrete sampling points in the discrete sampling point data are sequentially extracted to perform discrete Fourier transform, and 5 continuous discrete Fourier output phasor values are generated.
And 203, inputting the discrete sampling point number values in the transformation output phasor data and the discrete sampling point data into a preset intermediate parameter analysis function, and determining corresponding intermediate data.
The intermediate parametric analysis function is expressed as follows:
；
；
wherein ,outputting the real part value of the phasor value for the first transformation, +.>The real part value of the phasor value is output for the second transformation,outputting the real part value of the phasor value for the third transformation, +.>Outputting the real part value of the phasor value for the fourth transformation, +.>Outputting the real part value of the phasor value for the fifth transformation, +.>For discrete sample point number value, < >>Is the first intermediate parameter value,/->Is the second intermediate parameter value,/->Is the third intermediate parameter value,/->Is the fourth intermediate parameter value, +.>Is the fifth intermediate parameter value,/->Is the sixth intermediate parameter value.
In the embodiment of the application, the real part value of each discrete Fourier output phasor value is extracted, the discrete sampling point number values in a plurality of real part values and discrete sampling point data are input into a preset intermediate parameter analysis function, and corresponding intermediate data are determined.
The first intermediate parameter value, the second intermediate parameter value, the third intermediate parameter value, and the fourth intermediate parameter value can directly reflect the characteristics of two different attenuated dc components.
And 204, inputting the discrete sampling point number value and the intermediate data into a preset attenuation direct current influence function, and determining corresponding attenuation direct current influence data.
The decaying dc-affecting function is expressed as follows:
；
；
wherein ,to attenuate the DC influence value, < >>Is an imaginary factor, is->For the first intermediate variable value,/>For the second intermediate variable value,/>For the third intermediate variable value,/->For the fourth intermediate variable value,/->Discrete sample points are numbered values.
The attenuation direct current influence data refers to the influence of two attenuation direct current components on each discrete sampling point, and is expressed by attenuation direct current influence values.
In the embodiment of the application, the discrete sampling point number value and the intermediate data are input into a preset attenuation direct current influence function, and a plurality of attenuation direct current influence values are calculated.
Step 205, determining the power frequency alternating current phasors corresponding to the signals to be analyzed according to the attenuation direct current influence data, the transformation output phasor data and the discrete sampling point data.
Further step 205 comprises the sub-steps of:
s11, selecting a corresponding attenuation direct current influence value from the attenuation direct current influence data according to the discrete sampling point number value in the discrete sampling point data.
In the embodiment of the application, the attenuation direct current influence value corresponding to each discrete sampling point is selected from the attenuation direct current influence data according to the discrete sampling point number value in the discrete sampling point data.
And S12, adding the attenuation direct current influence values to generate a first sum.
In an embodiment of the application, a first sum value between all decaying dc-influencing values is calculated.
S13, multiplying the first sum value by a preset influence threshold value to generate a first multiplication value.
The influence threshold means the number of the attenuated dc components, and in this embodiment, the number of the attenuated dc components is 2, so the influence threshold is 2.
In an embodiment of the application, a first multiplier between the first sum and a preset impact threshold is calculated.
S14, performing ratio processing on the first multiplication value and the discrete sampling point number value to generate a first ratio value.
In the embodiment of the application, a first ratio between the first multiplication value and the discrete acquisition point number value is calculated, and the first ratio is determined as an attenuated direct current phasor caused by an attenuated direct current component in the first conversion output phasor value.
And S15, performing difference processing on a first transformation output phasor value in the transformation output phasor data and a first ratio value to generate a power frequency alternating current phasor corresponding to the signal to be analyzed.
In the embodiment of the application, a first difference value between a first transformation output phasor value and a first ratio in transformation output phasor data is calculated, and the first difference value is determined as a power frequency alternating current phasor corresponding to a signal to be analyzed.
It should be noted that the attenuation dc influence data, the transformation output phasor data and the discrete sampling point data can also be input into a preset power frequency ac phasor function to generate a power frequency ac phasor corresponding to the signal to be analyzed.
The power frequency alternating current phasor function is expressed as follows:
；
wherein ,is a power frequency alternating current phasor>Outputting a phasor value for the first transformation, +.>Is->In the decaying DC phasor caused by the decaying DC component,>is->Taking 1 to->Is +.>And (5) adding the value.
The first transformed output phasor value refers toThe discrete fourier transform of time outputs phasors.
For easy understanding, the signal to be analyzed extracts the application example of the power frequency alternating current phasor.
S1, defining a signal model to be analyzed:
；
wherein ,，/>is the power frequency of 50Hz.
S2, according to the fundamental wave frequency, the period0.02s; sampling interval->0.0004s, the discrete number of sampling points in one period is +.>50. To->For interval from time->The acquisition of signal transients starts in a time window of length one cycle plus 4 samples, and a discrete signal containing a 50Hz fundamental wave, 2 to 10 harmonics and two attenuated dc components containing 104 transients is obtained.
S3, for the discrete signal containing 104 instantaneous values, sequentially extracting from the first sampling point to the N sampling pointDiscrete Fourier transform is carried out on the discrete sampling points to obtain discrete Fourier transform output phasors +.>（/>=0,1,2,3,4）：
，
；/>
S4, substituting 5 continuous discrete Fourier output phasors into a preset intermediate parameter analysis function, and calculating six intermediate parameter values:
；
s5, dispersing six intermediate parameter valuesSubstituting the number of sampling points into a preset attenuation direct current influence function to obtain and />And find the sum term +.>Is the value of (1):
；
s6, obtaining power frequency alternating current phasors：
；
Industrial frequency ac phasor=/>。
And 206, judging whether the power frequency alternating current phasor is larger than a preset current threshold value.
The current threshold value refers to a rated current value set by the relay protection device
In the embodiment of the application, whether the power frequency alternating current phasor is larger than the rated current value set by the relay protection device is judged.
And 207, if the power frequency alternating current phasor is larger than the current threshold value, judging that the signal to be analyzed is a fault signal.
In the embodiment of the application, if the power frequency alternating current phasor is larger than the rated current value set by the relay protection device, the signal to be analyzed is judged to be a fault signal.
If the signal to be analyzed is judged to be a fault signal, the relay protection device acts or alarms.
And step 208, if the power frequency alternating current phasor is smaller than or equal to the current threshold value, judging that the signal to be analyzed is a normal signal.
In the embodiment of the application, if the power frequency alternating current phasor is smaller than or equal to the rated current value set by the relay protection device, the signal to be analyzed is judged to be a normal signal.
In the embodiment of the application, when a signal to be analyzed acquired by a relay protection device is received, discrete sampling point data of the signal to be analyzed is extracted according to a preset power frequency period, discrete Fourier transform is carried out on the discrete sampling point data, 5 continuous discrete Fourier output phasors are generated, discrete sampling point quantity values in the 5 continuous discrete Fourier output phasors and the discrete sampling point data are input into a preset intermediate parameter analysis function, corresponding intermediate data is determined, the discrete sampling point quantity values and the intermediate data are input into a preset attenuation direct current influence function, corresponding attenuation direct current influence data is determined, a power frequency alternating current phasor corresponding to the signal to be analyzed is determined according to the attenuation direct current influence data, the transformation output phasor data and the discrete sampling point data, whether the signal to be analyzed is a fault signal is judged according to the comparison result of the power frequency alternating current phasors and a preset current threshold value, and if the signal to be analyzed is the fault signal, the relay protection device is controlled to act. The method solves the technical problems that when the existing alternating current power system has short-circuit fault, the attenuation direct current component which cannot be filtered by a discrete Fourier algorithm is generated in a fault current signal, the accuracy of power frequency phasor extraction is greatly influenced, and the operation reliability of the relay protection device is reduced.
Referring to fig. 3, fig. 3 is a block diagram of a fault monitoring system of a relay protection device according to a third embodiment of the present application.
The application provides a fault monitoring system of a relay protection device, which is applied to the relay protection device and comprises the following components:
the discrete sampling point data module 301 is configured to extract, when receiving a signal to be analyzed acquired by the relay protection device, discrete sampling point data of the signal to be analyzed according to a preset period;
the transformation output phasor data module 302 is configured to perform discrete fourier transformation on the discrete sampling point data to generate transformation output phasor data;
the intermediate data module 303 is configured to input discrete sampling point number values in the transformed output phasor data and the discrete sampling point data into a preset intermediate parameter analysis function, and determine corresponding intermediate data;
the attenuation direct current influence analysis module 304 is configured to input the discrete sampling point number value and the intermediate data into a preset attenuation direct current influence function, and determine corresponding attenuation direct current influence data;
the extracting module 305 is configured to determine a power frequency ac phasor corresponding to the signal to be analyzed according to the attenuation dc influence data, the transformation output phasor data, and the discrete sampling point data;
the judging and analyzing module 306 is configured to judge whether the signal to be analyzed is a fault signal according to a comparison result of the power frequency ac phasor and a preset current threshold.
Further, the intermediate parameter analysis function is specifically:
；
；
wherein ,outputting the real part value of the phasor value for the first transformation, +.>The real part value of the phasor value is output for the second transformation,outputting the real part value of the phasor value for the third transformation, +.>Outputting the real part value of the phasor value for the fourth transformation, +.>Outputting the real part value of the phasor value for the fifth transformation, +.>For discrete sample point number value, < >>Is the first intermediate parameter value,/->Is the second intermediate parameter value,/->Is the third intermediate parameter value,/->Is the fourth intermediate parameter value, +.>Is the fifth intermediate parameter value,/->Is the sixth intermediate parameter value.
Further, the attenuation direct current influence function is specifically:
；
；
wherein ,to attenuate the DC influence value, < >>Is an imaginary factor, is->For the first intermediate variable value,/>For the second intermediate variable value,/>For the third intermediate variable value,/->For the fourth intermediate variable value,/->Discrete sample points are numbered values.
Further, the extracting module 305 includes:
the selecting submodule is used for selecting a corresponding attenuation direct current influence value from the attenuation direct current influence data according to the discrete sampling point number value in the discrete sampling point data;
the first sum value calculation sub-module is used for adding and processing the attenuation direct current influence values to generate a first sum value;
the first multiplication value calculation sub-module is used for carrying out multiplication value calculation on the first sum value and a preset influence threshold value to generate a first multiplication value;
the first ratio calculation sub-module is used for carrying out ratio processing on the first multiplied value and the discrete sampling point number value to generate a first ratio;
and the power frequency alternating current phasor extraction sub-module is used for performing difference processing on the first conversion output phasor value in the conversion output phasor data and the first ratio value to generate a power frequency alternating current phasor corresponding to the signal to be analyzed.
Further, the judgment analysis module 306 includes:
the first judging and analyzing sub-module is used for judging whether the power frequency alternating current phasor is larger than a preset current threshold value;
the second judging and analyzing sub-module is used for judging that the signal to be analyzed is a fault signal if the power frequency alternating current phasor is larger than the current threshold value;
and the third judging and analyzing sub-module is used for judging that the signal to be analyzed is a normal signal if the power frequency alternating current phasor is smaller than or equal to the current threshold value.
It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, which are not repeated herein.
In the several embodiments provided by the present application, it should be understood that the disclosed systems and methods may be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the 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 with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.
The above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application 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 application.
Claims (10)
1. The fault monitoring method for the relay protection device is characterized by being applied to the relay protection device and comprising the following steps of:
when a signal to be analyzed acquired by the relay protection device is received, discrete sampling point data of the signal to be analyzed are extracted according to a preset period;
performing discrete Fourier transform on the discrete sampling point data to generate transformed output phasor data;
inputting the discrete sampling point number values in the transformation output phasor data and the discrete sampling point data into a preset intermediate parameter analysis function, and determining corresponding intermediate data;
inputting the discrete sampling point number value and the intermediate data into a preset attenuation direct current influence function, and determining corresponding attenuation direct current influence data;
determining a power frequency alternating current phasor corresponding to the signal to be analyzed according to the attenuation direct current influence data, the transformation output phasor data and the discrete sampling point data;
and judging whether the signal to be analyzed is a fault signal or not according to the comparison result of the power frequency alternating current phasor and a preset current threshold value.
2. The fault monitoring method of the relay protection device according to claim 1, wherein the intermediate parameter analysis function specifically comprises:
；
；
wherein ,outputting the real part value of the phasor value for the first transformation, +.>Outputting the real part value of the phasor value for the second transformation, +.>Outputting the real part value of the phasor value for the third transformation, +.>Outputting the real part value of the phasor value for the fourth transformation, +.>Outputting the real part value of the phasor value for the fifth transformation, +.>For discrete sample point number value, < >>Is the first intermediate parameter value,/->As a value of the second intermediate parameter,is the third intermediate parameter value,/->Is the fourth intermediate parameter value, +.>Is the fifth intermediate parameter value,/->Is the sixth intermediate parameter value.
3. The fault monitoring method of the relay protection device according to claim 1, wherein the attenuation direct current influence function specifically comprises:
；
；
wherein ,To attenuate the DC influence value, < >>Is an imaginary factor, is->For the first intermediate variable value,/>For the second intermediate variable value,/>For the third intermediate variable value,/->For the fourth intermediate variable value,/->Discrete sample points are numbered values.
4. The fault monitoring method of the relay protection device according to claim 1, wherein the step of determining the power frequency ac phasor corresponding to the signal to be analyzed according to the attenuation dc influence data, the transformation output phasor data and the discrete sampling point data includes
Selecting a corresponding attenuation direct current influence value from the attenuation direct current influence data according to the discrete sampling point number value in the discrete sampling point data;
adding the attenuation direct current influence values to generate a first sum value;
performing multiplication operation on the first sum value and a preset influence threshold value to generate a first multiplication value;
performing ratio processing on the first multiplication value and the discrete sampling point number value to generate a first ratio value;
and performing difference processing on a first transformation output phasor value in the transformation output phasor data and the first ratio value to generate the power frequency alternating current phasor corresponding to the signal to be analyzed.
5. The fault monitoring method of the relay protection device according to claim 1, wherein the step of determining whether the signal to be analyzed is a fault signal according to a comparison result of the power frequency ac phasor and a preset current threshold value includes:
judging whether the power frequency alternating current phasor is larger than a preset current threshold value;
if the power frequency alternating current phasor is larger than the current threshold value, judging that the signal to be analyzed is a fault signal;
and if the power frequency alternating current phasor is smaller than or equal to the current threshold value, judging that the signal to be analyzed is a normal signal.
6. The utility model provides a fault monitoring system of overload protection device, its characterized in that is applied to overload protection device, includes:
the discrete sampling point data module is used for extracting discrete sampling point data of the signal to be analyzed according to a preset period when the signal to be analyzed acquired by the relay protection device is received;
the transformation output phasor data module is used for carrying out discrete Fourier transformation on the discrete sampling point data to generate transformation output phasor data;
the intermediate data module is used for inputting the discrete sampling point number values in the transformation output phasor data and the discrete sampling point data into a preset intermediate parameter analysis function and determining corresponding intermediate data;
the attenuation direct current influence analysis module is used for inputting the discrete sampling point number value and the intermediate data into a preset attenuation direct current influence function and determining corresponding attenuation direct current influence data;
the extraction module is used for determining the power frequency alternating current phasor corresponding to the signal to be analyzed according to the attenuation direct current influence data, the transformation output phasor data and the discrete sampling point data;
and the judging and analyzing module is used for judging whether the signal to be analyzed is a fault signal or not according to the comparison result of the power frequency alternating-current phasor and a preset current threshold value.
7. The fault monitoring system of the relay protection device according to claim 6, wherein the intermediate parameter analysis function specifically comprises:
；
；
wherein ,outputting the real part value of the phasor value for the first transformation, +.>Outputting the real part value of the phasor value for the second transformation, +.>Outputting the real part value of the phasor value for the third transformation, +.>Outputting the real part value of the phasor value for the fourth transformation, +.>Outputting the real part value of the phasor value for the fifth transformation, +.>For discrete sample point number value, < >>Is the firstAn intermediate parameter value,/->As a value of the second intermediate parameter,is the third intermediate parameter value,/->Is the fourth intermediate parameter value, +.>Is the fifth intermediate parameter value,/->Is the sixth intermediate parameter value.
8. The fault monitoring system of the relay protection device according to claim 6, wherein the decaying dc-affecting function is specifically:
；
；
wherein ,to attenuate the DC influence value, < >>Is an imaginary factor, is->For the first intermediate variable value,/>For the second intermediate variable value,/>For the third intermediate variable value,/->For the fourth intermediate variable value,/->Discrete sample points are numbered values.
9. The fault monitoring system of the relay protection device of claim 6, wherein the extraction module comprises:
the selecting submodule is used for selecting a corresponding attenuation direct current influence value from the attenuation direct current influence data according to the discrete sampling point number value in the discrete sampling point data;
the first sum value calculation submodule is used for carrying out addition processing on a plurality of attenuation direct current influence values to generate a first sum value;
the first multiplication value calculation sub-module is used for carrying out multiplication value calculation on the first sum value and a preset influence threshold value to generate a first multiplication value;
the first ratio calculation sub-module is used for carrying out ratio processing on the first multiplied value and the discrete sampling point number value to generate a first ratio;
and the power frequency alternating current phasor extraction sub-module is used for performing difference processing on the first conversion output phasor value in the conversion output phasor data and the first ratio value to generate the power frequency alternating current phasor corresponding to the signal to be analyzed.
10. The fault monitoring system of the relay protection device of claim 6, wherein the decision analysis module comprises:
the first judging and analyzing sub-module is used for judging whether the power frequency alternating current phasor is larger than a preset current threshold value or not;
the second judging and analyzing sub-module is used for judging that the signal to be analyzed is a fault signal if the power frequency alternating current phasor is larger than the current threshold value;
and the third judging and analyzing sub-module is used for judging that the signal to be analyzed is a normal signal if the power frequency alternating current phasor is smaller than or equal to the current threshold value.
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