CN109828183B - Waveform synchronous correction method and system suitable for transient recording type fault indicator - Google Patents

Abstract

The invention discloses a waveform synchronization correction method and a system suitable for a transient recording type fault indicator. The method includes acquiring a three-phase current recording waveform of an acquisition unit; sampling the last f/50*2 of the a-phase current waveform The modal analysis is carried out at the point of t1; read the trigger recording time of the a-phase current waveform, take f/50 sampling points forward, corresponding to time t1, the corresponding time of the next sampling point of t1 is t2, and so on, from tg to Then take f/50 sampling points; perform modal analysis to obtain error energy △E1, △E2...△Eg, and take the time window starting time point tfa corresponding to the minimum value; complete the b and c phase analysis in turn, and obtain three The fault starting time point of the phase, take the minimum value; shift the three-phase currents to the left respectively to obtain the three-phase synchronous recording waveform. The invention corrects the wave recording waveform of the transient wave recording type fault indicator, so as to ensure the high accuracy of the wave recording waveform used for the analysis of the main station.

Description

Waveform synchronization correction method and system suitable for transient waveform recording type fault indicator

technical field

The invention relates to a waveform synchronization correction method and system suitable for a transient recording type fault indicator, belonging to the technical field of power system distribution automation.

Background technique

At present, the power grid is actively promoting the construction of distribution automation, focusing on improving the application level of distribution automation. The transient wave recording type fault indicator is a device installed on the distribution line to monitor the field strength and current of the line, and to record the wave at the time of the fault. The transient wave recording type fault indicator can transmit the alarm signal and wave recording file to the main station, which is used for the main station fault judgment and analysis and decision-making.

The transient recording type fault indicator is composed of three acquisition units and one collection unit. The three acquisition units are respectively installed on the a, b, and c three-phase lines. The collection unit is installed on the utility pole. The connection between the collection unit and the collection unit is Through small wireless communication, the collection unit communicates with the master station through the wireless public network. One of the difficulties of the transient recording type fault indicator is that the a, b, and c three-phase recordings are out of synchronization, which leads to a large error in the synthesis of the zero-sequence components, which affects the waveform analysis results of the master station.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to overcome the defects of the prior art, and propose a waveform synchronization correction method and system suitable for the transient recording type fault indicator. Calibration to ensure high accuracy of recorded waveforms for master station analysis.

In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is as follows:

The waveform synchronization correction method applicable to the transient recording type fault indicator of the present invention comprises the following steps:

Step 1. The fault indicator collection unit acquires the a, b, and c three-phase current recording waveforms of the acquisition unit;

Step 2. Perform modal analysis on the last f/50*2 sampling points of the a-phase current waveform, where f is the sampling frequency of the acquisition unit; read the modal parameters with the largest amplitude in the modal: amplitude A0, frequency f0;

Step 3. Read the trigger recording time tg of the current waveform of phase a, take f/50 sampling points forward from tg, corresponding to time t1, the corresponding time of the next sampling point of t1 is t2, and so on, from tg to Then take f/50 sampling points, corresponding to time t(1+f/50*2);

Step 4. Perform modal analysis on a total of f/50*2 sampling points in the [t1, t(f/50*2)] time interval, and take n main modal parameters: A11, f11; A12, f12...A1n , f1n, calculate the error energy ΔE11, ΔE12...ΔE1n of the n main modes and the modes formed by A0, f0 respectively, take the minimum value of ΔE11, ΔE12...ΔE1n, and denote it as ΔE1;

Step 5. Move the time window of [t1, t(f/50*2)] backward by one sampling point, that is, for the time interval of [t2, t(f/50*2+1)], a total of f/50*2 Perform modal analysis at each sampling point, same as step 4, take the minimum error energy, denoted as ΔE2;

Step 6. Perform modal analysis on a total of f/50*2 sampling points in the [tx, t(x+f/50*2-1)] time interval. Same as step 4, take the minimum error energy, denoted as ΔEx, Until the modal analysis of f/50*2 sampling points with tg as the starting point is completed;

Step 7: Obtain the error energies ΔE1, ΔE2, ..., ΔEx, ..., ΔEg, and take the start time point tfa of the time window corresponding to the minimum value;

Step 8. Complete the b-phase and c-phase analysis in turn, and obtain the three-phase fault starting time points tfb and tfc, take the minimum value of tfa, tfb, and tfc, and record it as the three-phase synchronization time point tf when the fault occurs; The phase, b-phase, and c-phase currents are shifted to the left by tfa-tf, tfb-tf, and tfc-tf, respectively, to obtain three-phase synchronous waveforms.

When f/50 is a decimal, round up.

In step 2, the modal analysis method is as follows:

The waveform is modal decomposed, and a waveform is expressed as the sum of multiple modes, each mode is represented in the form of Asin(2*π*fx*t+a), where A is the amplitude of the mode, fx is the frequency of the mode, and a is the initial phase angle of the mode;

The following only applies to the amplitude A and frequency fx, that is, the modal can be simplified as Asin(2*π*fx*t), read the modal parameter with the largest amplitude in the modal, and record it as amplitude A0, frequency f0.

In step 3, the trigger wave recording time tg is located at half the power frequency cycle after the fault occurs.

In step 3, the time t1 is located at the power frequency cycle before tg, and the fault time is between [t1, tg].

In step 4, three main modal parameters are taken: A11, f11; A12, f12; A13, f13.

The definition of the three main modes is: the waveform W1 obtained by adding the three modal components, and the waveform W0 in the interval [t1, t(f/50*2)], the error energy △E is the smallest, and the error energy △E of the two waveforms is the smallest. is defined as the integral of the absolute value of the waveform difference over the time interval, where the error energy of W1 and W0 is expressed as:

Calculate the error energy ΔE11, ΔE12, ΔE13 of the three main modes and the modes formed by A0, f0, then ΔE11, ΔE12, ΔE13 are expressed as:

Take the minimum value of ΔE11, ΔE12, and ΔE13, and denote it as ΔE1.

In step 6, the waveform analysis window of f/50*2 sampling points is shifted backward in turn, one sampling point at a time, until the modal analysis of f/50*2 sampling points with tg as the starting point is completed.

The waveform synchronization correction system applicable to the transient recording type fault indicator of the present invention comprises a network interface, a memory and a processor; wherein,

The network interface is used for receiving and sending signals in the process of sending and receiving information with other external network elements;

the memory for storing computer program instructions executable on the processor;

The processor is configured to execute the steps of the above-mentioned waveform synchronization correction method applicable to the transient waveform recording type fault indicator when the computer program instructions are executed.

Compared with the prior art, the beneficial effect of the present invention is that the method of the present invention corrects the recorded waveform of the transient recording type fault indicator, which ensures that the recorded waveform used for the main station analysis has high accuracy, It is of great significance to the practical application of distribution automation system.

Description of drawings

FIG. 1 is a working flow chart of the waveform synchronization correction method applicable to the transient waveform recording type fault indicator of the present invention.

Detailed ways

The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

The waveform synchronization correction method applicable to the transient waveform recording type fault indicator provided by the present invention utilizes the collection unit of the transient waveform recording type fault indicator to correct the waveform recording waveform of the acquisition unit, as shown in FIG. 1 . The specific process is as follows:

Step 1. The fault indicator collection unit acquires the a, b, and c three-phase current recording waveforms of the acquisition unit;

Step 2. Perform modal analysis on the last f/50*2 sampling points of the a-phase current waveform, where f is the sampling frequency of the acquisition unit, and when f/50 is a decimal, round up, the following f/50 is the same, read Take the modal parameter with the largest amplitude in the modal, that is, the amplitude A0 and the frequency f0. The modal analysis method refers to the modal decomposition of the waveform, and a waveform is expressed as the sum of multiple modes. Each mode represents The form is Asin(2*π*fx*t+a), where A is the amplitude of the modal, fx is the frequency of the modal, and a is the initial phase angle of the modal. The following is only for the amplitude A and frequency fx To apply, the mode can be simplified as Asin(2*π*fx*t). Read the modal parameter with the largest amplitude in the modal, and record it as the amplitude A0 and the frequency f0. This modal is theoretically close to the power frequency of 50Hz. ;

Step 3. Read the trigger recording time tg of the current waveform of phase a, take f/50 sampling points forward from tg, corresponding to time t1, the corresponding time of the next sampling point of t1 is t2, and so on, from tg to Take f/50 sampling points later, corresponding to time t(1+f/50*2), the trigger recording time tg should be located at half the power frequency cycle after the fault occurs, and take f/50 sampling points forward from tg , the corresponding time is t1, so t1 is located at the power frequency cycle before tg, and the fault time should fall between [t1, tg]. The time corresponding to the next sampling point of t1 is t2, and so on, then take f/50 sampling points backward from tg, corresponding to time t(1+f/50*2);

取三个主模态参数：A11、f11； A12、f12；A13、f13，分别计算三个主模态与A0、f0所构成模态的误差能量ΔE11、ΔE12、ΔE13，则ΔE11、ΔE12、ΔE13可分别表示为：Step 4. Perform modal analysis on a total of f/50*2 sampling points in the [t1, t(f/50*2)] time interval, and take three main modal parameters: A11, f11; A12, f12; A13, f13, calculate the error energy ΔE11, ΔE12, ΔE13 of the three main modes and the modes formed by A0 and f0 respectively, take the minimum value of ΔE11, ΔE12, and ΔE13, and denote it as ΔE1. The definition of the three main modes is: The waveform W1 obtained by adding the three modal components, and the waveform W0 in the interval [t1, t(f/50*2)] have the smallest error energy △E, and the error energy △E of the two waveforms is defined as the absolute value of the waveform difference The integration over the time interval, where the error energy of W1 and W0 can be represented schematically as:

Take three main mode parameters: A11, f11; A12, f12; A13, f13, calculate the error energy ΔE11, ΔE12, ΔE13 of the three main modes and the modes formed by A0, f0, then ΔE11, ΔE12, ΔE13 can be expressed as:

Take the minimum value of ΔE11, ΔE12, and ΔE13, and denote it as ΔE1.

Step 5. Move the time window of [t1, t(f/50*2)] backward by one sampling point, that is, for the time interval of [t2, t(f/50*2+1)], a total of f/50*2 1 sampling point for modal analysis, same as above, take the minimum error energy, denoted as ΔE2;

Step 6. Carry out sequentially, move the waveform analysis window of f/50*2 sampling points backward in turn, and move one sampling point at a time, for the [tx, t(x+f/50*2-1)] time interval A total of f/50*2 sampling points for modal analysis, the same as above, take the minimum error energy and record it as ΔEx, until the modal analysis of f/50*2 sampling points with tg as the starting point is completed;

Step 7: Obtain the error energies ΔE1, ΔE2, . . . , ΔEx, .

Step 8. Complete the b-phase and c-phase analysis in turn, and obtain the three-phase fault starting time points tfb and tfc, take the minimum value of tfa, tfb, and tfc, and record it as the three-phase synchronization time point tf when the fault occurs. The phase, b-phase, and c-phase currents are shifted to the left by tfa-tf, tfb-tf, and tfc-tf, respectively, to obtain three-phase synchronous waveforms.

The waveform synchronization correction system suitable for the transient waveform recording type fault indicator of the present invention comprises a network interface, a memory and a processor; the network interface is used for receiving and sending signals in the process of sending and receiving information with other external network elements. the memory is used to store computer program instructions that can be run on the processor; the processor is used to execute the steps of the above-mentioned waveform synchronization correction method applicable to the transient waveform recording type fault indicator when the computer program instructions are executed.

The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and the descriptions in the above-mentioned embodiments and the description are only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have Various changes and modifications fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.

Claims (10)

1. The waveform synchronization correction method applicable to the transient recording waveform fault indicator is characterized in that, comprising the following steps: Step 1. Obtain the three-phase current waveform of the acquisition unit; Step 2. Perform modal analysis on the last f/50*2 sampling points of any phase current waveform; f is the sampling frequency of the acquisition unit; read the modal parameters with the largest amplitude in the modal: amplitude A0, frequency f0 ; Step 3. Read Step 2. Select the trigger recording time tg of the current waveform of one phase, take f/50 sampling points forward from tg, corresponding to time t1, the corresponding time of the next sampling point of t1 is t2, and so on, then Take f/50 sampling points backward from tg, corresponding to time t(1+f/50*2); Step 4. Perform modal analysis on a total of f/50*2 sampling points in the [t1, t(f/50*2)] time interval, and take n main modal parameters: A11, f11, A12, f12...A1n , f1n, calculate the error energy ΔE11, ΔE12...ΔE1n of the n main modes and the modes formed by A0, f0 respectively, take the minimum value of ΔE11, ΔE12...ΔE1n, and denote it as ΔE1; Step 5. Move the time window of [t1, t(f/50*2)] backward by one sampling point, that is, for the time interval of [t2, t(1+f/50*2)], a total of f/50*2 Perform modal analysis at each sampling point, same as step 4, take the minimum error energy, denoted as ΔE2; Step 6. Perform modal analysis on a total of f/50*2 sampling points in the [tx, t(x+f/50*2-1)] time interval. Same as step 4, take the minimum error energy, denoted as ΔEx, Until the modal analysis of f/50*2 sampling points with tg as the starting point is completed; Step 7: Obtain the error energies ΔE1, ΔE2, ..., ΔEx, ..., ΔEg, and take the start time point tfa of the time window corresponding to the minimum value; Step 8. Complete the other two-phase analysis in turn to obtain the three-phase fault starting time points tfb and tfc, take the minimum value among tfa, tfb, and tfc, and record it as the three-phase synchronization time point tf of the fault; Move tfa-tf, tfb-tf, and tfc-tf to the left, respectively, to obtain three-phase synchronous recording waveforms. 2 . The waveform synchronization correction method applicable to the transient waveform recording type fault indicator according to claim 1 , wherein, when f/50 is a decimal, it is rounded up. 3 . 3. The waveform synchronization correction method applicable to the transient recording type fault indicator according to claim 1, is characterized in that, in step 2, the method of described modal analysis is as follows: The waveform is modal decomposed, and a waveform is expressed as the sum of multiple modes, each mode is represented in the form of Asin(2*π*fx*t+a), where A is the amplitude of the mode, fx is the frequency of the mode, and a is the initial phase angle of the mode; The following only applies to the amplitude A and frequency fx, that is, the modal can be simplified as Asin(2*π*fx*t), read the modal parameter with the largest amplitude in the modal, and record it as amplitude A0, frequency f0. 4. The waveform synchronization correction method suitable for transient wave recording type fault indicator according to claim 1, wherein in step 3, the trigger wave recording time tg is located at the half power frequency cycle after the fault occurs . 5 . The waveform synchronization correction method suitable for a transient recording type fault indicator according to claim 1 , wherein, in step 3, the time t1 is located at a power frequency cycle before tg, and the fault time falls. 6 . between [t1, tg]. 6 . The waveform synchronization correction method suitable for transient wave recording type fault indicator according to claim 1 , wherein, in step 4, three main modal parameters are taken: A11, f11; A12, f12; A13 , f13. 7. The waveform synchronization correction method applicable to the transient recording type fault indicator according to claim 6, wherein the definition of the three main modes is: the waveform W1 obtained by adding the three modal components, and the The waveform W0 error energy △E in the interval [t1, t(f/50*2)] is the smallest, and the error energy △E of the two waveforms is defined as the integral of the absolute value of the waveform difference over the time interval, where W1 and W0 The error energy of is expressed as:

8 . The waveform synchronization correction method suitable for transient waveform recording type fault indicator according to claim 7 , wherein the error energies ΔE11 and ΔE12 of the three main modes and the modes formed by A0 and f0 are calculated respectively. 9 . , ΔE13, then ΔE11, ΔE12, ΔE13 are expressed as:

Take the minimum value of ΔE11, ΔE12, and ΔE13, and denote it as ΔE1. 9. The waveform synchronization correction method applicable to the transient recording type fault indicator according to claim 1, wherein in step 6, the waveform analysis window of f/50*2 sampling points is shifted backwards in turn , and translate one sampling point at a time until the modal analysis of f/50*2 sampling points with tg as the starting point is completed. 10. A waveform synchronization correction system suitable for a transient waveform recording type fault indicator, characterized in that the system comprises a network interface, a memory and a processor; wherein, The network interface is used for receiving and sending signals in the process of sending and receiving information with other external network elements; the memory for storing computer program instructions executable on the processor; The processor is configured to execute the steps of the waveform synchronization correction method applicable to the transient waveform recording type fault indicator according to any one of claims 1 to 9 when the computer program instructions are executed.

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