CN117214606A - Method for determining lightning stroke position through multi-source data fusion of lightning stroke disturbance identification - Google Patents

Abstract

The invention relates to a method for determining a lightning stroke position by multi-source data fusion of lightning stroke disturbance identification, and belongs to the technical field of relay protection of power systems. According to the lightning stroke position determining method, data cleaning is carried out on actually measured recording data, lightning stroke disturbance data are screened out by utilizing traveling wave mutation characteristics, and data matching is carried out on the lightning stroke disturbance data and the traveling wave distance measuring device by combining ground flash coordinates and time captured by a lightning point positioning system, so that the lightning stroke position is determined.

Description

A method for determining lightning strike location using multi-source data fusion for lightning strike disturbance identification

Technical field

The invention relates to a method for fusion of multi-source data to determine lightning strike location for lightning strike disturbance identification, and belongs to the technical field of power system relay protection.

Background technique

Because the lightning strike disturbance does not form a fault point on the line, the transient traveling wave refraction wave head cannot be obtained. At the same time, because its amplitude is small and cannot reach the setting threshold of the protection device, the protection action cannot be triggered and fault location information cannot be obtained. The lightning current caused by lightning strike disturbance only forms a flow path on the transmission line and will not cause flashover on the tower insulator, making it more difficult for line inspectors to obtain accurate lightning strike locations on specific towers. Except for the recording time of transient traveling wave faults, the lightning strike disturbance information obtained by the terminal device is very scarce.

Contents of the invention

The technical problem to be solved by this invention is to provide a method for fusion of multi-source data for lightning disturbance identification to determine the location of a lightning strike. By performing data cleaning on the measured wave recording data, the lightning strike disturbance waveform is screened out using the mutation characteristics of traveling waves, and at the same time, lightning points are used. The ground flash coordinates and time captured by the positioning system are matched with the traveling wave ranging information to determine the location of the lightning strike.

The technical solution of the present invention is: a method for determining lightning strike location by fusion of multi-source data for lightning disturbance identification. The specific steps are:

Step1: Perform data cleaning on the wave recording data.

Step 2: Extract features from the measured current wave data, and set thresholds based on the feature values to screen lightning disturbance waveforms.

Step3: Match the lightning strike disturbance information of the traveling wave ranging device with the relevant information of the lightning positioning system after screening to determine the location of the lightning strike.

The specific step 1 is:

Step1.1: Use the sampling values in the channel to concentrate on certain specific values to determine the damaged data, and set appropriate thresholds to eliminate damaged channels with a large number of bad pixels.

Step1.2: Sort the given data set and find the median in the data set.

Step1.3: For each data point, calculate the absolute value of the difference between it and the median.

Step1.4: For the difference between all data points and the median, calculate the median. This value is the absolute deviation of the median.

Step1.5: Divide the discrete value of each data point by the median absolute dispersion to obtain a proportional value.

Step1.6: Use thresholds to determine which data points are considered outliers.

Step1.7: For data points determined to be outliers, linear interpolation is used to obtain the corresponding data in the segment data to replace the outliers of the original data.

Step1.8: After processing all the bad pixels, obtain the repaired time series data and complete the repair of the bad pixels.

The specific step 2 is:

Step2.1: Extract the waveform kurtosis, that is, take the modulus of the repaired data and extract the kurtosis features.

Step2.2: Extract the three-phase traveling wave mutation ratio, that is, based on whether the three-phase traveling wave data has the same mutation trend at a certain position, distinguish the abnormal outliers missed after the traveling wave data preprocessing from the lightning current impulse signal .

Step2.3: Extract the maximum angle ratio of the bisection data, that is, divide the data sequence into two equal parts, calculate the angle between the range of each part and the length of the time window, and use the ratio of the angle between the two sections as a lightning strike disturbance filter Eigenvalues.

Step2.4: Set the characteristic value threshold to filter out the lightning interference waveforms in the massive wave recording data, that is, select the appropriate threshold corresponding to the three characteristics to filter the lightning interference data.

The specific step 3 is:

step3.1: Calculate the mutual distance between the towers based on the longitude and latitude coordinates and height of the towers.

Step3.2: Establish a triangular plane based on the ground-to-ground flash coordinates recorded by the lightning positioning system and the longitude and latitude coordinates of the two nearest towers. According to Helen's formula, calculate the normal distance between the ground-to-ground flash coordinates and the overhead transmission line perpendicular to it, and use this The intersection point of the normal line and the overhead transmission line is used as the point where the suspected lightning strike disturbance fault occurs on the transmission line corridor, and a plane model is constructed.

step3.3: Screen the time sequence of ground flashes near the recording time of traveling wave lightning in the lightning positioning system, represented by the vector T _lighting .

step3.4: Use T _wave to represent the time series of suspected faults corresponding to flashes on the transmission line at different times.

step3.5: The deviation of the occurrence time of the same ground flash measured by the traveling wave analysis and ranging device and the lightning positioning system is expressed as:

Δt＝|T _wave -T _lighting |

Then the fault location corresponding to Δt _min is the suspected lightning strike location on the transmission line.

Step3.6: Use eigenvalue screening to obtain the wave arrival time collected at the station after the lightning strike disturbance occurs, and use the lightning strike time captured by the lightning positioning system near the wave arrival time and its determined lightning strike location to calculate the suspected lightning strike accident details.

The beneficial effects of the present invention are: it can screen out the lightning disturbance waveform through the characteristics of the lightning disturbance waveform, and combine it with the information of the lightning positioning system to obtain the location where the lightning disturbance fault occurs. It saves time for line patrol personnel to troubleshoot fault points and improves work efficiency.

Description of drawings

Figure 1 is a flow chart of a lightning strike positioning method in an embodiment of the present invention.

Figure 2 is a plane modeling diagram of the location of the ground flash and its nearest tower in the embodiment of the present invention;

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Embodiment 1: As shown in Figure 1, a multi-source data fusion method for lightning strike disturbance identification is used to determine the lightning strike location. The specific steps are:

Step1: Perform data cleaning on the wave recording data.

Step 2: Extract features from the measured current wave data, and set thresholds based on the feature values to screen lightning disturbance waveforms.

Step3: Match the lightning strike disturbance information of the traveling wave ranging device with the relevant information of the lightning positioning system after screening to determine the location of the lightning strike.

The specific step 1 is:

Step1.1: Use the sampling values in the channel to concentrate on certain specific values to determine the damaged data, and set appropriate thresholds to eliminate damaged channels with a large number of bad pixels.

Step1.2: Sort the given data set and find the median in the data set.

Step1.3: For each data point, calculate the absolute value of the difference between it and the median.

Step1.4: For the difference between all data points and the median, calculate the median. This value is the median absolute dispersion.

Step1.5: Divide the discrete value of each data point by the median absolute dispersion to obtain a proportional value.

Step1.6: Use a threshold (3 times the standard deviation) to determine which data points are considered outliers.

Step1.7: For data points determined to be outliers, linear interpolation is used to obtain the corresponding data in the segment data to replace the outliers of the original data.

Step1.8: After processing all the bad pixels, obtain the repaired time series data and complete the repair of the bad pixels.

The specific step 2 is:

Step2.1: Take the modulo of the repaired data and extract the kurtosis features, specifically:

In the formula, X(i) represents the processed data value, n is the number of sampling points, is the data mean, and σ is the data variance.

Step2.2: Based on whether the three-phase traveling wave data has the same mutation trend at a certain position, the abnormal outliers missed after preprocessing of the traveling wave data can be clearly distinguished from the lightning current impulse signal.

Taking the A-phase current as an example, assuming that the A-phase current has the largest mutation, the mutation ratio formula is as follows:

X _A (i)＝index(max(X _A )) (2)

X _p =max(G _p (X _A (i)-n:X _A (i)+n)) p = B,C (3)

In equations (2 ₎ to ( _{4 )} : , n represents the maximum value of phase A corresponding to the forward and backward movement range of the index, X _p is used to represent the maximum value of the sudden change of two adjacent phases, and K ₂ is the ratio of the maximum current amplitudes of adjacent phases within a certain time range.

Step2.3: Divide the data sequence into two equal parts, calculate the angle between the range of each part and the length of the time window, and use the ratio of the angle between the two sections as one of the lightning strike disturbance screening characteristic values:

In the above formula, L ₁ and L ₂ are the lengths of the two segments of data, and K ₃ is the arc tangent angle ratio of the two segments of data before and after.

Step2.3: Select corresponding appropriate thresholds for the three characteristics to filter lightning disturbance data. The filtering thresholds for the three characteristics are as shown in the following table:

feature K ₁ K ₂ K ₃ threshold 50 1.2 2

Table 1: Feature filtering thresholds

The specific step 3 is:

step3.1: Calculate the mutual distance between the towers based on the longitude and latitude coordinates and height of the towers. Assume that the coordinates and altitude of the overhead transmission line tower are expressed as (L _on (N), L _at (N), h (N)), N is the fault line tower serial number, L _on , L _at and h are the longitude, latitude and h respectively. altitude, then the distance between the i-th base tower and the i+1-th base tower can be expressed as:

In the above formula, i is the i-th base tower, R is the radius of the earth, and the parameters a _i,i+1 , b _i,i+1 and h _i,i+1 are respectively

a _i,i+1 =sin ² [(Lat _j+1 -Lat _j )/2] (7)

h _i,i+1 =h _i -h _i+1 (9)

The distance between the i-th base tower and the line measurement end is:

Step3.2: Establish a triangular plane based on the ground-to-ground flash coordinates recorded by the lightning positioning system and the longitude and latitude coordinates of the two nearest towers. According to Helen's formula, calculate the normal distance between the ground-to-ground flash coordinates and the overhead transmission line perpendicular to it, and use this The intersection point of the normal line and the overhead transmission line is used as the suspected lightning strike disturbance fault occurrence point in the transmission line corridor, and a plane model is constructed as shown in Figure 2.

The area of a triangle is expressed as:

in, a, b and c can be calculated according to equation (6), where the ground-to-ground coordinate height is the average altitude of the two adjacent towers. The distance between the suspected lightning strike location and one end of the substation can be expressed as:

Use N to represent the serial number of the tower closest to the measuring end substation among the two towers closest to the ground-to-ground flash coordinates, N>1.

step3.3: Screen the time sequence of ground flashes near the recording time of traveling wave lightning in the lightning positioning system, represented by the vector T _lighting :

T _lighting =[t ₁ ,t ₂ ,...,t _n ] (13)

step3.4: Use T _wave to represent the time series of suspected faults corresponding to flashes on the transmission line at different times:

Among them, v represents the traveling wave speed, and the wave speed in this patent is 298m/μs.

step3.5: The occurrence time deviation of the same ground flash measured by the traveling wave analysis and ranging device and the lightning positioning system can be expressed as:

Δt＝|T _wave -T _lighting | (15)

Then the fault location corresponding to Δt _min is the suspected lightning strike location on the transmission line.

step3.6: Use eigenvalue screening to obtain the wave arrival time collected at the station after the lightning strike disturbance of a certain 220kV transmission line occurs, and use the lightning strike time captured by the lightning positioning system near the wave arrival time and its determined lightning strike location. The calculated suspected lightning fault information is shown in the table below, where n=1,2,3....

Table 2: Calculation results

Based on the above analysis and calculation, it was determined that this disturbance was caused by ground flash 1, and the fault location occurred between tower #21 and tower #22.

The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above-described embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, other modifications can be made without departing from the spirit of the present invention. Various changes.

Claims (4)

1. A method for determining the lightning stroke position by multi-source data fusion of lightning stroke disturbance identification is characterized by comprising the following steps:

step1: carrying out data cleaning on the recording data;

step2: extracting characteristics of the actually measured current traveling wave data, and setting a threshold according to the characteristic value to screen lightning disturbance waveforms;

step3: and matching the lightning disturbance information of the traveling wave ranging device after screening with the relevant information of the lightning positioning system, and determining the lightning stroke occurrence position.

2. The method for determining the lightning stroke position by multi-source data fusion for lightning stroke disturbance identification according to claim 1, wherein step1 is specifically as follows:

step1.1: judging damaged data by utilizing a large amount of sampling values in the channels to concentrate on certain specific values, and setting a proper threshold value to reject the damaged channels with a large amount of bad points;

step1.2: ordering a given dataset and then finding the median in the dataset;

step1.3: for each data point, calculating the absolute value of the difference between it and the median;

step1.4: calculating the median number of the differences between all the data points and the median, wherein the value is the median absolute deviation;

step1.5: dividing the discrete value of each data point by the median absolute deviation to obtain a proportional value;

step1.6: using a threshold to determine which data points are considered outliers;

step1.7: for the data points judged to be outliers, adopting linear interpolation to obtain corresponding data in the fragment data to replace the outliers of the original data;

step1.8: and after all the dead pixels are processed, obtaining the repaired time series data, and finishing the repair of the dead pixels.

3. The method for determining the lightning stroke position by multi-source data fusion for lightning stroke disturbance identification according to claim 1, wherein step2 is specifically:

step2.1: taking the model of the repaired data, and extracting kurtosis characteristics;

step2.2: distinguishing missing abnormal outliers from lightning current impulse signals after traveling wave data preprocessing according to whether the three-phase traveling wave data has the same abrupt change trend at a certain position;

step2.3: dividing the data sequence into two equal parts, respectively calculating the included angles between the range of each part and the length of the time window, and taking the ratio of the two included angles as a lightning disturbance screening characteristic value;

step2.4: and selecting corresponding proper thresholds for the three characteristics to screen lightning disturbance data.

4. The method for determining the lightning stroke position by multi-source data fusion for lightning stroke disturbance identification according to claim 1, wherein step3 is specifically:

step3.1: calculating the mutual distance between the towers according to the longitude and latitude coordinates and the height of the towers;

step3.2: establishing a triangular plane by using the ground flash coordinates recorded by the lightning positioning system and longitude and latitude coordinates of two towers closest to the ground flash coordinates, calculating a normal distance between the ground flash coordinates and the overhead transmission line according to a sea-state formula, and constructing a plane model by using an intersection point of the normal line and the overhead transmission line as a suspected lightning disturbance fault occurrence point on a transmission line corridor;

step3.3: screening time sequences of earth flashes near traveling wave lightning recording time in a lightning positioning system, and using a vector T _lighting A representation;

step3.4: by T _wave Indicating the corresponding suspected fault occurrence time sequences of the earth flashovers on the power transmission line at different moments;

step3.5: the time deviation of the same ground flash measured by the traveling wave analysis and ranging device and the lightning positioning system is expressed as follows:

Δt＝|T _wave -T _lighting |

deltat _min The corresponding fault position is the suspected lightning stroke position on the transmission line;

step3.6: and screening by utilizing the characteristic value, acquiring arrival time acquired at the station end after the lightning disturbance occurs, and calculating to obtain suspected lightning fault information by utilizing the lightning time captured by the lightning positioning system near the arrival time and the determined lightning position thereof.