CN113408383B - Audible noise invalid data judgment method based on bounded beta (g, h) distribution and MWKPCA - Google Patents
Audible noise invalid data judgment method based on bounded beta (g, h) distribution and MWKPCA Download PDFInfo
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Abstract
The audible noise invalid data judgment method based on the bounded beta (g, h) distribution and MWKPCA judges the invalid data of the collected audible noise data day by day through the bounded beta (g, h) distribution, and eliminates the invalid data outside the bounded beta (g, h) distribution judgment standard range; for processed audible noise data, T of MWKPCA principal element subspace is used 2 Judging invalid data in the audible noise data set day by day according to the statistic and the SPE statistic of the residual error subspace; respectively calculating L95 percentile, L50 percentile and L5 percentile of a data set which is not subjected to invalid data rejection, a data set which is bounded and distributed by beta (g, h) and subjected to invalid data rejection and a data set which is subjected to MWKPCA and subjected to invalid data rejection, and determining the change condition of the percentile before and after data processing, thereby determining whether the rejection of invalid data influences the subsequent audible noise data analysis. The method is more comprehensive, and meanwhile, the data is segmented in a moving window mode to reduce the influence of the change of meteorological factors on the judgment result.
Description
Technical Field
The invention relates to the technical field of power transmission line audible noise evaluation, in particular to an audible noise invalid data judgment method based on bounded beta (g, h) distribution and MWKPCA.
Background
The audible noise of the power transmission line is one of design standards of the power transmission line, and influences the wire selection, the corridor width, the insulator string length and the wire arrangement mode of the power transmission line. However, in the process of collecting the audible noise of the power transmission line, a large amount of background noise exists, and the noise is easily interfered by the background noise, and if the audible noise of the power transmission line is smaller than the background noise, the background noise has a high probability of becoming invalid data or abnormal values in the data set, i.e. invalid data. Invalid data may affect the evaluation of the transmission line.
The research types of the audible noise of the existing power transmission line are divided into the research of an alternating current power transmission line and the research of a direct current power transmission line, wherein the audible noise of the alternating current power transmission line can be divided into pure sound with the frequency being a multiple of 50Hz and broadband noise with the frequency range being concentrated in a range of 400Hz to 10kHz, positive ions in a positive polarity interval move outwards along a radial direction under the action of an alternating electric field to apply pressure to an air layer, negative ions formed by electrons attached to molecules in a negative polarity interval move outwards along the radial direction to apply pressure to the air layer, and therefore sound waves are transmitted outwards periodically.
The existing research mode of the audible noise effective data of the power transmission line comprises the steps of converting an 8kHz component of sound into an A sound level through an empirical formula and a machine learning algorithm so as to indirectly obtain the audible noise effective data of the power transmission line; and removing background noise in the collected sound signals through wavelet decomposition and a limited-length unit impact response filter, and directly obtaining effective data of audible noise of the power transmission line.
The above methods for removing background noise all directly process collected sound signals, and in most cases, process invalid data in a data set, and do not consider that sound signals collected at a certain sampling time are a result of the combined action of noises belonging to different frequency bands, and the sound emitted by a background noise sound source is at different frequencies, so a method capable of determining invalid data and considering noise of each frequency band is urgently needed.
Disclosure of Invention
In order to solve the technical problem, the invention provides an audible noise invalid data judgment method based on bounded beta (g, h) distribution and MWKPCA, which utilizes the bounded beta (g, h) distribution to sequentially judge 10 audible noise component invalid data of 16 Hz-8 kHz of octave; meanwhile, an MWKPCA method is utilized to carry out overall invalid data judgment on audible noise of 10 frequency bands of 16Hz to 8kHz of octave. Compared with the traditional method for judging invalid data by using single-dimensional data, the judging method has more comprehensive judging standard, and meanwhile, the data is segmented in a moving window mode, so that the influence of the change of meteorological factors on the judging result is reduced.
The technical scheme adopted by the invention is as follows:
a method for determining audible noise-null data based on a bounded β (g, h) distribution and MWKPCA, comprising the steps of:
step 1: carrying out invalid data judgment on the collected audible noise data through a bounded beta (g, h) distribution, and rejecting invalid data outside a bounded beta (g, h) distribution judgment standard range;
step 2: regarding the audible noise data processed in the step 1, the T of the MWKPCA principal element subspace is used by taking the audible noise components of each frequency band as a whole 2 The SPE statistics of the statistics and the residual error subspace are used for judging invalid data in the audible noise data set;
and step 3: respectively calculating L95 percentile, L50 percentile and L5 percentile of a data set which is not subjected to invalid data rejection, a data set which is bounded and distributed by beta (g, h) and subjected to invalid data rejection and a data set which is subjected to MWKPCA and subjected to invalid data rejection, and determining the change condition of the percentile before and after data processing, thereby determining whether the rejection of invalid data influences the subsequent audible noise data analysis.
In the step 1, the collected audible noise data is decomposed into 10 audible noise components of 169z, 31.5hz,63hz,125hz,250hz,500hz,1000hz,2000hz,4000hz and 8000hz, which are used as a data set for abnormal data rejection, the audible noise data of each frequency band is distributed by using bounded beta (g, h), and invalid data of each frequency band is rejected day by day.
In the step 1, the audible noise data is audible noise data of the alternating current transmission line, and the decomposed audible noise components of 10 frequency bands of 16Hz to 8kHz are divided in an octave form.
In step 2, invalid data in the audible noise data set is determined in the form of a moving window, wherein the moving window is in the form of: when data are collected, the audible noise data quantity of the power transmission line every day is used as the moving step length of the moving window function.
In the step 3, the L95, L50 and L5 percentiles refer to numerical values arranged at the first 95%, 50% and 5% positions when data are arranged from large to small.
The invention discloses an audible noise invalid data judgment method based on bounded beta (g, h) distribution and MWKPCA, which has the following technical effects:
1) The method has good running speed and accuracy when invalid data of each frequency band are removed in sequence through bounded beta (g, h) distribution, meanwhile, the method is used for judging the invalid data without the data conforming to normal distribution, the method has wider practicability, and the bounded beta (g, h) distribution is used for removing the invalid data before MWKPCA, so that the subsequent MWKPCA can obtain more accurate training data.
2) When the MWKPCA is used for judging invalid data in the data set, the elimination of abnormal data has a good effect no matter whether the characteristics in the data set are in a linear relation or a nonlinear relation. And the audible noise of the power transmission line is long in acquisition time span and large in meteorological factor change, and the judgment standard can be gradually updated in the day-by-day abnormal data judgment process by using a mobile window form, so that the negative influence on the judgment result caused by the change of the meteorological factor is prevented.
3) The method respectively eliminates the data which are not subjected to invalid data elimination, adopts bounded beta (g, h) distribution to eliminate abnormal data, adopts MWKPCA to eliminate the data sets of three stages after the abnormal data, compares L5, L50 and L95 percentiles of the data sets, and determines that the elimination of the invalid data does not influence the subsequent data analysis. And after the invalid data are removed, the accuracy of the prediction result is found to be improved by using a LightGBM algorithm to predict the audible noise A level of the electric transmission line by using 8000Hz components of the audible noise and meteorological factors, after the invalid data are removed from the data set by using the method disclosed by the invention, the RMSE error of the prediction result is reduced to 2.68 from 3.20, and the MAE error is reduced to 1.85 from 2.17.
4) The invention is innovated in detection means, adopts a day-by-day judgment method, and reduces the problems of repeated work and non-uniform judgment standards when the judgment is carried out manually. The bounded beta (g, h) distribution is utilized to sequentially judge 10 audible noise component invalid data of 16 Hz-8 kHz of octave, and the problem that the data are required to obey normal distribution in the traditional invalid data judging method is solved. The MWKPCA is used for carrying out overall invalid data judgment on audible noise of 10 frequency bands of 16Hz to 8kHz of octave, compared with the traditional single-dimensional data, the method has the advantages that the judgment standard is more comprehensive, the influence of the change of meteorological factors on the judgment result is reduced by segmenting the data in a moving window mode, and a new way is provided for extracting the effective data of the audible noise of the power transmission line.
Drawings
Fig. 1 is a first diagram of noise invalid data of a power transmission line according to the present invention;
fig. 2 is a second diagram of the noise invalid data of the transmission line according to the present invention.
FIG. 3 is a first diagram illustrating the effect of the bounded β (g, h) distribution culling on abnormal data according to the present invention;
FIG. 4 is a diagram illustrating the effect of the bounded β (g, h) distribution culling on abnormal data according to the present invention.
FIG. 5 is T of MWKPCA method proposed by the present invention 2 A statistical audible noise valid data decision graph.
Fig. 6 is a diagram of SPE statistic audible noise effective data determination in the MWKPCA method proposed by the present invention.
Detailed Description
A method for audible noise inefficiency (audi) data decision based on bounded beta (g, h) distribution and MWKPCA, comprising the steps of:
step 1: carrying out invalid data judgment on the collected audible noise data day by day through a bounded beta (g, h) distribution, and rejecting invalid data which is out of a bounded beta (g, h) distribution judgment standard range; invalid data is also referred to as "outliers".
Step 2: regarding the audible noise data processed in the step 1, the T of the MWKPCA principal element subspace is used as the whole audible noise component of each frequency band 2 The SPE statistics of the statistics and the residual error subspace judge invalid data in the audible noise data set in a moving window mode;
and step 3: respectively solving L95 percentiles, L50 percentiles and L5 percentiles of data sets which are not subjected to invalid data rejection, data sets which are subjected to invalid data rejection in bounded beta (g, h) distribution and data sets which are subjected to invalid data rejection in MWKPCA, and determining the change condition of the percentiles before and after data processing, thereby determining the rejection of invalid data and whether the subsequent audible noise data analysis is influenced.
The bounded β (g, h) distribution is described in reference to prior art documents [1], [2], and [3]:
document [1]: lin Honghua. Beta distribution of reconsideration error, statistical notation [ J ]. Proceedings of the national academy of metrology of china, 2004 (02): 10-15. Document [2]: lin Honghua, pan Feng. Bootstrap estimation of the beta distribution of repeated measurement data [ J ]. Proceedings of Beijing university of science and engineering, 2004 (11): 947-951.
Document [3]: xie Huichun, cui Xiang, wu Xiong, etc. statistical analysis of radio interference under good weather of 1000kV extra-high voltage alternating current single-circuit transmission line [ J ]. Report on China Motor engineering, 2016,36 (03): 861-870.
The bounded beta (g, h) distribution is a method for expressing the data distribution rule, the polymorphism of beta (g, h) is utilized to estimate the (g, h) parameter of a data set to be detected, and the distribution interval of data is further obtained by the following process
And then toAnd eliminating invalid data.
Wherein the content of the first and second substances,
the mean value of the expression u is,
the variance of u is expressed in terms of,
is the mean of the samples and σ is the standard deviation of the samples.
MWKPCA is the main component analysis of Moving Window kernel, MW (Moving Window) Moving Window, moving Window is a way to segment data set, the Moving Window in the invention segments data in daily unit, then analyzes data in time sequence in daily unit. KPCA (Kernal Principal Component Analysis) kernel Principal Component Analysis maps daily data to be detected in the invention to a high-dimensional feature space through a kernel function, centralizes the data in the high-dimensional feature space, and then calculates a feature vector and a feature value of a data matrix, thereby further calculating T of a Principal element subspace in the Principal element subspace 2 Statistical sum T 2 A statistic threshold, and SPE statistics for the residual subspace and SPE statistics threshold for the residual subspace.
MWKPCA refer to the description in the prior art documents [4], [5] and [6]:
document [4]: zhu Xiongzhuo, zhang Hanwen, bauschun. MWPCA blast furnace anomaly monitoring algorithm based on Gaussian mixture model [ J ]. Chemical reports, 2021,72 (03): 1539-1548.
Document [5]: li Zhenhua, li Chunyan, zhang Zhu electronic voltage transformer error state prediction based on Q-ARMA [ J ] china science: technical science, 2018,48 (12): 1401-1412.
Document [6]: zhang Zhu, chen Qin, hu Chen, et al, evaluating the metric of electronic transducers on-line based on VN-MWPCA [ J ]. Measurement,2018, 130.
Training data: selecting n groups of data of which each noise component is in a plurality of value intervals with the largest data quantity as initial training data, updating the training data in the process of carrying out invalid data judgment day by day, adding the data judged to be normal on the current day into the training data, and removing the data of corresponding groups from the previous training data so as to form the training data of the next day.
Invalid data: the invalid data in the invention is divided into two parts: the first part is invalid data in the single-dimensional data, i.e. a point in a certain period of time whose value is far greater or much smaller than the average value of the piece of data. The second part is invalid data in the multidimensional data, namely points which are far away from the center of the data cluster in the multidimensional space in which the multidimensional data are positioned within a certain time period. The invalid data in the single-dimensional data or the multi-dimensional data mostly result from errors in recording and calculation or accidental changes of test methods and test environments. The accuracy of subsequent research is affected.
The invention means the following day by day: and segmenting the data by taking the day as a unit, and judging the invalid data by taking the day as a unit in the invalid data judging process.
In the step 1, the collected audible noise data is decomposed into 10 audible noise components of 169z, 31.5hz,63hz,125hz,250hz,500hz,1000hz,2000hz,4000hz and 8000hz, which are used as a data set for abnormal data rejection, the audible noise data of each frequency band is distributed by using bounded beta (g, h), and invalid data of each frequency band is rejected day by day.
In the step 1, the audible noise data is audible noise data of the alternating current transmission line, and the decomposed audible noise components of 10 frequency bands including 16Hz to 8kHz are divided in an octave form.
In the step 2, the invalid data in the audible noise data set is determined in the form of a moving window, wherein the moving window is in the form of: and when data are collected, the audible noise data quantity of the transmission line every day is used as the moving step length of the moving window function.
In step 2, each frequency band of the audible noise is an octave, and the frequency center includes: 16Hz,31.5Hz,63Hz,125Hz,250Hz,500Hz,1000Hz,2000Hz,4000Hz,8000Hz.
T 2 Statistics, SPE statistics contains four parts: t is 2 Statistical threshold, SPE statistical threshold, T of each sample point 2 The statistical value and the SPE statistical value of each sampling point; for exceeding T 2 And (4) eliminating the data with the statistical threshold or the data exceeding the SPE statistical threshold. Wherein:
T 2 the statistic threshold is obtained from the training data of the daily data, T 2 The statistical value is obtained from the test data of daily data;
the SPE statistic threshold is obtained by training data of daily data, and the SPE statistic value is obtained by testing data of the daily data.
In the step 3, the L95, L50 and L5 percentiles refer to numerical values which are ranked in the first 95%, 50% and 5% positions when data are ranked from large to small.
Verification of the examples:
in order to further analyze the judgment of the audible noise invalid data of the power transmission line based on the bounded beta (g, h) distribution and MWKPCA, the invalid data of 1000kV alternating current power transmission line noise data collected at the night (0 point to 6 points) of 9-25-2016-2-16-2015 is eliminated.
The method comprises the following steps of firstly using bounded beta (g, h) distribution to sequentially remove audible noise invalid data of the power transmission line with 10 frequency bands from 16Hz to 8kHz day by day, then using the audible noise of the power transmission line with 10 frequency bands from 16Hz to 8kHz as a whole, judging the integral invalid data by using MWKPCA, respectively obtaining a data set without invalid data removal, using the bounded beta (g, h) distribution to remove the invalid data, using the MWKPCA to remove the invalid data, and judging whether the removing method of the invalid data used by the method affects the removing of the audible noise invalid data of the subsequent power transmission line according to L95, L50 and L5 percentiles of the three-stage data sets, wherein the results prove that: the method provided by the invention can not cause interference on the data analysis of audible noise of the subsequent power transmission line on the basis of eliminating invalid data.
Fig. 1 is a graph of sound level data at 30 a days 10 months 10 years 2015.
Fig. 2 is a graph of sound level data for 11/1/2015 day a.
The dotted black circles in fig. 1 and 2 indicate invalid data for invalid interpretation of sound level audible noise data on 1000kV ac transmission line a at 10/30 th 2015 and at 11/1 st 2015.
Fig. 3 is a graph of the trend of sound level data at 30 days a 10 months 10 years after 2015 for invalid data culling using a bounded β (g, h) distribution daily as proposed by the present invention.
Fig. 4 is a graph of the trend of sound level data at 11/1/2015 after invalid data culling using a bounded β (g, h) distribution on a daily basis as proposed by the present invention.
Compared with the traditional invalid data eliminating method which needs the data set to obey normal distribution, the bounded beta (g, h) distribution used by the method can also judge the invalid data in the data set without needing the data set to obey normal distribution.
FIG. 5 is a diagram of T using the MWKPCA principal element subspace proposed by the present invention 2 And the statistic value is the judgment result of judging the overall invalid data of the audible noise of the power transmission line with 10 frequency bands from 16Hz to 8 kHz.
Fig. 6 is a result of determining the total invalid data of the audible noise of the power transmission line in 10 frequency bands of 16Hz to 8kHz by using the SPE statistic of the MWKPCA residual subspace provided by the present invention.
Table 1 shows the L95, L50, L5 percentiles of three-stage datasets for datasets without invalid data culling, datasets with bounded β (g, h) distribution for invalid data culling, and datasets with MWKPCA for invalid data culling.
TABLE 1 original data set, bounded beta (g, h) distribution abnormal data elimination, MWKPCA abnormal data elimination, three stages of noise percentile of each frequency band
Through comparison of L95 percentiles, L50 percentiles and L5 percentiles of the three stages, the percentile difference of audible noise data of each frequency band in the three invalid data eliminating stages is not more than 2dB, so that the method for judging the audible noise invalid data of the power transmission line has no influence on subsequent data analysis.
Claims (3)
1. A method for determining audible noise-null data based on a bounded β (g, h) distribution and MWKPCA, comprising the steps of:
step 1: carrying out invalid data judgment on the collected audible noise data through a bounded beta (g, h) distribution, and rejecting invalid data outside a bounded beta (g, h) distribution judgment standard range;
step 2: regarding the audible noise data processed in the step 1, the T of the MWKPCA principal element subspace is used as the whole audible noise component of each frequency band 2 The SPE statistics of the statistics and the residual error subspace are used for judging invalid data in the audible noise data set;
in step 2, invalid data in the audible noise data set is determined in the form of a moving window, wherein the form of the moving window is as follows: when data are collected, the audible noise data quantity of the power transmission line every day is used as the moving step length of the moving window function;
and step 3: respectively solving L95 percentile, L50 percentile and L5 percentile of a data set which is not subjected to invalid data rejection, a data set which is bounded and distributed by beta (g, h) and subjected to invalid data rejection and a data set which is subjected to MWKPCA and subjected to invalid data rejection, and determining the change condition of the percentile before and after data processing; the L95, L50 and L5 percentiles refer to numerical values which are arranged at the first 95 percent, the first 50 percent and the first 5 percent of positions when the data are arranged from large to small.
2. The method of claim 1 for audible noise null data decision based on bounded β (g, h) distribution and MWKPCA, characterized by: in the step 1, the collected audible noise data is decomposed into 10 audible noise components of 169z, 31.5hz,63hz,125hz,250hz,500hz,1000hz,2000hz,4000hz and 8000hz, which are used as a data set for abnormal data rejection, the audible noise data of each frequency band is distributed by using bounded beta (g, h), and invalid data of each frequency band is rejected day by day.
3. The method of claim 1 for audible noise null data decision based on bounded β (g, h) distribution and MWKPCA, characterized by: in the step 1, the audible noise data is audible noise data of the alternating current transmission line, and the decomposed audible noise components of 10 frequency bands including 16Hz to 8kHz are divided in an octave form.
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