CN108490311A - Weak impact signal extraction based on power frequency sampling and separation method - Google Patents
Weak impact signal extraction based on power frequency sampling and separation method Download PDFInfo
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- CN108490311A CN108490311A CN201810240085.9A CN201810240085A CN108490311A CN 108490311 A CN108490311 A CN 108490311A CN 201810240085 A CN201810240085 A CN 201810240085A CN 108490311 A CN108490311 A CN 108490311A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/088—Aspects of digital computing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
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Abstract
The present invention provides the weak impact signal sampled based on power frequency extraction and separation methods, including：Line signal is acquired by high-speed sampling module, over-sampling algorithm is to sampled signal processing, change signal sampling frequencies and precision, transient signal in oversampled signals is isolated by starting filter, leak integrators processing, obtains transient signal mould maximum value, comparison signal situation of change, starting algorithm is judged according to signal intensity, provides respective response.Transient signal can be effectively extracted through the invention, and over-sampling algorithm extends the dynamic range of startup, and it is more than 60dB to make transient signal dynamic range.Equipment is high to the response sensitivity of transient signal, can be responded to the transient signal of power frequency component amplitude 0.1%.Equipment operation stability is high, strong antijamming capability.
Description
Technical field
The present invention relates to electrical equipment technical fields, and in particular to power failure distance-measuring equipment more particularly to one kind are based on
The weak impact signal extraction of power frequency sampling and separation method.
Background technology
Electric power system fault distance measuring method mainly two kinds of faulty analytic approach ranging and travelling wave ranging.Traveling wave method ratio in recent years
It is more popular, the new method for the high frequency transient travelling wave signal propagation time measurement distance that traveling wave method generates when being exactly according to failure.It is real
In border, length, the size of transition resistance of traveling wave propagation line length can all influence the shape and amplitude of wavefront, to traveling wave
For ranging, wavefront is impacted more serious, and identification wavefront is more difficult, when especially noise jamming is serious, holds
It is also easy to produce erroneous judgement, influences the accuracy rate of waveform analysis.How to efficiently extract traveling wave is to carry out the premise item of traveling wave fault location
Part.Travelling wave signal energy ratio power frequency component energy is much smaller, and only amplitude threshold is low as possible just can guarantee that travelling wave signal is responded,
Amplitude threshold is low when interference signal is bigger, is easy for that false alarm occurs.Distance-measuring equipment requires startup weak signal small as possible, resists
Interference performance is strong.
Invention content
In order to more preferably respond transient signal, anti-interference ability is improved, ensures that the reliable and stable operation of equipment, the present invention propose
Weak impact signal extraction based on power frequency sampling and separation method.
The present invention adopts the following technical scheme that：
Weak impact signal extraction based on power frequency sampling and separation method, include the following steps：
Step 1: obtaining test line voltage or current signal；
Step 2: the voltage or current signal to acquisition carry out over-sampling processing；
Step 3: starting filters filter by number falls power frequency component included in the oversampled signals of step 2,
Extract the transient signal in oversampled signals；
Step 4: carrying out peak value processing to transient signal；
Step 5: by comparing the Strength Changes of current sampling point signal and reference sample point signal, the class of signal is determined
Type, is realized the weak impact signal extraction sampled based on power frequency and detached.
Further, it in the step 1, obtains test line voltage or current signal includes：Power frequency component, traveling wave letter
Number and noise signal.
Further, in the step 2, voltage or current sampling signal to acquisition carry out over-sampling processing, pass through
Sampling algorithm obtains the low frequency oversampled signals of high sampling resolution.
Further, in the step 3, the transient signal in oversampled signals is extracted, specific method is：Pass through number
Start filter to handle low frequency oversampled signals, filter out the power frequency component in signal, leave including travelling wave signal and
The transient signal of noise signal.
Further, in the step 4, peak value processing is carried out to transient signal, specially：The transient signal extracted
It is handled by leak integrators, obtains current sample time transient signal mould maximum value.
Further, in the step 5, become by comparing the intensity of current sampling point signal and reference sample point signal
Change, determines that the type of signal is specially：
According to algorithmic formula e=Ua-3U(a-3)Judge the value of e；Wherein, UaFor current sampling point signal, U(a-3)For reference
Sampled point signal；
The judgements of e >=0 are fault traveling waves；
The judgements of e ＜ 0 are interference signals.
Further, the current sampling point signal is a sampled value apart from current time recently, reference sample point
It is set as fourth from the last sampled value.
Advantageous effect of the present invention：
1. the signal bandwidth coverage area of sampling channel is wide, the analysis requirement based on time domain can be met, reach 20Hz~
1MHz。
2. starting high sensitivity, transient signal is that power frequency component amplitude 0.1% can startup separator range unit.Equipment is transported
Row stability is high, transient signal accuracy of judgement.
3. the transient signal dynamic range of separation is more than 60dB.The response bandwidth of transient signal is better than 1KHz~1MHz, full
The analysis requirement of sufficient electric system.
Description of the drawings
The accompanying drawings which form a part of this application are used for providing further understanding of the present application, and the application's shows
Meaning property example and its explanation do not constitute the restriction to the application for explaining the application.
Fig. 1 is the weak impact signal extraction sampled based on power frequency and separation process figure；
Fig. 2 is to start filter filtering attenuation curve figure；
Fig. 3 (a)-(c) is the power frequency component sampled, step impact and its coupled signal oscillogram respectively；
Fig. 4 is the signal waveforms for starting filter process and crossing；
Fig. 5 is the processed signal waveforms of leak integrators.
Specific implementation mode
It is noted that following detailed description is all illustrative, it is intended to provide further instruction to the application.Unless another
It indicates, all technical and scientific terms used herein has usual with the application person of an ordinary skill in the technical field
The identical meanings of understanding.
Specific implementation mode is explained in conjunction with Fig. 1 flow charts, this example samples line voltage signal, at current signal
Reason is similar.Weak impact signal uses VP=500, the step signal of period=15ms, power frequency component use VP=20000
Voltage signal；High-speed a/d module samples frequency 1MHz, sampling resolution 16Bit, sampled value are denoted as ub；Low frequency over-sampling frequency
10KHz, sampling resolution 23, sampled value is denoted as Ua；
Weak impact signal based on power frequency sampling is extracted and is detached, and feature includes the following steps：
Step 1: obtaining test line voltage (electric current) signal.
Step 2: voltage (electric current) sampled signal over-sampling is handled.
Step 3: transient signal in extraction oversampled signals.
Step 4: transient signal peak value is handled.
Step 5: entry condition analyzes and determines.
It completes the weak impact signal extraction sampled based on power frequency and detaches.
Wherein, test line voltage signal is obtained described in step 1, specific method is：Pass through voltage sensor, acquisition electricity
Voltage signal in net, wherein voltage sensor passband 15Hz ... 5MHz, signal enter after hardware filtering enhanced processing
Sample frequency is the high-speed a/d module of 1MHz, and obtaining 16 voltage sample values, (sampled point is denoted as 0,1 ... 999999 successively, adopts
Sample value is denoted as u successively0、u1……u999999).Sampled value u hereinbFor signed number.Include power frequency component, traveling wave in voltage signal
Signal and noise.Fig. 3 (a)-(c) is respectively power frequency component, step impact signal and its coupled signal oscillogram.
Wherein, step 2 voltage sampling signal over-sampling is handled, and specific method is：The high frequency voltage obtained to step 1 is adopted
Sample signal does over-sampling processing, so that the sample frequency of voltage signal is become 10KHz, sampling resolution is 23.Sample frequency and position
Several changes is realized by over-sampling algorithm.Algorithm is according to formulaBy continuous 100 high audio sample value ub
It is merged into an over sampled values Ua, over sampled values UaFor signed number.Over-sampling treated voltage signal still includes that power frequency is believed
Number, travelling wave signal and noise.
Wherein, transient signal in step 3 extraction oversampled signals, specific method are：Start filters filter by number
Fall the power frequency component that step 2 oversampled signals are included, filter is designed as single-pole filter, and attenuation pole 50Hz is single
Pole filter transmission function isSingle-pole filter is to power frequency component
Decaying is more than 80dB, normalized frequency 1000Hz；Its attenuation curve such as Fig. 4.Travelling wave signal and noise etc. are obtained by decaying
Weak impact signal (transient signal).
Wherein, step 4 transient signal peak value is handled, and specific method is：After number starts filter, power frequency component
Decaying, weak impact signal retain, and obtained weak signal is handled by leak integrators, obtains current time weak impact signal mould most
Big value.Leak integrators treated signal such as Fig. 4, treated, and signal only has amplitude size not have direction.
Wherein, step 5 entry condition analyzes and determines, specific method is：Compare current sampling point U by comparing deviceaWith ginseng
Examine sampled point U(a-3)(current time fourth from the last sampled point) change in signal strength, by starting algorithm separation interference signal and
Fault traveling wave signal judges signal type.
Current sampling point and reference sample point are all peak value treated signals.Over-sampling frequency is 10khz, is corresponded in 1s
Sampled point has 10,000, and current sampling point is a sampled value recently, and reference sample point is to be set as fourth from the last sampling
Value.Assuming that currently there is 500 sampled values, then current sample values are the 500th, and reference sample point is the 497th sampled value.
According to algorithmic formula e=Ua-3U(a-3)Judge the value of e.E >=0 is considered that fault traveling wave, equipment start；E ＜ 0 recognize
To be interference signal, equipment does not start.
Above-mentioned, although the foregoing specific embodiments of the present invention is described with reference to the accompanying drawings, not protects model to the present invention
The limitation enclosed, those skilled in the art should understand that, based on the technical solutions of the present invention, those skilled in the art are not
Need to make the creative labor the various modifications or changes that can be made still within protection scope of the present invention.
Claims (7)
1. the weak impact signal extraction based on power frequency sampling and separation method, which is characterized in that include the following steps：
Step 1: obtaining test line voltage or current signal；
Step 2: the voltage or current signal to acquisition carry out over-sampling processing；
Step 3: starting filters filter by number falls power frequency component included in the oversampled signals of step 2, extract
Transient signal in oversampled signals；
Step 4: carrying out peak value processing to transient signal；
Step 5: by comparing the Strength Changes of current sampling point signal and reference sample point signal, the type of signal is determined, it is real
Weak impact signal now based on power frequency sampling is extracted and is detached.
2. the weak impact signal extraction based on power frequency sampling and separation method as described in claim 1, which is characterized in that described
In step 1, obtains test line voltage or current signal includes：Power frequency component, travelling wave signal and noise signal.
3. the weak impact signal extraction based on power frequency sampling and separation method as described in claim 1, which is characterized in that described
In step 2, voltage or current sampling signal to acquisition carry out over-sampling processing, and high sample bits are obtained by over-sampling algorithm
Several low frequency oversampled signals.
4. the weak impact signal extraction based on power frequency sampling and separation method as described in claim 1, which is characterized in that described
In step 3, the transient signal in oversampled signals is extracted, specific method is：Start filter to low frequency over-sampling by number
Signal is handled, and the power frequency component in signal is filtered out, and leaves the transient signal including travelling wave signal and noise signal.
5. the weak impact signal extraction based on power frequency sampling and separation method as described in claim 1, which is characterized in that described
In step 4, peak value processing is carried out to transient signal, specially：The transient signal extracted is handled by leak integrators, is obtained
To current sample time transient signal mould maximum value.
6. the weak impact signal extraction based on power frequency sampling and separation method as described in claim 1, which is characterized in that described
In step 5, by comparing the Strength Changes of current sampling point signal and reference sample point signal, determine that the type of signal is specific
For：
According to algorithmic formula e=Ua-3U(a-3)Judge the value of e；Wherein, UaFor current sampling point signal, U(a-3)For reference sample
Point signal；
The judgements of e >=0 are fault traveling waves；
The judgements of e ＜ 0 are interference signals.
7. the weak impact signal extraction based on power frequency sampling and separation method as described in claim 1, which is characterized in that described
Current sampling point signal is a sampled value apart from current time recently, and reference sample point is set as fourth from the last sampling
Value.
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