CN106443338B - Extraction Method of Small Perturbation Signal Superimposed on Slowly Varying Signal - Google Patents
Extraction Method of Small Perturbation Signal Superimposed on Slowly Varying Signal Download PDFInfo
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- CN106443338B CN106443338B CN201610850341.7A CN201610850341A CN106443338B CN 106443338 B CN106443338 B CN 106443338B CN 201610850341 A CN201610850341 A CN 201610850341A CN 106443338 B CN106443338 B CN 106443338B
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- 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
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Abstract
The microvariations method for extracting signal provided by the invention being superimposed upon in slow varying signal, it is directed to " the dual extraction algorithm " of disturbing signal, the complete cycle data additive operation of same rule twice is carried out to collected line current/voltage, include two steps: subtracting each other the adjacent periods of the Wave data of the voltage or current of gap periods injection microvariations signal with same datum time point including a., the continuous signal once extracted；B. it takes the identical method of same step a to extract the continuous signal once extracted, obtains the continuous signal of second extraction；The signal that the present invention extracts is enhanced in the case where not increasing route, equipment and technology, financial burden, the amplitude and amplitude-frequency characteristic for extracting signal are approximately twice for once extracting obtained signal, more easily disturbing signal is analyzed and is identified, the present invention has the advantages that simple principle, strong real-time and rapidity are good.
Description
Technical field
The present invention relates to power domain more particularly to a kind of microvariations method for extracting signal being superimposed upon in slow varying signal.
Background technique
POWER SYSTEM DISTURBANCE SIGNALS in power distribution network is usually by power electronic equipment in system power supply side (load side) voltage mistake
Zero crossings carry out controllable period conducting and the signal that generates, and system downstream load side can be transmitted to by power line carrier
(source side).In distribution system fault detection technique field, it is widely used in that the detection of distributed micro-grid isolated island, route is single-phase connects
The route selection and positioning of earth fault, long distance transmission line open-circuit fault are detected and positioned and the technologies such as the on-line monitoring of transformer
In.
Currently, the method that POWER SYSTEM DISTURBANCE SIGNALS is extracted has: by the waveform containing POWER SYSTEM DISTURBANCE SIGNALS and working normally waveform
Data are subtracted each other and (are hereinafter referred to as once subtracted), utilize the methods of wavelet analysis and Mathematical Morphology Method and Atomic Decomposition algorithm.It is logical
Cross voltage when the voltage containing disturbing signal collected on route, current waveform to be subtracted to normal work, current waveform
Method can obtain the waveform of characterization POWER SYSTEM DISTURBANCE SIGNALS, and the method is simple and easy to implement, but because disturbing signal amplitude is smaller and is
There are certain noise signals for system, so that can not be by load current fluctuations when the disturbing signal extracted and normal operation or by electricity
Voltage dip caused by power electronic device and disturbing signal for generating etc. is distinguished；Utilize wavelet analysis and Mathematical Morphology Method pair
Noise reduction, de-noising are carried out using the disturbing signal extracted once is subtracted, system self-noise can be effectively reduced to disturbing signal in this
The influence of extraction, but it is insufficient still without signal strength is solved the problems, such as；Using Atomic Decomposition algorithm to line voltage distribution current signal
In disturbing signal extract, but because background signal main component is power frequency steady-state quantity, and the energy of disturbing signal phase therewith
Than very little, lead to its Decomposition iteration often, extraction process is computationally intensive, otherwise possibly can not normal extraction to perturbation features,
This method also has certain limitation, therefore, needs a kind of new technological means, can overcome above-mentioned technical problem, is electric power
The fault detection of system provides enforceable necessary condition.
Summary of the invention
In view of this, the present invention provides a kind of microvariations method for extracting signal being superimposed upon in slow varying signal, it may be assumed that between being based on
Every the slow varying signal (current/voltage waveform) of period injection POWER SYSTEM DISTURBANCE SIGNALS, believed according to disturbing signal feature and slow become
The fluctuation characteristic of number (load current/voltage) proposes " the dual extraction algorithm " that is directed to disturbing signal, i.e., to collected signal
The complete cycle additive operation of same rule twice is carried out, to solve the above technical problems.
The microvariations method for extracting signal provided by the invention being superimposed upon in slow varying signal, including
A. by the adjacent periods of the Wave data of the voltage or current of gap periods injection microvariations signal with identical base
Quasi- time point subtracts each other, the continuous signal once extracted；
B. it takes the identical method of same step a to extract the continuous signal once extracted, obtains the company of second extraction
Continuous signal, using the continuous signal of the second extraction as the signal of characterization microvariations signal strength.
Further, microvariations signal is after gap periods injection, and the relationship after slow varying signal and microvariations Signal averaging is such as
Under:
CN (t)=i (t)+id(t), N=2n-1, n=1,2,3,4；
CN (t)=i (t), N=2n, n=1,2,3,4
Or
CN (t)=u (t)+ud(t), N=2n-1, n=1,2,3,4；
CN (t)=u (t), N=2n, n=1,2,3,4
Wherein, i (t) is slow varying signal, that is, the current waveform of route after breaking down, u (t) is slow varying signal, that is, is sent out
The voltage waveform of route, i after raw failured(t) and ud(t) the microvariations signal injected for signal source to system, C (t) indicate slow
The continuous signal of varying signal and microvariations Signal averaging, N indicate period number.
3, the microvariations method for extracting signal according to claim 2 being superimposed upon in slow varying signal, it is characterised in that:
The current or voltage waveform of gap periods injection POWER SYSTEM DISTURBANCE SIGNALS is subtracted each other by adjacent periods with same datum time point, is obtained
The continuous signal C once extracted12、C23、C34、C45、C56、C67, wherein
C12=C1-C2
C23=C2-C3
C34=C3-C4
C45=C4-C5
C56=C5-C6
C67=C6-C7
When the current or voltage waveform of gap periods injection POWER SYSTEM DISTURBANCE SIGNALS is to be obtained after once extracting in n period
N-1 continuous signal is taken, the n-1 continuous signal is the disturbing signal of actively injection.
4, the microvariations method for extracting signal according to claim 3 being superimposed upon in slow varying signal, it is characterised in that:
The n-1 continuous signal that the primary extraction is obtained, is subtracted each other again by adjacent continuous signal, obtains the new of second extraction
Continuous signal C123、C234、C345、C456、C567, wherein
C123=C12-C23=(C1-C2)-(C2-C3)
C234=C23-C34=(C2-C3)-(C3-C4)
C345=C34-C45=(C3-C4)-(C4-C5)
C456=C45-C56=(C4-C5)-(C5-C6)
C567=C56-C67=(C5-C6)-(C6-C7)
When the current or voltage waveform of gap periods injection POWER SYSTEM DISTURBANCE SIGNALS is n period, after second extraction
N-2 continuous signal is obtained, the n-2 continuous signal is the signal for characterizing disturbing signal intensity.
Beneficial effects of the present invention: the feature that the present invention is injected according to disturbing signal intermittence, the side subtracted each other by waveform
Formula eliminates other current or voltage signals in addition to disturbing signal, obtains the signal that can directly characterize disturbing signal intensity, just
It, not only can will be due to by carrying out second extraction to the continuous signal once extracted in carrying out signature analysis and identification to it
The disturbance of slow varying signal caused by load fluctuation is greatly lowered, at the same can also by useful disturbing signal do not increase route,
Enhanced in the case where equipment and technology, financial burden, the amplitude and amplitude-frequency characteristic for extracting signal are approximately primary extraction
Twice of obtained signal is more easily analyzed disturbing signal and is identified, the present invention simple, real-time with principle
By force, rapidity is good and meets engineering requirements and has the advantages of engineering construction condition.
Detailed description of the invention
The invention will be further described with reference to the accompanying drawings and examples:
Fig. 1 is the waveform diagram of slow varying signal and microvariations Signal averaging of the invention.
Fig. 2 is the waveform diagram of the invention once extracted to superposed signal waveform.
Fig. 3 is disturbing signal waveform diagram of the invention.
Fig. 4 is the principle of the present invention flow chart.
Specific embodiment
The invention will be further described with reference to the accompanying drawings and examples: Fig. 1 is that slow varying signal of the invention is disturbed with small
The waveform diagram of dynamic Signal averaging, Fig. 2 is the waveform diagram of the invention once extracted to superposed signal waveform, and Fig. 3 is this hair
Bright disturbing signal waveform diagram, Fig. 4 are the principle of the present invention flow charts.
The microvariations method for extracting signal being superimposed upon in slow varying signal in the present embodiment, including
A. by the adjacent periods of the Wave data of the voltage or current of gap periods injection microvariations signal with identical base
Quasi- time point subtracts each other, the continuous signal once extracted；
B. it takes the identical method of same step a to extract the continuous signal once extracted, obtains the company of second extraction
Continuous signal, using the continuous signal of the second extraction as the signal of characterization microvariations signal strength.
Method in the present embodiment it is special can effectively to enhance the signal extracted under the premise of not changing disturbing signal
Sign, calculating is simple and reliable, and enforceable necessary condition can be provided for Power System Faults Detection, in the present embodiment, for
It is spaced the voltage or current waveform of period injection POWER SYSTEM DISTURBANCE SIGNALS, when by the adjacent periods of Wave data with same datum
Between point subtract each other, obtain the new continuous signal once extracted, do not consider load current fluctuations or due to electric power when normal operation such as
Voltage dip caused by electronic device and the disturbing signal etc. generated, new continuous signal is POWER SYSTEM DISTURBANCE SIGNALS；By pair
The continuous signal once extracted takes the identical method of above-mentioned steps to re-start extraction, obtains the continuous signal of second extraction.
In the present embodiment, waveform of the slow varying signal together with microvariations Signal averaging is as shown in Figure 1, such as entitled slow change
The waveform diagram (by taking the current waveform of one period of interval injection disturbing signal as an example) of signal and microvariations Signal averaging, in figure
Microvariations signal is gap periods injection, wherein
CN (t)=i (t)+id(t), N=2n-1, n=1,2,3,4；
CN (t)=i (t), N=2n, n=1,2,3,4
Or
CN (t)=u (t)+ud(t), N=2n-1, n=1,2,3,4；
CN (t)=u (t), N=2n, n=1,2,3,4
Wherein, i (t) is slow varying signal, that is, the current waveform of route after breaking down, u (t) is slow varying signal, that is, is sent out
The voltage waveform of route after raw failure, id (t) and ud (t) are the microvariations signal that signal source is injected to system, and C (t) is indicated
The continuous signal of slow varying signal and microvariations Signal averaging, N represent period number.
Microvariations signal (electric power is superimposed in the dotted ellipse frame of C1, C3, C5, C7 for slow varying signal (current/voltage waveform)
Disturbing signal) after occur distortion.
As shown in Fig. 2, Fig. 2 is the signal waveform once extracted, by the electric current of gap periods injection POWER SYSTEM DISTURBANCE SIGNALS (or
Person's voltage) waveform subtracts each other by adjacent periods with same datum time point, obtain the continuous signal C once extracted12、C23、C34、C45、
C56、C67, wherein
C12=C1-C2
C23=C2-C3
C34=C3-C4
C45=C4-C5
C56=C5-C6
C67=C6-C7
When electric current (or voltage) waveform of gap periods injection POWER SYSTEM DISTURBANCE SIGNALS is n period, after once extracting
It will obtain n-1 continuous signal.In primary extract, obtained continuous signal has eliminated load current, line capacitance electric current
It influences, does not consider load current fluctuations or the voltage dip due to caused by power electronic devices and disturbing for generating when normal operation such as
Dynamic signal etc., which is disturbing signal.
Fig. 3 is the signal waveform of second extraction；N-1 obtained continuous signal will be once extracted, by adjacent continuous signal
Subtracted each other again, obtains the new continuous signal C of second extraction123、C234、C345、C456、C567, wherein
C123=C12-C23=(C1-C2)-(C2-C3)
C234=C23-C34=(C2-C3)-(C3-C4)
C345=C34-C45=(C3-C4)-(C4-C5)
C456=C45-C56=(C4-C5)-(C5-C6)
C567=C56-C67=(C5-C6)-(C6-C7)
When the current or voltage waveform of gap periods injection POWER SYSTEM DISTURBANCE SIGNALS is n period, by once extracting then
N-2 continuous signal is obtained after second extraction.It, not only can be by background caused by load fluctuation by " dual extraction algorithm "
Disturbing signal is greatly lowered, while useful current perturbation signal strength can also nearly double.Side in the present embodiment
Method has the advantages that calculate simple, rapidity and implementation is good, provides enforceable necessary condition for Power System Faults Detection.
Finally, it is stated that the above examples are only used to illustrate the technical scheme of the present invention and are not limiting, although referring to compared with
Good embodiment describes the invention in detail, those skilled in the art should understand that, it can be to skill of the invention
Art scheme is modified or replaced equivalently, and without departing from the objective and range of technical solution of the present invention, should all be covered at this
In the scope of the claims of invention.
Claims (3)
1. a kind of microvariations method for extracting signal being superimposed upon in slow varying signal, it is characterised in that: including
When a. by the adjacent periods of the Wave data of the voltage or current of gap periods injection microvariations signal with same datum
Between point subtract each other, the continuous signal once extracted；
B. it takes the identical method of same step a to extract the continuous signal once extracted, obtains the continuous letter of second extraction
Number, using the continuous signal of the second extraction as the signal of characterization microvariations signal strength；
For microvariations signal after gap periods injection, slow varying signal and the relationship after microvariations Signal averaging are as follows:
CN (t)=i (t)+id(t), N=2n-1, n=1,2,3,4；
CN (t)=i (t), N=2n, n=1,2,3,4
Or
CN (t)=u (t)+ud(t), N=2n-1, n=1,2,3,4；
CN (t)=u (t), N=2n, n=1,2,3,4
Wherein, i (t) is slow varying signal, that is, the current waveform of route after breaking down, u (t) is slow varying signal, that is, event occurs
The voltage waveform of route, i after barrierd(t) and ud(t) the microvariations signal injected for signal source to system, C (t) indicate slow and become letter
Continuous signal number with microvariations Signal averaging, N indicate period number.
2. the microvariations method for extracting signal according to claim 1 being superimposed upon in slow varying signal, it is characterised in that: by between
The current or voltage waveform of the POWER SYSTEM DISTURBANCE SIGNALS of phase injection every other week is subtracted each other by adjacent periods with same datum time point, is obtained primary
The continuous signal C of extraction12、C23、C34、C45、C56、C67, wherein
C12=C1-C2
C23=C2-C3
C34=C3-C4
C45=C4-C5
C56=C5-C6
C67=C6-C7
When the current or voltage waveform of gap periods injection POWER SYSTEM DISTURBANCE SIGNALS is n period, after once extracting, acquisition n-
1 continuous signal, the n-1 continuous signal are the disturbing signal of actively injection.
3. the microvariations method for extracting signal according to claim 2 being superimposed upon in slow varying signal, it is characterised in that: by institute
The n-1 continuous signal once extracted and obtained is stated, is subtracted each other again by adjacent continuous signal, the new continuous of second extraction is obtained
Signal C123、C234、C345、C456、C567, wherein
C123=C12-C23=(C1-C2)-(C2-C3)
C234=C23-C34=(C2-C3)-(C3-C4)
C345=C34-C45=(C3-C4)-(C4-C5)
C456=C45-C56=(C4-C5)-(C5-C6)
C567=C56-C67=(C5-C6)-(C6-C7)
When the current or voltage waveform of gap periods injection POWER SYSTEM DISTURBANCE SIGNALS is n period, by being obtained after second extraction
N-2 continuous signal, the n-2 continuous signal are the signal for characterizing disturbing signal intensity.
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