CN108957132A  A kind of Measurement of Harmonics in Power System device and its detection method based on synchronized sampling complete cycle  Google Patents
A kind of Measurement of Harmonics in Power System device and its detection method based on synchronized sampling complete cycle Download PDFInfo
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 CN108957132A CN108957132A CN201811006902.0A CN201811006902A CN108957132A CN 108957132 A CN108957132 A CN 108957132A CN 201811006902 A CN201811006902 A CN 201811006902A CN 108957132 A CN108957132 A CN 108957132A
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Abstract
The present invention provides a kind of Measurement of Harmonics in Power System device and its detection method based on synchronized sampling complete cycle, and the harmonic measurement device includes current transformer, voltage transformer, signal conditioning circuit, A/D conversion module, frequency multiplication of phase locked loop circuit and signal acquisition process module；The harmonic measurement device obtains electric current, information of voltage by the current transformer and the voltage transformer, the electric current, the information of voltage that detect are improved by the conditioning circuit, the digital signal input signal acquisition process module is converted by the A/D conversion module again, the signal acquisition process module can be monitored voltage fundamental frequency and current first harmonics frequency, analytical calculation, and then realize harmonic detection function, and will test result and carry out storage and show.The present invention provides a kind of Measurement of Harmonics in Power System device and its detection method based on synchronized sampling complete cycle, effectively increases the accuracy of electric harmonic detection.
Description
Technical field
The invention belongs to technical field of electric power detection, in particular to a kind of electric system based on synchronized sampling complete cycle is humorous
Wave detection device and its detection method.
Background technique
Since entry into the electric era, electric power has been 21st century indispensable important energy source, not with society
Disconnected progress and rapid development of economy, the production and living level of the mankind are all greatly improved, various types in electric system
Number the nonlinear loads such as motor, fairing, electric arc furnaces and alternating currentdirect current convertor equipment and impact load be continuously increased,
Cause the electric harmonic problem in utility network more serious.The direct performance of influence of these nonlinear loads to electric system
It is the Severe distortion of electric current, voltage waveform, not there is only frequency sinusoidal quantity identical with power supply, referred to as fundametal compoment,
A series of sinusoidal components for the integral multiple that frequency is fundametal compoment frequency are had also appeared, a series of this component is exactly electric harmonic.
For electric system, the seriousness of harmonic pollution is very important, it will cause the production, transmission and utilization of electric energy
Efficiency reduce；What it can have no sign just generates some failures, may make machine that can be burned out；It additionally can severe jamming electricity
The normal work etc. of communication Instrument in Force system.In electric power and electronics industry, the harmfulness of the harmonic pollution in power grid day
It is increasingly acute, it is necessary to which that the harmonic content effectively in analysis power grid selects corresponding necessary suppression according to the data cases in content respectively
Method processed.In order to ensure the safety of operation of power networks, Harmfulness Caused by Harmonics don't fail to be avoided by harmonic controling within safe range
It generates and expands.Therefore, problem for power system harmonics is in depth studied, harmonic carcellation pollution is allowing harmonic content control
In range, to the safe and economic operation of power supply system, the protection of electric system and the safe operation of electrical equipment have great meaning
Justice.Electric harmonic detection technique frequency resolution is not high at present, influences vulnerable to spectral leakage, and how to improve optimization becomes electricity
One of the work of power harmonic detecting technique.
Summary of the invention
The present invention provides a kind of Measurement of Harmonics in Power System device and its detection method based on synchronized sampling complete cycle, has
Effect improves the accuracy of electric harmonic detection.
The present invention is specially a kind of Measurement of Harmonics in Power System device based on synchronized sampling complete cycle, the harmonic detecting
Device includes that current transformer, voltage transformer, signal conditioning circuit, A/D conversion module, frequency multiplication of phase locked loop circuit and signal are adopted
The input terminal of collection processing module, the current transformer and voltage transformer is connect with power grid, the current transformer and voltage
The output end of mutual inductor is connected with the input terminal of the signal conditioning circuit, the output end of the signal conditioning circuit and institute
The input terminal for stating A/D conversion module is connected, and the output end of the A/D conversion module and the signal acquisition process module input
End is connected, and the input terminal of the frequency multiplication of phase locked loop circuit is connect with the output end of the voltage transformer, the phaselocked loop times
The output end of frequency circuit is connected with the signal acquisition process module；The harmonic measurement device passes through the current transformer
Electric current, information of voltage are obtained with the voltage transformer, by the signal conditioning circuit to electric current, the information of voltage detected
It is improved and digital data transmission is converted into the signal acquisition process module, the letter by the A/D conversion module again
Number acquisition processing module can be monitored, analyze and calculate to voltage fundamental frequency and current first harmonics frequency, and then realize
Harmonic detection function, and will test result and carry out storage and show.
The signal conditioning circuit includes add circuit and filter circuit, realizes the adjustment to input signal to reach described
The job requirement of A/D conversion module.
The method that the frequency multiplication of phase locked loop circuit takes in one cycle measured signal uniform sampling at equal intervals, can
Realize synchronized sampling complete cycle, avoiding the acquisition link of signal, there is a phenomenon where spectral leakages；The frequency multiplication of phase locked loop circuit is adopted
Use CD4046 chip as phaselocked loop, 3~18V of supply voltage range, input impedance 100M Ω were realized in a complete cycle
Sample frequency is 128.
The signal acquisition process module can calculate the threephase current of the power grid, threephase voltage, active power, idle
Power and percent harmonic distortion, the signal acquisition process module include arm processor, memory module, display module and communication
Module, the arm processor are connected respectively to the memory module, the display module and the communication module；At the ARM
Reason device is analyzed and processed the signal of acquisition using minimum modulus multiple signal classification algorithm, obtains the amplitude and frequency of each harmonic
Rate and their parameter characteristic can obtain required parameter by relevant mathematical computations, realize harmonic detection function,
And then stored by the memory module, it is shown, is realized by the communication module remote by the display module
Cheng Tongxin.
The harmonic measurement device using minimum modulus multiple signal classification algorithm carry out harmonic detecting, detection method include with
Lower step:
Step 1 lists discrete time function according to signal acquisition process module input signal
The x (n) is sampled signal, and the M is overtone order, the b_{i}For the amplitude of ith harmonic wave, the f_{i}Ith is humorous
Wave frequency rate, the Δ t are sampling time interval, and the v (n) is white noise；
Step 2, establishes autocorrelation function according to the discrete time function, forms autocorrelation by the autocorrelation function
Eigenvalue matrix and corresponding space vector matrix that autocorrelation matrix includes signal frequency information is calculated in matrix, described
Autocorrelation function isThe N is sampling number；By (p+1) a r_{x}(m) composition it is described from
Correlation matrixPass through signal vector matrix e_{i}=[1, exp (j2 π
f_{i}),···,exp(j2πf_{i}p)]^{T}, i=1,2, M calculates the eigenvalue matrix and correspondence of the autocorrelation matrix
Space vector matrix；
Step 3 determines number of sources, the minimum description according to eigenvalue matrix using Minimum description length criterion
Length criteriaThe C is the number of the characteristic value,
It is describedIt is describedIt is describedThe λ_{i}For ith of characteristic value；
The M is exactly required number of sources；
Step 4 carries out separation using spatial noise vector of the minimum modulus method to multiple signal classification algorithm and transformation is repaired
Just, power spectrumanalysis curve is obtainedThe e (ω)=
[1,exp(j2πf_{i}),···,exp(j2πf_{i}p)]^{T}, describedThe E_{N}For noise subspace except m with
Remaining outer row, the m are the first row in noise vector space；The power spectrumanalysis curve is relatively gentle, in ω=ω_{i}Place
Spike is presented, corresponding frequency is the frequency of harmonic signal at peak point.
Detailed description of the invention
Fig. 1 is a kind of structural schematic diagram of the Measurement of Harmonics in Power System device based on synchronized sampling complete cycle of the present invention.
Specific embodiment
It is a kind of based on the Measurement of Harmonics in Power System device of synchronized sampling complete cycle and inspection to the present invention with reference to the accompanying drawing
The specific embodiment of survey method elaborates.
As shown in Figure 1, harmonic measurement device of the invention include current transformer, voltage transformer, signal conditioning circuit,
A/D conversion module, frequency multiplication of phase locked loop circuit and signal acquisition process module, the input of the current transformer and voltage transformer
End connect with power grid, the output end of the current transformer and voltage transformer with the input terminal phase of the signal conditioning circuit
Connection, the output end of the signal conditioning circuit are connected with the input terminal of the A/D conversion module, the A/D conversion module
Output end be connected with the signal acquisition process module input terminal, the input terminal of the frequency multiplication of phase locked loop circuit and the electricity
The output end connection of mutual inductor is pressed, the output end of the frequency multiplication of phase locked loop circuit is connected with the signal acquisition process module；
The harmonic measurement device obtains electric current, information of voltage by the current transformer and the voltage transformer, by described
Signal conditioning circuit, which improves the electric current, the information of voltage that detect, is converted into digital letter by the A/D conversion module again
Number it is transmitted to the signal acquisition process module, the signal acquisition process module can be to voltage fundamental frequency and electric current base
Wave frequency rate is monitored, analyzes and calculates, and then realizes harmonic detection function, and will test result and carry out storage and show.
The signal conditioning circuit includes add circuit and filter circuit, realizes the adjustment to input signal to reach described
The job requirement of A/D conversion module.
The method that the frequency multiplication of phase locked loop circuit takes in one cycle measured signal uniform sampling at equal intervals, can
Realize synchronized sampling complete cycle, avoiding the acquisition link of signal, there is a phenomenon where spectral leakages；The frequency multiplication of phase locked loop circuit is adopted
Use CD4046 chip as phaselocked loop, 3~18V of supply voltage range, input impedance 100M Ω were realized in a complete cycle
Sample frequency is 128.
The signal acquisition process module can calculate the threephase current of the power grid, threephase voltage, active power, idle
Power and percent harmonic distortion, the signal acquisition process module include arm processor, memory module, display module and communication
Module, the arm processor are connected respectively to the memory module, the display module and the communication module；At the ARM
Reason device is analyzed and processed the signal of acquisition using minimum modulus multiple signal classification algorithm, obtains the amplitude and frequency of each harmonic
Rate and their parameter characteristic can obtain required parameter by relevant mathematical computations, realize harmonic detection function,
And then stored by the memory module, it is shown, is realized by the communication module remote by the display module
Cheng Tongxin.
The harmonic measurement device using minimum modulus multiple signal classification algorithm carry out harmonic detecting, detection method include with
Lower step:
Step 1 lists discrete time function according to signal acquisition process module input signal
The x (n) is sampled signal, and the M is overtone order, the b_{i}For the amplitude of ith harmonic wave, the f_{i}Ith is humorous
Wave frequency rate, the Δ t are sampling time interval, and the v (n) is white noise；
Step 2, establishes autocorrelation function according to the discrete time function, forms autocorrelation by the autocorrelation function
Eigenvalue matrix and corresponding space vector matrix that autocorrelation matrix includes signal frequency information is calculated in matrix, described
Autocorrelation function isThe N is sampling number；By (p+1) a r_{x}(m) composition it is described from
Correlation matrixPass through signal vector matrix e_{i}=[1, exp (j2 π
f_{i}),···,exp(j2πf_{i}p)]^{T}, i=1,2, M calculates the eigenvalue matrix and correspondence of the autocorrelation matrix
Space vector matrix；
Step 3 determines number of sources, the minimum description according to eigenvalue matrix using Minimum description length criterion
Length criteriaThe C is the number of the characteristic value,
It is describedIt is describedIt is describedThe λ_{i}For ith of characteristic value；
The M is exactly required number of sources；
Step 4 carries out separation using spatial noise vector of the minimum modulus method to multiple signal classification algorithm and transformation is repaired
Just, power spectrumanalysis curve is obtainedThe e (ω)=
[1,exp(j2πf_{i}),···,exp(j2πf_{i}p)]^{T}, describedThe E_{N}For noise subspace except m with
Remaining outer row, the m are the first row in noise vector space；The power spectrumanalysis curve is relatively gentle, in ω=ω_{i}Place
Spike is presented, corresponding frequency is the frequency of harmonic signal at peak point.
Finally it should be noted that only illustrating technical solution of the present invention rather than its limitations in conjunction with abovedescribed embodiment.Institute
The those of ordinary skill in category field is it is to be understood that those skilled in the art can repair a specific embodiment of the invention
Change or equivalent replacement, but these modifications or change are being applied among pending claims.
Claims (5)
1. a kind of Measurement of Harmonics in Power System device based on synchronized sampling complete cycle, which is characterized in that the harmonic detecting dress
It sets including current transformer, voltage transformer, signal conditioning circuit, A/D conversion module, frequency multiplication of phase locked loop circuit and signal acquisition
The input terminal of processing module, the current transformer and voltage transformer is connect with power grid, and the current transformer and voltage are mutual
The output end of sensor is connected with the input terminal of the signal conditioning circuit, the output end of the signal conditioning circuit with it is described
The input terminal of A/D conversion module is connected, the output end of the A/D conversion module and the signal acquisition process module input terminal
It is connected, the input terminal of the frequency multiplication of phase locked loop circuit is connect with the output end of the voltage transformer, the frequency multiplication of phase locked loop
The output end of circuit is connected with the signal acquisition process module；The harmonic measurement device by the current transformer and
The voltage transformer obtains electric current, information of voltage, by the signal conditioning circuit to detect electric current, information of voltage into
Row conditioning is converted into digital data transmission to the signal acquisition process module, the signal by the A/D conversion module again
Acquisition processing module can be monitored, analyze and calculate to voltage fundamental frequency and current first harmonics frequency, and then realize humorous
Wave detection function, and will test result and carry out storage and show.
2. a kind of Measurement of Harmonics in Power System device based on synchronized sampling complete cycle according to claim 1, feature
It is, the signal conditioning circuit includes add circuit and filter circuit, realizes the adjustment to input signal to reach the A/D
The job requirement of conversion module.
3. a kind of Measurement of Harmonics in Power System device based on synchronized sampling complete cycle according to claim 1, feature
It is, the method that the frequency multiplication of phase locked loop circuit takes in one cycle measured signal uniform sampling at equal intervals, Neng Goushi
Existing synchronized sampling complete cycle, avoiding the acquisition link of signal, there is a phenomenon where spectral leakages；The frequency multiplication of phase locked loop circuit uses
CD4046 chip realizes adopting in a complete cycle as phaselocked loop, 3~18V of supply voltage range, input impedance 100M Ω
Sample frequency is 128.
4. a kind of Measurement of Harmonics in Power System device based on synchronized sampling complete cycle according to claim 1, feature
It is, the signal acquisition process module can calculate threephase current, threephase voltage, active power, the idle function of the power grid
Rate and percent harmonic distortion, the signal acquisition process module include arm processor, memory module, display module and communication mould
Block, the arm processor are connected respectively to the memory module, the display module and the communication module；The ARM processing
Device is analyzed and processed the signal of acquisition using minimum modulus multiple signal classification algorithm, obtains the amplitude and frequency of each harmonic
And their parameter characteristic, required parameter can be obtained by relevant mathematical computations, realizes harmonic detection function, into
And stored by the memory module, it is shown, is realized by the communication module longrange by the display module
Communication.
5. a kind of Measurement of Harmonics in Power System dress described in any one of 4 based on synchronized sampling complete cycle according to claim 1
The detection method set, which is characterized in that the harmonic measurement device carries out harmonic wave inspection using minimum modulus multiple signal classification algorithm
It surveys, detection method includes the following steps:
Step 1 lists discrete time function according to signal acquisition process module input signal
N=0,1, N1, the x (n) is sampled signal, and the M is overtone order, the b_{i}For the amplitude of ith harmonic wave,
The f_{i}Ith harmonic frequency, the Δ t are sampling time interval, and the v (n) is white noise；
Step 2, establishes autocorrelation function according to the discrete time function, forms autocorrelation matrix by the autocorrelation function,
The eigenvalue matrix and corresponding space vector matrix that autocorrelation matrix includes signal frequency information, the autocorrelation is calculated
Function isThe N is sampling number；By (p+1) a r_{x}(m) the autocorrelation square formed
Battle arrayPass through signal vector matrix e_{i}=[1, exp (j2 π
f_{i}),···,exp(j2πf_{i}p)]^{T}, i=1,2, M calculates the eigenvalue matrix and correspondence of the autocorrelation matrix
Space vector matrix；
Step 3 determines number of sources, the minimum description length according to eigenvalue matrix using Minimum description length criterion
CriterionThe C is the number of the characteristic value, institute
It statesIt is describedIt is describedThe λ_{i}For ith of characteristic value；Institute
Stating M is exactly required number of sources；
Step 4 is separated and is converted amendment using spatial noise vector of the minimum modulus method to multiple signal classification algorithm,
Obtain power spectrumanalysis curveK=M+1, p+1, the e (ω)=[1,
exp(j2πf_{i}),···,exp(j2πf_{i}p)]^{T}, describedThe E_{N}It is noise subspace in addition to m
Remaining row, the m be noise vector space the first row；The power spectrumanalysis curve is relatively gentle, in ω=ω_{i}Place is in
Show spike, corresponding frequency is the frequency of harmonic signal at peak point.
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CN109800634A (en) *  20181211  20190524  中国科学院新疆天文台  A kind of broader frequency spectrum Signal Denoising Method based on adjacent DataStatistics 
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CN113884764A (en) *  20210927  20220104  国网新疆电力公司哈密供电公司  Monitoring system and early warning method for harmonic abnormal motion of distribution cable 
CN114252837A (en) *  20211217  20220329  常州同惠电子股份有限公司  Highprecision equal sampling system and method for harmonic measurement of digital power meter 
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CN116125342A (en) *  20221214  20230516  广州汇电云联互联网科技有限公司  Harmonic detection system, method and device for direct current and storage medium 
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CN109800634A (en) *  20181211  20190524  中国科学院新疆天文台  A kind of broader frequency spectrum Signal Denoising Method based on adjacent DataStatistics 
CN113381970A (en) *  20200310  20210910  南京南瑞继保电气有限公司  Main station end broadband measurement preposed data acquisition and processing system 
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CN112962209A (en) *  20210203  20210615  武汉纺织大学  Largescale electric knitting needle array driving method and system for knitting machinery 
CN113777401A (en) *  20210823  20211210  国网江苏省电力有限公司南通供电分公司  Distributed power supply harmonic detection method comprising inverter 
CN113884764A (en) *  20210927  20220104  国网新疆电力公司哈密供电公司  Monitoring system and early warning method for harmonic abnormal motion of distribution cable 
CN113884764B (en) *  20210927  20240503  国网新疆电力公司哈密供电公司  Early warning method of monitoring system for harmonic fluctuation of distribution cable 
CN114252837B (en) *  20211217  20240227  常州同惠电子股份有限公司  Highprecision equal sampling system and method for harmonic measurement of digital power meter 
CN114252837A (en) *  20211217  20220329  常州同惠电子股份有限公司  Highprecision equal sampling system and method for harmonic measurement of digital power meter 
CN115524533A (en) *  20221025  20221227  南方电网数字电网研究院有限公司  Electrical quantity integrated measuring device and method 
CN116125342B (en) *  20221214  20231208  广州市均能科技有限公司  Harmonic detection system, method and device for direct current and storage medium 
CN116125342A (en) *  20221214  20230516  广州汇电云联互联网科技有限公司  Harmonic detection system, method and device for direct current and storage medium 
CN117330834A (en) *  20231009  20240102  国网山东省电力公司东营市东营区供电公司  Dualsamplingbased power grid harmonic content testing method and system 
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