CN111505377A - Voltage flicker real-time monitoring and early warning system and method - Google Patents
Voltage flicker real-time monitoring and early warning system and method Download PDFInfo
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- CN111505377A CN111505377A CN202010415820.2A CN202010415820A CN111505377A CN 111505377 A CN111505377 A CN 111505377A CN 202010415820 A CN202010415820 A CN 202010415820A CN 111505377 A CN111505377 A CN 111505377A
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- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G01R23/16—Spectrum analysis; Fourier analysis
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
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Abstract
The invention discloses a voltage flicker real-time monitoring and early warning system and a method, which relate to the electric power detection technology, wherein the voltage flicker real-time monitoring and early warning system comprises: the device comprises a signal acquisition module, a voltage and current signal conditioning module, an A/D sampling module, a flicker analysis module, a display module, a data sharing module, a flicker prediction module, an early warning module and an early warning information release module; the signal acquisition module, the voltage and current signal conditioning module, the A/D sampling module and the flicker analysis module are sequentially connected; the flicker analysis module is respectively connected with the display module and the data sharing module; the data sharing module is sequentially connected with the flicker prediction module, the early warning module and the early warning information issuing module. The system and the method of the invention realize the integration of monitoring, forecasting and early warning; the time of occurrence of the flicker can be determined, and model prediction is carried out according to the monitoring data, so that early warning processing can be carried out on the voltage flicker in time.
Description
Technical Field
The invention relates to the technical field of electric power detection, in particular to a voltage flicker real-time monitoring and early warning system and method.
Background
At present, with the rapid development of the economic level, the electric load is increasing. The voltage fluctuation in the power grid is aggravated by the massive access of distributed power supplies in the power grid and the input of various nonlinear, impact and fluctuating loads, the voltage flicker in the power grid frequently appears, the safe operation of a power system is influenced, and the industrial production and the social life are seriously influenced.
At present, flicker detection under IEC standard needs to pass through a series of procedures of square detection filtering, band-pass and weighting filtering, squarer low-pass filtering, statistics and the like, the design of an actual digital flicker meter is very complex, and errors caused by non-ideal amplitude-frequency characteristics of filters can have great influence on a measurement result. In order to simplify the detection steps and the model while ensuring the accuracy of the voltage flicker measurement, an improvement in the flicker measurement method is required.
Therefore, the voltage flicker is detected and monitored on the premise of ensuring good power quality, and meanwhile, the voltage flicker is predicted, and an early warning mechanism is sent out in advance for a line which is likely to flicker, so that the occurrence of power accidents can be effectively slowed down.
Disclosure of Invention
The invention mainly aims to provide a voltage flicker real-time monitoring and early warning system and method, which realize the integration of monitoring, prediction and early warning, can quickly detect the voltage flicker degree, and perform pre-judgment, ensure the power quality and slow down the occurrence of power accidents.
According to one aspect of the invention, a voltage flicker real-time monitoring and early warning system is provided,
the method comprises the following steps:
the device comprises a signal acquisition module, a voltage and current signal conditioning module, an A/D sampling module, a flicker analysis module, a display module, a data sharing module, a flicker prediction module, an early warning module and an early warning information release module;
the signal acquisition module, the voltage and current signal conditioning module, the A/D sampling module and the flicker analysis module are sequentially connected;
the flicker analysis module is respectively connected with the display module and the data sharing module;
the data sharing module is sequentially connected with the flicker prediction module, the early warning module and the early warning information release module;
the voltage flicker monitoring and predicting system improves the IEC standard flicker detection system process through the acquired signals, analyzes the voltage flicker value and displays, transmits and shares data; and establishing a prediction model according to the monitored data, performing flicker prediction, and giving out early warning to the line with the voltage flicker index exceeding.
Furthermore, the signal conditioning module mainly comprises non-electric quantity conversion, signal conversion,
The amplifying, filtering, linearization, common mode rejection and isolation circuit converts the non-electric quantity and non-standard electric signals into standard electric signals; the signal conditioning module is arranged between the sensor and the A/D sampling module.
Furthermore, the A/D sampling module adopts a 16-bit AD7705 conversion chip to carry out A/D
Converting; and the flicker analysis module adopts DSP TMS320C5000 to calculate and analyze data.
Furthermore, the flicker prediction module is used for processing data, establishing a prediction model and outputting a prediction result, and the flicker prediction module adopts a gray model, a linear model and a random time series model to adaptively weight and preferably combine to obtain the prediction result.
Furthermore, the early warning module is used for judging the integrity of data and the voltage flicker index threshold
And (4) outputting the value, the judgment early warning level and the early warning result.
According to still another aspect of the present invention, there is provided a voltage flicker real-time monitoring and early warning method,
the method comprises the following steps:
s1, voltage flicker analysis and measurement method;
s2, voltage flicker prediction method.
Further, the step S1 includes:
s11, sampling the voltage and current signals by PT/CT conversion, resistance sampling and capacitance filtering conversion;
s12, A/D conversion is carried out through the A/D conversion module, and the input voltage flicker analysis processing module;
s13, dynamically displaying the processed data;
s14, carrying out FFT conversion on the acquired voltage signal, judging whether a flicker signal appears or not, and storing real-time data to obtain a peak value and a valley value;
s15, sampling the voltage value in one or half periodCalculating the corresponding root mean square value of the voltage according to the following formula:
S17, fitting the frequency points of the voltage fluctuation values;
s18, calculating a certain voltage sequenceThe instantaneous flicker visual sensitivity is subjected to Fourier decomposition to obtain the instantaneous flicker visual sensitivity corresponding to each harmonicThe values of (a) are summed:
s19, calculating the instantaneous flicker value of the voltage signal
Further, the step S2 includes:
s21, establishing a model according to the flicker historical data;
s22, identifying the parameters of the model, and establishing a calculation model of parameter estimation by taking the maximum likelihood criterion as the fitness function of the particle swarm optimization algorithm;
and S23, an early warning mechanism based on the prediction data.
The invention has the advantages that:
the voltage flicker real-time monitoring and early warning system and method realize the integration of monitoring, prediction and early warning. The method has the advantages that the detection process of the flicker is improved, the process is simplified, the accuracy is improved, the occurrence time of the flicker can be determined, the data are shared and dynamically displayed, and model prediction is carried out according to the monitoring data, so that early warning treatment can be carried out on the voltage flicker in time.
In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention.
FIG. 1 is a block diagram of a voltage flicker real-time monitoring and early warning system according to an embodiment of the present invention;
FIG. 2 is a schematic block diagram of a prediction module of a real-time voltage flicker monitoring and early warning system according to an embodiment of the present invention;
FIG. 3 is a schematic block diagram of an early warning module of the real-time voltage flicker monitoring and early warning system according to the embodiment of the present invention;
fig. 4 is a flowchart of a voltage flicker real-time monitoring and early warning method according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example 1
Referring to fig. 1, as shown in fig. 1, a voltage flicker real-time monitoring and early warning system includes:
the device comprises a signal acquisition module, a voltage and current signal conditioning module, an A/D sampling module, a flicker analysis module, a display module, a data sharing module, a flicker prediction module, an early warning module and an early warning information release module;
the signal acquisition module, the voltage and current signal conditioning module, the A/D sampling module and the flicker analysis module are sequentially connected;
the flicker analysis module is respectively connected with the display module and the data sharing module;
the data sharing module is sequentially connected with the flicker prediction module, the early warning module and the early warning information release module;
the voltage flicker monitoring and predicting system improves the IEC standard flicker detection system process through the acquired signals, analyzes the voltage flicker value and displays, transmits and shares data; and establishing a prediction model according to the monitored data, performing flicker prediction, and giving out early warning to the line with the voltage flicker index exceeding.
The voltage flicker real-time monitoring and early warning system and method realize the integration of monitoring, prediction and early warning. The method has the advantages that the detection process of the flicker is improved, the process is simplified, the accuracy is improved, the occurrence time of the flicker can be determined, the data are shared and dynamically displayed, and model prediction is carried out according to the monitoring data, so that early warning treatment can be carried out on the voltage flicker in time.
The signal conditioning module mainly comprises non-electric quantity conversion, signal conversion, amplification, filtering,
The linearization, common mode rejection and isolation circuit converts the non-electric quantity and non-standard electric signals into standard electric signals; the signal conditioning module is arranged between the sensor and the A/D sampling module.
The A/D sampling module adopts a 16-bit AD7705 conversion chip to carry out A/D conversion; the flash
And the variable analysis module adopts the DSP TMS320C5000 to calculate and analyze data.
Referring to fig. 2, as shown in fig. 2, the flicker prediction module is used for processing data, establishing a prediction model and outputting a prediction result, and the flicker prediction module adopts a gray model, a linear model and a random time series model to adaptively weight and preferably combine to obtain the prediction result.
Referring to fig. 3, as shown in fig. 3, the early warning module is used for data integrity determination and voltage flash
And changing the index threshold, judging the early warning grade and outputting the early warning result.
Example 2
Referring to fig. 4, as shown in fig. 4, a voltage flicker real-time monitoring and early warning method includes the following steps
The method comprises the following steps:
s1, voltage flicker analysis and measurement method;
s2, voltage flicker prediction method.
The step S1 includes:
s11, sampling voltage and current signals by PT/CT (potential/current transformer) conversion, resistance sampling and capacitance filtering conversion;
s12, A/D conversion is carried out through the A/D conversion module, and the input voltage flicker analysis processing module;
s13, dynamically displaying the processed data;
s14, carrying out FFT conversion on the acquired voltage signal, judging whether a flicker signal appears or not, and storing real-time data to obtain a peak value and a valley value;
s15, sampling the voltage value in one or half periodCalculating the corresponding root mean square value of the voltage according to the following formula:
The invention adopts FFT decomposition, which requires the number of sampling points N to be a certain power of 2,the spectrum resolution of the image sensor is different with the sampling point number, when the sampling point number is 2048 times, namely the spectrum resolution is 0.0244, the instantaneous flicker visibility isThe calculated value of (a) is substantially close to the theoretical value;
s17, according to the definition of voltage fluctuationIn a clear view of the above, it is known that,is composed ofThe voltage fluctuation value under the frequency is 2 times of the amplitude of the square root curve of the sinusoidal voltage; then instantaneous flicker visual acuity at that frequencyCalculated by the following formula:
for the voltage fluctuation and flicker problem caused by the impact load, the flicker frequency of the voltage fluctuation and flicker problem is not necessarily at the discrete frequency points given by the IEC standard, so that the voltage fluctuation value needs to be fitted to the frequency points;
s18, calculating a voltage sequence with the square of the RMS equal to the sum of the squares of the RMS of the harmonics of the signalThe instantaneous flicker visual sensitivity is subjected to Fourier decomposition to obtain the instantaneous flicker visual sensitivity corresponding to each harmonicThe values of (a) are summed:
S19, calculating the instantaneous flicker value of the voltage signal
The step S2 includes:
s21, establishing a model according to the flicker historical data; the accuracy of the prediction model depends on the reasonability of model selection, and because the linear regression model, the random time sequence model and the gray model are single models, the voltage flicker problem influenced by multiple factors is difficult to predict, and an optimal combined prediction model is formed for improving the prediction accuracy to predict the future voltage flicker condition;
s22, identifying the parameters of the model, in order to avoid the particle algorithm from falling into the local optimal solution in the later stage, but ensure that the particle algorithm can search in a larger range in the earlier stage of optimization, an improved parameter estimation algorithm, namely a Cooperative Particle Swarm Optimization (CPSO) algorithm is provided, the method divides the population into two groups which are respectively used for global search and local optimization, and establishes a calculation model of parameter estimation by taking the maximum likelihood criterion as the fitness function of the CPSO algorithm;
and S23, an early warning mechanism based on the prediction data. The prediction data has the advance property, the early warning mechanism of the prediction data is constructed, and the early warning information can be issued before the voltage flicker occurs, so that the monitoring personnel can make preventive measures in advance, the power quality is ensured, and the accident frequency is reduced.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (8)
1. The utility model provides a voltage flicker real-time supervision and early warning system which characterized in that includes:
the device comprises a signal acquisition module, a voltage and current signal conditioning module, an A/D sampling module, a flicker analysis module, a display module, a data sharing module, a flicker prediction module, an early warning module and an early warning information release module;
the signal acquisition module, the voltage and current signal conditioning module, the A/D sampling module and the flicker analysis module are sequentially connected;
the flicker analysis module is respectively connected with the display module and the data sharing module;
the data sharing module is sequentially connected with the flicker prediction module, the early warning module and the early warning information release module;
the voltage flicker monitoring and predicting system improves the IEC standard flicker detection system process through the acquired signals, analyzes the voltage flicker value and displays, transmits and shares data; and establishing a prediction model according to the monitored data, performing flicker prediction, and giving out early warning to the line with the voltage flicker index exceeding.
2. The system of claim 1, wherein the voltage flicker is monitored and pre-warned in real time
The signal conditioning module mainly comprises a non-electric quantity conversion circuit, a signal conversion circuit, an amplification circuit, a filtering circuit, a linearization circuit, a common mode rejection circuit and an isolation circuit, and is used for converting non-electric quantity and non-standard electric signals into standard electric signals; the signal conditioning module is arranged between the sensor and the A/D sampling module.
3. The system of claim 1, wherein the voltage flicker is monitored and pre-warned in real time
The A/D sampling module adopts a 16-bit AD7705 conversion chip to carry out A/D conversion; and the flicker analysis module adopts DSP TMS320C5000 to calculate and analyze data.
4. The system of claim 1, wherein the voltage flicker is monitored and pre-warned in real time
The flicker prediction module is used for processing data, establishing a prediction model and outputting a prediction result, and the flicker prediction module adopts a gray model, a linear model and a random time sequence model to adaptively weight and optimally combine to obtain the prediction result.
5. The system of claim 1, wherein the voltage flicker is monitored and pre-warned in real time
The early warning module is used for judging the integrity of data, the voltage flicker index threshold, judging the early warning level and outputting the early warning result.
6. A voltage flicker real-time monitoring and early warning method is characterized by comprising the following steps
The method comprises the following steps:
s1, voltage flicker analysis and measurement method;
s2, voltage flicker prediction method.
7. The system of claim 6, wherein the voltage flicker is monitored and pre-warned in real time
In that, the step S1 includes:
s11, sampling the voltage and current signals by PT/CT conversion, resistance sampling and capacitance filtering conversion;
s12, A/D conversion is carried out through the A/D conversion module, and the input voltage flicker analysis processing module;
s13, dynamically displaying the processed data;
s14, carrying out FFT conversion on the acquired voltage signal, judging whether a flicker signal appears or not, and storing real-time data to obtain a peak value and a valley value;
s15, sampling the voltage value in one or half periodCalculating the corresponding root mean square value of the voltage according to the following formula:
S17, fitting the frequency points of the voltage fluctuation values;
s18, calculating the instantaneous flicker visibility of a certain voltage sequence, and carrying out Fourier decomposition to obtain the instantaneous flicker visibility corresponding to each subharmonicThe values of (a) are summed:
s19, calculating the instantaneous flicker value of the voltage signal
8. The system of claim 6, wherein the voltage flicker is monitored and pre-warned in real time
In that, the step S2 includes:
s21, establishing a model according to the flicker historical data;
s22, identifying the parameters of the model, and establishing a calculation model of parameter estimation by taking the maximum likelihood criterion as the fitness function of the particle swarm optimization algorithm;
and S23, an early warning mechanism based on the prediction data.
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