CN115236392A - Multi-characteristic-quantity electric energy metering method and device, terminal and storage medium - Google Patents
Multi-characteristic-quantity electric energy metering method and device, terminal and storage medium Download PDFInfo
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- CN115236392A CN115236392A CN202210827046.5A CN202210827046A CN115236392A CN 115236392 A CN115236392 A CN 115236392A CN 202210827046 A CN202210827046 A CN 202210827046A CN 115236392 A CN115236392 A CN 115236392A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R22/00—Arrangements for measuring time integral of electric power or current, e.g. electricity meters
- G01R22/06—Arrangements for measuring time integral of electric power or current, e.g. electricity meters by electronic methods
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Abstract
The invention relates to the technical field of electric power metering, in particular to an electric energy metering method, device, terminal and storage medium with multiple characteristic quantities. The waveform is then sampled to obtain a waveform data set. Then, the waveform is fourier-transformed based on the waveform data set to obtain a fundamental wave and a plurality of higher harmonics. Finally, a plurality of characteristic quantities of the fundamental wave and the plurality of higher harmonics are operated, and measuring data of the plurality of characteristic quantities are obtained. According to the embodiment of the invention, the reasonable sampling rate can be determined through the waveform, the accuracy of each harmonic after conversion can be ensured, the complexity of sampling and calculation is reduced, the two are considered, after the harmonic obtained by conversion is converted, the metering data such as harmonic active power, harmonic reactive power, power factors, harmonic factors, main harmonic and the like can be respectively calculated according to the harmonic, and the accuracy of the metering data is ensured.
Description
Technical Field
The invention relates to the technical field of electric power metering, in particular to an electric energy metering method, device, terminal and storage medium with multiple characteristic quantities.
Background
Electric energy is an indispensable important energy commodity in production and life of modern society, and the production, the sale and the use of the electric energy depend on a system consisting of a power plant, a power supply part and a user. Therefore, the accuracy and the reasonability of the electric energy metering directly influence the economic benefits of the sending party, the supplying party and the using party and the fairness of the transaction. With the increasing popularity of wind power generation and solar power generation, distributed power sources are distributed throughout each node of a power transmission line, so that more complexity and diversity are brought to the metering of electric energy.
At present, the existing electric energy meters at home and abroad lack an effective metering mode for a plurality of characteristic quantities and a plurality of power supply forms, and the electric energy metering of transient distortion signals is useless. However, in a power supply application scenario, frequent starting of a motor, input of a load, fluctuation of distributed power generation and the like all generate huge transient power, and an electric energy meter cannot realize metering, so that a power department suffers huge loss.
Therefore, the influence of each characteristic of the new energy accessed to the power grid and how to realize accurate and reasonable electric energy metering under the background have important theoretical and practical significance.
Based on this, it is necessary to develop and design a multi-characteristic electric energy metering method.
Disclosure of Invention
The embodiment of the invention provides a multi-characteristic-quantity electric energy metering method, a multi-characteristic-quantity electric energy metering device, a multi-characteristic-quantity electric energy metering terminal and a multi-characteristic-quantity storage medium, which are used for solving the problem that a means for accurately metering multi-characteristic quantity of a power grid is lacked in the prior art.
In a first aspect, an embodiment of the present invention provides a multi-characteristic-quantity electric energy metering method, including: acquiring a waveform of a feeder terminal, wherein the feeder is used for accessing a load and/or a power supply, and the waveform is used for representing a waveform of electric energy transmitted by the feeder;
sampling the waveform to obtain a waveform data set;
performing Fourier transform on the waveform based on the waveform data set to obtain a fundamental wave and a plurality of higher harmonics;
and performing a plurality of characteristic quantity operations on the fundamental wave and the plurality of higher harmonics, and acquiring measurement data of the plurality of characteristic quantities, wherein the measurement data represents the attribute characteristics of the electric energy.
In one possible implementation, the sampling rate is determined based on a waveform, including:
obtaining a plurality of sample waveforms, wherein the sample waveforms correspond to a target capacity gear, and the target capacity gear is determined based on the capacity of input electric energy and/or the capacity of output electric energy;
for each sample waveform in the plurality of sample waveforms, obtaining a sampling rate corresponding to a target capacity level by:
sampling the sample waveform at a sample sampling rate to obtain a sample waveform data set;
performing Fourier transform on the sample waveform based on the sample waveform dataset to obtain a sample fundamental wave and a plurality of sample higher harmonics;
determining a transformed deviation ratio according to the sample waveform, the sample fundamental wave and the plurality of sample higher harmonics;
if the deviation rate is lower than a threshold value, screening out a plurality of harmonics with harmonic rates higher than the threshold value from the plurality of sample higher harmonics as typical harmonics, wherein the harmonic rate is the ratio of the amplitude of the sample higher harmonics to the amplitude of the sample fundamental wave;
and determining a target sampling rate according to the frequency of the highest harmonic in the typical harmonic, and taking the target sampling rate as the sampling rate of the sample waveform corresponding to the target capacity gear.
In one possible implementation, the determining a transformed deviation ratio according to the sample waveform, the sample fundamental wave, and the plurality of sample higher harmonics includes:
according to the sample sampling rate, respectively sampling the sample fundamental wave and the plurality of sample higher harmonics to obtain a plurality of conversion sets, wherein the plurality of conversion sets correspond to a plurality of sampling points, and the conversion sets comprise sampling values of the fundamental wave and sampling values of the plurality of sample higher harmonics;
for each of the plurality of transformation sets, performing the following steps to obtain a deviation ratio of a plurality of sampling points:
accumulating the sampling value of the fundamental wave in the transformation set and the sampling value of the sampling of the higher harmonic waves of the plurality of samples to obtain an accumulated sum;
finding waveform data values in the sample waveform data set according to the sampling positions corresponding to the transformation set;
calculating the deviation rate of the accumulated sum and the waveform data value as the deviation rate of a sampling point;
and calculating the average value of the deviation ratios of the plurality of sampling points as the converted deviation ratio.
In one possible implementation, the sampling employs a dynamic sampling rate, and the sampling the waveform to obtain a waveform data set includes:
acquiring a time pane, wherein the time pane comprises a time period;
taking out a section of waveform from the waveforms according to the time window;
turning the section of waveform to obtain a turned waveform, wherein the turning is to turn the negative half cycle of the waveform to the positive half cycle in an amplitude mirror image mode;
integrating the reversed waveform to obtain an effective value of the waveform;
and selecting a dynamic sampling rate according to the effective value, sampling the waveform, and acquiring a waveform data set, wherein the dynamic sampling rate is acquired based on a sampling rate set, the sampling rate set comprises sampling rates of a plurality of target capacity gears, and the sampling rate of the target capacity gear corresponds to the target capacity gear.
In one possible implementation, the fourier transforming the waveform based on the waveform dataset to obtain a fundamental wave and a plurality of higher harmonics includes:
acquiring a sampling rate corresponding to the waveform data set;
determining a transformation target frequency according to the sampling rate, wherein the transformation target frequency is the frequency of the highest harmonic in a plurality of higher harmonics obtained by Fourier transformation;
calculating to obtain a fundamental wave and a plurality of higher harmonics according to the transformation target frequency, the waveform data set and the first formula, wherein the first formula is as follows:
where X [ k ] is the k-th converted wave, X [ N ] is the nth element in the waveform data set, and N is the total amount of data in the waveform data set.
In one possible implementation manner, the multi-feature-quantity metering data includes: the active power that corresponds a plurality of harmonics and the reactive power that corresponds a plurality of harmonics, the fundamental wave and a plurality of harmonics include the fundamental wave of voltage, a plurality of harmonics of voltage, the fundamental wave of electric current and the higher harmonic of electric current, to the fundamental wave and a plurality of higher harmonics carry out the operation of a plurality of characteristic vectors, obtain the measurement data of a plurality of characteristic vectors, include:
pairing the fundamental wave of the voltage, the plurality of harmonics of the voltage, the fundamental wave of the current and the harmonics of the current according to the frequencies of the fundamental wave and the harmonics to generate a plurality of voltage-current pairs;
respectively carrying out dot multiplication operation and cross multiplication operation on the plurality of voltage-current pairs to obtain active power of a plurality of harmonics and reactive power of the plurality of harmonics;
and respectively accumulating the active power of the plurality of harmonics and the reactive power of the plurality of harmonics to obtain total active power and total reactive power.
In one possible implementation manner, the multi-feature-quantity metering data includes: the power factor corresponding to a plurality of harmonics, the fundamental wave and the plurality of harmonics include a fundamental wave of voltage, a plurality of harmonics of voltage, a fundamental wave of current and a harmonic of current, the fundamental wave and the plurality of harmonics are operated by a plurality of characteristic quantities, and measurement data of the plurality of characteristic quantities is acquired, the power factor corresponding to the plurality of harmonics includes:
pairing the fundamental wave of the voltage, the plurality of harmonics of the voltage, the fundamental wave of the current and the harmonics of the current according to the frequencies of the fundamental wave and the harmonics to generate a plurality of voltage-current pairs;
determining power factors of a plurality of harmonics according to the plurality of voltage-current pairs and a second formula, wherein the second formula is as follows:
in the formula, cos k (theta) is the power factor of the kth harmonic, X u (k) Is the kth harmonic of the voltage, X i (k) The kth harmonic of the current.
In a second aspect, an embodiment of the present invention provides a multi-characteristic-quantity electric energy metering device, including:
the device comprises a waveform acquisition module, a power supply acquisition module and a control module, wherein the waveform acquisition module is used for acquiring the waveform of a feeder terminal, the feeder is used for accessing a load and/or a power supply, and the waveform is used for representing the waveform of electric energy transmitted by the feeder;
the waveform sampling module is used for sampling the waveform to obtain a waveform data set;
a Fourier transform module for performing Fourier transform on the waveform based on the waveform data set to obtain a fundamental wave and a plurality of higher harmonics;
and the number of the first and second groups,
and the multi-characteristic quantity metering module is used for carrying out operation of a plurality of characteristic quantities on the fundamental wave and the plurality of higher harmonics and acquiring metering data of the plurality of characteristic quantities, wherein the metering data represent attribute characteristics of electric energy.
In a third aspect, an embodiment of the present invention provides a terminal, including a memory and a processor, where the memory stores a computer program operable on the processor, and the processor executes the computer program to implement the steps of the method according to the first aspect or any possible implementation manner of the first aspect.
In a fourth aspect, the present invention provides a computer-readable storage medium, which stores a computer program that, when executed by a processor, implements the steps of the method as described in the first aspect or any one of the possible implementations of the first aspect.
Compared with the prior art, the implementation mode of the invention has the following beneficial effects:
the embodiment of the invention discloses an electric energy metering method with multiple characteristic quantities, which comprises the steps of firstly obtaining a waveform of a feeder terminal, wherein the feeder is used for being connected to a load and/or a power supply, and the waveform is used for representing the waveform of electric energy transmitted by the feeder. The waveform is then sampled to obtain a waveform data set. Then, the waveform is fourier-transformed based on the waveform data set to obtain a fundamental wave and a plurality of higher harmonics. And finally, carrying out a plurality of characteristic quantity operations on the fundamental wave and the plurality of higher harmonics, and acquiring measurement data of the plurality of characteristic quantities, wherein the measurement data represents the attribute characteristics of the electric energy. According to the embodiment of the invention, the reasonable sampling rate can be determined through the waveform, the accuracy of each harmonic after conversion can be ensured, the complexity of sampling and calculation is reduced, the two are considered, after the harmonic obtained by conversion is converted, the metering data such as harmonic active power, harmonic reactive power, power factors, harmonic factors, main harmonic and the like can be respectively calculated according to the harmonic, and the accuracy of the metering data is ensured.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive labor.
FIG. 1 is a flow chart of a multi-characteristic electric energy metering method provided by an embodiment of the invention;
fig. 2 is a schematic diagram of a power transmission line with distributed power sources according to an embodiment of the present invention;
FIG. 3 is a time domain diagram of a waveform sample and a Fourier transform provided by an embodiment of the present invention;
FIG. 4 is a functional block diagram of a multi-characteristic electric energy metering device provided by the embodiment of the invention;
fig. 5 is a functional block diagram of a terminal according to an embodiment of the present invention.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the following description is made with reference to the accompanying drawings.
The following is a detailed description of the embodiments of the present invention, which is implemented on the premise of the technical solution of the present invention, and the detailed implementation and the specific operation procedures are given, but the scope of the present invention is not limited to the following embodiments.
Fig. 1 is a flowchart of a multi-characteristic-quantity electric energy metering method according to an embodiment of the present invention.
As shown in fig. 1, it shows a flowchart of an implementation of the multi-feature electric energy metering method provided by the embodiment of the present invention, and details are as follows:
in step 101, a waveform at a feeder terminal is obtained, wherein the feeder is used for accessing a load and/or a power supply, and the waveform is used for representing a waveform of electric energy transmitted by the feeder.
Illustratively, as shown in fig. 2, fig. 2 shows a schematic diagram of a power transmission line with distributed power sources provided by an embodiment of the present invention, in the prior art, a power transmission network bus 201 is provided with a plurality of feeders 202, and there are loads 203 and possibly distributed power sources 204 on the feeders, and the forms of the distributed power sources are many, such as wind power generation, solar power generation, and the like.
In the application scenario, the electric energy metering situation is very complicated due to loads and/or distributed power sources connected to the feeder lines, for example, in some feeder lines, grid-connected power generation is performed on the bus 201 in some time periods, and electricity is used through the bus 201 in some time periods. The waveform may be a voltage waveform, a current waveform, or both, as the case may be, and is not limited herein.
In step 102, the waveform is sampled to obtain a waveform data set.
In some embodiments, the sampling rate is determined based on a waveform, including:
obtaining a plurality of sample waveforms, wherein the sample waveforms correspond to a target capacity gear, and the target capacity gear is determined based on the capacity of input electric energy and/or the capacity of output electric energy;
for each sample waveform in the plurality of sample waveforms, obtaining a sampling rate corresponding to a target capacity level by:
sampling the sample waveform at a sample sampling rate to obtain a sample waveform data set;
performing Fourier transform on the sample waveform based on the sample waveform dataset to obtain a sample fundamental wave and a plurality of sample higher harmonics;
determining a transformed deviation ratio according to the sample waveform, the sample fundamental wave and the plurality of sample higher harmonics;
if the deviation rate is lower than a threshold value, screening out a plurality of harmonics with harmonic rates higher than the threshold value from the plurality of sample higher harmonics as typical harmonics, wherein the harmonic rate is the ratio of the amplitude of the sample higher harmonics to the amplitude of the sample fundamental wave;
and determining a target sampling rate according to the frequency of the harmonic of the highest order in the typical harmonic, and taking the target sampling rate as the sampling rate of the sample waveform corresponding to the target capacity gear.
In some embodiments, the determining a transformed deviation ratio from the sample waveform, the sample fundamental, and the plurality of sample higher harmonics comprises:
according to the sample sampling rate, respectively sampling the sample fundamental wave and the plurality of sample higher harmonics to obtain a plurality of conversion sets, wherein the plurality of conversion sets correspond to a plurality of sampling points, and each conversion set comprises a sampling value of the fundamental wave and a sampling value of the plurality of sample higher harmonics;
for each of the plurality of transformation sets, performing the following steps to obtain a deviation ratio of a plurality of sampling points:
accumulating the sampling value of the fundamental wave and the sampling values of the multiple sample higher harmonic samples in the transformation set to obtain an accumulated sum;
finding out waveform data values in the sample waveform data set according to the sampling positions corresponding to the transformation set;
calculating the deviation rate of the accumulated sum and the waveform data value as the deviation rate of a sampling point;
and calculating the average value of the deviation ratios of the plurality of sampling points as the converted deviation ratio.
In some embodiments, the sampling employs a dynamic sampling rate, and step 102 includes:
acquiring a time pane, wherein the time pane comprises a time period;
taking out a section of waveform from the waveforms according to the time window;
turning the section of waveform to obtain a turned waveform, wherein the turning is to turn the negative half cycle of the waveform to the positive half cycle in an amplitude mirror image mode;
integrating the reversed waveform to obtain an effective value of the waveform;
and selecting a dynamic sampling rate according to the effective value, sampling the waveform, and acquiring a waveform data set, wherein the dynamic sampling rate is acquired based on a sampling rate set, the sampling rate set comprises sampling rates of a plurality of target capacity gears, and the sampling rate of the target capacity gear corresponds to the target capacity gear.
Illustratively, for the aspect of transforming the waveform, one form of transformation is discrete fourier transform, that is, the waveform is sampled to obtain a plurality of sampled data points, and based on the plurality of data points, fourier transform is performed to obtain fundamental waves and higher harmonics of the waveform.
However, the number of harmonics is not determined based on the uncertainty of power consumption and power generation in reality, for example, when a feeder acquires power from a bus, the higher the power consumption, the more the harmonics, and the less the harmonics, the more the harmonics, and the more the harmonics.
Correspondingly, as known from shannon's theorem, the sampling rate should be at least twice the target frequency to be sampled, and when the highest harmonic frequency is determined, the sampling rate is determined. The degree of sampling rate, the precision after relation transformation, the data processing speed and the like are the key points for guaranteeing the metering precision of the multi-feature quantity.
Based on the derivation process, in the embodiment of the invention, the historical waveforms are sorted, a plurality of sample waveforms are collected, and the sample waveforms correspond to corresponding capacity files.
Then, the step of determining the sampling rate is performed for each sample of the plurality of sample waveforms, and the sampling is performed according to the sample sampling rate, wherein the frequency of the sample sampling rate is high, so that sufficient conditions can be provided for the subsequent Fourier transform. Then, fourier transform is performed according to the sampled data to transform fundamental waves and higher harmonics, wherein the frequency of the obtained higher harmonics is set to be high, then, the higher harmonics are screened according to the ratio of the amplitude of the fundamental waves to the amplitude of the fundamental waves, the higher harmonics with the amplitude of the fundamental waves are cut off, only the higher harmonics with the amplitude of the fundamental waves are reserved, then, the fundamental waves 302 and the reserved higher harmonics 303 are sampled again and accumulated according to the mode shown in FIG. 3, then, the accumulated harmonics are compared with the waveform 301 sampled data at the same time, if the comparison result shows that the deviation between the two is small, the obtained decomposed higher harmonics at present are satisfied, finally, the highest harmonic in the harmonics is taken as the highest harmonic after transformation, the frequency of the highest harmonic is multiplied by two, and a certain margin is added to be used as the sampling rate of the sample waveform, namely, the sampling rate of the target volume gear. It should be noted that, in some embodiments, the deviation of the accumulated sum from the waveform data sampling value is obtained by averaging the deviations of a plurality of simultaneous points, and this average may be an arithmetic average, or an average calculated by other calculation methods, and is not limited herein.
In the aspect of applying the dynamic sampling rate, the invention provides a mode for determining the sampling rate through a current waveform, specifically, a current waveform of a time window is taken out each time, the time window spans a time period, then, a waveform is taken out, the lower half part of the waveform is mirrored to the upper half part by taking the horizontal axis as a mirror axis, then, the waveform is integrated, an effective value of the current waveform is obtained, and the sampling rate corresponding to the capacity is selected according to the size of the effective value.
In step 103, the waveform is fourier transformed based on the waveform data set, and a fundamental wave and a plurality of higher harmonics are acquired.
In some embodiments, step 103 comprises:
acquiring a sampling rate corresponding to the waveform data set;
determining a transformation target frequency according to the sampling rate, wherein the transformation target frequency is the frequency of the highest harmonic in a plurality of higher harmonics obtained by Fourier transformation;
calculating to obtain a fundamental wave and a plurality of higher harmonics according to the transformation target frequency, the waveform data set and the first formula, wherein the first formula is as follows:
where X [ k ] is the k-th converted wave, X [ N ] is the nth element in the waveform data set, and N is the total amount of data in the waveform data set.
Illustratively, after determining the target sampling rate, we can determine the frequency of the highest harmonic after variation according to the target sampling rate (according to shannon's theorem, the frequency of the highest harmonic should be 1/2 of the sampling rate), so as to obtain the fundamental wave and the higher harmonic of the waveform by the discrete fourier transform formula, where the transform formula is:
where X [ k ] is the k-th converted wave, X [ N ] is the nth element in the waveform data set, and N is the total amount of data in the waveform data set.
In step 104, a plurality of characteristic quantities are performed on the fundamental wave and the plurality of higher harmonics, and measurement data of the plurality of characteristic quantities are obtained, wherein the measurement data represent attribute characteristics of the electric energy.
In some embodiments, the multi-feature metric metrology data comprises: the step 104 includes the steps of providing active power corresponding to a plurality of harmonics and reactive power corresponding to a plurality of harmonics, the fundamental wave and the plurality of harmonics including a fundamental wave of voltage, a plurality of harmonics of voltage, a fundamental wave of current, and a harmonic of current:
pairing the fundamental wave of voltage, a plurality of harmonics of voltage, the fundamental wave of current and the harmonics of current according to the frequencies of the fundamental wave and the harmonics to generate a plurality of voltage-current pairs;
respectively carrying out dot multiplication operation and cross multiplication operation on the plurality of voltage-current pairs to obtain active power of a plurality of harmonics and reactive power of the plurality of harmonics;
and respectively accumulating the active power of the plurality of harmonics and the reactive power of the plurality of harmonics to obtain total active power and total reactive power.
In some embodiments, the multi-feature metric metrology data comprises: a power factor corresponding to a plurality of harmonics, the fundamental wave and the plurality of harmonics including a fundamental wave of voltage, a plurality of harmonics of voltage, a fundamental wave of current, and a harmonic of current, step 104 comprising:
pairing the fundamental wave of the voltage, the plurality of harmonics of the voltage, the fundamental wave of the current and the harmonics of the current according to the frequencies of the fundamental wave and the harmonics to generate a plurality of voltage-current pairs;
determining power factors of a plurality of harmonics according to the plurality of voltage-current pairs and a second formula, the second formula being:
in the formula, cos k (theta) is the power factor of the kth harmonic, X u (k) Is the kth harmonic of the voltage, X i (k) The kth harmonic of the current.
For example, the voltage waveform and the current waveform are sampled and converted at the same time, and the obtained fundamental wave and the obtained higher harmonic are very important for obtaining a plurality of characteristics of electric energy, for example, active, reactive or power factors of each harmonic can be obtained, and the following description is provided in relation to some application scenarios.
For the active or reactive aspect of each harmonic, because the waveforms of different frequencies of the fundamental wave and the higher harmonic are orthogonal (the length of the waveform taken out by a time pane ensures orthogonality), in the active and reactive aspects, only the voltage harmonic and the current harmonic need to be paired according to the frequency, after the pairing is completed, the voltage harmonic and the current harmonic are subjected to point multiplication to obtain the active power under the harmonic frequency, the voltage harmonic and the current harmonic are subjected to cross multiplication to obtain the reactive power under the harmonic frequency, the active power under multiple harmonic frequencies is accumulated to obtain the total active power, and similarly, the reactive power under multiple harmonic frequencies is accumulated to obtain the total reactive power.
For power factor, after the voltage harmonic and the current harmonic are paired according to the frequency, the power factor at the harmonic can be calculated according to the following formula:
in the formula, cos k (theta) is the power factor of the kth harmonic, X u (k) Is the kth harmonic of the voltage, X i (k) The kth harmonic of the current.
According to the embodiment of the electric energy metering method with the multiple characteristic quantities, firstly, the waveform of a feeder terminal is obtained, wherein the feeder is used for being connected to a load and/or a power supply, and the waveform is used for representing the waveform of electric energy transmitted by the feeder. The waveform is then sampled to obtain a waveform data set. Next, fourier transform is performed on the waveform based on the waveform dataset to obtain a fundamental wave and a plurality of higher harmonics. And finally, carrying out operation of a plurality of characteristic quantities on the fundamental wave and the plurality of higher harmonics, and acquiring measurement data of the plurality of characteristic quantities, wherein the measurement data represent the attribute characteristics of the electric energy. According to the embodiment of the invention, the reasonable sampling rate can be determined through the waveform, the accuracy of each harmonic after conversion can be ensured, the complexity of sampling and calculation is reduced, the two are considered, after the harmonic obtained by conversion is converted, the metering data such as harmonic active power, harmonic reactive power, power factors, harmonic factors, main harmonic and the like can be respectively calculated according to the harmonic, and the accuracy of the metering data is ensured.
It should be understood that the sequence numbers of the steps in the above embodiments do not mean the execution sequence, and the execution sequence of each process should be determined by the function and the inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.
The following are apparatus embodiments of the invention, and for details not described in detail therein, reference may be made to the corresponding method embodiments described above.
Fig. 4 is a functional block diagram of a multi-feature electric energy metering device according to an embodiment of the present invention, and referring to fig. 4, the multi-feature electric energy metering device 4 includes: a waveform acquisition module 401, a waveform sampling module 402, a fourier transform module 403, and a multi-feature metric module 404.
The waveform obtaining module 401 is configured to obtain a waveform of a feeder end, where the feeder is used to access a load and/or a power supply, and the waveform is used to represent a waveform of electric energy transmitted by the feeder;
a waveform sampling module 402, configured to sample the waveform to obtain a waveform data set;
a fourier transform module 403, configured to perform fourier transform on the waveform based on the waveform data set, so as to obtain a fundamental wave and a plurality of higher harmonics;
and a multi-feature-quantity metering module 404, configured to perform a plurality of feature-quantity operations on the fundamental wave and the plurality of higher harmonics, and obtain metering data of a plurality of feature quantities, where the metering data represents an attribute feature of the electric energy.
Fig. 5 is a functional block diagram of a terminal according to an embodiment of the present invention. As shown in fig. 5, the terminal 5 of this embodiment includes: a processor 500 and a memory 501, the memory 501 having stored therein a computer program 502 executable on the processor 500. The processor 500 executes the computer program 502 to implement the above-mentioned multi-feature electric energy metering method and the steps in the embodiment, such as the steps 101 to 104 shown in fig. 1.
Illustratively, the computer program 502 may be partitioned into one or more modules/units that are stored in the memory 501 and executed by the processor 500 to implement the present invention.
The terminal 5 may be a desktop computer, a notebook, a palm computer, a cloud server, or other computing devices. The terminal 5 may include, but is not limited to, a processor 500, a memory 501. It will be appreciated by those skilled in the art that fig. 5 is merely an example of a terminal 5 and does not constitute a limitation of the terminal 5, and may include more or fewer components than shown, or some components may be combined, or different components, e.g., the terminal may also include input output devices, network access devices, buses, etc.
The Processor 500 may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic device, discrete hardware component, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory 501 may be an internal storage unit of the terminal 5, such as a hard disk or a memory of the terminal 5. The memory 501 may also be an external storage device of the terminal 5, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card) and the like provided on the terminal 5. Further, the memory 501 may also include both an internal storage unit and an external storage device of the terminal 5. The memory 501 is used for storing the computer program and other programs and data required by the terminal. The memory 501 may also be used to temporarily store data that has been output or is to be output.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of the functional units and modules is illustrated, and in practical applications, the above-mentioned function distribution may be performed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-mentioned functions. Each functional unit and module in the embodiments may be integrated in one processing unit, or each unit may exist alone physically, or two or more units are integrated in one unit, and the integrated unit may be implemented in a form of hardware, or in a form of software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. For the specific working processes of the units and modules in the system, reference may be made to the corresponding processes in the foregoing method embodiments, which are not described herein again.
In the above embodiments, the description of each embodiment is focused on, and for parts that are not described or recited in a certain embodiment, reference may be made to the description of other embodiments.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
In the embodiments provided in the present invention, it should be understood that the disclosed apparatus/terminal and method may be implemented in other manners. For example, the above-described apparatus/terminal embodiments are merely illustrative, and for example, the division of the modules or units is only one type of logical function division, and other division manners may exist in actual implementation, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated modules/units, if implemented in the form of software functional units and sold or used as separate products, may be stored in a computer readable storage medium. Based on such understanding, all or part of the flow in the method according to the above embodiments may be implemented by a computer program, which may be stored in a computer readable storage medium and used by a processor to implement the steps of the method and apparatus embodiments. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, read-Only Memory (ROM), random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, and the like.
The above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may be modified or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.
Claims (10)
1. A multi-characteristic-quantity electric energy metering method is characterized by comprising the following steps:
acquiring a waveform of a feeder terminal, wherein the feeder is used for accessing a load and/or a power supply, and the waveform is used for representing a waveform of electric energy transmitted by the feeder;
sampling the waveform to obtain a waveform data set;
performing Fourier transform on the waveform based on the waveform data set to obtain a fundamental wave and a plurality of higher harmonics;
and performing a plurality of characteristic quantity operations on the fundamental wave and the plurality of higher harmonics, and acquiring measurement data of the plurality of characteristic quantities, wherein the measurement data represents the attribute characteristics of the electric energy.
2. The multi-feature quantity electric energy metering method according to claim 1, wherein the sampling rate is determined based on a waveform, and includes:
obtaining a plurality of sample waveforms, wherein the sample waveforms correspond to a target capacity gear, and the target capacity gear is determined based on the capacity of input electric energy and/or the capacity of output electric energy;
for each sample waveform in the plurality of sample waveforms, obtaining a sampling rate corresponding to a target capacity level by:
sampling the sample waveform at a sample sampling rate to obtain a sample waveform data set;
performing Fourier transform on the sample waveform based on the sample waveform dataset to obtain a sample fundamental wave and a plurality of sample higher harmonics;
determining a transformed deviation ratio according to the sample waveform, the sample fundamental wave and the plurality of sample higher harmonics;
if the deviation rate is lower than a threshold value, screening out a plurality of harmonics with harmonic rates higher than the threshold value from the plurality of sample higher harmonics as typical harmonics, wherein the harmonic rate is the ratio of the amplitude of the sample higher harmonics to the amplitude of the sample fundamental wave;
and determining a target sampling rate according to the frequency of the harmonic of the highest order in the typical harmonic, and taking the target sampling rate as the sampling rate of the sample waveform corresponding to the target capacity gear.
3. The multi-signature-quantity electric energy metering method according to claim 2, wherein the determining a transformed deviation ratio from the sample waveform, the sample fundamental wave, and the plurality of sample higher harmonics comprises:
according to the sample sampling rate, respectively sampling the sample fundamental wave and the plurality of sample higher harmonics to obtain a plurality of conversion sets, wherein the plurality of conversion sets correspond to a plurality of sampling points, and the conversion sets comprise sampling values of the fundamental wave and sampling values of the plurality of sample higher harmonics;
for each of the plurality of transformation sets, performing the following steps to obtain a deviation ratio of a plurality of sampling points:
accumulating the sampling value of the fundamental wave and the sampling values of the multiple sample higher harmonic samples in the transformation set to obtain an accumulated sum;
finding waveform data values in the sample waveform data set according to the sampling positions corresponding to the transformation set;
calculating the deviation rate of the accumulated sum and the waveform data value as the deviation rate of a sampling point;
and calculating the average value of the deviation ratios of the plurality of sampling points as the converted deviation ratio.
4. The multi-feature-quantity electric energy metering method according to claim 1, wherein the sampling adopts a dynamic sampling rate, and the sampling the waveform to obtain a waveform data set comprises:
acquiring a time pane, wherein the time pane comprises a time period;
taking out a section of waveform from the waveforms according to the time window;
turning the section of waveform to obtain a turned waveform, wherein the turning is to turn the negative half cycle of the waveform to the positive half cycle in an amplitude mirror image mode;
integrating the reversed waveform to obtain an effective value of the waveform;
and selecting a dynamic sampling rate according to the effective value, sampling the waveform, and acquiring a waveform data set, wherein the dynamic sampling rate is acquired based on a sampling rate set, the sampling rate set comprises sampling rates of a plurality of target capacity gears, and the sampling rate of the target capacity gear corresponds to the target capacity gear.
5. The multi-characteristic quantity electric energy metering method according to claim 1, wherein the fourier transforming the waveform based on the waveform data set, obtaining a fundamental wave and a plurality of higher harmonics, comprises:
acquiring a sampling rate corresponding to the waveform data set;
determining a transformation target frequency according to the sampling rate, wherein the transformation target frequency is the frequency of the highest harmonic in a plurality of higher harmonics obtained by Fourier transformation;
calculating and obtaining a fundamental wave and a plurality of higher harmonics according to the transformation target frequency, the waveform data set and the first formula, wherein the first formula is as follows:
where X [ k ] is the k-th converted wave, X [ N ] is the nth element in the waveform data set, and N is the total amount of data in the waveform data set.
6. The multi-characteristic-quantity electric energy metering method according to any one of claims 1 to 5, characterized in that the multi-characteristic-quantity metering data comprises: the active power corresponding to a plurality of harmonics and the reactive power corresponding to a plurality of harmonics, the fundamental wave and the plurality of harmonics include fundamental wave of voltage, a plurality of harmonics of voltage, fundamental wave of current and harmonics of current, the fundamental wave and the plurality of harmonics are operated by a plurality of characteristic quantities, and the measurement data of the plurality of characteristic quantities are acquired, and the method comprises the following steps:
pairing the fundamental wave of the voltage, the plurality of harmonics of the voltage, the fundamental wave of the current and the harmonics of the current according to the frequencies of the fundamental wave and the harmonics to generate a plurality of voltage-current pairs;
respectively performing dot multiplication operation and cross multiplication operation on the voltage-current pairs to obtain active power of a plurality of harmonics and reactive power of the plurality of harmonics;
and respectively accumulating the active power of the plurality of harmonics and the reactive power of the plurality of harmonics to obtain total active power and total reactive power.
7. The multi-characteristic-quantity electric energy metering method according to any one of claims 1 to 5, characterized in that the multi-characteristic-quantity metering data comprises: the power factor corresponding to a plurality of harmonics, the fundamental wave and the plurality of harmonics include a fundamental wave of voltage, a plurality of harmonics of voltage, a fundamental wave of current, and a harmonic of current, the operation of a plurality of characteristic quantities is performed on the fundamental wave and the plurality of harmonics, and measurement data of a plurality of characteristic quantities is acquired, including:
pairing the fundamental wave of voltage, a plurality of harmonics of voltage, the fundamental wave of current and the harmonics of current according to the frequencies of the fundamental wave and the harmonics to generate a plurality of voltage-current pairs;
determining power factors of a plurality of harmonics according to the plurality of voltage-current pairs and a second formula, wherein the second formula is as follows:
in the formula, cos k (theta) is the power factor of the kth harmonic, X u (k) Is the kth harmonic of the voltage, X i (k) The kth harmonic of the current.
8. A multi-characteristic-quantity electric energy metering device, comprising:
the device comprises a waveform acquisition module, a power supply acquisition module and a control module, wherein the waveform acquisition module is used for acquiring the waveform of a feeder terminal, the feeder is used for accessing a load and/or a power supply, and the waveform is used for representing the waveform of electric energy transmitted by the feeder;
the waveform sampling module is used for sampling the waveform to obtain a waveform data set;
a Fourier transform module for performing Fourier transform on the waveform based on the waveform data set to obtain a fundamental wave and a plurality of higher harmonics;
and the number of the first and second groups,
and the multi-characteristic quantity measuring module is used for carrying out operation on a plurality of characteristic quantities on the fundamental wave and the plurality of higher harmonics and acquiring measuring data of the plurality of characteristic quantities, wherein the measuring data represents the attribute characteristics of the electric energy.
9. A terminal comprising a memory and a processor, the memory having stored therein a computer program operable on the processor, wherein the processor, when executing the computer program, performs the steps of the method according to any of claims 1 to 7.
10. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 7.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116068452A (en) * | 2023-03-08 | 2023-05-05 | 石家庄科林电气股份有限公司 | Power supply type judging method based on power supply characteristics, double-source electric energy metering method and double-source metering electric energy meter |
| CN116106624A (en) * | 2023-04-12 | 2023-05-12 | 石家庄科林电气股份有限公司 | Electric quantity calculation method and device and terminal equipment |
| CN116381325A (en) * | 2023-03-29 | 2023-07-04 | 四川辰鳗科技有限公司 | Distributed energy metering method, system, electronic equipment and medium |
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2022
- 2022-07-13 CN CN202210827046.5A patent/CN115236392A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116068452A (en) * | 2023-03-08 | 2023-05-05 | 石家庄科林电气股份有限公司 | Power supply type judging method based on power supply characteristics, double-source electric energy metering method and double-source metering electric energy meter |
| CN116068452B (en) * | 2023-03-08 | 2023-06-06 | 石家庄科林电气股份有限公司 | Power supply type judging method based on power supply characteristics, double-source electric energy metering method and double-source metering electric energy meter |
| CN116381325A (en) * | 2023-03-29 | 2023-07-04 | 四川辰鳗科技有限公司 | Distributed energy metering method, system, electronic equipment and medium |
| CN116106624A (en) * | 2023-04-12 | 2023-05-12 | 石家庄科林电气股份有限公司 | Electric quantity calculation method and device and terminal equipment |
| CN116106624B (en) * | 2023-04-12 | 2023-08-01 | 石家庄科林电气股份有限公司 | Electric quantity calculation method and device and terminal equipment |
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