CN113030835A - Electric energy meter metering method - Google Patents
Electric energy meter metering method Download PDFInfo
- Publication number
- CN113030835A CN113030835A CN202110166850.9A CN202110166850A CN113030835A CN 113030835 A CN113030835 A CN 113030835A CN 202110166850 A CN202110166850 A CN 202110166850A CN 113030835 A CN113030835 A CN 113030835A
- Authority
- CN
- China
- Prior art keywords
- electric energy
- current
- energy meter
- metering
- data
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/04—Testing or calibrating of apparatus covered by the other groups of this subclass of instruments for measuring time integral of power or current
Abstract
The invention relates to an electric energy meter metering method, which comprises the following steps: the MCU in the electric energy meter before leaving factory stores a first adjusting coefficient for adjusting the metering data of the full-wave current and a second adjusting coefficient for adjusting the metering data of the half-wave current; the MCU reads and stores current waveform sampling data in the metering chip, performs discrete Fourier transform on the current waveform sampling data, and calculates the even harmonic content and the odd harmonic content; then judging whether the even harmonic content is in a set threshold range and the odd harmonic content is 0 or a value close to 0; if yes, judging that the current is half-wave current, and calling a second adjustment coefficient to adjust the electric energy measured by the electric energy meter; if not, the first adjusting coefficient is called to adjust the electric energy measured by the electric energy meter. The method can realize the error adjustment and calibration of the half-wave current, and improves the metering accuracy of the electric energy meter.
Description
Technical Field
The invention relates to the field of electric energy meters, in particular to a metering method of an electric energy meter.
Background
The electric energy meter is used as a standard electric energy metering device, and whether the metering is accurate or not is related to the vital interests of a power grid company and a power utilization user. With the wide application of power electronic technology, half-wave rectification power supply circuits (such as switching power supplies) in power utilization environments are increasing.
The conventional electric energy meter is designed aiming at a power frequency sine wave (full wave), the existing sampling element is also used for metering the full wave, and at present, the common sampling element is a current transformer, so that the electric energy meter for metering the full wave is applied to a half-wave current electricity utilization environment under the common condition. In addition, the power utilization environment can be a waveform except for full waves and half waves, but the current electric energy meter for measuring the full waves cannot completely and accurately measure the power utilization data of a user, so that further improvement is needed.
Disclosure of Invention
The invention aims to solve the technical problem of providing a method for metering an electric energy meter with high metering accuracy aiming at the current situation of the prior art.
The technical scheme adopted by the invention for solving the technical problems is as follows: the utility model provides an electric energy meter metering method, be provided with MCU and the measurement circuit who is connected with MCU in the electric energy meter, measurement circuit includes measurement chip and the current sampling module who is connected with measurement chip, its characterized in that: the electric energy meter metering method comprises the following steps:
step 3, the MCU reads and stores the current waveform sampling data x (N) in the step 2, wherein N is 0, 1 and 2 … N-1;
step 4, performing discrete Fourier transform on the current waveform sampling data x (n) in the MCU to obtain data X (k) after the discrete Fourier transform: k is the harmonic order, k is 0, 1, 2 … N-1;
step 5, calculating the even harmonic content q [ i ] and the odd harmonic content rj according to the X (k) in the step 4; i is an even number, j is an odd number; i belongs to k, and j belongs to k;
step 6, judging whether the even harmonic content q [ i ] is in a set threshold range and the odd harmonic content rj is 0 or a numerical value close to 0; if yes, judging that the current is half-wave current, and turning to step 7; if not, the step 8 is carried out;
step 7, the MCU calls a second adjustment coefficient B to adjust the electric energy measured by the electric energy meter, the adjusted electric energy data is stored as the actual electric energy used by the user, and the step 9 is carried out;
step 8, the MCU calls a first adjustment coefficient A to adjust the electric energy measured by the electric energy meter, the adjusted electric energy data is used as the actual electric energy used by the user to be stored, and the step 9 is carried out;
and 9, continuously processing the current waveform sampling data of the next period by adopting the same method in the steps 2 to 6, and calling the adjustment coefficient according to the same method in the steps 7 and 8 to adjust the electric energy measured by the electric energy meter.
Specifically, the calculation formula of x (k) in step 4 is:
further, the specific calculation formula in step 5 is as follows:
the calculation formula of the k-th harmonic value Result [ k ] is as follows:
wherein real (k) is the real part of X (k),
imag (k) is the imaginary part of X (k),
the calculation formulas of the even harmonic content q [ i ] and the odd harmonic content r [ j ] are respectively as follows:
q[i]＝Result[i]/Result[1]
r[j]＝Result[j]/Result[1]
wherein Result [ i ] is the ith harmonic value, and Result [1] is the 1 st harmonic value, namely the fundamental wave; result [ j ] is the jth harmonic value.
As an improvement, a current sampling element is arranged in the current sampling module, and the current sampling element is an anti-direct current transformer.
In this embodiment, the number N of sampling points in step 2 is 64, 128, or 256.
Preferably, the number of sampling points in step 2 is N-128.
Preferably, in the step 5, i is 2, 4, 6 … 20; j is 1, 3, 5 … 21.
The specific method in the step 6 is as follows: it is determined whether the order 2, 4, 6 and 8 harmonic content is within a selected threshold range and the order 3, 5, 7 harmonic content is 0 or a value close to 0.
In a further improvement, in the step 1, before the electric energy meter leaves the factory, the method further includes the following steps:
and (3) accessing other current waveforms except the full wave and the half wave into the electric energy meter, then performing the processing in the steps (2) to (5), establishing a current characteristic information base of various different currents according to the even harmonic content and the odd harmonic content obtained by calculating in the step (5) of various different currents, and additionally establishing a metering and adjusting base corresponding to various different currents.
Further, the method comprises the following steps:
processing the actual power utilization current waveform sampling data according to the methods in the step 4 and the step 5 to obtain current characteristic information;
searching whether an object matched with the current characteristic information exists in a current characteristic information base, if so, selecting a calibration coefficient corresponding to the current characteristic information in a measurement calibration base; if not, selecting a first adjustment coefficient A for adjusting the measurement data of the full-wave current as an adjustment coefficient;
and the MCU adjusts the electric energy measured by the electric energy meter by using the adjustment coefficient, and saves the adjusted electric energy data as the actual electric energy of the user.
Compared with the prior art, the invention has the advantages that: and processing and analyzing the current waveform sampling data to judge whether the current is half-wave current, and adjusting the metering data by using the corresponding adjustment coefficient when the electricity environment is half-wave current when the electricity environment is judged to be half-wave current, or adjusting the metering data by using the corresponding adjustment coefficient when the electricity environment is full-wave current. According to the metering method, metering data adjustment is realized when the electricity environment is half-wave current by distinguishing half-wave current from full-wave current. In addition, the measurement data of more different current waveforms can be calibrated by establishing a current characteristic information base and a current error calibration base of other waveforms. Therefore, the method improves the metering accuracy and is more reasonable and practical.
Drawings
FIG. 1 is a graph of a current waveform during a certain period according to an embodiment of the present invention;
FIG. 2 is a graph of the content of harmonics of the waveform of FIG. 1 after discrete Fourier transform;
FIG. 3 is a flow chart of a method for metering an electric energy meter according to an embodiment of the present invention;
fig. 4 is a flowchart illustrating another embodiment of adjusting the electric energy measured by the current waveform.
Detailed Description
The invention is described in further detail below with reference to the accompanying examples.
The general electric energy meter is internally provided with an MCU and a metering circuit connected with the MCU, wherein the metering circuit comprises a metering chip, a current sampling module and a voltage sampling module which are connected with the metering chip, and the metering circuit is a commonly used structure in the existing electric energy meter; as shown in fig. 3, the present embodiment discloses a method for metering an electric energy meter, which includes the following steps:
in general, the electricity environment of a user is generally full-wave current, in the step, the measurement data of the full-wave current of the electric energy meter before delivery is calibrated by using a method commonly used in the measurement field of the existing electric energy meter so as to determine a first calibration coefficient A, and meanwhile, the measurement data of the half-wave current is calibrated by using the same method as the calibration of the measurement data of the full-wave current so as to determine a second calibration coefficient B;
step 3, the MCU reads and stores the current waveform sampling data x (N) in the step 2, wherein N is 0, 1 and 2 … N-1; opening up a storage space of the current waveform sampling data in an MCU of the electric energy meter;
step 4, performing discrete Fourier transform on the current waveform sampling data x (n) in the MCU to obtain data X (k) after the discrete Fourier transform: in the above formula, the current waveform sampling data x (n) are real signals, i.e. the imaginary part is 0, i.e. the discrete fourier transform is expanded into the following formula, and the specific calculation formula is:
wherein k is the harmonic order, and k is 0, 1, 2 … N-1;
in this embodiment, each harmonic data is obtained by 128-point fourier transform;
step 5, calculating the even harmonic content q [ i ] and the odd harmonic content rj according to the X (k) in the step 4; is even, j is odd; i belongs to k, and j belongs to k; in the scheme, the harmonic content of 1-21 times is preferably calculated, so that i is 2, 4 and 6 … 20; j ═ 1, 3, 5 … 21;
the calculation formulas of the even harmonic content q [ i ] and the odd harmonic content r [ j ] are respectively as follows:
q[i]＝Result[i]/Result[1]
r[j]＝Result[j]/Result[1]
wherein Result [ i ] is the ith harmonic value, and Result [1] is the 1 st harmonic value, namely the fundamental wave; result [ j ] is the jth harmonic value;
wherein, the calculation formula of the kth harmonic value Result [ k ] is as follows:
wherein real (k) is the real part of X (k),
imag (k) is the imaginary part of X (k),
step 6, judging whether the even harmonic content q [ i ] is in a set threshold range and the odd harmonic content rj is 0 or a numerical value close to 0; if yes, judging that the current is half-wave current, and turning to step 7; if not, the step 8 is carried out; where a value close to 0 means a negligible value, for example: a value within 0 to 0.1;
in this embodiment, as shown in fig. 1 and fig. 2, fig. 2 is a diagram illustrating the harmonic content of each order calculated after performing discrete fourier transform on the waveform in fig. 1, for example, the harmonic content of 50HZ is a harmonic (fundamental wave) of 1 th order, and the DC content indicates that the DC content exists in the half-wave current and affects the sampling of the current transformer; the content of the 2nd (2nd) harmonic is 20%, the content of the 4 th (4nd) harmonic is 5%, the corresponding harmonic content is gradually reduced when the frequency is larger, and the odd harmonic content in the graph is basically 0, so that in the embodiment, whether the 2nd, 4 th, 6 th and 8 th harmonic content is in the selected threshold range and the 3 rd, 5 th and 7 th harmonic content is 0 or a numerical value close to 0 is only required to be judged; in this embodiment, the preferred selected threshold ranges of the 2nd, 4 th and 6 th harmonic contents are respectively: the content of 20% <2 th harmonic < 25%, the content of 3% <4 th harmonic < 6%, and the content of 1% <6 th harmonic < 3%;
step 7, the MCU calls a second adjustment coefficient B to adjust the electric energy measured by the electric energy meter, the adjusted electric energy data is stored as the actual electric energy used by the user, and the step 9 is carried out;
wherein, the electric energy W (P) T (U) I cos (psi) measured by the electric energy meter;
p is power, T is time, U is voltage value, I is current value, cos (ψ) is tuning coefficient, the electric energy is tuned by using the second tuning coefficient B as cos (ψ);
step 8, the MCU calls a first adjustment coefficient A to adjust the electric energy measured by the electric energy meter, the adjusted electric energy data is used as the actual electric energy used by the user to be stored, and the step 9 is carried out;
and 9, continuously processing the current waveform sampling data of the next period by adopting the same method in the steps 2 to 6, and calling the adjustment coefficient according to the same method in the steps 7 and 8 to adjust the electric energy measured by the electric energy meter.
The current sampling module is provided with a current sampling element, and the current sampling element outputs a sampling signal to the metering chip. The current sampling element in the existing electric energy meter is generally a current transformer, but the current transformer can generate a magnetic saturation condition due to the direct current component of half-wave current when performing current sampling, so that the current sampling is out of alignment.
The method is only limited to the two cases of full-wave and half-wave current, but in the actual electricity utilization process, the current has other waveform situations except the full-wave and the half-wave, so that the method further comprises the following steps in order to better realize accurate measurement of the current:
as shown in fig. 4, before the electric energy meter leaves the factory, the method further includes the following steps: and (3) accessing other current waveforms except the full wave and the half wave into the electric energy meter, then performing the processing in the steps (2) to (5), establishing a current characteristic information base of various different currents according to the even harmonic content and the odd harmonic content obtained by calculating in the step (5) of various different currents, and additionally establishing a metering and adjusting base corresponding to various different currents.
In the actual metering process of the electric energy meter, processing the actual power utilization current waveform sampling data according to the methods in the steps 4 and 5 to obtain current characteristic information;
searching whether an object matched with the current characteristic information exists in a current characteristic information base, if so, selecting a calibration coefficient corresponding to the current characteristic information in a measurement calibration base; if not, selecting a first adjustment coefficient A for adjusting the measurement data of the full-wave current as an adjustment coefficient;
and the MCU adjusts the electric energy measured by the electric energy meter by using the adjustment coefficient, and saves the adjusted electric energy data as the actual electric energy of the user.
The method can also adjust the measurement data under other currents except for full wave and half wave, so that the accurate measurement of the electric energy can be further realized by selecting the adjustment coefficient corresponding to the current characteristic information of the actual current waveform from the measurement adjustment library.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. The utility model provides an electric energy meter metering method, be provided with MCU and the measurement circuit who is connected with MCU in the electric energy meter, measurement circuit includes measurement chip and the current sampling module who is connected with measurement chip, its characterized in that: the electric energy meter metering method comprises the following steps:
step 1, storing a first calibration coefficient A for calibrating the metering data of the full-wave current and a second calibration coefficient B for calibrating the metering data of the half-wave current in an MCU (microprogrammed control Unit) in the electric energy meter before the electric energy meter leaves a factory;
step 2, the current sampling module transmits the sampled current to a metering chip, and the metering chip stores the current waveform sampling data; the number of current sampling points in one period is N, and N is a positive integer;
step 3, the MCU reads and stores the current waveform sampling data x (N) in the step 2, wherein N is 0, 1 and 2.. N-1;
step 4, performing discrete Fourier transform on the current waveform sampling data x (n) in the MCU to obtain data X (k) after the discrete Fourier transform: k is the harmonic number, k is 0, 1, 2.. N-1;
step 5, calculating the even harmonic content q [ i ] and the odd harmonic content rj according to the X (k) in the step 4; i is an even number, j is an odd number; i belongs to k, and j belongs to k;
step 6, judging whether the even harmonic content q [ i ] is in a set threshold range and the odd harmonic content rj is 0 or a numerical value close to 0; if yes, judging that the current is half-wave current, and turning to step 7; if not, the step 8 is carried out;
step 7, the MCU calls a second adjustment coefficient B to adjust the electric energy measured by the electric energy meter, the adjusted electric energy data is stored as the actual electric energy used by the user, and the step 9 is carried out;
step 8, the MCU calls a first adjustment coefficient A to adjust the electric energy measured by the electric energy meter, the adjusted electric energy data is used as the actual electric energy used by the user to be stored, and the step 9 is carried out;
and 9, continuously processing the current waveform sampling data of the next period by adopting the same method in the steps 2 to 6, and calling the adjustment coefficient according to the same method in the steps 7 and 8 to adjust the electric energy measured by the electric energy meter.
2. The method of metering an electric energy meter according to claim 1, wherein: the calculation formula of x (k) in step 4 is:
3. the method of metering an electric energy meter according to claim 2, wherein: the specific calculation formula in the step 5 is as follows:
the calculation formula of the k-th harmonic value Result [ k ] is as follows:
wherein real (k) is the real part of X (k),
imag (k) is the imaginary part of X (k),
the calculation formulas of the even harmonic content q [ i ] and the odd harmonic content r [ j ] are respectively as follows:
q[i]＝Result[i]/Result[1]
r[j]＝Result[j]/Result[1]
wherein Result [ i ] is the ith harmonic value, and Result [1] is the 1 st harmonic value, namely the fundamental wave; result [ j ] is the jth harmonic value.
4. The method of metering an electric energy meter according to claim 1, wherein: the current sampling module is internally provided with a current sampling element, and the current sampling element is an anti-direct current transformer.
5. The method of metering an electric energy meter according to claim 1, wherein: the number of sampling points N in step 2 is 64, 128 or 256.
6. The method of metering an electric energy meter according to claim 5, wherein: the number of sampling points in the step 2 is N-128.
7. The method of metering an electric energy meter according to claim 1, wherein: in the step 5, i is 2, 4, 6.. 20; j ═ 1, 3, 5.. 21.
8. The method of metering an electric energy meter according to claim 7, wherein: the specific method in the step 6 comprises the following steps: it is determined whether the order 2, 4, 6 and 8 harmonic content is within a selected threshold range and the order 3, 5, 7 harmonic content is 0 or a value close to 0.
9. The method of metering an electric energy meter according to claim 1, wherein: in the step 1, before the electric energy meter leaves the factory, the method further comprises the following steps:
and (3) accessing other current waveforms except the full wave and the half wave into the electric energy meter, then performing the processing in the steps (2) to (5), establishing a current characteristic information base of various different currents according to the even harmonic content and the odd harmonic content obtained by calculating in the step (5) of various different currents, and additionally establishing a metering and adjusting base corresponding to various different currents.
10. The method of metering an electric energy meter according to claim 9, wherein: further comprising the steps of:
processing the actual power utilization current waveform sampling data according to the methods in the step 4 and the step 5 to obtain current characteristic information;
searching whether an object matched with the current characteristic information exists in a current characteristic information base, if so, selecting a calibration coefficient corresponding to the current characteristic information in a measurement calibration base; if not, selecting a first adjustment coefficient A for adjusting the measurement data of the full-wave current as an adjustment coefficient;
and the MCU adjusts the electric energy measured by the electric energy meter by using the adjustment coefficient, and saves the adjusted electric energy data as the actual electric energy of the user.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110166850.9A CN113030835B (en) | 2021-02-05 | 2021-02-05 | Electric energy meter metering method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110166850.9A CN113030835B (en) | 2021-02-05 | 2021-02-05 | Electric energy meter metering method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113030835A true CN113030835A (en) | 2021-06-25 |
| CN113030835B CN113030835B (en) | 2022-04-26 |
Family
ID=76460287
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110166850.9A Active CN113030835B (en) | 2021-02-05 | 2021-02-05 | Electric energy meter metering method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113030835B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115526068A (en) * | 2022-11-28 | 2022-12-27 | 北京志翔科技股份有限公司 | Misalignment model parameter determination method, device, equipment and storage medium |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ATE160051T1 (en) * | 1990-12-28 | 1997-11-15 | Eaton Corp | VOLTAGE REGULATOR, POWER SUPPLY AND CALIBRATOR |
| CN2773696Y (en) * | 2004-12-31 | 2006-04-19 | 武汉盛帆电子有限公司 | Capacity-resistance voltage devided electronic intelligent three phase kilowatt meter |
| CN102520382A (en) * | 2012-01-12 | 2012-06-27 | 江西省电力科学研究院 | Method for detecting half-wave current transformation error of current transformer |
| CN109407043A (en) * | 2018-12-29 | 2019-03-01 | 华立科技股份有限公司 | Electric energy meter calibration method, device and equipment |
| CN109557496A (en) * | 2017-09-27 | 2019-04-02 | 宁波三星医疗电气股份有限公司 | A kind of correction method of electric energy meter |
| CN110007137A (en) * | 2019-05-06 | 2019-07-12 | 国网四川省电力公司电力科学研究院 | A kind of intelligent electric energy meter merging multiple terminal monitoring function |
| CN111650435A (en) * | 2020-08-04 | 2020-09-11 | 南京衡瑞电子科技有限公司 | Electric energy metering chip system |
-
2021
- 2021-02-05 CN CN202110166850.9A patent/CN113030835B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ATE160051T1 (en) * | 1990-12-28 | 1997-11-15 | Eaton Corp | VOLTAGE REGULATOR, POWER SUPPLY AND CALIBRATOR |
| CN2773696Y (en) * | 2004-12-31 | 2006-04-19 | 武汉盛帆电子有限公司 | Capacity-resistance voltage devided electronic intelligent three phase kilowatt meter |
| CN102520382A (en) * | 2012-01-12 | 2012-06-27 | 江西省电力科学研究院 | Method for detecting half-wave current transformation error of current transformer |
| CN109557496A (en) * | 2017-09-27 | 2019-04-02 | 宁波三星医疗电气股份有限公司 | A kind of correction method of electric energy meter |
| CN109407043A (en) * | 2018-12-29 | 2019-03-01 | 华立科技股份有限公司 | Electric energy meter calibration method, device and equipment |
| CN110007137A (en) * | 2019-05-06 | 2019-07-12 | 国网四川省电力公司电力科学研究院 | A kind of intelligent electric energy meter merging multiple terminal monitoring function |
| CN111650435A (en) * | 2020-08-04 | 2020-09-11 | 南京衡瑞电子科技有限公司 | Electric energy metering chip system |
Non-Patent Citations (1)
| Title |
|---|
| 陈培余 等: "基于电能表的单点校正检测算法研究", 《机电产品开发与创新》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115526068A (en) * | 2022-11-28 | 2022-12-27 | 北京志翔科技股份有限公司 | Misalignment model parameter determination method, device, equipment and storage medium |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113030835B (en) | 2022-04-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Cataliotti et al. | Compensation of nonlinearity of voltage and current instrument transformers | |
| Lin et al. | On power quality indices and real time measurement | |
| Wen et al. | Frequency estimation of distorted and noisy signals in power systems by FFT-based approach | |
| Zeng et al. | Harmonic phasor analysis based on improved FFT algorithm | |
| Yao et al. | Fast S-transform for time-varying voltage flicker analysis | |
| CN103308766A (en) | Harmonic analysis method based on Kaiser self-convolution window dual-spectrum line interpolation FFT (Fast Fourier Transform) and device thereof | |
| CN108318852B (en) | Square wave influence test method for intelligent electric energy meter | |
| CN108279396A (en) | Anti- DC component current transformer error tester and its test method | |
| CN105487034A (en) | 0.05-level electronic transformer verification method and system | |
| CN110967658B (en) | Analog input merging unit calibrator tracing method based on digital differential method | |
| CN106405470A (en) | Overall detection method and apparatus for harmonic accuracy of electronic current transformer | |
| CN113030835B (en) | Electric energy meter metering method | |
| CN106291092A (en) | The anti-outside Constant charge soil interference method of a kind of intelligent electric meter | |
| US5072187A (en) | Method and apparatus for determining the total harmonic distortion and power factor of a non-linear load circuit | |
| CN108416148A (en) | A kind of high-altitude electromagnetic pulse field wire coupling uncertainty acquisition methods based on polynomial chaos expression | |
| CN109030957B (en) | Dielectric loss measuring method | |
| CN112649652B (en) | Tracing method and system for impulse current magnitude | |
| CN109581045A (en) | A kind of m-Acetyl chlorophosphonazo power measurement method meeting IEC standard frame | |
| CN111289940A (en) | Step delay-based direct-current voltage mutual inductance transient characteristic testing method | |
| CN208207186U (en) | Anti- DC component current transformer error tester | |
| CN116256601A (en) | Sensing method and sensing device for single-phase earth fault of power distribution network and power distribution network | |
| Bucci et al. | Development of a low cost power meter based on a digital signal controller | |
| CN110133563B (en) | Method and device for detecting direct current resistance of current sensor | |
| CN107064633A (en) | Urban track traffic Load harmonic current superposition coefficient determines method | |
| Marais et al. | Reduction of static electricity meter errors by broadband compensation of voltage and current channel differences |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |