CN116125136A - Self-adaptive intelligent ammeter and sampling method - Google Patents
Self-adaptive intelligent ammeter and sampling method Download PDFInfo
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- 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 is applicable to the technical field of intelligent electric meters, and relates to a self-adaptive intelligent electric meter and a sampling method, wherein the self-adaptive intelligent electric meter comprises the following steps: the device comprises a first operational amplifier, a second operational amplifier, a first ADC, a second ADC, a first data processing unit, a second data processing unit and an operation processor; the first operational amplifier, the first ADC, the first data processing unit and the operation processor are sequentially connected, the second operational amplifier, the second ADC, the second data processing unit and the operation processor are sequentially connected, the first operational amplifier and the second operational amplifier are used for receiving and amplifying voltage and current signals, the first ADC and the second ADC are used for collecting the voltage and current signals and converting the voltage and current signals into digital signals, the first data processing unit and the second data processing unit are used for processing the voltage and current data, and the operation processor is used for carrying out correlation calculation on the voltage and current data. The invention has the advantages of simple structure, convenient sampling, wide sampling range and high accuracy.
Description
Technical Field
The invention belongs to the technical field of intelligent electric meters, and particularly relates to a self-adaptive intelligent electric meter and a sampling method.
Background
Along with the high-quality development of the smart power grid, the advanced metering reform is continuously carried out, innovative driving is adhered to, the metering system is continuously perfected, the metering capability is continuously improved, the national modern advanced measuring system is actively constructed, higher requirements are provided for the accuracy of the smart power meter, along with the domestic realization of the carbon neutralization target, the new energy in China is marked to enter the rapid development stage, the investment of new energy projects such as wind power, photovoltaic and electric vehicles is increased, and the high-accuracy metering requirement of the smart power meter is increased.
In addition, compared with the traditional power system, the novel power system has the power supply structure taking new energy as a main body, the strong uncertainty, volatility and a large number of harmonic wave introduction of the novel power system under the access of the high-proportion new energy source can lead the power equipment to bear more extreme and violent-change operation conditions, the new energy source has obvious randomness, volatility and intermittence characteristics, the non-power frequency electric quantity generated by the power electronic equipment in the power grid is more and more abundant, the safety operation of the electric equipment is endangered, the wide-frequency-band and multi-mode oscillation phenomenon can be formed with the power grid in an interaction mode, the deviation of the novel power grid power equipment to state perception, state evaluation, fault hidden danger early warning and the like is caused, and the influence of the wide-frequency-band environment on the power equipment is not ignored. In the prior art, there are two general designs for wide-band signal processing, one is a scheme of using a common ADC (analog-digital converter) and span switching, and the scheme is to judge the sampling point value or judge according to the waveform effective value, and the span switching inevitably needs to introduce a feedback control link, so that the scheme has a time lag effect. For loads with frequent switching characteristics, there is a high probability that the feedback delay causes a miscontrol of the range switching, thereby causing a metering error. The other is a non-range switching scheme directly using a high-precision ADC, the ADC of the scheme needs to be used with a peripheral sampling resistor, a larger sampling resistor is used for accurately measuring smaller external input signals, but the input range of the ADC is limited, the measuring range of the ADC is exceeded when measuring large signals, if the smaller sampling resistor is used, the larger external input signals can be accurately measured, but small signals cannot be accurately measured, the application determines that the wide range cannot be achieved, the signal range is particularly wide, and the signal is relatively random and cannot be accurately measured and sampled.
The patent with publication number CN114002642A discloses a field metering performance acquisition system of an intelligent ammeter, which comprises a wiring device and a metering information acquisition device, wherein the wiring device is connected with the metering information acquisition device; the wiring device is used for connecting a pulse positive terminal, a pulse negative terminal, a phase line output terminal and a zero line output terminal of the monitored intelligent ammeter by adopting a crimping structure and transmitting signals output by the terminals to the current sensor or the voltage sensor; the metering information acquisition device is used for periodically acquiring electricity consumption data metered by the monitored intelligent ammeter through the current sensor and the voltage sensor, recording the pulse number output by the intelligent ammeter and sending the electricity consumption data and the pulse number to the remote server through a wireless network. Although the detection accuracy of the metering performance of the intelligent ammeter is improved, a corresponding technical scheme is not provided for the purpose of better adapting to wide-frequency sampling in a wide-frequency sampling environment.
Therefore, how to provide a smart meter that can adapt to wide-range sampling and has high metering accuracy is a problem to be solved by those skilled in the art.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a self-adaptive intelligent ammeter so as to solve the problems that wide-range sampling and low metering accuracy cannot be achieved in the prior art; in addition, the invention also provides a sampling method of the self-adaptive intelligent ammeter.
In order to solve the technical problems, the invention adopts the following technical scheme:
in a first aspect, the present invention provides an adaptive smart meter comprising:
the device comprises a first operational amplifier, a second operational amplifier, a first ADC, a second ADC, a first data processing unit, a second data processing unit and an operation processor;
the first operational amplifier, the first ADC, the first data processing unit and the operation processor are sequentially connected, the second operational amplifier, the second ADC, the second data processing unit and the operation processor are sequentially connected, the first operational amplifier and the second operational amplifier are used for receiving and amplifying voltage and current signals, the first ADC and the second ADC are used for collecting the voltage and current signals and converting the voltage and current signals into digital signals, the first data processing unit and the second data processing unit are used for processing the voltage and current data, and the operation processor is used for carrying out relevant calculation on the voltage and current data.
Further, a voltage-current signal threshold judgment point is set in the operation processor, and the operation processor adaptively switches and calculates according to the detected voltage-current effective value.
Further, when the detected effective value of the voltage and the current is larger than the threshold value, the voltage and the current sampling data acquired by the second ADC are used for calculation, and when the detected effective value of the voltage and the current is smaller than the threshold value, the voltage and the current sampling data acquired by the first ADC are used for calculation.
Further, when the effective value of the voltage and the current is greater than the threshold value, the correlation coefficient of the sampled data is synchronously adjusted, and a specific adjustment formula is as follows:
coef_i new ＝coef_i old /k min
coef_v new ＝coef_v old /k min
coef_p new ＝coef_p old /k min
wherein coef_i new 、coef_v new 、coef_p new For the adjusted calculated current, voltage and power coefficient coef_i old 、coef_v old 、coef_p old K is the previous voltage, current and power coefficient min Is the gain factor of the second ADC.
Further, when the effective value of the voltage and the current is smaller than the threshold value, the correlation coefficient of the sampled data is synchronously adjusted, and a specific adjustment formula is as follows:
coef_i new ＝coef_i old /k max
coef_v new ＝coef_v old /k max
coef_p new ＝coef_p old /k max
wherein k is max Is the gain factor of the first ADC.
Further, the amplification factor of the first operational amplifier is smaller than that of the second operational amplifier.
Further, the gain factor of the first ADC is greater than the gain factor of the second ADC.
Further, the sampling data includes a voltage value, a current value, and a power value.
In a second aspect, the present invention further provides a sampling method of an adaptive smart meter, including the following steps:
s10, respectively acquiring voltage and current data through a first ADC and a second ADC;
s20, judging the magnitude relation between the effective value of the voltage and the current and the threshold value set in the operation processor, and if the effective value of the voltage and the current is larger than the threshold value, calculating by adopting voltage and current data acquired by the second ADC to obtain voltage, current and power coefficients; if the effective value of the voltage and the current is smaller than the threshold value, calculating by adopting the voltage and the current data acquired by the first ADC and obtaining the voltage, the current and the power coefficient;
and S30, calculating according to the voltage, the current and the power coefficient obtained in the step S20 to obtain a voltage value, a current value and a power value.
Further, before the step S10, the voltage and current signals are amplified by a first operational amplifier and a second operational amplifier.
Compared with the prior art, the self-adaptive intelligent ammeter and the sampling method provided by the invention have at least the following steps
The beneficial effects are that:
in the prior art, an ADC adopts a range switching mode that a small current is detected, and then an amplification factor is replaced to perform sampling, so that a time error exists in the mode, and resampling is performed while the small amplification factor is switched, at this time, the current may have changed, so that a hysteresis effect cannot be avoided for a place where a load rapidly fluctuates. According to the invention, two groups of data are sampled simultaneously through two high-precision ADCs, threshold judgment is carried out on single-cycle data on software processing to carry out corresponding processing, the software is not required to switch amplification factors to wait for resampling the data, errors caused by hysteresis effects are avoided, no delay exists, the precision is high, and the response speed is high; meanwhile, according to the range of different current and voltage signals, two operational amplifiers and ADCs with different gains are adopted, the sampling range of the whole intelligent ammeter is greatly improved, and the sampling precision of the intelligent ammeter can be ensured for large signals and small signals.
Drawings
In order to more clearly illustrate the solution of the invention, a brief description will be given below of the drawings required for the description of the embodiments, it being apparent that the drawings in the following description are some embodiments of the invention and that other drawings may be obtained from these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a block diagram of an adaptive smart meter according to an embodiment of the present invention;
fig. 2 is a flowchart of a sampling method of an adaptive smart meter according to an embodiment of the present invention.
Detailed Description
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs; the terms used in the specification are used herein for the purpose of describing particular embodiments only and are not intended to limit the present invention, for example, the orientations or positions indicated by the terms "length", "width", "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are orientations or positions based on the drawings, which are merely for convenience of description and are not to be construed as limiting the present invention.
The terms "comprising" and "having" and any variations thereof in the description of the invention and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion; the terms first, second and the like in the description and in the claims or in the above-described figures, are used for distinguishing between different objects and not necessarily for describing a sequential or chronological order. In the description of the invention and the claims and the above figures, when an element is referred to as being "fixed" or "mounted" or "disposed" or "connected" to another element, it can be directly or indirectly on the other element. For example, when an element is referred to as being "connected to" another element, it can be directly or indirectly connected to the other element.
Furthermore, references herein to "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.
The invention provides a self-adaptive intelligent ammeter which is applied to measurement of various wide dynamic voltage and current signals in a power grid system, and comprises the following components: the device comprises a first operational amplifier, a second operational amplifier, a first ADC, a second ADC, a first data processing unit, a second data processing unit and an operation processor; the first operational amplifier, the first ADC, the first data processing unit and the operation processor are sequentially connected, the second operational amplifier, the second ADC, the second data processing unit and the operation processor are sequentially connected, the first operational amplifier and the second operational amplifier are used for receiving and amplifying voltage and current signals, the first ADC and the second ADC are used for collecting the voltage and current signals and converting the voltage and current signals into digital signals, the first data processing unit and the second data processing unit are used for processing the voltage and current data, and the operation processor is used for carrying out correlation calculation on the voltage and current data.
In the prior art, an ADC adopts a range switching mode that a small current is detected, and then an amplification factor is replaced to perform sampling, so that a time error exists in the mode, and resampling is performed while the small amplification factor is switched, at this time, the current may have changed, so that a hysteresis effect cannot be avoided for a place where a load rapidly fluctuates. According to the invention, two groups of data are sampled simultaneously through two high-precision ADCs, software is not required to switch amplification factors to wait for resampling the data, errors caused by hysteresis effects are avoided, delay is avoided, the precision is high, and the response speed is high; meanwhile, according to the range of different current and voltage signals, two operational amplifiers and ADCs with different gains are adopted, the sampling range of the whole intelligent ammeter is greatly improved, and the sampling precision of the intelligent ammeter can be ensured for large signals and small signals.
In order to make the person skilled in the art better understand the solution of the present invention, the technical solution of the embodiment of the present invention will be clearly and completely described below with reference to the accompanying drawings.
The invention provides a self-adaptive intelligent ammeter which is applied to measurement of various wide dynamic voltage and current signals in a power grid system, as shown in figure 1, and comprises the following components:
the device comprises a first operational amplifier, a second operational amplifier, a first ADC, a second ADC, a first data processing unit, a second data processing unit and an operation processor; the first operational amplifier, the first ADC, the first data processing unit and the operation processor are sequentially connected, the second operational amplifier, the second ADC, the second data processing unit and the operation processor are sequentially connected, the first operational amplifier and the second operational amplifier are used for receiving and amplifying voltage and current signals, the first ADC and the second ADC are used for collecting the voltage and current signals and converting the voltage and current signals into digital signals, the first data processing unit and the second data processing unit are used for processing the voltage and current data, and the operation processor is used for carrying out correlation calculation on the voltage and current data.
In this embodiment, the amplification factor of the first operational amplifier is smaller than that of the second operational amplifier.
In this embodiment, the gain factor of the first ADC is greater than the gain factor of the second ADC.
Further, in this embodiment, an effective value determining rule is adopted, a voltage and current signal threshold value determining point is set in the operation processor, a specific value of the threshold value is set through an actual field situation, and the operation processor adaptively switches and calculates according to the detected voltage and current effective value.
Specifically, when the detected effective value of the voltage and the current is greater than a threshold value, the current sampling data buffer area is adaptively adjusted to be switched into a sampling data buffer area of the small-gain ADC, and voltage and current sampling data acquired by the second ADC are used for calculation; and when the detected effective value of the voltage and the current is smaller than the threshold value, the current sampling data buffer area is adaptively adjusted to be switched into the sampling data buffer area of the large-gain ADC, and the voltage and the current sampling data acquired by the first ADC are used for calculation.
Further, when the effective value of the voltage and the current is greater than the threshold value, synchronously adjusting the correlation coefficient of the sampling data, wherein the sampling data comprises the voltage value, the current value and the power value, and the specific adjustment formula is as follows:
coef_i new ＝coef_i old /k min
coef_v new ＝coef_v old /k min
coef_p new ＝coef_p old /k min
wherein coef_i new 、coef_v new 、coef_p new For the adjusted calculated current, voltage and power coefficient coef_i old 、coef_v old 、coef_p old K is the previous voltage, current and power coefficient min Is the gain factor of the second ADC.
Further, when the effective value of the voltage and the current is smaller than the threshold value, the correlation coefficient of the sampled data is synchronously adjusted, and a specific adjustment formula is as follows:
coef_i new ＝coef_i old /k max
coef_v new ＝coef_v old /k max
coef_p new ＝coef_p old /k max
wherein k is max Is the gain factor of the first ADC.
The embodiment of the invention also provides a sampling method of the self-adaptive intelligent ammeter, which comprises the following steps:
s10, amplifying voltage and current signals through a first operational amplifier and a second operational amplifier, and respectively acquiring voltage and current data through a first ADC and a second ADC;
s20, judging the magnitude relation between the effective value of the voltage and the current and the threshold value set in the operation processor, and if the effective value of the voltage and the current is larger than the threshold value, calculating by adopting voltage and current data acquired by the second ADC to obtain voltage, current and power coefficients; if the effective value of the voltage and the current is smaller than the threshold value, calculating by adopting the voltage and the current data acquired by the first ADC and obtaining the voltage, the current and the power coefficient;
and S30, calculating according to the voltage, the current and the power coefficient obtained in the step S20 to obtain a voltage value, a current value and a power value.
In the foregoing embodiment, unlike the prior art, in the prior art, an ADC adopts a range switching manner to detect a small current, and then replaces an amplification factor to perform sampling, so that there is a time error in the manner, and resampling is performed while switching the small amplification factor, at this time, the current may have changed, so that a hysteresis effect cannot be avoided for a place where the load rapidly fluctuates. According to the invention, two groups of data are sampled simultaneously through two high-precision ADCs, threshold judgment is carried out on single-cycle data on software processing to carry out corresponding processing, the software is not required to switch amplification factors to wait for resampling the data, errors caused by hysteresis effects are avoided, no delay exists, the precision is high, and the response speed is high; meanwhile, according to the range of different current and voltage signals, two operational amplifiers and ADCs with different gains are adopted, the sampling range of the whole intelligent ammeter is greatly improved, and the sampling precision of the intelligent ammeter can be ensured for large signals and small signals.
It is apparent that the above-described embodiments are merely preferred embodiments of the present invention, not all of which are shown in the drawings, which do not limit the scope of the invention. This invention may be embodied in many different forms, but rather, embodiments are provided in order to provide a thorough and complete understanding of the present disclosure. Although the invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing description, or equivalents may be substituted for elements thereof. All equivalent structures made by the content of the specification and the drawings of the invention are directly or indirectly applied to other related technical fields, and are also within the scope of the invention.
Claims (10)
1. An adaptive smart meter, comprising:
the device comprises a first operational amplifier, a second operational amplifier, a first ADC, a second ADC, a first data processing unit, a second data processing unit and an operation processor;
the first operational amplifier, the first ADC, the first data processing unit and the operation processor are sequentially connected, the second operational amplifier, the second ADC, the second data processing unit and the operation processor are sequentially connected, the first operational amplifier and the second operational amplifier are used for receiving and amplifying voltage and current signals, the first ADC and the second ADC are used for collecting the voltage and current signals and converting the voltage and current signals into digital signals, the first data processing unit and the second data processing unit are used for processing the voltage and current data, and the operation processor is used for carrying out relevant calculation on the voltage and current data.
2. The adaptive smart meter according to claim 1, wherein a voltage-current signal threshold decision point is set in the operation processor, and the operation processor adaptively switches calculation according to the detected voltage-current effective value.
3. The adaptive smart meter of claim 2, wherein the voltage and current sampling data collected by the second ADC is used for calculation when the detected voltage and current effective value is greater than the threshold value, and the voltage and current sampling data collected by the first ADC is used for calculation when the detected voltage and current effective value is less than the threshold value.
4. The adaptive smart meter of claim 3, wherein when the effective voltage and current value is greater than the threshold value, the correlation coefficient of the sampled data is synchronously adjusted according to the following specific adjustment formula:
coef_i new ＝coef_i old /k min
coef_v new ＝coef_v old /k min
coef_p new ＝coef_p old /k min
wherein coef_i new 、coef_v new 、coef_p new For the adjusted calculated current, voltage and power coefficient coef_i old 、coef_v old 、coef_p old K is the previous voltage, current and power coefficient min Is the gain factor of the second ADC.
5. The adaptive smart meter of claim 4, wherein when the effective voltage and current value is less than the threshold value, the correlation coefficient of the sampled data is adjusted synchronously, and the specific adjustment formula is as follows:
coef_i new ＝coef_i old /k max
coef_v new ＝coef_v old /k max
coef_p new ＝coef_p old /k max
wherein k is max Is the gain factor of the first ADC.
6. The adaptive smart meter of claim 1, wherein the first operational amplifier has a smaller amplification factor than the second operational amplifier.
7. The wide range high accuracy adaptive smart meter of claim 1, wherein the gain factor of the first ADC is greater than the gain factor of the second ADC.
8. An adaptive smart meter according to claim 1, wherein the sampled data includes voltage values, current values and power values.
9. A sampling method applied to the adaptive smart meter of any one of claims 1 to 8, comprising the steps of:
s10, respectively acquiring voltage and current data through a first ADC and a second ADC;
s20, judging the magnitude relation between the effective value of the voltage and the current and the threshold value set in the operation processor, and if the effective value of the voltage and the current is larger than the threshold value, calculating by adopting voltage and current data acquired by the second ADC to obtain voltage, current and power coefficients; if the effective value of the voltage and the current is smaller than the threshold value, calculating by adopting the voltage and the current data acquired by the first ADC and obtaining the voltage, the current and the power coefficient;
and S30, calculating according to the voltage, the current and the power coefficient obtained in the step S20 to obtain a voltage value, a current value and a power value.
10. The adaptive sampling method according to claim 9, wherein the voltage-current signal is amplified by a first operational amplifier and a second operational amplifier prior to the step S10.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116593769A (en) * | 2023-07-17 | 2023-08-15 | 烟台东方威思顿电气有限公司 | High-precision electric energy calculation method with wide dynamic range |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116593769A (en) * | 2023-07-17 | 2023-08-15 | 烟台东方威思顿电气有限公司 | High-precision electric energy calculation method with wide dynamic range |
| CN116593769B (en) * | 2023-07-17 | 2023-10-27 | 烟台东方威思顿电气有限公司 | High-precision electric energy calculation method with wide dynamic range |
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