CN104635027A - Electronic current transformer data acquisition system - Google Patents
Electronic current transformer data acquisition system Download PDFInfo
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- CN104635027A CN104635027A CN201310568144.2A CN201310568144A CN104635027A CN 104635027 A CN104635027 A CN 104635027A CN 201310568144 A CN201310568144 A CN 201310568144A CN 104635027 A CN104635027 A CN 104635027A
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Abstract
An electronic current transformer data acquisition system mainly comprises a signal conditioning circuit, an analog-digital conversion unit and an optical fiber transmission system. The optical fiber transmission system comprises optical fibers, a DSP (digital signal processor), an electric-optical converter and an optical-electric converter, a Rogowski coil sensor senses current analog signals from a power grid, the analog signals are outputted via the signal conditioning circuit and converted into digital signals via the analog-digital conversion unit prior to being transmitted by one optical fiber, the electric-optical converter and the optical-electric converter are respectively equipped at two ends of the optical fiber, the digital signals transmitted by the optical fiber are processed by the DSP at the low-voltage end, on the other hand, and clock signals are provided by the DSP and transmitted through the other optical fiber prior to being subjected to frequency division via a frequency dividing circuit to be transmitted to the analog-digital converter to ensure the signals are synchronously sampled. The electronic current transformer data acquisition system is good in anti-interference performance and high in measurement accuracy, requirements of electronic current transformers on timeliness, reliability and accuracy in signal acquisition are met, power consumption of the system is lowered, and system performance is improved.
Description
Technical field
The present invention relates to a kind of harvester, especially electronic current mutual inductor data acquisition system (DAS).
Background technology
Along with improving constantly and the continuous increase of transmission capacity of electric pressure in electric system, some problems of traditional electromagnetic current transducer also with regard to exposed day by day out, as: volume is large, dynamic range is little, service band is narrow, and there is ferroresonance, secondary side can not be opened a way, and therefore seeks more preferably novel current transformer imperative.The more traditional current transformer of novel electronic current mutual inductor has done a lot of improvements, structurally with optical fiber, high-low pressure two ends is kept apart, has good insulation effect; Hardware adopts Lip river Paderewski coil as sensing head, the AD7894 of 14 and novel there is powerful controlling functions, problem that Software for Design that the DSP2812 chip of data-handling capacity at a high speed combines makes traditional mutual inductor come out obtains good solution.And electronic current mutual inductor has also adapted to the trend of electric-power metering and protection digitizing, Microcomputer and automation development.Electronic current mutual inductor mainly comprises data acquisition system (DAS) and data handling system, and the precision of whole system depends primarily on the precision of the data acquisition system (DAS) of design.
Summary of the invention
The technical matters that the application will solve overcomes above-mentioned defect, provides a kind of high-precision electronic current mutual inductor data acquisition system (DAS).
For solving the problems of the technologies described above, the technical scheme of employing is:
Electronic current mutual inductor data acquisition system (DAS), mainly comprise signal conditioning circuit, A/D converter, fibre-optic transmission system (FOTS) 3 part, fibre-optic transmission system (FOTS) comprises optical fiber, DSP, electric to optic converter and light/electric transducer, Rogowski coil sensor induces current analog signal from electrical network, through signal conditioning circuit outputting analog signal, be converted to after digital signal through A/D converter, adopt Optical Fiber Transmission, optical fiber two ends are equipped with electric to optic converter and light/electric transducer respectively, DSP mono-aspect of low pressure end passes the digital signal of coming to optical fiber and processes, there is provided clock signal on the other hand, by another road Optical Fiber Transmission, and after frequency dividing circuit frequency division, reach A/D converter to ensure signal synchronized sampling.
Signal conditioning circuit comprises amplifying circuit and anti-phase integrator.
The invention has the beneficial effects as follows: this data acquisition system (DAS) anti-interference is good, measuring accuracy is high, meet 0.2 class precision standard of IEC60044-8, can the collection of settling signal well, meet the requirement of electronic current mutual inductor to the real-time of signals collecting, reliability, accuracy, this design reduces the power consumption of system simultaneously, improve the performance of system.
Accompanying drawing explanation
Fig. 1 is electronic current mutual inductor data acquisition system (DAS) circuit theory diagrams;
Fig. 2 is signal conditioning circuit circuit diagram;
Fig. 3 is frequency dividing circuit circuit diagram.
Embodiment
Electronic current mutual inductor data acquisition system (DAS) mainly comprises signal conditioning circuit, A/D converter, fibre-optic transmission system (FOTS) 3 part.Rogowski coil is the most frequently used sensing element of electronic current mutual inductor, usually adopts hollow coil and LPCT as current sensing, has the good linearity and accuracy.
Rogowski coil sensor induces current analog signal from electrical network, again through the process such as anti-aliasing filter, amplification, anti-phase integration of signal conditioning circuit to signal, it is digital signal that the simulating signal meeting A/D sampled voltage scope that A/D converter is responsible for modulate circuit to export converts timing conversion by A/D.For ensureing transmission speed and quality, adopt optical fiber to transmit, optical fiber two ends are equipped with electric to optic converter and light/electric transducer respectively.DSP mono-aspect of low pressure end passes the digital signal of coming to a road optical fiber and processes, there is provided clock signal on the other hand, by another road Optical Fiber Transmission, and after frequency dividing circuit frequency division, produce the sequential needed for A/D converter, thus reach the effect of signal synchronized sampling.Design of data acquisition system schematic diagram as shown in Figure 1.
Because the coefficient of mutual inductance of sensing head Rogowski coil is low, the voltage induced is very little, and for preventing it to be attenuated after integrator, therefore signal processing need add amplification integral element.Signal conditioning circuit as shown in Figure 2.U
1(t) and U
2t be amplifying circuit between (), enlargement factor is primarily of R
3and R
4ratio to determine.U
2be anti-phase integrator between (t) and Uo (t), consider integrator drift problem, so on the basis of ideal integrator, at integrating capacitor C
3the feedback resistance R8 of a two ends mega-ohms in parallel, and a simple RC low-pass filter has been added between amplification and anti-phase integration, the improvement for signal to noise ratio (S/N ratio) plays a significant role.
A/D converter, primarily of the part such as A/D converter, sequential control composition, realizes synchronously detecting and the sampling of control A/D, conversion and verification by the DSPTMS320F2812 device of low pressure end.According to the accuracy requirement (reaching 0.2 grade) of electronic current mutual inductor and the sample frequency of setting, the A/D converter that precision comparison is high should be selected.In addition, undistorted in order to ensure less than 7 times harmonic components in signal, the slewing rate of A/D converter also requires than very fast and conversion accuracy temperature influence is little.Select AD7894AR 1 analog/digital conversion chip.AD7894AR 1 is a low-power consumption, low cost, high performance quick 14 A/D converters, adopt 5V single power supply, sample/hold amplifier, 1 sheet internal clock and 1 HSSI High-Speed Serial Interface in built-in 1 gradual approaching/number converter, 1 sheet.
The method controlling analog/digital conversion has a lot, and this research adopts the frequency dividing circuit be made up of CD4020 counting/frequency divider etc. to control the carrying out of analog/digital conversion, and CD4020 is a 14 binary serial counting/frequency dividers.Frequency dividing circuit figure as shown in Figure 3.In Fig. 3,10 pin of CD4020 receive continuous clock signal CLK, this clock signal is produced by the timer in low pressure end DSP, CD4020 carries out 32 frequency divisions to it, from 6 pin export the cycles be 32 times to the square-wave signal of CLK, after this square wave signals reverse with CLK phase with, as the read data clock signal of AD7894.6 pin of same CD4020 export and produce short pulse signal through resistor capacitor circuit.
Fibre-optic transmission system (FOTS) principle is: electric signal is transformed into light signal by a LED emitter, and is coupled in Transmission Fibers, and light signal arrives optical receiver by optical fiber, and it reverts to original electric signal the light signal received and exports.Fibre-optic transmission system (FOTS) mainly comprises E/O converter and driving circuit, O/E converter and receiving circuit, optical fiber etc.The optical transmitter of E/O conversion selects the low-power consumption LED type transmitter HFBRl414 of Agilent company, and the optical receiver of O/E conversion adopts the HFBR2412 of Agilent company.
Claims (2)
1. electronic current mutual inductor data acquisition system (DAS), it is characterized in that: mainly comprise signal conditioning circuit, A/D converter, fibre-optic transmission system (FOTS) 3 part, fibre-optic transmission system (FOTS) comprises optical fiber, DSP, electric to optic converter and light/electric transducer, Rogowski coil sensor induces current analog signal from electrical network, through signal conditioning circuit outputting analog signal, be converted to after digital signal through A/D converter, adopt Optical Fiber Transmission, optical fiber two ends are equipped with electric to optic converter and light/electric transducer respectively, DSP mono-aspect of low pressure end passes the digital signal of coming to optical fiber and processes, there is provided clock signal on the other hand, by another road Optical Fiber Transmission, and after frequency dividing circuit frequency division, reach A/D converter to ensure signal synchronized sampling.
2. electronic current mutual inductor data acquisition system (DAS) according to claim 1, is characterized in that: signal conditioning circuit comprises amplifying circuit and anti-phase integrator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310568144.2A CN104635027A (en) | 2013-11-14 | 2013-11-14 | Electronic current transformer data acquisition system |
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| CN201310568144.2A CN104635027A (en) | 2013-11-14 | 2013-11-14 | Electronic current transformer data acquisition system |
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| CN104635027A true CN104635027A (en) | 2015-05-20 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104953714A (en) * | 2015-07-10 | 2015-09-30 | 成都振中电气有限公司 | Intelligent monitoring terminal for power grid distribution |
| CN106526308A (en) * | 2016-07-01 | 2017-03-22 | 南京新联电力自动化有限公司 | 10kV distribution network high-voltage metering device based on electronic-type sensor |
| CN106841767A (en) * | 2017-03-10 | 2017-06-13 | 三峡大学 | A kind of low current signal monitoring system |
| CN107976585A (en) * | 2017-12-29 | 2018-05-01 | 中国电力科学研究院有限公司 | A kind of ion flow density measurement system |
-
2013
- 2013-11-14 CN CN201310568144.2A patent/CN104635027A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104953714A (en) * | 2015-07-10 | 2015-09-30 | 成都振中电气有限公司 | Intelligent monitoring terminal for power grid distribution |
| CN106526308A (en) * | 2016-07-01 | 2017-03-22 | 南京新联电力自动化有限公司 | 10kV distribution network high-voltage metering device based on electronic-type sensor |
| CN106841767A (en) * | 2017-03-10 | 2017-06-13 | 三峡大学 | A kind of low current signal monitoring system |
| CN106841767B (en) * | 2017-03-10 | 2019-07-09 | 三峡大学 | A kind of low current signal monitoring system |
| CN107976585A (en) * | 2017-12-29 | 2018-05-01 | 中国电力科学研究院有限公司 | A kind of ion flow density measurement system |
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Application publication date: 20150520 |
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| WD01 | Invention patent application deemed withdrawn after publication |