CN203444012U - High accuracy and rapid speed measurement circuit of wide range current in power system - Google Patents
High accuracy and rapid speed measurement circuit of wide range current in power system Download PDFInfo
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- CN203444012U CN203444012U CN201320552439.6U CN201320552439U CN203444012U CN 203444012 U CN203444012 U CN 203444012U CN 201320552439 U CN201320552439 U CN 201320552439U CN 203444012 U CN203444012 U CN 203444012U
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Abstract
The utility model discloses a high accuracy and rapid speed measurement circuit of wide range current in a power system. The circuit comprises a current transformer, a signal conditioning circuit, a limiter, an A/D converter and a CPU, wherein the current transformer, the signal conditioning circuit, the limiter, the A/D converter and the CPU are sequentially connected. The signal conditioning circuit comprises a preamplifier, a main amplifier and a self-adaptive amplifier, wherein the preamplifier, the main amplifier and the self-adaptive amplifier are sequentially connected. The preamplifier is connected with the current transformer. The self-adaptive amplifier is connected with the limiter. A node between the main amplifier and the self-adaptive amplifier is connected with three branches. Each branch is provided with an average extraction circuit and a voltage comparator, wherein the average extraction circuit and the voltage comparator are sequentially connected. The average extraction circuit is connected with the input end of the self-adaptive amplifier. The voltage comparator is connected with a multiway switch through a first level converter. The circuit has an automatic level discrimination and coding circuit of multiple levels of voltage comparators, can automatically select appropriate feedback resistance and magnification factor for the amplifiers, can improve the measurement accuracy of a wide range current signal, and at the same time has rapid measurement speed.
Description
Technical field
The utility model relates to for power system simulation amount fields of measurement, relates in particular to the high-precision rapid survey circuit of wide region electric current in electric system.
Background technology
The electric current of electric system is the important parameter of reflection operation states of electric power system; electric system need to obtain the various analytical calculations that current value carries out electric system when normal operation; during fault, also to obtain current value and realize various relay protection functions with the safety of protection system and equipment, so current measure device is one of essential equipment of electric system.But because size of current is subject to subscriber equipment working condition, affect, the variation range of current value when normal operation is very large.Common survey equipment can only guarantee have compared with high measurement accuracy near current rating, and measuring accuracy can reduce when current value changes in wide region.Research for to from zero to ratings even more the electric current of wide region all there is the equipment compared with high measurement accuracy, significant and practical value.
In order to realize at wide region, there is higher current measurement precision, the solution of power domain is to adopt two cover circuit at present, and circuit kit is responsible for providing and is monitored and metering current value, and its precision is very high, but it is little to adapt to range of current, normally zero to rated current; Another set of circuit is provided by the current value that provides protection to need, and the former is slightly poor for its ratio of precision, but it is large to adapt to range of current, can be zero to tens times of rated current.
In industrial instrument field, can adopt at present automatic range technology to improve the measuring accuracy of wide region signal.Its cardinal principle is first signal to be carried out to preliminary surveying, estimates its roughly numerical value, and then the enlargement factor of corresponding adjustment amplifier, makes it to reach optimum matching with the range of A/D converter, thereby improves measuring accuracy.But this scheme needs software and hardware to coordinate carries out twice even repeatedly measurement to signal, need to progressively attempt reaching best magnification, has therefore affected measuring speed.
Generally speaking, need at present the urgent technical matters solving of those skilled in the art to be: how can realize accurately and quickly the measurement of wide region current signal.
Utility model content
The purpose of this utility model is exactly in order to address the above problem, and the high-precision rapid survey circuit of wide region electric current in electric system is provided.Basic thought of the present utility model is also by adjusting the enlargement factor of amplifier, to improve the measuring accuracy of wide region current signal, but improvements are that judgement is not to change and software estimation by A/D to current signal numerical range, but automatically complete by hardware voltage comparator, therefore the utility model can rely on hardware circuit automatically to adjust to best magnification completely, only needs one-shot measurement just to obtain the exact value of electric current.So not only reach the accurate measurement requirement to wide region electric current, and greatly improved measuring speed.
To achieve these goals, the utility model adopts following technical scheme:
The high-precision rapid survey circuit of wide region electric current in electric system, comprise: current transformer, described current transformer is transferred to signal conditioning circuit after power current is transformed into little current signal, signal conditioning circuit becomes voltage signal after current signal is nursed one's health and is transferred to limiter, described limiter is transferred to A/D converter by signal, and described A/D converter carries out transferring data to CPU(central processing unit after analog to digital conversion to signal);
Described signal conditioning circuit comprises: prime amplifier, described prime amplifier converts current signal voltage signal to and sends into main amplifier, main amplifier is sent into adaptive amplifier after signal is further amplified, the signal of adaptive amplifier can be transferred to limiter, the further amplifying signal of main amplifier also can extract circuit through three mean values simultaneously, by three mean values, extract the average voltage obtaining after circuit and be transferred to respectively three voltage comparators, by three voltage comparators relatively after, three voltage comparators are exported respectively high/low level, and by high/low level transmissions, give two level translators respectively, wherein the first level translator is transferred to multicircuit switch by the signal after conversion, described multicircuit switch also receives the output of adaptive amplifier.Second electrical level converter is transferred to CPU by the signal after conversion.
Described mean value extracts circuit and comprises three branch roads in parallel, article one, on branch road and second branch road, be equipped with the diode of two series connection, article three, branch road is provided with capacitor C, the positive pole of the first diode D1 on described article one branch road connects input end, the positive pole of described the first diode D1 also connects the negative pole of the 3rd diode, the negative pole of described the first diode D1 connects output terminal, the plus earth of described the 3rd diode D3, the positive pole of the second diode D2 on described second branch road connects input end, the positive pole of described the second diode D2 also connects the negative pole of the 4th diode D4, the negative pole of described the second diode D2 connects output terminal, the plus earth of described the 4th diode D4, the two ends of described capacitor C are ground connection and output terminal respectively.
Described level translator comprises three identical level shifting circuits, every level shifting circuit is provided with triode, the base stage of described triode is connected with input end by the first resistance, the grounded emitter of described triode, the collector of described triode connects power supply (wherein by the second resistance, the first level translator connects power vd D, and second electrical level converter connects power supply VCC), the collector of described triode is connected with output terminal.
The beneficial effects of the utility model are:
1, when solving wide region current measurement problem, for a plurality of different feedback resistances of adaptive amplifier configuration, can automatically select suitable feedback resistance according to the level of input voltage signal, adjust the enlargement factor of amplifier, thereby improve measuring accuracy.
2, by a plurality of voltage comparators are set, do not need first to carry out as classic method to adjust again enlargement factor and carry out final A/D conversion after one or many A/D conversion and software estimation, but utilize the automatic electric-level of devices at full hardware to differentiate and the disposable enlargement factor of adjusting of coding circuit, thereby there is measuring speed faster when improving measuring accuracy.
When 3, the utility model is introduced measuring method for succinct understandable be that to take three voltage comparators be example, but reality also can be supported more voltage comparators, thereby further improves measuring accuracy, therefore has good extendability and application value.
Accompanying drawing explanation
Fig. 1 principle schematic of the present utility model;
Fig. 2 enforcement illustration of the present utility model;
Fig. 3 mean value extracts circuit diagram;
Fig. 4 the first level translator schematic diagram;
Fig. 5 second electrical level converter schematic diagram;
Wherein, 1, current transformer, 2, prime amplifier, 3, main amplifier, 4, adaptive amplifier, 5, limiter, 6, A/D converter, 7, CPU, 8, mean value extracts circuit, 9, voltage comparator, the 10, first level translator, 11, multicircuit switch, 12, second electrical level converter.
Embodiment
Below in conjunction with accompanying drawing and embodiment, the utility model is described in further detail.
As illustrated in fig. 1 and 2, the high-precision rapid survey circuit of wide region electric current in electric system, comprising: the current transformer 1, signal conditioning circuit, limiter 5, A/D converter 6 and the CPU7 that connect successively,
Described signal conditioning circuit comprises prime amplifier 2, main amplifier 3, the adaptive amplifier 4 connecting successively, and described prime amplifier 2 is connected with current transformer 1, and described adaptive amplifier 4 is connected with limiter 5,
Described main amplifier 3 is connected three branch roads with the node between adaptive amplifier 4, on every branch road, be equipped with the mean value connecting successively and extract circuit 8, voltage comparator 9, wherein said mean value extracts the input end that circuit 8 is connected to adaptive amplifier 4, voltage comparator 9 is connected with multicircuit switch 11 by the first level translator 10, and multicircuit switch 11 is connected with the output terminal of adaptive amplifier 4; Each voltage comparator 9 is also connected with CPU7 by second electrical level converter 12.
As shown in Figure 3, described mean value extracts circuit 8 and comprises three branch roads in parallel, article one, on branch road and second branch road, be equipped with the diode of two series connection, article three, branch road is provided with capacitor C, the positive pole of the first diode D1 on described article one branch road connects input end, the positive pole of described the first diode D1 also connects the negative pole of the 3rd diode, the negative pole of described the first diode D1 connects output terminal, the plus earth of described the 3rd diode D3, the positive pole of the second diode D2 on described second branch road connects input end, the positive pole of described the second diode D2 also connects the negative pole of the 4th diode D4, the negative pole of described the second diode D2 connects output terminal, the plus earth of described the 4th diode D4, the two ends of described capacitor C are ground connection and output terminal respectively.
As shown in Figure 4 and Figure 5, described level translator comprises three identical level shifting circuits, every level shifting circuit is provided with triode, the base stage of described triode is connected with input end by the first resistance, the grounded emitter of described triode, the collector of described triode connects power supply by the second resistance, and (wherein, the first level translator connects power vd D, second electrical level converter connects power supply VCC), the collector of described triode is connected with output terminal.
Although above-mentioned, by reference to the accompanying drawings embodiment of the present utility model is described; but the not restriction to the utility model protection domain; one of ordinary skill in the art should be understood that; on the basis of the technical solution of the utility model, those skilled in the art do not need to pay various modifications that creative work can make or distortion still in protection domain of the present utility model.
Claims (3)
1. the high-precision rapid survey circuit of wide region electric current in electric system, it is characterized in that, comprise: current transformer, described current transformer is transferred to signal conditioning circuit after power current is transformed into little current signal, signal conditioning circuit is transferred to limiter after current signal conditioning is converted to voltage signal, described limiter is transferred to A/D converter by signal, and described A/D converter carries out transferring data to CPU after analog to digital conversion to electric current;
Described signal conditioning circuit comprises: prime amplifier, described prime amplifier converts current signal voltage signal to and sends into main amplifier, main amplifier is sent into adaptive amplifier after signal is further amplified, the signal of adaptive amplifier can be transferred to limiter, the further amplifying signal of main amplifier also can extract circuit through three mean values simultaneously, by three mean values, extract the average voltage obtaining after circuit and be transferred to respectively three voltage comparators, by three voltage comparators relatively after, three voltage comparators are exported respectively high/low level, and by high/low level transmissions, give two level translators respectively, wherein the first level translator is transferred to multicircuit switch by the signal after conversion, described multicircuit switch also receives the output of adaptive amplifier, for adaptive amplifier is adjusted enlargement factor automatically, second electrical level converter is transferred to CPU by the signal after conversion.
2. metering circuit as claimed in claim 1, it is characterized in that, described mean value extracts circuit and comprises three branch roads in parallel, article one, on branch road and second branch road, be equipped with the diode of two series connection, article three, branch road is provided with capacitor C, the positive pole of the first diode D1 on described article one branch road connects input end, the positive pole of described the first diode D1 also connects the negative pole of the 3rd diode, the negative pole of described the first diode D1 connects output terminal, the plus earth of described the 3rd diode D3, the positive pole of the second diode D2 on described second branch road connects input end, the positive pole of described the second diode D2 also connects the negative pole of the 4th diode D4, the negative pole of described the second diode D2 connects output terminal, the plus earth of described the 4th diode D4, the two ends of described capacitor C are ground connection and output terminal respectively.
3. metering circuit as claimed in claim 1, it is characterized in that, described level translator comprises three identical level shifting circuits, every level shifting circuit is provided with triode, the base stage of described triode is connected with input end by the first resistance, the grounded emitter of described triode, the collector of described triode connects power supply by the second resistance, and the collector of described triode is connected with output terminal.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201320552439.6U CN203444012U (en) | 2013-09-06 | 2013-09-06 | High accuracy and rapid speed measurement circuit of wide range current in power system |
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| CN201320552439.6U CN203444012U (en) | 2013-09-06 | 2013-09-06 | High accuracy and rapid speed measurement circuit of wide range current in power system |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103543319A (en) * | 2013-09-06 | 2014-01-29 | 国家电网公司 | High-precision fast measuring circuit and method for wide-range currents in power system |
| CN103944168A (en) * | 2014-04-17 | 2014-07-23 | 中国科学院电工研究所 | High-power power quality comprehensive compensation device |
| CN104965116A (en) * | 2015-06-29 | 2015-10-07 | 昆明电器科学研究所 | Instrument electric quantity signal collection circuit board |
| CN105242104A (en) * | 2015-10-13 | 2016-01-13 | 欣旺达电子股份有限公司 | Current detection method, current detection device, and current detector |
| CN109405733A (en) * | 2018-12-14 | 2019-03-01 | 中核新科（天津） 精密机械制造有限公司 | Quick high accuracy plane parallelism measurement device |
| CN110082587A (en) * | 2019-04-23 | 2019-08-02 | 深圳供电局有限公司 | Detection circuit and multi-branch identification device |
-
2013
- 2013-09-06 CN CN201320552439.6U patent/CN203444012U/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103543319A (en) * | 2013-09-06 | 2014-01-29 | 国家电网公司 | High-precision fast measuring circuit and method for wide-range currents in power system |
| CN103543319B (en) * | 2013-09-06 | 2016-06-15 | 国家电网公司 | The measuring method of the high-precision rapid survey circuit of power system inner width range current |
| CN103944168A (en) * | 2014-04-17 | 2014-07-23 | 中国科学院电工研究所 | High-power power quality comprehensive compensation device |
| CN104965116A (en) * | 2015-06-29 | 2015-10-07 | 昆明电器科学研究所 | Instrument electric quantity signal collection circuit board |
| CN105242104A (en) * | 2015-10-13 | 2016-01-13 | 欣旺达电子股份有限公司 | Current detection method, current detection device, and current detector |
| CN109405733A (en) * | 2018-12-14 | 2019-03-01 | 中核新科（天津） 精密机械制造有限公司 | Quick high accuracy plane parallelism measurement device |
| CN109405733B (en) * | 2018-12-14 | 2024-04-09 | 中核新科（天津）精密机械制造有限公司 | Quick high-precision plane parallelism measuring device |
| CN110082587A (en) * | 2019-04-23 | 2019-08-02 | 深圳供电局有限公司 | Detection circuit and multi-branch identification device |
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140219 Termination date: 20160906 |