CN202563025U - 100,000-time interference resistance digitization frequency-selecting measuring device - Google Patents
100,000-time interference resistance digitization frequency-selecting measuring device Download PDFInfo
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- CN202563025U CN202563025U CN2012201955035U CN201220195503U CN202563025U CN 202563025 U CN202563025 U CN 202563025U CN 2012201955035 U CN2012201955035 U CN 2012201955035U CN 201220195503 U CN201220195503 U CN 201220195503U CN 202563025 U CN202563025 U CN 202563025U
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Abstract
The utility model provides a 100,000-time interference resistant digitization frequency-selecting measuring device and relates to the field of measuring technique. The 100,000-time interference resistant digitization frequency-selecting measuring device comprises a central processing unit (CPU), an operational amplification unit, an isolated amplification unit, filtering units, measuring range automatic switchover units and the like, one measuring range automatic switchover unit is connected with one filtering unit which is connected with the isolated amplification unit, and the isolated amplification unit is connected with the CPU. A pair of voltage measuring terminals is arranged on the one measuring range automatic switchover unit which is further connected with the CPU, another measuring range automatic switchover unit is connected with the another filtering unit which is connected with the operational amplification unit, and the operational amplification unit is connected with the CPU. The another measuring range automatic switchover unit connected with the CPU is further connected with a current transformer which is provided with current measuring terminals. The 100,000-time interference resistant digitization frequency-selecting measuring device can achieve frequency-selecting measuring which is resistant to +/- 1 hertz 100,000-time interference, thereby having important applications in the field of electrical measurements, and particularly in the field of electric system measurements in the context with strong interference.
Description
Technical field
The utility model relates to field of measuring technique.
Background technology
Most electric equipment operations are depressed in the 50Hz industrial-frequency alternating current; Need to measure the state parameter under the power frequency 50Hz under a lot of situation; Wherein be direct measuring voltage current signal mostly, or convert various physical quantitys into voltage and current signal through sensor and measure then.Owing to exist in the electrical network very strong 50Hz to disturb, so some faint test signals are often brought very big error even can't be measured because of being difficult to measure with the 50Hz strong jamming at the scene.So; On a lot of electrical parameters measure projects, can adopt the alien frequencies method to measure, promptly on equipment, add the sine wave source such as the 55Hz that differ from power frequency, utilize the frequency-selective filtering technology to suppress 50Hz then and disturb; Only measure the pairing parameter of this 55Hz signal, can try to achieve A as a result.Try to achieve B as a result by measuring 45Hz in power frequency symmetry offset frequency then, get the average of A+B and can think the C as a result under the 50Hz with quadrat method.This method both can (like 45Hz, 55Hz), also can be measured (as 45,47,53,55Hz) to improve result's accuracy and confidence level in the frequency conversion of multiple spot symmetry in two point symmetry frequency conversions measurement.This frequency conversion (or claiming alien frequencies) mensuration can effectively be avoided the error that strong jamming brought of 50Hz power frequency, can be at the environment such as the high voltage substation that have strong power frequency to disturb, the accurate measuring electrical device parameter of power plant.The frequency conversion method of testing is used on multiple testing tool, like the frequency-conversion anti-jamming dielectric loss tester, and alien frequencies line parameter circuit value tester, frequency conversion ground connection parameter test system etc.
The frequency conversion method of testing will reach interference-free this final purpose of accurately measuring, and relates generally to the technology of two aspects: frequency conversion and frequency-selecting.Frequency conversion is need the mains supply of 50Hz be transformed into all adjustable sinusoidal wave variable-frequency power sources of voltage and frequency, and frequency-selecting then is in the interference of various complicacies at the scene the feeble signal after the frequency conversion to be extracted, and accurately measures.The converter technique development time early, comparative maturity comparatively speaking, the source as in " source-Biao " measuring system does not relate to measurements and calculations result's output.All pass through simultaneously isolating transformer as the one of which and isolate with external interference, interference-free influence only need be pressed himself internal circuit program frequency conversion and got final product.So this part major technique difference of variable-frequency power sources is watt level, other technical indicator aspect generally there is not difference.
It is complicated a lot of that frequency-selecting technology is wanted comparatively speaking, and as the table in " source-Biao " measuring system, it will be isolated faint frequency variation signal and measure the output result under the disturbed condition of various complicacies.Often the useful frequency variation signal amplitude of jam-to-signal strong several times to tens times, useful frequency variation signal " is flooded " in various undesired signals.And power frequency interference, high frequency interference, harmonic interference have been comprised in the signal of being surveyed; Be superimposed with frequency variation signal again; The waveform disorderly and unsystematic no clear and definite rule complicated and changeable that become; Will in the waveform of so mixed and disorderly complicacy, reduce and extract useful feeble signal and also will accurately measure, difficulty is well imagined.And test frequency and interfering frequency are near more, and the difficulty of frequency-selecting is just big more.Obviously, the frequency-selecting technology direct relation complete frequency conversion measuring system result's accuracy, is that can integrated system reach the gordian technique of getting rid of this final purpose of the accurate measurement of interference, is the technical bottleneck of integrated system.
Existing frequency-selecting measuring technique mainly is based on analog filtering circuit or title hardware filtering circuit, like LC inductance capacitance device etc.But analog filtering circuit exists following shortcoming, 1, the interference that can only suppress and decay, and can not real fully filtering interfering.2, analogue filter circuit is suitable for test signal and the big situation (like 120Hz and 50Hz) of interfering frequency difference limit, and (like 51Hz and 50Hz) then is difficult to reach ideal effect for two very approaching frequencies; 3, limited by the hardware circuit self-characteristic, its antijamming capability can only reach tens of/one; 4, inconsistent because of hardware circuit to different frequencies and amplitude response characteristic, be difficult to guarantee under each range of each frequency, all measure accurately; 5, mimic channel is unfavorable for intellectuality, and robotization is integrated.
The utility model content
The utility model provides a kind of anti-100,000 times to disturb digitizing frequency-selecting measurement mechanism; Purpose is to overcome present deficiency of the prior art; Design a kind of digitizing frequency-selective filtering measuring system that can any frequency-selecting of 1Hz stepping in the 40-70Hz scope, can improve the antijamming capability that frequency-selecting is measured greatly.Can very measure, thereby can obtain characterisitic parameter near power frequency near the frequency (like 51Hz and 49Hz) of power frequency.The system core is based on high-performance CPU and Wavelet Transformation Algorithm, but not the hardware filtering circuit.Measuring system can resist 100,000 times to disturb and data are not drifted about, and at 200V, 50Hz disturbs down that frequency-selecting 51Hz measures and can interference be suppressed to below the 0.1mV, and frequency-selecting measuring voltage current signal and both phase differential simultaneously.
The realization of the system core performance of the utility model is mainly based on the digitized wavelet transformation operational analysis of CPU; Can resist the frequency-selecting of 100,000 times of interference to measure by realization ± 1Hz; In the electric measurement field, particularly the electric system field tests under the strong jamming background has important purposes.
For addressing the above problem; The utility model adopts following technical scheme: anti-100,000 times are disturbed digitizing frequency-selecting measurement mechanism, comprise CPU8, computing amplifying unit 7, isolate amplifying unit 6, filter unit 5, range automatic switch unit 4, current transformer 3, current measurement terminal 2 and voltage measurement terminal 1;
A range automatic switch unit 4 connects filter unit 5, and filter unit 5 connects isolates amplifying unit 6, isolates amplifying unit 6 and connects CPU8, and range automatic switch unit 4 is provided with a pair of voltage measurement terminal 1, and this range automatic switch unit 4 also connects CPU8;
Another one range automatic switch unit 4 connects another filter unit 5, filter unit 5 concatenation operation amplifying units 7, and computing amplifying unit 7 connects CPU8; This range automatic switch unit 4 connects CPU8, and range automatic switch unit 4 also connects current transformer 3, and current transformer 3 is provided with current measurement terminal 2.
CPU8 also connects display unit 9.
CPU8 also connects menu operation knob 10.
CPU8 also connects storage card 11.
CPU8 also connects printer 12.
Compared with prior art, the digitizing frequency-selecting measuring system of the utility model has following advantage: (1) frequency-selecting antijamming capability is strong, simulates the frequency selection circuit antijamming capability than in the past and improves more than hundreds of times.(2) but any 1Hz frequency conversion of digitizing frequency-selecting under the 50Hz strong jamming, also can select very near 49Hz, the 51Hz equifrequent is measured, this has just guaranteed the equivalence of measurement result and power frequency.(3) can digitizedly carry out software calibration, guarantee the accuracy that each frequency and each range are measured down.(4) intelligent degree is high.But automatic switching range can be preserved print result, can preserve and derive test waveform, is very beneficial for further technical Analysis.(5) circuit framework is clear, and analog front end circuit is simpler.(6) system core is CPU and software algorithm partly, helps protecting the intellectual property.
This measuring system is in the electric measurement field, and particularly in power plant, the electrical equipment parameter measurement field under the strong interference environments such as transformer station has a wide range of applications and economic worth.
Description of drawings
Fig. 1 is the utility model structural representation.
Symbol description among the figure: voltage measurement terminal 1, current measurement terminal 2, current transformer 3, range automatic switch unit 4, filter unit 5, isolation amplifying unit 6, computing amplifying unit 7, CPU8, display unit 9, menu operation knob 10, storage card 11, printer 12.
Embodiment
With illustrated embodiments the utility model is done detailed explanation below.
As shown in Figure 1, anti-100,000 times are disturbed digitizing frequency-selecting measurement mechanism, comprise CPU8, computing amplifying unit 7, isolate amplifying unit 6, filter unit 5, range automatic switch unit 4, current transformer 3, current measurement terminal 2 and voltage measurement terminal 1;
A range automatic switch unit 4 connects filter unit 5, and filter unit 5 connects isolates amplifying unit 6, isolates amplifying unit 6 and connects CPU8, and range automatic switch unit 4 is provided with a pair of voltage measurement terminal 1, and this range automatic switch unit 4 also connects CPU8;
Another one range automatic switch unit 4 connects another filter unit 5, filter unit 5 concatenation operation amplifying units 7, and computing amplifying unit 7 connects CPU8; This range automatic switch unit 4 connects CPU8, and range automatic switch unit 4 also connects current transformer 3, and current transformer 3 is provided with current measurement terminal 2.
CPU8 also connects display unit 9.
CPU8 also connects menu operation knob 10.
CPU8 also connects storage card 11.
CPU8 also connects printer 12.
Voltage measurement function front-end circuit of the present invention is by the voltage measurement terminal, the range automatic switch unit, and the filtering circuit unit isolates amplifying unit and forms; Its current measurement function front-end circuit is by the current measurement terminal, current transformer, range automatic switch unit, filter unit; The computing amplifying unit is formed, and system also comprises CPU, display unit; The menu operation knob, SD storage card, printer unit.The voltage signal input range automatic switch unit of voltage measurement terminal; CPU sends signal controlling range automatic switch unit automatic conversioning broad; The range automatic switch unit is received filter unit; Filter unit is received the isolation amplifying unit, isolates amplifying unit output and is connected to CPU, carries out analyzing and processing by CPU.The current signal of current measurement terminal is input to the range automatic switch unit through current transformer; CPU sends signal controlling range automatic switch unit automatic conversioning broad; The range automatic switch unit is received filter unit; Filter unit is received the computing amplifying unit, and the output of computing amplifying unit is connected to CPU, carries out analyzing and processing by CPU.Display unit, SD storage card, printer, the menu operation knob is all linked CPU.
The voltage measurement terminal is received the range automatic switch unit, and the range switch unit is in series by the resistance of a plurality of different resistances, tells 5 ranges in different positions, the corresponding 20mV of difference, 200mV, 2V, 20V, 200V range.The CPU procedure identification is also controlled the relay that switches correspondence automatically, makes the signal amplitude size in the measurement range of the best.Range switches the back point voltage sends into filter unit, and the PI filtering circuit that filter unit is made up of inductance capacitance can be with the filtering of part high-frequency signal.Signal is seen off by filter unit, receives isolated amplifier, receives the AD pin of CPU after being isolated by isolated amplifier, carries out sampling analysis.
Two current measurement terminals are through the lead short circuit, pass current transformer on the lead and induce voltage signal and receive the range switch unit, and the resistance that range switches by a plurality of different resistances is in series; Tell 4 ranges in different positions, the corresponding 20mA of difference, 200mA; 2A, the 20A range.The CPU procedure identification is also controlled the relay that switches correspondence automatically, makes the signal amplitude size in the measurement range of the best.Range switches back voltage sends into filter unit, and the PI filtering circuit that filter unit is made up of inductance capacitance can be with the filtering of part high-frequency signal.Signal is seen off by filter unit, advances the AD pin of receiving CPU after the amplifier unit amplifies, carries out sampling analysis.
The different AD pin that voltage, current signal divide two-way to send into CPU carries out the high-speed sampling analog to digital conversion, the discernible digital signal of the program that converts to through the built-in A/D convertor circuit of CPU.CPU carries out wavelet transformation analysis to digital signal then, from the waveform of complicacy, isolates the Weak frequency sine wave signal of required measurement.CPU can isolate the voltage under the assigned frequency simultaneously through software, and current signal also calculates phase differential between the two.CPU control store is simultaneously printed, and shows functions such as menu operation.
The CPU optional DSP of TI company model such as TMS320F2812 commonly used also can be other general processors, like the ARM architecture processor.DSP also claims digital signal processor, is a kind of microprocessor with special construction.The Harvard structure that the inside of dsp chip adopts program and data to separate has special hardware multiplier, extensively adopts stream line operation, and special DSP instruction is provided, and can be used for realizing apace various digital signal processing algorithms.According to the requirement of digital signal processing, dsp chip generally has some following principal features: a multiplication and a sub-addition can be accomplished in (1) in an instruction cycle.(2) program and data space separate, simultaneously access instruction and data.(3) have quick RAM in the sheet, usually can be through independently data bus visit simultaneously in two.(4) has low expense or do not have expense circulation and the hardware supports of redirect.(5) Interrupt Process and Hardware I/O supports fast.(6) have a plurality of hardware address generators of in the monocycle, operating.(7) can a plurality of operations of executed in parallel.(8) support stream line operation, operations such as getting finger, decoding and execution can overlappingly be carried out.
Frontier that develops rapidly in wavelet transformation current application mathematics and the engineering discipline, through nearly 10 years exploratory development, important mathematical form system is set up, and theoretical foundation is more sturdy.Traditional signal theory is based upon on the Fourier analysis basis, and Fourier transform is as a kind of variation of overall importance, and it has certain limitation.People begin Fourier transform is carried out various improvement in practical application, and wavelet analysis has produced thus.Wavelet analysis is a kind of emerging branch of mathematics, and it is the most perfect crystallization of functional, Fourier analysis, harmonic analysis, numerical analysis; In application, particularly in signal Processing, Flame Image Process, speech processes and numerous nonlinear science field, it is considered to the another effective Time-Frequency Analysis Method after Fourier analysis.Wavelet transformation is compared with Fourier transform; Be time and frequency domain the local conversion thereby can information extraction from signal effectively; Through calculation functions such as flexible and translations function or signal are carried out multiscale analysis, solved the indeterminable many difficult problems of Fourier transform.
What should explain at last is: obviously, the foregoing description only be for explain clearly that the utility model does for example, and be not qualification to embodiment.For the those of ordinary skill in affiliated field, on the basis of above-mentioned explanation, can also make other multi-form variation or change.Here need not also can't give exhaustive to all embodiments.And conspicuous variation of being amplified out thus or change still are among the protection domain of the utility model.
Claims (5)
1. anti-100,000 times are disturbed digitizing frequency-selecting measurement mechanism; It is characterized in that, comprise CPU (8), computing amplifying unit (7), isolate amplifying unit (6), filter unit (5), range automatic switch unit (4), current transformer (3), current measurement terminal (2) and voltage measurement terminal (1);
A range automatic switch unit (4) connects filter unit (5); Filter unit (5) connects isolates amplifying unit (6); Isolate amplifying unit (6) and connect CPU (8), range automatic switch unit (4) is provided with a pair of voltage measurement terminal (1), and this range automatic switch unit (4) also connects CPU (8);
Another one range automatic switch unit (4) connects another filter unit (5), filter unit (5) concatenation operation amplifying unit (7), and computing amplifying unit (7) connects CPU (8); This range automatic switch unit (4) connects CPU (8), and range automatic switch unit (4) also connects current transformer (3), and current transformer (3) is provided with current measurement terminal (2).
2. anti-according to claim 1 100,000 times are disturbed digitizing frequency-selecting measurement mechanism, it is characterized in that CPU (8) also connects display unit (9).
3. anti-according to claim 1 100,000 times are disturbed digitizing frequency-selecting measurement mechanism, it is characterized in that CPU (8) also connects menu operation knob (10).
4. anti-according to claim 1 100,000 times are disturbed digitizing frequency-selecting measurement mechanism, it is characterized in that CPU (8) also connects storage card (11).
5. anti-according to claim 1 100,000 times are disturbed digitizing frequency-selecting measurement mechanism, it is characterized in that CPU (8) also connects printer (12).
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| Application Number | Priority Date | Filing Date | Title |
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| CN2012201955035U CN202563025U (en) | 2012-05-03 | 2012-05-03 | 100,000-time interference resistance digitization frequency-selecting measuring device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2012201955035U CN202563025U (en) | 2012-05-03 | 2012-05-03 | 100,000-time interference resistance digitization frequency-selecting measuring device |
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| CN202563025U true CN202563025U (en) | 2012-11-28 |
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| CN2012201955035U Expired - Lifetime CN202563025U (en) | 2012-05-03 | 2012-05-03 | 100,000-time interference resistance digitization frequency-selecting measuring device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103163350A (en) * | 2013-03-26 | 2013-06-19 | 广东电网公司电力科学研究院 | Frequency-selecting universal meter for measuring voltage and current |
-
2012
- 2012-05-03 CN CN2012201955035U patent/CN202563025U/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103163350A (en) * | 2013-03-26 | 2013-06-19 | 广东电网公司电力科学研究院 | Frequency-selecting universal meter for measuring voltage and current |
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Granted publication date: 20121128 |
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| CX01 | Expiry of patent term |