CN1007091B - Method and device for directly reading and ckecking dc mutual inductor comparison value difference - Google Patents
Method and device for directly reading and ckecking dc mutual inductor comparison value differenceInfo
- Publication number
- CN1007091B CN1007091B CN 87108187 CN87108187A CN1007091B CN 1007091 B CN1007091 B CN 1007091B CN 87108187 CN87108187 CN 87108187 CN 87108187 A CN87108187 A CN 87108187A CN 1007091 B CN1007091 B CN 1007091B
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- China
- Prior art keywords
- current
- winding
- measuring
- input end
- comparator
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- 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.)
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- Measurement Of Current Or Voltage (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
The present invention relates to a ratio difference direct measuring technology of a DC current transformer and a fabricated ratio difference direct reading check meter of the DC current transformer for realizing the technology. The ratio difference direct measuring technology realized by the check meter breaks the conventional method for measuring the ratio difference of a DC current transformer by an indirect measuring method at home and abroad. The check meter not only can directly read out ratio difference values and symbols, but also has the characteristics of high precision, low cost, small size, light weight and simple operation. Thus, the check meter is an ideal check meter for measuring units.
Description
A kind of calibration equipment that relates to DC current transformer ratio direct measuring and realize this technology manufacturing.
At present, current transformer is than difference measurements, and two kinds of methods are arranged.A kind of is the direct method of measurement, and another kind is the indirect method of measurement.The direct method of measurement is US-2911591(approval day as the patent No.: " instrument transformer test unit " 1959,11,3).The formed error voltage of error current that it adopts tested current transformer and standard current transformer to compare to obtain is realized the direct measurement of tested current transformer ratio and angular difference with the method for compensating for mutually with proportional in-phase voltage of standard current transformer output current and quadrature voltage.But this measuring method only is suitable for the measurement of AC current transformer ratio and angular difference.This is because in-phase voltage that compensates for mutually with error voltage and quadrature voltage are to realize by current transformer and mutual inductor respectively with the getting in touch of output current of standard current transformer, and this current transformer and mutual inductor are inoperative for DC current.Therefore, this measuring method is unsuitable for the direct-reading verification of DC current transformer ratio.Measurement to the DC current transformer ratio, all adopt the indirect method of measurement both at home and abroad, promptly tested DC current transformer and standard DC current transformer standard direct current current ratio devices such as (or) DC current comparators are compared, measure the secondary current of the absolute error and the standard DC current transformer of tested DC current transformer secondary current, by calculating the corresponding ratio of tested DC current transformer.The shortcoming of this measuring method is:
1, because the ratio of DC current transformer is to be calculated by two measurement data (absolute error value of secondary current and working current value), so, from the differentiation of the calculating that measures ratio of data and its symbol all than more complicated, therefore, inefficiency.
2, because the measuring equipment of this method, it is digital voltmeter by two high resolving power, high input impedance, plural precision resister device, a high-precision DC current proportioning device is formed, so metering circuit complexity, cumbersome, the measuring equipment cost height of operation.
3, this method accuracy is low, can not verification high precision DC current ratio instrument.
Purpose of the present invention: realize the direct verification of DC current transformer ratio.
The technology of the present invention solution is:
Adopt double-current comparator (detecting current comparator and switching current comparator) realization DC current transformer ratio directly to measure.At first, with the primary and secondary current conversion of tested DC current transformer the error current and the normalization electric current of reflection DC current transformer ratio through the double-current comparator; Be error current and normalization current conversion measuring voltage and bucking voltage respectively by measuring resistance network and compensating resistance network then; Realize the comparison of measuring voltage and bucking voltage at last by the computing zero indicator: regulate the compensation resistance values in the compensating resistance network, when bucking voltage and measuring voltage balance, the compensation resistance values of compensating resistance network will directly provide the ratio difference of DC current transformer, thereby realize the purpose of DC current transformer ratio direct-reading verification.
The DC current transformer ratio direct-reading calibration equipment of realizing such scheme detects current comparator mainly by the switching current comparer, demodulator amplifier, and the measuring resistance network, compensating resistance network and computing zero indicator are formed.
Advantage of the present invention is:
1, ratio direct-reading, simple to operate, under the working current of determining, regulate ratio measuring disk (promptly regulating the compensating resistance in the compensating resistance network), when computing zero indicator nulling, just can directly read on the measuring disk the ratio difference of tested DC current transformer.And in measuring process, be subjected to the influence of working current fluctuation hardly, high efficiency.
2, accuracy height, it not only can directly measure the ratio of DC current transformer, and can also the high-precision DC current ratio of verification instrument.Be suitable for as enterprise, metrological service's DC current ratio measurement standard.
3, applicability is strong, uses flexibly.During the work of this calibration equipment, do not need other optional equipment, can be equipped with high precision DC current ratio instrument yet and use.Not only can also be suitable for the on-line testing of industry spot in laboratory work.
Below in conjunction with description of drawings most preferred embodiment of the present invention.
Fig. 1 and Fig. 2 are respectively the fundamental diagram of two embodiment of the present invention.
In Fig. 1 and Fig. 2,1 is that detection current comparator, 2 is that switching current comparer, 3,4 is that demodulator amplifier, 5 is that measuring resistance network, 6 is that compensating resistance network, 7 is that computing zero indicator, 8 is that tested DC current transformer, 9 is direct supply, I
1Be tested DC current transformer primary current, I
2For tested DC current transformer secondary current, I are error current, I
' 2Be normalization electric current, W
1Elementary winding, W for switching current comparer 2
2Secondary winding, W for switching current comparer 2
cDetection winding, N for switching current comparer 2
1For detecting elementary winding, the N of current comparator 1
2For detecting secondary winding, the N of current comparator 1
cFor the detection winding that detects current comparator 1, N for detecting the feedback winding of current comparator 1.
In Fig. 1, the secondary winding W of switching current comparer 2
2, detect the secondary winding N of current comparator 1
2, compensating resistance network 6 and demodulator amplifier 4 closed successively connection of output terminal; The feedback winding N of detection current comparator 1, the output terminal of demodulator amplifier 3 and measuring resistance network 5 are closed successively to be connected; Detect the detection winding N of current comparator 1
cLink to each other with the input end of demodulator amplifier 3; The detection winding W of switching current comparer 2
cLink to each other with the input end of demodulator amplifier 4; Computing zero indicator 7 links to each other with compensating resistance network 6 with measuring resistance network 5 respectively; Detect the elementary winding N of current comparator 1
1, tested DC current transformer 8 closed successively connection of input end and direct supply 9; The elementary winding W of switching current comparer 2
1Link to each other with tested DC current transformer 8 output terminals.
In Fig. 2, the secondary winding W of switching current comparer 2
2, demodulator amplifier 4 closed successively connection of output terminal and compensating resistance network 6; The feedback winding N of detection current comparator 1, the output terminal of demodulator amplifier 3 and measuring resistance network 5 are closed successively to be connected; The detection winding W of switching current comparer 2
cLink to each other with the input end of demodulator amplifier 4; Detect the detection winding N of current comparator 1
cLink to each other with the input end of demodulator amplifier 3; Computing zero indicator 7 links to each other with compensating resistance network 6 with measuring resistance network 5 respectively; The secondary winding N of the output terminal of tested DC current transformer 8, detection current comparator 1
2Elementary winding W with switching current comparer 2
1Closed successively linking to each other; Detect the elementary winding N of current comparator 1
1, tested DC current transformer 8 closed successively linking to each other of input end and direct supply 9.
In Fig. 1, Fig. 2, switching current comparator (comprising switching current comparer 2 and demodulator amplifier 4) is with the secondary current I of tested DC current transformer 8
2Be converted to the normalization electric current I
' 2, this electric current is by the secondary winding W of switching current comparer 2
2The magnetic potential that is produced equates with the elementary magnetic potential of switching current comparer 2, i.e. W
1I
2=W
2I
' 2In Fig. 1, the normalization electric current I
' 2By detecting the secondary winding N of current comparator 1
2Magnetic potential that is produced and electric current I
1By detecting the elementary winding N of current comparator 1
1The magnetic potential that is produced is compared, and its magnetic potential difference is N
1I
1-N
2I
' 2In Fig. 2, the secondary current I of tested DC current transformer 8
2By detecting the secondary winding N of current comparator 1
2Magnetic potential that is produced and primary current I
1By detecting the elementary winding N of current comparator 1
1The magnetic potential that is produced is compared, and its magnetic potential difference is N
1I
1-N
2I
2In magnetic potential difference described in Fig. 1, Fig. 2, detect by detecting current comparator (comprise and detect current comparator 1 and demodulator amplifier 3), promptly by detecting the detection winding N in the current comparator 1
cDetect, through demodulator amplifier 3 output error electric current I, this error current produces the feedback magnetic potential by the feedback winding N that detects current comparator 1, makes the magnetic potential that detects current comparator 1 reach balance, i.e. N
1I
1-N
2I
' 2=NI(Fig. 1) or N
1I
1-N
2I
2=NI(Fig. 2).
Fig. 3 is the principle of work circuit diagram of measuring resistance network 5 and compensating resistance network 6, and wherein: R is the measuring resistance of measuring resistance network 5, R
1Be the compensating resistance of compensating resistance network 6, and resistance R, R
1For measuring resistance R and compensating resistance R are regulated in interlock
1The adjustable side link to each other with the E of computing zero indicator 7 end, H end respectively; Measuring resistance R and compensating resistance R
1Stiff end all link to each other (D holds ground connection) with the D of computing zero indicator end.
In Fig. 3, error current I forms measuring voltage IR, normalization electric current I on the measuring resistance R of measuring resistance network 5
' 2Compensating resistance R at compensating resistance network 6
1Last formation bucking voltage I
' 2R
1
Fig. 4 is the circuit theory diagrams of computing zero indicator 7.It comprises amplifier A
1, A
2, A
3The voltage follower I of Zu Chenging, II, III, amplifier A respectively
4With computing resistance r
1, r
2, r
3, r
4, r
5The plus and minus calculation device IV, indicator 10 and the change-over switch K that form
1, K
2, its connected mode is:
A, amplifier A
1, A
2, A
3Output terminal be connected to form voltage follower I, II, III with separately inverting terminal respectively; Amplifier A
1, A
2, A
3In-phase input end and the output terminal input end and the output terminal that are respectively voltage follower I, II, III.
B, computing resistance r
1, r
2An end and amplifier A
4Inverting terminal connect; Computing resistance r
4With amplifier A
4Inverting terminal be connected with output terminal; Computing resistance r
3, r
5An end and amplifier A
4In-phase input end be connected; Computing resistance r
5The other end and circuit ground (being the D end) be connected; Computing resistance r
1, r
2, r
3The other end be input end p Q, the L of plus and minus calculation device IV, the output terminal with voltage follower I, II, III is connected respectively; Amplifier A
4Output terminal be the output terminal M of plus and minus calculation device IV.
The input end E of c, voltage follower I is the input end of measuring voltage IR; The output terminal of voltage follower I is connected with the input end P of plus and minus calculation device IV.
The input end F of d, voltage follower II ratio indicating value f when negative by change-over switch K
2With bucking voltage I
' 2R
1Input end H be connected; Otherwise input end F is by change-over switch K
1Ground connection (being the D end); The output terminal of voltage follower II is connected with the input end Q of plus and minus calculation device IV.
The input end G of e, voltage follower III ratio indicating value f when negative by change-over switch K
1Ground connection (being the D end); Otherwise input end G is by change-over switch K
2With bucking voltage I
' 2R input end H is connected; The output terminal of voltage follower III is connected with the input end L of plus and minus calculation device IV.
The two ends of f, indicator 10 are connected with the D end with the output terminal M of plus and minus calculation device IV respectively.
In Fig. 3, Fig. 4, when regulating compensating resistance R
1When making indicator 10 nullings, bucking voltage I
' 2R
1IR balances each other with measuring voltage.When ratio f is timing, IR=+I
' 2R
1; When ratio f when negative, IR=-I
' 2R
1The ratio f of tested DC current transformer when Fig. 1 is:
When Fig. 2 be:
As (N
2R ± the R of)/(N)
1Or (N
2(the W of)/(N)
2)/(W
1) R ± R
1When being a constant C, f=± R then
1So/C is compensating resistance R
1The percentage of constant C is the percentage of tested DC current transformer ratio, and the symbol of ratio is by change-over switch K
1Or K
2Determining positions.Like this by regulating compensating resistance R
1Realize that indicator 10 nullings have just reached the purpose of tested DC current transformer ratio direct-reading verification.
Claims (5)
1, a kind of method of DC current transformer ratio direct-reading verification is characterized in that:
A, employing double-current comparator (detecting current comparator and switching current comparator), the switching current comparator is with the secondary current I of tested DC current transformer (8)
2Be converted to the normalization electric current I
2The primary current I of tested DC current transformer (8)
1With the normalization electric current I
2' on detection current comparator (1), compare, with magnetic potential difference N relatively
1I
1-N
2I
' 2Be converted to error current I;
Measuring resistance R in the b usefulness measuring resistance network (5) and the compensating resistance R in the compensating resistance network (6)
1, respectively with error current I and normalization electric current I
1 2Be converted to measuring voltage IR and bucking voltage I
1 2R
1
C, by computing zero indicator (7) with measuring voltage IR with bucking voltage I
1 2R
1Compare, regulate the compensating resistance R in the compensating resistance network (6)
1, make computing zero indicator (7) nulling, realize bucking voltage I
1 2R
1With the balance of measuring voltage IR, i.e. IR=± I
1 2R
1, the ratio of tested DC current transformer this moment (8) is:
In this formula: R
1For compensating resistance, R are that measuring resistance, N are for detecting the feedback winding of current comparator (1), N
2For detecting the secondary winding of current comparator (1);
In d, the measuring process, the compensating resistance R in regulating compensating resistance network (6)
1The time, the measuring resistance R in the measuring resistance network (5) changes thereupon, and keeps ((N
2The R of)/(N)
R
1) be constant C, the ratio of then tested DC current transformer (8) is: f=± R
1/C
In this formula, c=(N
2The R of)/(N)
R
1, wherein, N is for detecting feedback winding, the N of current comparator (1)
2For detecting secondary winding, the R of current comparator (1)
1For compensating resistance, R are measuring resistance.
2, a kind of method of DC current transformer ratio direct-reading verification is characterized in that:
A, employing double-current comparator (detecting current comparator and switching current comparator), the switching current comparator is with the secondary current I of tested DC current transformer (8)
2Be converted to the normalization electric current I
' 2; The primary current I of tested DC current transformer (8)
1With secondary current I
2On detection current comparator (1), compare, with magnetic potential difference N relatively
1I
1-N
2I
2Be converted to error current I;
Measuring resistance R in b, the usefulness measuring resistance network (5) and the compensating resistance R in the compensating resistance network (6)
1Respectively with error current I and normalization electric current I
' 2Be converted to measuring voltage IR and bucking voltage I
' 2R
1;
C, by computing zero indicator (7) with measuring voltage IR and bucking voltage I
' 2R
1Compare, regulate the compensating resistance R in the compensating resistance network (6)
1, make computing zero indicator (7) nulling, realize bucking voltage I
' 2R
1With the balance of measuring voltage IR, i.e. IR=± I
' 2R
1, the ratio of tested DC current transformer this moment (8) is: f=
In this formula, R is a measuring resistance, R
1For compensating resistance, N are feedback winding, the N that detects current comparator (1)
2For detecting secondary winding, the W of current comparator (1)
1Elementary winding, W for switching current comparer (2)
2Secondary winding for switching current comparer (2);
In d, the measuring process, the compensating resistance R in regulating compensating resistance network (6)
1The time, the measuring resistance R in the measuring resistance network (5) changes thereupon, and keeps ((N
2)/(N) (W2)/(W1) R
R
1) be constant c, the ratio of then tested DC current transformer (8) is: f=± R/C
In this formula, C=(N
2(the W of)/(N)
2)/(W
1) R
R
1, wherein N is for detecting the feedback winding of current comparator (1), N
2For detecting the secondary winding of current comparator (1), W
1Be the elementary winding of switching current comparer (2), W
2Be the secondary winding of switching current comparer (2), R is a measuring resistance, R
1Be compensating resistance.
3, a kind of DC current transformer ratio direct-reading calibration equipment of realizing the described DC current transformer ratio of claim 1 direct-reading method of calibration, it is characterized in that: this device is formed by detecting current comparator (1), switching current comparer (2), demodulator amplifier (3) (4), measuring resistance network (5), compensating resistance network (6) and computing zero indicator (7), wherein, detecting current comparator (1) comprising: elementary winding N
1, secondary winding N
2, feedback winding N and detect winding N
c; Switching current comparer (2) comprising: elementary winding W
1, secondary winding W
2With detection winding W
c; Being connected to of this device: the elementary winding N that detects current comparator (1)
1, tested DC current transformer (8) closed successively connection of input end and direct supply (9); Detect the feedback winding N of current comparator (1)
cThe output terminal of demodulator amplifier (3) is connected with measuring resistance network (5) is closed successively; Detect the detection winding N of current comparator (1)
cLink to each other with the input end of demodulator amplifier (3); Detect the secondary winding N of current comparator (1)
2, switching current comparer (2) secondary winding W
2, demodulator amplifier (4) closed successively connection of output terminal and compensating resistance network (6); The elementary winding W of switching current comparer (2)
1Link to each other with the output terminal of tested DC current transformer (8); The detection winding W of switching current comparer (2)
cLink to each other with the input end of demodulator amplifier (4); Computing zero indicator (7) two ends link to each other with compensating resistance network (6) with measuring resistance network (5) respectively.
4, a kind of DC current transformer ratio direct-reading calibration equipment of realizing the described DC current transformer ratio of claim 2 direct-reading method of calibration, it is characterized in that: this device is formed by detecting current comparator (1), switching current comparer (2), demodulator amplifier (3), (4), measuring resistance network (5), compensating resistance network (6) and computing zero indicator (7), wherein, detecting current comparator (1) comprising: elementary winding N
1, secondary winding N
2, feedback winding N and detect winding N
c; Switching current comparer (2) comprising: elementary winding W
1, secondary winding W
2With detection winding W
c; Being connected to of this device:
Detect the elementary winding N of current comparator (1)
1, tested DC current transformer (8) closed successively connection of input end and direct supply (9); The feedback winding N of detection current comparator (1), the output terminal of demodulator amplifier (3) and measuring resistance network (5) are closed successively to be connected; Detect the detection winding N of current comparator (1)
cLink to each other with the input end of demodulator amplifier (3); Detect the secondary winding N of current comparator (1)
2, switching current comparer (2) elementary winding W
1With closed successively connection of output terminal of tested DC current transformer (8); The secondary winding W of switching current comparer (2)
2, demodulator amplifier (4) closed successively connection of output terminal and compensating resistance network (6); The detection winding W of switching current comparer (2)
cLink to each other with the input end of demodulator amplifier (4); Computing zero indicator (7) two ends link to each other with compensating resistance network (6) with measuring resistance network (5) respectively.
5, according to claim 3 or 4 described DC current transformer ratio direct-reading calibration equipments, it is characterized in that: described computing zero indicator (7) comprises by amplifier A
1, A
2, A
3The voltage follower of Zu Chenging (I), (II), (III) respectively, amplifier A
4With computing resistance r
1, r
2, r
3, r
4, r
5The plus and minus calculation device (VI), indicator (10) and the change-over switch K that form
1, K
2, its connected mode is:
A, computing resistance r
1, r
2An end all with amplifier A
4Inverting terminal link to each other; Computing resistance r
3, r
5An end all with amplifier A
4In-phase input end link to each other; Computing resistance r
1, r
2, r
3The other end be respectively input end p, Q, the L of plus and minus calculation device (VI); Computing resistance r
5Other end ground connection (be D end); Computing resistance r
4Two ends respectively with amplifier A
4Inverting terminal link to each other with output terminal; Amplifier A
4Output terminal M be the output terminal of plus and minus calculation device (IV);
The input end E of b, voltage follower (I) is the input end of measuring voltage IR; The output terminal of voltage follower (I) links to each other with the input end p of addition, subtraction operation device (IV);
The input end F of c, voltage follower (II), at ratio f when negative, by change-over switch K
2With bucking voltage I
' 2R
1Input end H link to each other; Otherwise input end F is by change-over switch K
1Ground connection (being the D end); The output terminal of voltage follower (II) links to each other with the input end Q of plus and minus calculation device (IV);
The input end G of d, voltage follower (III) is timing at ratio f, by change-over switch K
2With measuring voltage I
' 2R
1Input end H link to each other; Otherwise input end G is by change-over switch K
1Ground connection (being the D end); The output terminal of voltage follower (III) links to each other with the input end L of plus and minus calculation device (IV);
The two ends of e, indicator (10) link to each other with the D end with the output terminal M of plus and minus calculation device (IV) respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 87108187 CN1007091B (en) | 1987-12-16 | 1987-12-16 | Method and device for directly reading and ckecking dc mutual inductor comparison value difference |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 87108187 CN1007091B (en) | 1987-12-16 | 1987-12-16 | Method and device for directly reading and ckecking dc mutual inductor comparison value difference |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN87108187A CN87108187A (en) | 1988-07-27 |
| CN1007091B true CN1007091B (en) | 1990-03-07 |
Family
ID=4816397
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 87108187 Expired CN1007091B (en) | 1987-12-16 | 1987-12-16 | Method and device for directly reading and ckecking dc mutual inductor comparison value difference |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1007091B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1963556B (en) * | 2006-11-24 | 2010-04-14 | 中国计量科学研究院 | Apparatus for integrality checking proportion of cryo-current comparator and the method thereof |
| CN103885022B (en) * | 2014-03-31 | 2015-11-04 | 国家电网公司 | Based on the rated current ratio measuring method of mutual-inductor tester |
-
1987
- 1987-12-16 CN CN 87108187 patent/CN1007091B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CN87108187A (en) | 1988-07-27 |
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