CN103018704A - Correction method for instrument voltage transformer - Google Patents

Abstract

The invention discloses a correction method for an instrument voltage transformer, and comprises the steps of: firstly combining at least two inductive voltage dividers in a primary-secondary cascade connection, and configurating the transformation ratio tap positions of a primary inductive voltage divider and a secondary inductive voltage divider to enable the transformation ratio after the primary-secondary cascade connection combination to be the same as that of a certain tap position of the instrument voltage transformer; then obtaining errors of the primary inductive voltage divider and the secondary inductive voltage divider by self-correcting and verifying; and finally calibrating the self-corrected and verified primary inductive voltage divider and secondary inductive voltage divider to be a voltage ratio criterion, and comparatively transmitting the voltage ration criterion to the instrument voltage transformer to realize the correction of the change of a certain tap position of the instrument voltage transformer. The correction method for the instrument voltage transformer can improve the correction accuracy of voltage/voltage conversion under the condition of a low-voltage output of the instrument voltage transformer.

Description

A kind of bearing calibration of instrument voltage transformer

Technical field

The present invention relates to a kind of bearing calibration of normal component, be specifically related to a kind of bearing calibration of instrument voltage transformer.

Background technology

The effect of instrument voltage transformer is: high voltage in proportion relation transformation become low standard secondary voltage, for protection, metering, metering device.Because the electronic surveying in the fields such as industry, military affairs, metering, scientific research needs, the precision instrumentation technical development is swift and violent, and new technical requirement has appearred in instrument voltage transformer:

1) output voltage is below 10V, the specified 4V that is output as of electronic type voltage transformer secondary that uses such as the digital transformer substation of intelligent grid.

2) input conversion reaches the ppm magnitude to the accuracy requirement of output, such as the trace to the source voltage/voltage ratio benchmark of 50-100-200-400V/4V of needs of electric parameter baseline system.

Country not yet issues the vertification regulation of instrument voltage transformer at present, and the legal unit of measurement (department) is not carried out transmission of quantity value work yet.Metrological service to the bearing calibration of instrument voltage transformer is now: adopt first the exemplary reference potentiometric method of regulation in " national metrological verification regulations (JJG244-2003) " that inductive voltage divider is examined and determine, draw the transmission ratio error of inductive voltage divider and determine the accuracy of inductive voltage divider, inductive voltage divider after will examining and determine again is as the voltage ratio benchmark, according to " JJG314-2010 measures with voltage ct calibrating rules " prescriptive procedure, instrument voltage transformer is compared, the error that obtains instrument voltage transformer comprises ratio and angular difference, to have realized the correction to instrument voltage transformer.

In " national metrological verification regulations (JJG244-2003) " calibration method to inductive voltage divider, single-deck inductive voltage divider structure principle chart as shown in Figure 1, inductive voltage divider transmits the ratio that ratio (also being called inductive voltage divider dividing potential drop coefficient) is defined as Open Output Voltage phasor and input voltage phasor:

In the formula:

---inductive voltage divider Open Output Voltage phasor;

---inductive voltage divider input voltage phasor.

The error that inductive voltage divider transmits ratio is defined as:

$e=\frac{{\stackrel{\·}{U}}_o-{\stackrel{\·}{U}}_2}{{\stackrel{\·}{U}}_1}=\frac{\mathrm{\Δ}\stackrel{\·}{U}}{{\stackrel{\·}{U}}_1}$

In the formula:

---the nominal value of inductive voltage divider Open Output Voltage phasor;

---the difference of inductive voltage divider Open Output Voltage phasor and nominal value;

E---inductive voltage divider transmits the phasor of ratio error, is decomposed into:

$\left|e\right|=\sqrt{e_p^2+e_q^2}$

In the formula:

e _p---inductive voltage divider transmits the in-phase component of ratio error;

e _q---inductive voltage divider transmits the quadrature component of ratio error.

The accuracy of inductive voltage divider is determined with the limit of transmitting the ratio error mould.Stipulate in " national metrological verification regulations (JJG244-2003) " calibration method to inductive voltage divider: accurate inductive voltage divider transmits ratio error can use absolute inspection principle, namely based on the manufacturing process of inductive voltage divider: the coiling of multistage wire stranding, the segmentation AC impedance strictly equates, thereby makes every section the identical accurately intrinsic standoff ratio that obtains of dividing potential drop coefficient after the serial connection.In other words, inductive voltage divider transmits the relative scale measurement that the absolute check of ratio error is exactly AC impedance or alternating voltage.

In " national metrological verification regulations (JJG244-2003) " calibration method to inductive voltage divider, as shown in Figure 2, among Fig. 2: Fx is tested inductive voltage divider to the exemplary reference potentiometric method that adopts (absolute inspection principle), generally adopts the FG2 inductive voltage divider, Fs is reference divider, F _GBe the shielding protection potential divider,

Be supply voltage,

Be 1/N section supply voltage nominal value,

Be reference potential, N is the total hop count of inductive voltage divider, and D is zero indicator, and Δ i is the elementary errors compensator,

Eei=eip+jeiq wherein.Compare with the secondary voltage (being reference potential) of reference divider and each section voltage of tested inductive voltage divider, can get:

Es=1/N*SUM(Eei)

Ei=N*(Eei-Es)=N*Eei-SUM(Eei)

Eio=1/i*SUM(Ei)

Eii=1/N*SUM(Ei)

In the formula:

The error of Es---reference potential;

N---sense minute total hop count/elementary errors generator operating voltage and section voltage ratio;

The error of SUM (Ei)---i the tap section of comprising of inductive voltage divider and;

Ei---the section error of tested inductive voltage divider i section, complex representation Ei=α+j β;

The error of output is converted in Eio---i tap of tested inductive voltage divider;

The error of input is converted in i tap of Eii---inductive voltage divider.

The transmission ratio error of inductive voltage divider is comprised of Magnetic Measurement error and capacitive coupling error.

But, with above exemplary reference potentiometric method calibrating inductive voltage divider, with following problems may be encountered:

(1) calibrating needs to use specialized equipment: shielding protection potential divider, reference divider, elementary errors compensator and zero indicator are accurate specialized equipments, generally only are equipped with in the laboratory of national level;

(2) the reference divider frequency characteristic affects calibration accuracy, particularly the angular difference precision;

(3) the elementary errors compensation needs manually-operated, and the calibrating time is long;

(4) be when being input as the FG2 inductive voltage divider of 1ppm when examining and determine the conversion of existing approved product such as design accuracy, output rated voltage is designed to 100V, the operating voltage of supporting tester also is 100V, can not move under full scale voltage when being used for the comparison instrument voltage transformer with this standard;

(5) in order to satisfy different voltage ratio demands, the FG2 inductive voltage divider is that a plurality of single-deck inductive voltage dividers form the polydisc inductive voltage divider by cascade, (voltage change ratio of general instrument voltage transformer is all less than 10:1 during less than 10:1 when the instrument voltage transformer voltage change ratio of comparison, precision such as 100V/4V is the segmentation equivalent potential screen inductive voltage divider of 1ppm, and the 50-100-200-400V/4V instrument double-stage voltage transformer of precision 2ppm), the first dish of FG2 inductive voltage divider is with no-output, if but want the FG2 inductive voltage divider to guarantee 1ppm no-load voltage ratio precision, its the first dish output can not be 0, also be, when the first dish no-output, its precision will reduce greatly, and accurate instrument voltage transformer convert the input the inductive voltage divider error reached 4 * 10 ^-8, be difficult to find the higher standard that satisfies relative check with the relative method of inspection; (the relative method of inspection: compared by calibration equipment and standard device and obtain relative error) is because " national metrological verification regulations (JJG244-2003) " regulation: the precision for the standard device of tracing to the source should exceed by order of magnitude of calibration equipment, can ignore the impact of standard device error this moment, so the FG2 inductive voltage divider in the classic method can only can not as the standard of tracing to the source, also namely can't be proofreaied and correct instrument voltage transformer as the comparison reference in accurate instrument voltage transformer verification.

To sum up, because defects, existing high precision instrument voltage transformer just can not satisfy above-mentioned new technical requirement: 1) output voltage is that low-voltage is that no-load voltage ratio is lower than 10:1; 2) the conversion accuracy requirement is high.

In addition, Chinese utility model patent ZL201120055472.9 discloses a kind of high precision combined multifunctional calibrator, this prover is relatively instrument of binary channels alternating voltage, have two input channels, can make the voltage ratio benchmark of input independently carry out the calibration of two passage consistencies and zero phase absolute calibration, two Channel Perfect isolation, capacitive is leaked minimum, and the precision measurement frequency is high.

Summary of the invention

Technical matters to be solved by this invention just provides a kind of bearing calibration of instrument voltage transformer, is implemented under the condition of instrument voltage transformer low-voltage output, improves the high accuracy of voltage/voltage transformation.

For solving the problems of the technologies described above, the present invention is achieved through the following technical solutions:

A kind of bearing calibration of instrument voltage transformer comprises:

Elder generation is according to the needs of instrument voltage transformer no-load voltage ratio, the mode of at least two inductive voltage dividers by the major-minor cascade made up, dispose the no-load voltage ratio gear of major and minor inductive voltage divider, make the no-load voltage ratio behind the major-minor cascading identical with the no-load voltage ratio of a certain shelves of instrument voltage transformer; The self-correcting calibrating obtains the error of major and minor inductive voltage divider again; At last the major and minor inductive voltage divider after the self-correcting calibrating is demarcated as the voltage ratio benchmark, relatively be passed to instrument voltage transformer, realize the correction of a certain shelves of instrument voltage transformer no-load voltage ratio.

On the basis of the above, the present invention can do following improvement:

Inductive voltage divider of the present invention adopts segmentation equivalent potential screen inductive voltage divider, to eliminate Magnetic Measurement error and capacitive coupling error.

Further, the calibration method of major and minor inductive voltage divider error of the present invention is as follows:

Adopt relatively instrument of binary channels alternating voltage, two passages with binary channels alternating voltage comparison instrument are measured each section in the inductive voltage divider successively, use reference potential method self-correcting and calculate the error of major and minor each section of inductive voltage divider, by making up major and minor inductive voltage divider, obtain the no-load voltage ratio of needs, and calculate the final error after the combination.

Further, the present invention comprises that also the gear of instrument voltage transformer having been proofreaied and correct by the reference potential method is passed to other gear of instrument voltage transformer, to realize the correction of other gear of instrument voltage transformer.

Further, the method for other gear of correction instrument voltage transformer of the present invention is as follows:

Adopt relatively instrument of binary channels alternating voltage, measure instrument voltage transformer with A channel first and wherein one do not proofread and correct the impedance error of gear section, proofreaied and correct gear and instrument voltage transformer with the B channel measurement and exported impedance error between the reference edge; The measuring object that exchanges again A, B passage is to offset self systematic error of A, B passage, thereby directly obtain each by binary channels alternating voltage comparison instrument and do not proofread and correct the impedance error of the gear section of gear, the final error and uncertainty that calculates each gear that obtains instrument voltage transformer is realized the correction to other gear.

Compared with prior art, the present invention has following beneficial effect:

(1) the present invention adopts the mode of major and minor inductive voltage divider cascade to obtain no-load voltage ratio, is convenient to obtain the Voltage-output less than 10V, is applicable to the output of correction demand fully less than the instrument voltage transformer of 10V;

(2) the present invention saved traditional calibrating the specialized equipment that must use, the binary channels alternating voltage comparison instrument that adopts can conveniently use in common lab; Simultaneously, avoid the impact of reference divider frequency characteristic on proofreading and correct, saved the handling time of elementary errors compensation;

(3) inductive voltage divider of the present invention can move under full scale voltage when the comparison instrument voltage transformer;

(4) binary channels alternating voltage comparison instrument of the present invention can be eliminated self systematic error in measurement, adopt simultaneously segmentation equivalent potential screen inductive voltage divider also to eliminate Magnetic Measurement error and capacitive coupling error, make it have very high conversion precision, have fabulous amplitude versus frequency characte and phase-frequency characteristic, be used in the high-precision requirement of instrument voltage transformer;

(5) the present invention can measure direct-reading by binary channels alternating voltage comparison instrument, and data deviation is little and proving time short.

Description of drawings

Fig. 1 is existing single-deck inductive voltage divider structure principle chart;

Fig. 2 is the schematic diagram of existing exemplary reference potentiometric method calibrating inductive voltage divider;

Fig. 3 is the relatively theory diagram of instrument internal measurement circuit of binary channels alternating voltage of the present invention;

Fig. 4 is for comparing the wiring diagram of transmission to the 100V/4V shelves of instrument voltage transformer (double-stage voltage transformer);

Fig. 5 is the wiring diagram to other grade transmission of instrument voltage transformer (double-stage voltage transformer).

Embodiment

A kind of bearing calibration of instrument voltage transformer comprises:

(1) elder generation is according to the needs of instrument voltage transformer no-load voltage ratio, the mode of two inductive voltage dividers by the major-minor cascade made up, dispose the no-load voltage ratio gear of major and minor inductive voltage divider, make the no-load voltage ratio behind the major-minor cascading identical with the no-load voltage ratio of a certain shelves of instrument voltage transformer.

Wherein: the gear of proofreading and correct first of present embodiment instrument voltage transformer is the 100V/4V shelves.

The voltage transformer (VT) that present embodiment adopts (being called for short sense divides) is segmentation equivalent potential screen inductive voltage divider, to be specially the frequency of operation design of power frequency to 1000Hz, theoretical analysis shows: inductive voltage divider transmits ratio error and is comprised of magnetic error and capacitive error, wherein the magnetic error can be solved by assembling iron core and the coiling of multistage wire stranding of inductive voltage divider, its capacitive error is that intersegmental electric capacity and turn-to-turn capacitance but make the segmentation AC impedance strictly not equate, make inductive voltage divider when frequency is higher, produce very large error, this segmentation equivalent potential screen inductive voltage divider obtains each section voltage from field copper, and this voltage correspondence is connected in the shielding winding of each section of ratio winding, the capacitive error is reduced greatly, thereby its frequency performance is promoted greatly.

The binary channels alternating voltage of present embodiment relatively instrument (abbreviation comparator) adopts the disclosed a kind of high precision combined multifunctional calibrator of Chinese utility model patent ZL201120055472.9, its internal measurement schematic block circuit diagram is grouped into by input buffer circuit, analog to digital conversion circuit, DC reference voltage circuit, insulating power supply feed circuit and digital processes as shown in Figure 3.Have for A channel and the B passage of measuring sampling, under the continuous sampling mode of operation, power frequency resolution error amplitude reaches 0.2ppm, and phase place reaches 0.2 μ rad.Comparator can carry out A, the calibration of B two passage consistencies and zero phase absolute calibration at any time, two Channel Perfect isolation design, and capacitive is leaked minimum, and the precision measurement frequency can reach 3000Hz.

(2) the self-correcting calibrating obtains the error of major and minor inductive voltage divider:

Step 1:

A) it is high-end that comparator A channel signal input part connects the 1st section of sense minute N section impedance, and comparator A channel reference input connects the 1st section low side;

B) it is high-end that comparator B channel signal input end connects the 2nd section of sense minute N section impedance, and comparator B channel reference input end connects the 2nd section low side;

C) input 50V voltage is to sense minute, automatically measures two voltage and the phase value that read comparator, gets 30 groups of valid data and produces record;

D) adopt anti-phase connection, comparator B channel signal input end is connected the 2nd section low side of N section impedance, B channel reference input end connects the 2nd section high-end;

E) input 50V voltage is to sense minute, automatically measures two voltage and the phase value that read the binary channels comparator, gets 30 groups of valid data and produces record;

F) comparator B passage is measured the 3rd section successively to the N section, measures the wiring step by above-mentioned step a) ~ e) at every turn.

Step 2:

After exchanging signal source height electric potential connection, repeating step one.

Calculate respectively ratio error and the phase error that sense divides every section according to top step, experimental data is as shown in table 1.

Table 1

Calculated by following formula again and obtain ratio error and the phase error that sense divides:

Krp=1/N*SUM(Kri)；Φp=1/N*SUM(Φi)；

αi=Kri-Krp；βi=Φi-Φp；

Eio(α)=1/i*SUM(αi)；Eio(β)=1/i*SUM(βi)；

Eii(α)=1/N*SUM(αi)；Eii(β)=1/N*SUM(βi)。

In table 1 and the following formula, the elementary errors balance reading of Kei---i section, namely the section impedance ratio Kri that obtains of comparator angle Φ i;

Es---reference potential error, namely the reference impedance that obtains of comparator method than Krp angle Φ p;

The section error of Ei---i section, complex representation Ei=α+j β;

The error of SUM (Ei)---i gear (tap) section of comprising and;

N---sense minute total Duan Shuo elementary errors generator operating voltage and a section voltage ratio (can direct-reading from comparator);

Eio---sense minute i gear (tap) conversion is to the error of output;

Eii---sense minute i gear (tap) conversion is to the error of input;

Present embodiment because baseline system 100V/4V only concern minimum tap, so in the table 1 only to the 1st section error evaluation:

The ratio error that sense divides:

E1o(α)=0.2ppm；Eii(α)=0.02ppm

The phase error that sense divides:

E1o(β)=0.4urad；Eii(β)=0.04urad。(phase differential that sense divides and the phase differential of comparator represent opposite in sign)

(3) the major and minor inductive voltage divider after the self-correcting calibrating being demarcated is the voltage ratio benchmark: adopt relatively instrument of binary channels alternating voltage, two passages with binary channels alternating voltage comparison instrument are measured each section in the inductive voltage divider successively, use reference potential method self-correcting and calculate the error of major and minor each section of inductive voltage divider, by making up major and minor inductive voltage divider, obtain the no-load voltage ratio of needs, and calculate the final error after the combination.

In the present embodiment, be with ten sections coilings owing to feel the technique for coiling that divides, when input 100V, a section voltage nominal value of every section is 10V, and previous test is based on 50% linearity that sense divides, and obtains every section voltage 5V under 50V, limits with the amount that adapts to comparator.And the 4V that needs is integer intersegmental (minimum is not 100:10), the way of examining and determine this special tap is with one main one secondary two sense minute cascadings, secondary sense minute is identical with the manufacture method of main sense minute, i.e. two 10 sections cooperations that sense divides, first is led to feel dividing and obtains 100V/10V, divides by the pair sense to obtain 10V/4V again.When demarcating as the voltage ratio benchmark to major and minor inductive voltage divider, need to divide and the absolute error of cascade is carried out measurements and calculations the pair sense, the error of acquisition is finished the demarcation of 10V/4V benchmark with regard to being equivalent to.

The measurement result data are as shown in table 2.

Table 2

In the table 2, main: main sense divides; Secondary: secondary sense divides; Absolute value: absolute value error; Relative value: relative value error.

As can be seen from Table 3, during the major-minor cascade, the auxiliary connection sense divide load on the error of main sense minute substantially without impact, i.e. the master feels dividing and does not substantially introduce other error during cascade, when setting up the standard of instrument voltage transformer, the additive error of introducing is the smaller the better.

Table 3

Do optimal combination according to absolute checking data, i.e. the 100/4V that master's sense divides makes the first order, and the 100/4V that secondary sense divides does the second level, and the combination calculating absolute error ratio of this moment is 0.2ppm, and angular difference is 0.1 μ rad.

The section voltage power supply that secondary sense divides is in 10% of ratings, and power supply and table meter can't satisfy testing requirement, can only carry out qualitative analysis and assessment to its nonlinearity erron:

I) the equipotential sense excitation impedance of dividing is measured as 60(k Ω), the equiva lent impedance of ratio winding can be calculated, design concept according to the twin-stage winding, the electric current of inflow ratio winding is the error current of field copper, calculate by field copper error 0.1%, the equiva lent impedance of ratio winding is 60(M Ω), i.e. every section impedance is 6(M Ω).

II) owing to changing the every section impedance identical change that produces, exciting current will the dividing potential drop ratio not exerted an influence.

III) because the non-linear effects of the inhomogeneous generation of leakage reactance, if producing 6 ohm positive dirction, certain section ratio impedance changes (relatively greatly 1ppm), then this section impedance is positioned at tap interval or interval in tap, its calculating partial pressure amount of impact equal respectively 0.15ppm or-0.1ppm, i.e. the variation of arbitrary section impedance of the secondary sense in the second level minute on the impact of dividing potential drop ratio less than 20% of this section variable quantity.

IV) because the non-linear section impedance influences of the inhomogeneous generation of leakage reactance is obeyed the statistical average rule, namely can reduce the impact of dividing potential drop ratio.

In sum, the second level secondary sense component voltage work in ratings 10% the time, its with respect to nonlinearity erron assessment of 100% full scale less than 0.2ppm and 0.2 μ rad.The precision of vertical this 100V:4V voltage ratio benchmark of then building is higher.

(4) the voltage ratio benchmark comparison value with the 100V:4V that sets up is passed to instrument voltage transformer, realizes the correction of a certain shelves of instrument voltage transformer no-load voltage ratio:

(4-1) wiring diagram of 100V/4V transmission as shown in Figure 4, the instrument voltage transformer of present embodiment is double-stage voltage transformer, it is the voltage transformer (VT) that comprises 50-100-200-400V/4V volume limit, the twin-stage voltage of this double-stage voltage transformer is from 50V ~ 400V, and the error of calculation is controlled at the 5ppm scope.Because the benchmark of 100V/4V is set up, and relatively can obtain the error E 0 of double-stage voltage transformer 100V/4V, the principle of this comparative approach is identical with the Method And Principle that the major and minor sense of calibrating divides.

(4-2) to the correction of other gear:

Present embodiment adopts relatively instrument of binary channels alternating voltage, measures instrument voltage transformer with A channel first and wherein one does not proofread and correct the impedance error of gear section, has proofreaied and correct gear and instrument voltage transformer with the B channel measurement and has exported impedance error between the reference edge; The measuring object that exchanges again A, B passage is to offset self systematic error of A, B passage, thereby directly obtain each by binary channels alternating voltage comparison instrument and do not proofread and correct the impedance error of the gear section of gear, the final error and uncertainty that calculates each gear that obtains instrument voltage transformer, realization is to the correction of other gear, its wiring diagram and shown in Figure 5, concrete steps are as follows:

4-2-a) input 100V voltage is to the input end of double-stage voltage transformer, comparator A channel signal input part connects the 50/4V tap of double-stage voltage transformer, the A channel reference input connects the 100/4V tap of double-stage voltage transformer, the nominal voltage of tap is 4V, measuring error is Ea+E1, and Ea and E1 are respectively comparator A channel error and double-stage voltage transformer is measured 50/4V to the impedance error (or claiming potential error) of 100/4V section.

4-2-b) comparator B channel signal input end connects double-stage voltage transformer output reference edge, B channel reference input end connects the 100/4V tap of double-stage voltage transformer, measure another section 4V voltage, measuring error is Eb+E0, Eb and E0 are respectively comparator B channel error and 100/4V to the impedance error (or claiming potential error) of the measuring section of double-stage voltage transformer output reference edge, i.e. 100/4V error.The comparative result of two passages of comparator is e1=Eb+E0-Ea-E1.

4-2-c) automatically measure two vector voltages that two passages obtain, read 30 valid data and produce record.

4-2-d) comparator B channel signal input end connects the 50/4V tap of double-stage voltage transformer, B channel reference input end connects the 100/4V tap of double-stage voltage transformer, measuring error is Eb+E1, and Eb and E1 are respectively comparator B channel error and 50/4V to the impedance error (or claiming potential error) of 100/4V measuring section.And comparator A channel signal input part connects twin-stage mutual inductor output reference edge, the A channel reference input connects the 100/4V tap of double-stage voltage transformer, measuring error is Ea+E0, the impedance error that Ea and E0 are respectively comparator A channel error and 100/4V exports the measuring section of reference edge to double-stage voltage transformer (or claims potential error, be reference impedance), passage comparative result e2=Eb+E1-Ea-E0(in relative error is measured for convenience of calculation, always be made as zero with reference to standard error, after obtaining a result again the modified value with reference to standard take into account).

4-2-e) automatically measure two vector voltages that two passages obtain, read 30 valid data and produce record.

4-2-f) since e1 and e2 directly obtain by comparator, calculate again (e2-e1)/2=((Eb+E1-Ea-E0)-(Eb+E0-Ea-E1))/2=E1, calculate (e2+e1)/2=((Eb+E1-Ea-E0)+(Eb+E0-Ea-E1))/2=Eb-Ea, then can obtain E1 and offset the systematic error of two passages self of comparator.

4-2-g) input 200V voltage is to the input end of double-stage voltage transformer, reaching between 200/4V tap and the twin-stage mutual inductor output reference edge between 100/4V tap this moment and the 200/4V tap is two vector voltages, also calibrates by the step of above 4-2-a to 4-2-f.

4-2-h) input 400V voltage also adopts the step of the same 4-2-a to 4-2-f to calibrate to the input end of double-stage voltage transformer.

The calculating of each section impedance in the above-mentioned calibration:

Make four tap impedances be respectively Z50, Z100, Z200 and Z400, double-stage voltage transformer 100/4V section is E0 with respect to the error of inductive voltage divider 100/4V section; Relative impedance (or electromotive force) error is measured in three times of above-mentioned double-stage voltage transformer, and to be respectively the reference impedance that E1, E2, E3(measure for three times be respectively Z100, Z100-Z200, Z200-Z400), each section impedance phase is as follows to measuring computation process:

$\mathrm{<figure-callout\; id="50"\; label="Z"\; filenames="HDA00002503265300031.png"\; state="\{\{state\}\}">Z</figure-callout>}50=Z100(1+E1)+\mathrm{<figure-callout\; id="100"\; label="Z"\; filenames="HDA00002503265300022.png,HDA00002503265300031.png"\; state="\{\{state\}\}">Z</figure-callout>}100=2\&times;Z100(1+\frac{E1}{2})---\left(1\right)$

$\frac{Z200-(Z100-Z200)}{Z100-\mathrm{<figure-callout\; id="200"\; label="Z"\; filenames="HDA00002503265300031.png"\; state="\{\{state\}\}">Z</figure-callout>}200}=E2---\left(2\right)$

$\&DoubleRightArrow;2\&times;Z200-\mathrm{<figure-callout\; id="100"\; label="Z"\; filenames="HDA00002503265300022.png,HDA00002503265300031.png"\; state="\{\{state\}\}">Z</figure-callout>}100=\mathrm{<figure-callout\; id="100"\; label="Z"\; filenames="HDA00002503265300022.png,HDA00002503265300031.png"\; state="\{\{state\}\}">Z</figure-callout>}100\&times;E2-\mathrm{<figure-callout\; id="200"\; label="Z"\; filenames="HDA00002503265300031.png"\; state="\{\{state\}\}">Z</figure-callout>}200\&times;E2---\left(3\right)$

$\&DoubleRightArrow;Z200(2+E2)=Z100(1+E2)---\left(4\right)$

$\&DoubleRightArrow;\mathrm{<figure-callout\; id="200"\; label="Z"\; filenames="HDA00002503265300031.png"\; state="\{\{state\}\}">Z</figure-callout>}200=\frac{Z100(1+E2)}{2+E2}=\frac{\mathrm{<figure-callout\; id="100"\; label="Z"\; filenames="HDA00002503265300022.png,HDA00002503265300031.png"\; state="\{\{state\}\}">Z</figure-callout>}100}{2}\&times;\frac{1+E2}{1+\frac{E2}{2}}$

By approximate derivation formula 1/ (1-X)=1+X(when X be very in a small amount the time, and it is in a small amount above to have omitted second order), following formula can be similar to the form that is written as formula (5):

$\mathrm{<figure-callout\; id="200"\; label="Z"\; filenames="HDA00002503265300031.png"\; state="\{\{state\}\}">Z</figure-callout>}200=\frac{\mathrm{<figure-callout\; id="100"\; label="Z"\; filenames="HDA00002503265300022.png,HDA00002503265300031.png"\; state="\{\{state\}\}">Z</figure-callout>}100}{2}\&times;(1+\frac{E2}{2})---\left(5\right)$

In like manner:

$\mathrm{<figure-callout\; id="400"\; label="Z"\; filenames="HDA00002503265300031.png"\; state="\{\{state\}\}">Z</figure-callout>}400=\frac{\mathrm{<figure-callout\; id="200"\; label="Z"\; filenames="HDA00002503265300031.png"\; state="\{\{state\}\}">Z</figure-callout>}200}{2}\&times;(1+\frac{E3}{2})---\left(6\right)$

If Z0 is the error free impedance that the sense of relative segmentation equipotential divides, continuing to derive has:

$\frac{Z100}{Z0}-1=E0---\left(7\right)$

$\&DoubleRightArrow;\mathrm{<figure-callout\; id="100"\; label="Z"\; filenames="HDA00002503265300022.png,HDA00002503265300031.png"\; state="\{\{state\}\}">Z</figure-callout>}100=Z0\&times;(1+E0)---\left(8\right)$

With formula (8) substitution formula (1):

$\mathrm{<figure-callout\; id="50"\; label="Z"\; filenames="HDA00002503265300031.png"\; state="\{\{state\}\}">Z</figure-callout>}50=2\&times;Z0(1+E0)(1+\frac{E1}{2})$

$\&DoubleRightArrow;\frac{\mathrm{<figure-callout\; id="50"\; label="Z"\; filenames="HDA00002503265300031.png"\; state="\{\{state\}\}">Z</figure-callout>}50}{2\&times;Z0}-1=E0+\frac{E1}{2}---\left(9\right)$

Omitted a small amount of of second order in the formula (9).

In like manner with formula (8) substitution formula (5) and formula (6), can get:

$\frac{Z200}{Z0/2}-1=E0+\frac{E2}{2}---\left(10\right)$

$\frac{Z400}{Z0/4}-1=E0+\frac{E2+E3}{2}---\left(11\right)$

The experimental data of double-stage voltage transformer is as shown in table 4.

(a main sense minute modified value is-1.43ppm 0.17 μ rad)

Table 4

The absolute value error of general mutual inductor is to adopt compensating circuit to carry out translation, and nonlinearity erron needs Design and manufacture technique to guarantee, so nonlinearity erron is more even more important than absolute value error, more than can obtain following result:

The nonlinearity erron of 50-100-200-400V/4V double-stage voltage transformer:

The ratio nonlinearity erron is 1.7ppm;

The phase nonlinear error is 0.5 μ rad;

The trace to the source uncertainty (result's that namely traces to the source confidence level) of measurement result of 50-100-200-400V/4V double-stage voltage transformer:

The ratio uncertainty is 0.3ppm;

The phase place uncertainty is 0.4 μ rad.

More than the gear instrument voltage transformer proofreaied and correct by the reference potential method be passed to other gear of instrument voltage transformer, to realize the correction of other gear of instrument voltage transformer.

Embodiments of the present invention are not limited to this; according to foregoing of the present invention; utilize ordinary skill knowledge and the customary means of this area; do not breaking away under the above-mentioned basic fundamental thought of the present invention prerequisite; the present invention can also make modification, replacement or the change of other various ways, all drops within the rights protection scope of the present invention.

Claims (5)

1. the bearing calibration of an instrument voltage transformer is characterized in that comprising:

Elder generation is according to the needs of instrument voltage transformer no-load voltage ratio, the mode of at least two inductive voltage dividers by the major-minor cascade made up, dispose the no-load voltage ratio gear of major and minor inductive voltage divider, make the no-load voltage ratio behind the major-minor cascading identical with the no-load voltage ratio of a certain shelves of instrument voltage transformer; The self-correcting calibrating obtains the error of major and minor inductive voltage divider again; At last the major and minor inductive voltage divider after the self-correcting calibrating is demarcated as the voltage ratio benchmark, relatively be passed to instrument voltage transformer, realize the correction of a certain shelves of instrument voltage transformer no-load voltage ratio.

2. the bearing calibration of instrument voltage transformer according to claim 1 is characterized in that: described inductive voltage divider adopts segmentation equivalent potential screen inductive voltage divider.

3. the bearing calibration of instrument voltage transformer according to claim 2 is characterized in that: the calibration method of described major and minor inductive voltage divider error is as follows:

Adopt relatively instrument of binary channels alternating voltage, two passages with binary channels alternating voltage comparison instrument are measured each section in the inductive voltage divider successively, use reference potential method self-correcting and calculate the error of major and minor each section of inductive voltage divider, by making up major and minor inductive voltage divider, obtain the no-load voltage ratio of needs, and calculate the final error after the combination.

4. according to claim 1-3 bearing calibration of each described instrument voltage transformer, it is characterized in that: comprise that also the gear of instrument voltage transformer having been proofreaied and correct by the reference potential method is passed to other gear of instrument voltage transformer, to realize the correction of other gear of instrument voltage transformer.

5. the bearing calibration of instrument voltage transformer according to claim 4 is characterized in that: the method for described other gear of correction instrument voltage transformer is as follows:

Adopt relatively instrument of binary channels alternating voltage, measure instrument voltage transformer with A channel first and wherein one do not proofread and correct the impedance error of gear section, proofreaied and correct gear and instrument voltage transformer with the B channel measurement and exported impedance error between the reference edge; The measuring object that exchanges again A, B passage is to offset self systematic error of A, B passage, thereby directly obtain each by binary channels alternating voltage comparison instrument and do not proofread and correct the impedance error of the gear section of gear, the final error and uncertainty that calculates each gear that obtains instrument voltage transformer is realized the correction to other gear.

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