MEASUREMENT SYSTEM FOR HIGH CURRENT SHUNTS DC

CHARACTERIZATION AT CMI

Nováková Zachovalová, V., Šíra, M. and Streit, J.Czech Metrology Institute, Okruzni 31, 638 00 Brno, Czech Republic,

vnovakovazachovalova@cmi.cz

MEASUREMENT SET UP

Method: measurement of ratio of output voltages of the tested and the reference standard by dual channel multimeter. Thus, the resistance of tested standard is calculated:

Standards: oil filled and placed in the oil bath, traceability to QHS.

EE

XX R

U

UR ⋅=

Set up for TC measurement

Nom.value Current level Type Producer0,1 Ω 1A - 3A 1682 Tinsley0,02 Ω 5A - 10A 1682 Tinsley0,01 Ω 10A - 20A RN I Metra0,001 Ω 30A - 100A RN I Metra

Shunt

Air boxDual channel

DMM

Air box

temperature

control

Oil bath

temperature

control

Voltage source

Transconductance

amplifier

Oil bath

with reference

standard

PC AND TC MEASUREMENTS

The power coefficient is easily to calculate as:

PRPCR ∆∆= /

PCR measured and calculated in current range of 50% - 100% of nominal current.

Typical values of PCR

Foil shunts:< ± 4 ppm, unc. < 3.1ppm

Cage shunts:< ±1.5 ppm, unc. < 1.5 ppm

POWER COEFFICIENT MEASUREMENTS

TEMPERATURE COEFFICIENT MEASUREMENTS

The temperature coefficient is easily to calculate as:

TRTCR ∆∆= /

TCR measured in temperature range from 18 °C up to 28(30) °C at 1/10 of nominal current.

Typical values of TCR

Foil shunts:-2.8 +0.2 +8 ppm, unc. < 2.1ppm

Cage shunts:-0.8 +1.7 ppm, unc. < 1.7 ppm

FOIL SHUNTS RESULTS

Power dependence

-300

-250

-200

-150

-100

-50

0

50

100

0 20 40 60 80 100 120

Power (W)

rela

tive

chan

ge o

f R to

1/1

0 of

no

min

al p

ower

(pp

m)

BM1 BM2 BM3 BZ3 BZ4 B50/1 V12/80A/2

Temperature dependence

-40

-20

0

20

40

60

80

100

120

15 17 19 21 23 25 27 29 31

Temperature (°C)

rela

tive

chan

ge o

f R to

18°

C

(ppm

)

BM1 BM2 BM3 BZ3 BZ4 B50/1 V12/80A/2 V12/40A/2 BZ2

FOIL SHUNTS RESULTS

Temperature dependence of foil shunts TC and PC measurements combined

-250

-200

-150

-100

-50

0

50

100

150

15 20 25 30 35 40 45 50 55

Temperature (°C)

rela

tive

chan

ge o

f R to

18°

C (

ppm

)

B50/1 TC B50/1 PC V12/80A/2 TC V12/80A/2 PC BZ3 TC

BZ3 PC BM1 TC BM1 PC BZ4 TC BZ4 PC

FOIL SHUNTS RESULTS

Producer’s specs

Power dependence

-30

-20

-10

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80 90

Power (W)

rela

tive

chan

ge o

f R to

1/1

0 of

no

min

al p

ower

(pp

m)

SP CS3C-0703 SP CS2D-0812 SP CS2D-0813 JV 10 ACMI 10 A SIQ 20 A SIQ 5 A

CAGE SHUNTS RESULTS

Temperature dependence

-10

-5

0

5

10

15

20

25

30

35

40

17 19 21 23 25 27 29

Temperature (°C)

rela

tive

chan

ge o

f R to

18°

C

(ppm

)

SP CS3C 0703 SP SC2D-0812 SP CS2D-0813 JV 10A

SIQ 20 A SIQ 5 A CMI 10A/1

CAGE SHUNTS RESULTS

Temperature dependence of cage shuntsTC and PC measurements combined

-30

-25

-20

-15

-10

-5

0

5

10

15

20

0 5 10 15 20 25 30 35 40 45

Temperature (°C)

rela

tive

chan

ge o

f R to

18°

C

(ppm

)

SP CS3C-0703 TC SP CS3C-0703 PC CMI10A/1 TC CMI10A/1 PC

CAGE SHUNTS RESULTS

CALCULATED TC AND PC OF SHUNTS

1,04,110A…20A0,73,218°C…28°C2cage3520SIQ07025SIQ

0,82-0,2510A…20A0,331,6718°C…28°C2cage4020CS3C-0703SP

1,22,52,5A…5A0,71,118°C…28°C0,5cage1505SIQ07023SIQ

0,20-0,0650A…100A1,71,218°C…28°C10cage8100CS2D-0813SP

1,2-28,35A…15A----foil4215BZ1BEV

3,1-1,410A…20A----foil2020V16/20A/3BEV

0,681,4840A…80A2,18,018°C…30°C10foil580V12/80A/2BEV

0,21-3,9750A…100A1,07,718°C…30°C10foil10100B50/1BEV

0,16-2,2350A…100A1,5-2,818°C…28°C10foil8,5100BZ3BEV

1,2-11,910A…20A0,480,2018°C…28°C2foil2720BZ2BEV

1,70,5120A…40A1,16,818°C…30°C5foil9,540V12/40A/2BEV

0,51-0,0730A…50A0,831,2218°C…28°C5cage1650CS2D-0812SP

1,01,025A…50A1,37,418°C…28°C5foil1550BM1BEV

0,90-0,6850A…100A0,50,518°C…28°C10foil5,5100BZ4BEV

1,0-1,150A…100A1,57,318°C…28°C10foil5100BM2BEV

Orig

in

Se

rial

No

.

No

min

al

I

(A)

No

min

al

R

(mΩ

)

Sh

un

tty

pe

I (A)

tem

p.

ran

ge

(° C)

TC

(pp

m/° C

)

Un

c.

(pp

m/K

)

curre

nt

ran

ge

(A)

PC

(pp

m/W

)

Un

c.

(pp

m/W

)

CMI CMI/10A/1 10 100 cage 1 18°C…28°C -0,8 0,33 5A…10A -1,5 1,2

JV - 10 90 cage 1 18°C…28°C 4,0 0,9 5A…10A 5,7 1,2

BEV BM3 100 5 foil 10 18°C…28°C 6,8 1,5 50A…100A -1,3 1,0

CONCLUSION AND ACKOWLEDGEMENT

REFERENCES

[1] V. Novakova Zachovalova, L. Indra, M. Sira, “Measurement System for DC Characterization of Low Resistance Standards,” NCSL Int. Conf. Proc.2009, San Antonio, USA, July 26-30, 2009.

[2] V. Novakova Zachovalova, L. Indra, M. Sira, J.Streit, “Measurement System for High Current Shunts DC Characterization at CMI,” CPEM 2010 Digest, pp. 607-608.

[3] M. Garcocz, P. Scheibenreiter, W. Waldmann and G. Heine: “Expanding the measurement capability for AC-DC Current Transfer atBEV”,CPEM 2004 Digest, pp. 461-462.

[4] K. -E. Rydler, V. Tarasso, “Extending ac-dc current transfer measurement to 100 A, 100 kHz, ” CPEM 2008 Digest, pp. 28-29.[5] V. Novakova Zachovalova, “AC-DC current transfer difference in CMI,” CPEM 2008 Digest, pp. 362-363.[6] B. Voljc, M. Lindic, R. Lapuh, “Direct Measurement of AC Current by Measuring the Voltage Drop on the Coaxial Current Shunt,” IEEE Trans.

on Instr. and Meas., vol. 58, no. 4, pp. 863-867, 2009.

ACKOWLEDGEMENTS

Authors special thank Mr. Martin Garcocz (BEV), Valter Tarasso (SP), Matjaz Lindic (SIQ) and KåreLind for cooperation and shunts lending.The research presented in this paper is part of the EURAMET joint research project on "Power and Energy" and has received funding from the European Community's Seventh Framework Programme, ERA-NET Plus, under Grant Agreement No. 217257.

CONCLUSIONS

Most significant influences of measurements (except of working standard calibration): temperature influence on air cooled shunts and/or standard deviation of measured voltages ratio.Future work focus on measuring of temperature dependence of Vishays resistors.