Betrouwbaar meten van transformator verliezen Uncertainty matters!

Ernest Houtzager

Gert Rietveld

ehoutzager@vsl.nl

23-03-2017

Outline

Dutch Power “Transformatoren ingewikkeld!?’’ 23-03-2017 2

• VSL

• Transformer loss measurement

• Uncertainty matters!

• Measurement challenge

• TMS System Calibration

• Conclusion

• Nationale Meetstandaarden

• Bedrijf met publieke taak

(100 fte, 50 % universitair)

• Kalibraties, referentiematerialen, R&D,

consultancy, training

• Onafhankelijk, betrouwbaar, top meetgebied,

internationaal

• Focus: energie, industrie

VSL – nationaal meetinstituutMassa, druk, viscositeit

Thermometrie, vocht

Gas analyse

Gas & vloeistof stroming

Optica, radiometrie

Geometrie, nanometrologie

Electriciteit: DC/LF & HF

Tijd & frequentie

Ioniserende straling

Beyond all doubt

Transformer Loss Measurement

Dutch Power “Transformatoren ingewikkeld!?’’ 23-03-2017 4

TMS typical measurement range: 0 – 100 kV, 0 – 2 kA

Uncertainty: 3 % - 5 % (IEEE C57.12.00, IEC 60076-19, Ecodesign)

Traceable to international measurement standards

Power supply

Uncertainty matters!

Dutch Power “Transformatoren ingewikkeld!?’’ 23-03-2017 5

Actual loss

…. Limit

Pro

bab

ility

Loss

Risk of false-negative decision(failure to detectcompliance)

High accuracy = low risk of incorrect decisions

Commercial Limit:

Agreement with customer

Possible fine or higher

material cost.

Ecodesign Limit:

Allows no tolerance: if

measured loss is above the

limit, the transformer is not

in conformity

Accurate test

Inaccurate test

Measurement challenge

Dutch Power “Transformatoren ingewikkeld!?’’ 23-03-2017 6

Power: P = U ∙ I ∙ cos φ with φ 90

P = U ∙ I ∙ cos (90 - ) = U ∙ I ∙ with = (90- φ) 0

Phase accuracy, not amplitude accuracy required!!

TMS consists of high-quality components

U and I are large numbers 1 % uncertainty is very easy

is a very small number: for PF=0.01, = 0.57 1 % uncertainty is a big challenge!

(6 m, 0.34 min, 100 µrad)1 % losses

TMS System Calibration

Dutch Power “Transformatoren ingewikkeld!?’’ 23-03-2017 7

Control (DSP)

Power amplifier (G)

Transformer / current generator

Power reference (RD22 watt meter)

CTs(3-stage compensated)

VT (CC-based capacitive divider)

VSL

X

Phantom impedance simulator

Minimal impedances:

Inductance 160 mH

Capacitance 64 uF

Resistance 50 Ohm

Conclusion

Dutch Power “Transformatoren ingewikkeld!?’’ 23-03-2017 8

Power transformer efficiency measurements need reliability calibration!

VSL system: DSP gives speed & flexibility, with accuracy < 50 µrad (0.5 % at PF=0.01)