Post on 12-Apr-2017
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)