With the topic of “energy transition” dominating the news almost daily, we see that accurate electrical power and energy measurement is in full swing. Just think of the introduction of the smart kWh meter. And all the charging stations for electric vehicles. These are used to settle transactions and therefore need to be calibrated. As specifications are tightened, measurement and monitoring activities become more important.

Power & Energy Calibration

For power and energy calibration, a reference / calibration instrument is required for the accurate generation of parameters related to electrical power and electrical energy. This reference source provides stability and accuracy to users within, for example; national measurement institutes, calibration organisations, electronics manufacturers, production lines, energy companies and quality and standards laboratories.

Meatest’s 1/3 Phase Power & Energy Calibrator M133 series has been specially developed for testing and calibrating 1/3 phase AC measuring equipment such as power meters, energy/kWh meters, power transducers and power quality analysers. The M133C can be used to calibrate or verify measured values such as, VA, VAR, phase angle, power factor, voltage and current.

Its key features can be described as follows;

  • All-in-one solution for calibration of voltage, current, Power and energy meters, and power quality analysers
  • Three phases in one instrument
  • Potential-free current outputs
  • Built-in process multimeter (for monitoring transducers)
  • High accuracy (power from 0.044%) and flexibility
  • Remote control via : IEEE488 / RS232 / Ethernet


The M133C is available in a 1 or 3 phase version with the following specifications;

  • Voltage (3x) 1 – 600 Vac / 280 Vdc, 150 ppm
  • Current (3x) 8 mA – 30 A ac/dc. 250 ppm
  • Current tot 2250 A (externe current coils)
  • Fundamental frequency 15 Hz – 1 Khz.
  • Power & Energy (3x). 8 mW – 8.4 kWdc / 18kWac, 440 ppm
  • Phase angle adjustable in the range of : 0 – 360° range
  • PQ modes:
  • Harmonic (up to 50th), Interharmonic (up to 5 kHz), Modulation, Flicker, Dip / Swell, energy functions.



The M133C comes with a traceable (ISO17025) calibration certificate as standard. An annual, periodic calibration is recommended.

Improvement in resolution and accuracy

Also due to a phase accuracy of 0.01°, the resolution and accuracy of the M133C is generally more than sufficient for the calibration of most common test and measurement instruments. In certain calibration setups where even higher accuracy is desirable, the M133C is also sometimes used in combination with a high accuracy power analyser.

In such a setup, the M133C can be used as a source. The applied Power analyzer then forms the traceable, calibrated reference. Especially in measurement setups where there is a relatively low power factor, phase accuracy is of great importance in correctly measuring W/VA in the range of PF: 1 to 0.01. By adding an external power analyser, 0.003° phase accuracy or even better is achievable. In addition, higher phase accuracy also helps to determine/measure higher harmonics and THD.

Phase accuracy

The influence of a phase error in a measurement increases at low power factor (PF) and this is easily illustrated with some simple calculations. Let’s look at the influence of a phase error of 0.01° at a power factor of 1 (nominal phase angle of 0°) and also at a power factor of 0.01 (phase angle of 89.43°). Such low PF values occur in loss measurements on inductance and capacitive DUTs, among others.

For simplicity, we assume 100Vrms and 10Arms which equals a power of 1000VA and we know that W = V x A x Cos Ø so:

Power factor 1 (0°) plus 0.01° phase error
100 x 10 x PF 1 (COS0°) = 1000W
0° + 0.01° phase error = 0.01°
100 x 10 x COS 0.01° = 999.9W è 0.01% error in measured Watts

Power factor 0.01 (89.43°) plus 0.01° phase error
100 x 10 x PF 0.01(COS 89.43°) = 9.948W
89.43° + 0.01° phase error = 89.44°
100 x 10 x COS 89.44° = 9.774W è 1.75% error in measured Watts

So it is clear that phase error has a significantly greater impact on the accuracy of measured power at a low power factor.

In conclusion

For applications involving different voltages and currents than the M133 series mentioned here, several alternative solutions are available. These include AC/DC voltage and current sources, High voltage dividers, High Current dividers, current shunts including active zero flux sensors, phase standards and AC/DC high voltage meters.


Arnold Memelink

Arnold Memelink


"The ABB Power Grids Jumet organisation is an innovative development and production facility of ABB that manufactures active filters and battery energy storage systems to support a stable grid. To test these systems we have acquired two Cinergia GE/EL +120kVA eplus units capable of doing grid emulation (AC + DC), operating as an electronic load (AC +DC) and being a battery emulator. We have experienced very good support from TTMS in obtaining these two Cinergia units. This included organising an on-site demonstration and supplying loan systems prior to the delivery of our final systems. This way we could start testing as early as possible. TTMS also organised training for the operators from the original manufacturer. This support allowed us to introduce the first battery energy storage systems even prior to the full delivery of the Cinergia systems."

University of Luxembourg

Sasan Rafii-Tabrizi

University of Luxembourg

“At the Energy and Environment department of the Faculty of Science, Technology and Medicine (FSTM) of the University of Luxembourg we do have different research projects related to green energy contributing to the development of eco-cities. As a long-standing partner of our research unit, TT&MS has proven that they are able to answer even the most complex questions in a professional manner. They have shown that they are always up to date with the latest technology and do not spare any effort to look at the application and even the situation on site. The exchange of ideas was always very pleasant and took place quickly. We look forward to further years of fruitful cooperation.”


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