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Better measurement of transformer losses brings us closer to a clean energy future

by Michael Rietvelt May 17, 2022

With fossil fuels increasingly out of favour, electricity is regarded as the power of the future. Because it can be generated from ‘clean’ sources, free from the carbon dioxide that contributes to climate change, everything from cars to industry to homes is expected to make greater use of electricity in the coming years.

This increased reliance on electricity will see demand explode – in fact, it is set to soar to as much as 40 TWh a year by 2040. This makes efficient distribution paramount – with such high demand straining the ability of generation, there is not a single kilowatt to waste.

Transformers play a crucial role in the power grid, stepping voltages up and down across the distribution network. As with all such processes, some power is lost – transformers are actually responsible for some 4% of distribution network losses. This means that achieving more efficient transformers has never been more important.

Owners of distribution networks obviously want to keep these losses to the bare minimum. This is why they impose penalties on transformer manufacturers according to the losses measured during the no load test. As these penalties can exceed 15,000 USD per kilowatt and include the measurement uncertainty, transformer manufacturers want to produce products that are as efficient as possible.

So, before each new transformer is shipped to site, its manufacturer will want to verify that it is producing the minimum possible losses. To do this it needs to measure these losses accurately and with minimum uncertainty. The aim is to lower the cost of penalties and also build greater trust with customers, who want to know that the manufacturer cares as much about losses as they do.

This makes it vital to have a measurement instrument with the highest possible accuracy.

As the world’s most accurate power analyzer, the Yokogawa WT5000 Precision Power Analyzer -Transformer Version certainly meets this need. It offers accuracy of 0.008% at unity power factor and the best accuracies at low power factors for commercial frequencies of 45 to 66 Hz. Low power factors have a dramatic effect on accuracy. The instrument offers accuracy of 0.6% of the reading for measurement, even at power factors as low as 0.001 at 100 V and 1 A.

The WT5000 Transformer Version is optimized by ISO17025 accredited calibration at 53 Hz at power factors of 1, 0.5, 0.05, 0.01 and 0.001. Further calibration at up to 100 kHz gives top performance even when measuring distorted waveforms, for example, during no-load loss current measurements of transformers.

Although highly capable, this doesn’t come at the expense of ease of use, a feature appreciated by busy verification engineers. A full touchscreen is supported by hardware hotkeys and powerful software for remote data capture – the result is a seamless and intuitive experience that makes connecting, configuring, and measuring easier than ever before.

With the ability to check line voltage and phase voltage simultaneously without changing wiring, as well as advanced harmonic analysis, the WT5000 is a major tool in the fight to keep transformers as efficient as possible and ensure we can all benefit from the switch away from fossil fuels and towards electricity from sustainable sources.