Unlike (Yokogawa says) some other manufacturers’ specifications which may appear to offer better accuracy, these figures are based on RMS values rather than waveform peak values. Because power ranges are the multiple of the voltage and current ranges, the actual power measurement error due to an uncertainty of 0.03% of range in a WT3000E is less than 0.01% of range for a power meter based on peak values.
These accuracy levels are important for testing devices such as solar inverters, which are already working at overall efficiencies of 90-96%. To increase the efficiency, even by a few decimal points, is a challenging and important goal for the manufacturers, and the WT3000E provides the necessary levels of precision to truly confirm even the smallest improvements in efficiency.
“The focus on renewable energy and the need to optimise efficiency and comply with international power quality standards is placing ever greater emphasis on the importance on high-quality measurements”, comments Terry Marrinan, Yokogawa’s Vice President, Test & Measurement, for Europe & Africa: “... the WT3000E provides the necessary levels of precision to carry out these measurements, giving R&D engineers an enhanced tool that is not only the benchmark for energy efficiency measurement but also a reference for calibrating power measuring instruments in standards laboratories.”
The focus on sustainable and renewable energy has also raised the importance and need for manufacturers to comply with IEC standards during their product development. The WT3000E provides the flexibility to mix 30A and 2A input current elements, which enables users to test the compliance of their products with today’s harmonics, flicker and standby power standards in a single instrument.
The WT3000E has a variety of alphanumeric and graphic display formats, including the ability to display the input signal as waveforms for easy analysis. It also offers high-speed data updating which allows users to capture fast-changing transient signals with high precision. Further analysis can then be performed using the captured data. The WT3000E also includes as standard two features previously only available as options: delta calculation and cycle-by-cycle analysis. The delta calculation function allows users to calculate individual phase voltages from the line voltage measured in a 3-phase/3-wire system: an important feature for determining the phase voltage in applications such as motor testing where there are no neutral lines.