Commercial LMS are widely used by High Voltage (HV) transformer and reactor manufacturers. Typical state-of-the-art accuracies in industrial loss measurements are in the range of 1-3 % for power factors down to 0.01, corresponding to an LMS uncertainty of 100–300 µW/VA. Driven by the Ecodesign Directive, utility companies are now calling for 3-5 % accuracies down to a power factor of 0.001, particularly for shunt reactors, requiring LMS uncertainties of 30-50 µW/VA.
New high-voltage measurement techniques including prototypes are being realised by this project that will allow this factor of 2–5 improvement in uncertainty with respect to the current state of the art. A further, major advantage of the new techniques is that they will allow three-phase loss measurement of reactors, resulting in significant time saving during tests.