Coordinator: Gert Rietveld

Test results of power transformer and reactor losses are only reliable if these are performed using a calibrated LMS, ensuring traceability to international measurement standards. Advanced industrial LMSs thus need calibration using a reference setup which should have a factor of 3 to 5 better uncertainty than the 50 μW/VA of the industrial LMS.

A primary reference setup was developed for the on-site calibration of advanced industrial loss measurement systems (LMS) with accuracy down to 20 μW/VA, at voltages and currents up to 230 kV and 2000 A respectively. This required two major improvements with respect to the state of the art, namely larger test signals (higher voltage) and better uncertainty levels.

Since it is highly uncertain whether a factor of 3 to 5 better uncertainty, i.e., 10‑16 μW/VA, can be technically realised, a realistic aim of an uncertainty of better than 20 μW/VA in the reference setup was set. This is a major step forward with respect to the state of the art for loss calibration reference setups, which is 50 μW/VA up to 100 kV, and close to the limits of what is considered to be technically possible by experts in the field.

For more information, see the project webpage >>