A phase angle standard

A phase angle standard for power frequencies (40–400 Hz) with a very low measuring uncertainty of 3 µrad is developed. The standard is based on a two-channel high-stability arbitrary waveform AC source for voltages up to 120 V and currents up to 6 A with high phase angle resolution which is realized as a development device with full computer control. A proper auto-calibration method is implemented for achieving ultimate performance in phase angle accuracy. The high performance of the phase angle standard is thoroughly evaluated and presented briefly.