US 12489288 B2 / Dec 2, 2025

Multi-phase AC voltage fault detection based on virtual voltage

In an embodiment, voltage fault detection is performed for alternating current (AC) multi-phase power systems based on a reconstructed or virtual voltage signal derived from voltage samples captured in a shortened sample window to reduce fault detection time. The embodiment of the present disclosure constructs the virtual voltage signal (emulating the root mean square (RMS) voltage of any of the phases) from the voltage samples captured from signals of the multi-phase power system. The embodiment of the present disclosure employs a shortened sample window of T/2/N (N is the number of phases ≥3) to capture the voltage samples, thereby reducing measurement and fault detection delay. The virtual voltage signal is used determine root mean square (RMS) voltage for voltage fault detection.