Abstract: Systems and methods of determining fault location on a DC microgrid feeder need to be extremely fast to protect the circuit breaker and converter-source components. This disclosure develops a seminal theoretical foundation for fast fault location on a DC feeder that uses only single-ended local measurements in time domain. The theory provides a closed-form deterministic solution for fault location, making the resulting fault location method agnostic to system-topology and immune to fault resistance. The theory is developed with ideal DC voltage sources and is extended to practical converter-sources. The performance of the resulting method is demonstrated by simulating a DC feeder with converters connected at both ends, modeled in PSCAD (power systems computer-aided design).

Abstract: A digital relay and concomitant method comprising employing an analog-to-digital converter, and via control logic providing oversampled output of the converter to determine likely digital values corresponding to the output, and wherein the control logic substantially eliminates aliasing resulting from waveform transients in input to the converter, and wherein no anti-aliasing filter is employed providing the input. Also, a digital relay and concomitant method comprising employing an analog-to-digital converter, and via control logic providing oversampled output of the converter to determine via Fourier transform likely digital values corresponding to the output, and wherein the control logic substantially eliminates aliasing resulting from waveform transients in input to the converter.