DC ground fault detector and system-interconnected generation device using the DC ground fault detector

摘要

For detecting DC ground faults with low cost and high accuracy to ensure high safety, a zero-phase current transformer (ZCT) (41) measures a difference between DC currents flowing in plural DC power lines (39A, 39B) via a detecting core (44) and outputs a measured current signal. A temperature sensor (50) measures a temperature in the vicinity of the zero-phase current transformer (ZCT) (41) and outputs a measured temperature signal. A MPU (53) temperature-corrects the current difference corresponding to the measured current signal using the temperature corresponding to the measured temperature signal and, based on the temperature-corrected current difference, detects a ground fault caused on target conductive lines to be measure.