CPC H02H 3/331 (2013.01) [G01R 31/52 (2020.01); H02H 3/162 (2013.01)] | 20 Claims |
1. A grounded neutral fault detector, comprising:
induction circuits configured to:
generate a leakage signal corresponding to a current imbalance between a line conductor and a neutral conductor for a load; and
a controller configured to:
determine a frequency of a test signal by:
measuring load noise based on a first leakage signal without the test signal being injected, the first leakage signal corresponding to a first current imbalance between the line conductor and the neutral conductor for the load when the test signal is not being injected into the neutral conductor;
analyzing a frequency spectrum of the load noise; and
selecting the frequency of the test signal based on the frequency spectrum of the load noise;
inject the test signal at the selected frequency to the neutral conductor;
measure impedance of a current loop formed by a potential grounded neutral fault based on a second leakage signal corresponding to a second current imbalance with the test signal being injected; and
determine a grounded neutral fault based on the measured impedance.
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