Ship DC line protection method based on leakage current and low voltage

Abstract

A ship direct-current line protection method based on leakage current and low voltage comprises the steps that after a leakage current sensor detects that a direct-current load line has a single-pole grounding fault, a ground insulation resistance value, namely a grounding resistance value, of a branch is calculated according to bus voltage, balance branch resistance value and current, and meanwhile a grounding protection system sends out an alarm signal; and tripping off the fault branch after time delay, and judging the grounding fault by detecting the leakage current of the line when the load line has the single-pole grounding fault. No signal is added to the direct current system, so that no interference is generated; the calculation of the resistance value of the grounding resistor is not influenced by distributed capacitance of the system; when the single pole of the direct-current bus has a grounding fault, the leakage current value is small, and false operation cannot be caused; the condition that multiple branches are grounded at the same time can be detected.

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