System and method for high resistance ground fault detection and protection in power distribution systems

摘要

A system and method for detecting high resistance ground faults in a power distribution system is disclosed. A fault detection and protection system is provided that includes a plurality of current sensors to measure current on the three phase output of the converter-inverter arrangement of the power distribution system and a controller configured to measure the three phase current on the three phase output, extract a fundamental current component for each phase of the three phase output, extract a third harmonic component for each phase of the three phase output, compare the fundamental current component and the third harmonic component extracted from each phase to a first threshold and a second threshold, respectively, and detect a ground fault on a phase of the three phase output based on the comparisons of the fundamental current component and the third harmonic component to the first and second thresholds.

主权项

1. A power distribution system comprising:
a converter-inverter arrangement having an input connectable to a three phase AC power source and a three phase output connectable to an input terminal of a load, the converter-inverter arrangement configured to control current flow and terminal voltages in the load; and a fault detection and protection system connected to the converter-inverter arrangement, the fault detection and protection system comprising:
a plurality of current sensors configured to measure a current on the three phase output of the converter-inverter arrangement; anda controller configured to:
measure the three phase current on the three phase output of the converter-inverter arrangement;extract a fundamental current component for each phase of the three phase output of the converter-inverter arrangement;extract a third harmonic component for each phase of the three phase output of the converter-inverter arrangement;compare the fundamental current component and the third harmonic component extracted from each phase to a first threshold and a second threshold, respectively;detect a ground fault on a phase of the three phase output based on the comparisons of the fundamental current component and the third harmonic component to the first and second thresholds; anddeclare a ground fault when one phase of the three phase output has a fundamental current component that exceeds the first threshold and a third harmonic component that exceeds the second threshold.