Patent ID: 11870235
Assignee: LS ELECTRIC CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 0:
1. A self power relay comprising:
a self power generator for converting a system power as a source power to a driving power having a preset driving power level to generate the driving power of the self power relay; and
a relay unit configured to:
measure a power amount of the system power in real time while operating using the driving power; and
in an event of failure of the system power, prevent the system power from being transmitted to a load and stop a relaying operation thereof and an operation of the self power generator while operating using an external rated power,

wherein the relay unit is further configured to:
upon determination based on a plurality of predefined abnormality occurrence conditions that abnormality occurs in three phases system currents used as a source power of the self power generator, generate a fail signal to stop the relaying operation thereof and the operation of the self power generator,
after the relaying operation stops due to the fail signal, sample the three phases system currents under a sampling condition changed due to the stop of the relaying operation,
calculate differences between sampling values of the three phases system currents as sampled under the changed sampling condition and monitor change in each of the three phases system currents in real time, based on the calculated differences, and
when the plurality of predefined abnormality occurrence conditions are not met, normally activate the relaying operation thereof and the operation of the self power generator operation.