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

Claim 11:
12. The method of claim 11, wherein monitoring the change in the source power and stopping the operation of the self power generator and the relaying operation of the relay unit include:
detecting three phases system currents and voltage used as the source power using at least one of a current transformer or a voltage transformer;
sampling change in a current of each of the three phases system powers at a preset period;
calculating differences between sampling values of three phases system currents of the three phases system powers obtained via a predefined number of samplings and monitoring changes in the three phases system currents in real time, based on the calculated differences;
storing a plurality of predefined abnormality occurrence conditions, and supporting a monitoring unit to monitor the differences between the sampling values of the three phases system currents under the abnormality occurrence conditions; and
generating a second fail signal and sending the second fail signal to the relay controller and the self power generator when the monitoring unit determines that abnormality occurs in the three phases system currents.