US 12,334,736 B2
Power grid monitoring system and power grid monitoring method
Ravikant Pandey, Tokyo (JP); Daichi Kato, Tokyo (JP); Tohru Yoshihara, Tokyo (JP); Shinya Ohara, Tokyo (JP); and Yutaka Kokai, Tokyo (JP)
Assigned to Hitachi, Ltd., Tokyo (JP)
Appl. No. 18/292,392
Filed by Hitachi, Ltd., Tokyo (JP)
PCT Filed Aug. 1, 2022, PCT No. PCT/JP2022/029514
§ 371(c)(1), (2) Date Jan. 26, 2024,
PCT Pub. No. WO2023/032554, PCT Pub. Date Mar. 9, 2023.
Claims priority of application No. 2021-145034 (JP), filed on Sep. 6, 2021.
Prior Publication US 2024/0348055 A1, Oct. 17, 2024
Int. Cl. H02J 3/24 (2006.01); H02J 3/38 (2006.01)
CPC H02J 3/241 (2020.01) [H02J 3/381 (2013.01); H02J 2300/28 (2020.01)] 12 Claims
OG exemplary drawing
 
1. A power grid monitoring system comprising:
a storage unit that stores power control system (PCS) impedance data indicative of a PCS impedance that is an impedance of a PCS-based energy source at a plurality of operation points, the PCS-based energy source being connected to an electric power system, the PCS-based energy source including a voltage source and a PCS that regulates power generated by the voltage source and supplies the power to the electric power system;
a real time calculation unit that calculates a power grid impedance based on a power flow measured at a point of connection where the PCS-based energy source and the electric power system are connected to each other, the power grid impedance being an impedance of the electric power system; and
a stability check unit that performs a stability check to detect low frequency oscillation (LFO) at the point of connection based on the PCS impedance data and the power grid impedance.