公开(公告)号：US11121553B2

公开(公告)日：2021-09-14

申请号：US16652091

申请日：2017-10-31

Applicant: Hitachi, Ltd.

Inventor： Yuki Tsujii ,  Masatoshi Kumagai ,  Kenedward Kawakita ,  Masahiro Watanabe

IPC: H02J3/24 ,  H02J13/00 ,  G05B15/02

Abstract: There is provided a power system stability analysis device that analyzes stability of a power system by obtaining measurement data from a high-accuracy measurement device and existing measuring instruments installed in the power system, the apparatus including: a system state estimation unit that estimates a system state of the power system by using measurement data from the existing measuring instruments at a plurality of points in the power system; a synchronous stability analysis unit that analyzes synchronous stability in an assumed failure by using an estimation result of the system state; and a synchronous stability analysis correction unit that corrects the synchronous stability according to a difference between the estimation result of the system state and the measurement data of the high-accuracy measurement device to improve accuracy of synchronous stability analysis of the power system.

公开(公告)号：US11784489B2

公开(公告)日：2023-10-10

申请号：US17046318

申请日：2019-02-08

Applicant: HITACHI, LTD.

Inventor： Yuki Tsujii ,  Toshiyuki Furukawa

IPC: H02J3/00 ,  G06Q10/04 ,  G06Q50/06 ,  H02J3/38 ,  H02J3/46 ,  H02J3/24 ,  H02J13/00

CPC classification number: H02J3/004 ,  G06Q10/04 ,  G06Q50/06 ,  H02J3/003 ,  H02J3/008 ,  H02J3/24 ,  H02J3/381 ,  H02J3/46 ,  H02J13/00002 ,  H02J2203/20 ,  H02J2300/22 ,  H02J2300/28

Abstract: A supply and demand adjustment monitoring device of a power grid includes an output actual power value database that stores an output actual power value of at least one generator, an output power command value database that stores an output power command value issued to the generator, a planned adjustment capacity value database that stores a planned adjustment capacity value for the generator, and an adjustment capacity evaluation unit that evaluates an adjustment capacity based on the output actual power value, the output power command value, and the planned adjustment capacity value.

公开(公告)号：US11088569B2

公开(公告)日：2021-08-10

申请号：US16339078

申请日：2017-09-13

Applicant: Hitachi, Ltd.

Inventor： Yuki Tsujii ,  Kenedward Kawakita ,  Masatoshi Kumagai ,  Masahiro Watanabe ,  Akira Kikuchi

IPC: H02J13/00 ,  G05B19/042 ,  H02J3/00 ,  H02J3/24 ,  G05B23/02

Abstract: The purpose of the present invention is to provide a power flow monitoring device for a power system, a power system stabilization device, and a power flow monitoring method for a power system, which are highly reliable and accurate. The present invention is characterized by being provided with: a power system information database which stores measurement data obtained at a first node of the power system; a phase measurement value database which stores temporally synchronized phase measurement data obtained at a second node of the power system; a fault condition database which stores a power flow state under an assumed fault condition of the power system; a state estimation unit which estimates a state quantity of the power system using information in the power system information database as an input; a stability error detection index calculation unit which calculates a stability error detection index using, as an input, a state quantity estimation value which is an output of the state estimation unit, information of the state quantity from the phase measurement value database, and information in the fault condition database; and an error detection alert generation unit which compares the stability error detection index with a threshold value thereof and generates an alert when the stability error detection index exceeds the threshold value, wherein the magnitude of deviation of the state quantity estimation value with respect to the information of the state quantity from the phase measurement data is evaluated according to the assumed fault condition before the alert is generated.

公开(公告)号：US11770001B2

公开(公告)日：2023-09-26

申请号：US16098399

申请日：2017-06-27

Applicant: HITACHI, LTD.

Inventor： Yuki Tsujii ,  Masahiro Watanabe ,  Masachika Nakatani ,  Ryousuke Nakamura ,  Masataka Imabayashi

IPC: H02J3/00 ,  H02J3/24 ,  H02J13/00 ,  G05B19/042

CPC classification number: H02J3/00 ,  G05B19/042 ,  H02J3/001 ,  H02J3/24 ,  H02J13/00 ,  H02J13/00002 ,  G05B2219/2639

Abstract: A power system stability monitoring device comprising: a simple stability calculation unit that calculates the angular velocity and internal phase angle of a generator in each fault case based on fault conditions and the system configuration of the power system; a severity indicator calculation unit that calculates a severity indicator that represents the degree of system instability based on the angular velocity and internal phase angle; a PCS power supply severe parallel-off condition extracting unit that calculates a PCS power supply parallel-off severity indicator based on a parallel-off sensitivity indicator representing a degree of influence of PCS power supply parallel-off on the degree of instability and the severity indicator, and that extracts fault cases where the parallel-off severity indicator exceeds a prescribed threshold; and a detailed stability calculation unit that performs a detailed stability calculation for each extracted fault case based on the severity indicator or parallel-off severity indicator.

公开(公告)号：US12155209B2

公开(公告)日：2024-11-26

申请号：US17622916

申请日：2020-04-14

Applicant: Hitachi, Ltd.

Inventor： Yuki Tsujii ,  Shota Omi

IPC: H02J3/00 ,  G05B19/042

Abstract: A regulated power procurement segment determination unit refers to a renewable energy theoretical maximum value database and a renewable energy output database and determines segments for procurement of regulated power, a demand/supply control simulation unit refers to the renewable energy output database, a demand database, and a power generator database, performs demand/supply control simulation by using the segments for procurement of regulated power, renewable energy output data, demand data, and power generator data, and predicts, on the basis of the demand/supply control simulation results, frequency changes and procurement costs regarding the segments for procurement of regulation power, and a segment selection unit refers to a cost database and a frequency change database and selects a segment for procurement of regulation power on the basis of the frequency changes and the procurement costs regarding the segments on which prediction has been performed.

公开(公告)号：US11042134B2

公开(公告)日：2021-06-22

申请号：US16338039

申请日：2017-10-20

Applicant: Hitachi, Ltd.

Inventor： Masahiro Watanabe ,  Yuki Tsujii ,  KenEdward Kawakita ,  Masatoshi Kumagai

IPC: G05B13/04 ,  G06F17/13 ,  H02J13/00 ,  H02J3/00 ,  G06Q10/04 ,  G06Q50/06 ,  H02J3/18

Abstract: Provided is a power system status estimation device capable of increasing the likelihood that status estimation calculations converge. Thus, a power system status estimation device 1 is equipped with: a measured value selection unit 102 for selecting a prescribed combination of measured values using which it is predicted that the power system status estimation calculations will converge, from among the measured values from each sensor provided in the power system; and a status estimation calculation unit 101 for estimating the status of the power system on the basis of the prescribed combination of measured values selected by the measured value selection unit and the system model for the power system.

公开(公告)号：US11811409B2

公开(公告)日：2023-11-07

申请号：US17298235

申请日：2020-01-24

Applicant: Hitachi, Ltd.

Inventor： Yuki Tsujii ,  Shota Omi

IPC: G05B15/02 ,  H03K5/00 ,  H02J3/00 ,  H02J3/06

CPC classification number: H03K5/00006 ,  G05B15/02 ,  H02J3/003 ,  H02J3/007 ,  H02J3/0075 ,  H02J3/06

Abstract: In order to suppress frequency fluctuation caused by a load frequency, an AR calculating section calculates an AR using system frequency deviation and tie-line power flow deviation as inputs. An output distribution ratio determining section determines a ratio of output distribution according to merit order based on the AR calculated by the AR calculating section. An output distributing section determines output distribution according to an output change speed based on the output distribution ratio determined by the output distribution ratio determining section according to the output change speed. An output distributing section determines output distribution according to the merit order based on the output distribution ratio determined by the output distribution ratio determining section according to the merit order. An output distribution instruction value determining section determines an output distribution instruction value to each regulated power source using, as inputs, output distribution values determined by the output distributing sections.