Hitachi, Ltd.

Yutaka Kokai

Daichi Kato

Yasunori Katayama

Masahiro Yatsu

Kunihiko Tsunedomi

Junzo Kawakami

Eisuke Kuroda

Chihiro Fukui

Sumito Tobe

Yasushi Harada

Kenta Kirihara

Shinya Ohara

Tohru Yoshihara

Shigeru Tamura

Hiroo Horii

Akira Tsubota

Ravikant Pandey

Tadayoshi Saitou

A power grid monitoring system includes 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.

Power grid monitoring system and power grid monitoring method

Provided are an operation limit value management unit managing an operation limit value related to the power flow power of system equipment and a determination unit calculating the power flow state for each set time of the future of a power system based on load dispatching information including a power generation plan value, a predicted output value, and a predicted value of power demand and determining whether or not stable is each power flow state by comparison with the operation limit value. The determination unit sequentially changes the first output power of a first power source defined by the power generation plan value of the first power source and calculates each power flow state based on power including the changed first output power and a predicted value of the output of a second power source.

Renewable energy system stabilization system and system stabilization support method

This power system operation assisting device is provided with: a multiple signal frequency specifying unit that uses, as inputs, measured data of an object to be measured and a frequency specifying parameter for calculating a frequency component of the measured data to calculate an oscillation frequency; a generation source candidate calculation unit that uses, as an input, the calculated oscillation frequency to calculate a generation source candidate of an unstable oscillation occurring in a power system; a generation source guarantee test unit that calculates the guarantee test result of the generation source candidate; and a display unit that displays the oscillation frequency, the generation source candidate, and the guarantee test result.

Power system operation assisting device and method, and oscillation suppression system

In a control system equipped with a plurality of subsystems and a supervising subsystem for supervising these subsystems, a subgoal achievement performance is calculated by the subsystem using its own knowledge and its own condition with respect to a subgoal defined by the supervising subsystem, and the supervising subsystem controls a control system by utilizing the knowledge and conditions of the respective subsystems by applying a subgoal execution instruction to the subsystem based upon the calculation result. Since not only the knowledge but also the condition of the subsystems, proper controls can be realized in not only such a case that the supervising goal is directed to a static temporal aspect, but also such a case that the supervising goal contains a temporal element.

Distributed control system

Growing community of inventors

Tokyo, Japan

Yutaka Kokai