Hitachi, Ltd.

Eisuke Kuroda

Masahiro Yatsu

Osamu Tomobe

Yasuo Sato

Jun Yamazaki

Sumito Tobe

Taichiro Kawahara

Kouichi Hara

Daichi Kato

Toshiyuki Miyake

Kunihiko Tsunedomi

Nao Saito

Haruki Miyoshi

Masahiro Watanabe

Yuki Tsujii

Shota Omi

Masato Saito

Yasuyuki Tada

Kenta Kirihara

Yutaka Kokai

Akira Tsubota

Shinya Ohara

Shintaro Ueno

Taichirou Kawahara

Daiki Nishimura

A power supply-demand adjustment device performs output distribution to M adjustment power supplies among N adjustment power supplies in a system, based on adjustment information and supply-demand imbalance. The adjustment information includes output change rate, a distributed output, and an output limit value for each adjustment power supply. For each period, the output distribution satisfying the following (x) and (y) is performed; where (x) is the distribution of an output to the adjustment power supply in an increasing direction in ascending or descending order of the adjustment cost; and (y) is regardless of whether an output direction is the increasing or decreasing direction, an output to be distributed to the adjustment power supply in the period is in a reducing direction with respect to reduction in a difference between the distributed output to the adjustment power supply and the output limit value of the adjustment power supply.

Power supply-demand adjustment device and method

A power system operation plan creation assistance device and method capable of maintaining or improving system stability or economy includes an optimization target snapshot power flow determination unit that uses one or more pieces of foundational information to determine an optimization target snapshot power flow. The foundational information includes a power generation plan, a total demand prediction, a sales plan, a renewable energy prediction, a work stoppage plan, system data, and a setting value. A system manipulation variable candidate extraction unit uses the one or more pieces of foundational information and the optimization target snapshot power flow to extract a candidate for a variable for a variable manipulating the system. An optimal system configuration calculation unit uses the one or more pieces of foundational information and the system manipulation variable candidate to calculate an optimal system configuration.

Power system operation plan creation assistance device and 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

A voltage stability monitoring device and a method capable of obtaining information of voltage stability that can be served to practical use within a range of assumed conditions during a predetermined monitoring period are provided. The present invention provides a voltage stability monitoring device for estimating a voltage stability by using a voltage stability curve representing the voltage stability in an electric power system, including a voltage stability limit prediction unit for predicting a voltage stability limit, a voltage stability calculation condition determination unit for determining voltage stability calculation conditions by using a prediction result of voltage stability limit, a voltage stability curve calculation unit for calculating the voltage stability curve using a result of the voltage stability calculation condition determination, and a voltage stability margin calculation unit for calculating a voltage stability margin using a calculation result of the voltage stability curve.

Voltage stability monitoring device and method

The voltage and reactive power monitoring/control method includes: measurement data for the power system and data for the system equipment of the power system are used to calculate the system status for the power system at the time of measurement; data for a status estimation calculation result and predicted data for the power generation and load of the power system are used to predictively calculate a system status at a future time from the time of the power system measurement; a fluctuation component is obtained for the predicted value of the data obtained from the power system; the reactive power required to suppress the fluctuation component is obtained, as a required reactive power amount; a reactive power distribution subject is selected from a plurality of pieces of control subject equipment; an output distribution calculation is performed for the required reactive power amount for the selected control subject equipment.

Voltage and reactive power monitoring/control device and method for calculating required reactive power amount for suppressing a fluctuation component and selecting an appropriate equipment

There is provided a voltage/reactive power control device, method, and a voltage/reactive power control system that allow a proper control even with a control delay or in a situation where the system conditions at the time of setting the voltage reference value may not be always reproduced. A voltage/reactive power control system is applied to a power system in which a monitoring point is set in a local system divided as appropriate from the power system and the local system includes a voltage/reactive power control device capable of adjusting voltage and reactive power at the monitoring point. The voltage/reactive power control system includes: a central control unit that sets a control target value of the voltage and reactive power at the monitoring point in the local system based on optimal power flow calculation using total system data on the power system, generates a correction function to correct the control target value in accordance with a change in state of the power system relating to the monitoring point by using past history information on the states of the power system, and outputs the control target value and at least one or more correction functions; a local control apparatus that, when the control target value is different from system data on the local system, uses the correction function to calculate a controlled variable for the voltage/reactive power control device necessary to attain the control target value; and a device control apparatus that controls the voltage/reactive power control device in accordance with the controlled variable from the local control apparatus.

Voltage/reactive power control apparatus, method, and voltage/reactive power control system

In a power system voltage reactive power monitoring control device, a balance between the power system voltage and the reactive power can be maintained even when, for example, the output of renewable energy varies over time due to the weather, or the power supply configuration or system configuration changes, and the economic efficiency can be improved. In the power system voltage reactive power monitoring control device, which supplies transmission data to individual devices capable of adjusting the voltage and the reactive power of a power system, indices indicating the stability of the power system are used to determine one or more target value restrictions, information about the target value is obtained from the target value restrictions, transmission data containing information about the target value is supplied to the individual devices, and the voltage and reactive power at the relevant installation site are adjusted by the individual devices.

Power system voltage reactive power monitoring control device and method

A system stability monitoring device monitors the stability of a power system and is equipped with: a storage unit for storing spot information indicating the positional relationship between a plurality of measurement spots in the power system; a receiving unit for receiving time-series measurement information measured by a measuring device provided at each of the measurement spots; and a calculation unit for detecting the frequency components of the power fluctuation from the measurement information, selecting, based on the frequency components, measurement spot group candidates that are measurement spots among the plurality of measurement spots, obtaining the electrical distances between the measurement spot group candidates on the basis of the spot information, and categorizing the measurement spot group candidates into at least one measurement spot group on the basis of the electrical distances.

System stability monitoring device and system stability monitoring system

The setting range of the voltage and the reactive power of a power system is maintained during variations of voltage and power flow due to the output variation of renewable energy of a large number of power supplies which fluctuate due to weather. A voltage/reactive power operation assisting device is provided with a first database for storing the data to be evaluated, target value data, individual control device control method data, and individual control device data of an individual control device for adjusting the voltage/reactive power of a power system. A second database stores the device operation data of the individual control device; and the operation of the individual control device is predicted from the data stored in the first database to obtain individual control device operation prediction data. A display unit displays the individual control device operation prediction data and the device operation data in a contrastive manner.

Voltage/reactive power operation assisting device and assisting method, and voltage/reactive power operation monitoring control device and monitoring control method

A voltage stability monitoring device, which monitors voltage stability of a power system, produces a plurality of assumed change scenarios indicating a scenario of a change that is assumed based on at least one of a system configuration of the power system and a change of a tide state, calculates the voltage stability using the assumed change scenario, calculates a voltage stability margin indicating margin degree of the voltage stability, based on the voltage stability selects an assumed change scenario with high severity of the voltage stability for each assumed change scenario, based on the voltage stability margin calculates which buses in the power system are vulnerable buses that decrease voltage stability, based on the assumed change scenario which is selected, and changes a monitoring target of the voltage stability, based on information of the vulnerable bus.

A system stabilization control device controls a control instrument within a power system on the basis of measurement information from a plurality of measurement points within the power system. The system stabilization control device includes an equipment information database storing information of system equipment interconnected with the power system; a control priority determining unit determining the control priority of the control instrument on the basis of the information of the system equipment; a control target determining unit determining a control target on the basis of the measurement information from the plurality of measurement points and the control priority; a destabilization time calculating unit calculating destabilization time of the power system from the measurement information from the plurality of measurement points; and a control time determining unit determining control time of the control instrument on the basis of the destabilization time and the information of the system equipment.

System stabilization control device and power system control system

In order to maintain a system frequency within a permissible range under limitations of the output of a power source to be controlled, a calculation device pertaining to a load-frequency-controlling device of the present invention: predicts time-series data indicating the status of individual power sources in a future control period, the prediction being carried out on the basis of system model data, system data, and renewable energy data; calculates, on the basis of power source data, and for each of the power sources, at least any one of a deviation state indicating the degree to which the time-series data deviates from the limitations and/or a surplus state indicating the degree to which the time-series data shows a surplus with respect to the limitations; resolves the deviation state; and calculates the amount of adjustment in the output of each of the power sources, on the basis of the deviation state and the surplus state, under the condition that the total output of the power sources is maintained.

Device and method for controlling power system

When vibration information calculated using measurement information is classified using a distance between measurement points which is calculated using the point information, even in a case in which a plurality of vibration modes with close vibration frequencies are present at the same time, stability determination at a high speed and a high accuracy is realized. A system stability monitoring apparatus which monitors system stability of a power system includes a measurement information collecting unit that collects measurement information of a plurality of points in the power system, a vibration analyzing unit that calculates vibration information indicating vibration of a system state in the plurality of points using the measurement information, an information storage unit that stores point information including position information of the plurality of points, and a vibration classifying unit that classifies the vibration information based on the point information.

System stability monitoring apparatus and method

In administration based on the existing (N&#x2212;1) reliability criteria, an appropriate administration plan may be not drafted in a power system in which renewable energy increases. Accordingly, according to the invention, a power system monitoring apparatus that monitors a power system includes: an input unit that inputs assumable system breakdown data including an occurrence frequency of each assumable breakdown of the power system and assumable output change data including an occurrence frequency of each assumable output change of each generator connected to the power system; and an output unit that generates conditions by which events of the assumable breakdowns and the assumable output changes are combined based on the occurrence frequencies of the assumable breakdown and the assumable output change and outputs a control plan for each of the conditions.

Power system monitoring apparatus, power system control apparatus, and power system monitoring method employing events of assumable breakdowns and assumable output changes

A command system of a power conditioning system of the present invention receives return pattern information including a time instance and an upper output limit, and issues a command with respect to the upper output limit of the power conditioning system, the return pattern information being for preventing the frequency of an isolated power system, which is calculated by a planning server, from causing a sharp change.

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Tokyo, Japan

Eisuke Kuroda