Hitachi, Ltd.

Tohoku Electric Power Company, Inc.

Tohoku Electric Manufacturing Co., Ltd.

Katsuhiro Matsuda

Masahiro Watanabe

Kenichiro Yamane

Hirotaka Takahashi

Jun Murakoshi

Ryo Egashira

Takashi Oda

Masatoshi Kumagai

Yasushi Tomita

Masahiro Adachi

Tsukasa Onishi

Tsukasa Oonishi

Takuya Matsumoto

Tomoya Sato

Takafumi Futakami

Toshiyuki Seto

Eri Isozaki

Kazuhiro Horikoshi

A distributed-generator power-generation-amount estimation apparatus and method capable of more accurately and easily estimating output by reflecting a power factor are disclosed. The apparatus estimates a power generation amount of a distributed generator interconnected to an electric power system from active power and reactive power measured at regular intervals by measurement means, the apparatus including power-factor estimation means for estimating, as a ratio of a time change amount of the active power and the reactive power, a power factor of the distributed generator interconnected to a demand side of the electric power system, distributed-generator power-generation-amount estimation means for having, from active power and reactive power measured at a time of no power when the distributed generator interconnected to the electric power system is not generating power, a first characteristic line representing a load characteristic on a coordinate plane based on active power and reactive power, a second characteristic line representing a distributed-generator characteristic on the coordinate plane, and estimating the difference between the active power and the reactive power at an intersection point of the first characteristic line and the second characteristic line, and the measured active power and the measured reactive power as the power generation amount of the distributed generator, and output means for outputting power-generation-amount estimation information on the distributed generator estimated by the distributed-generator power-generation-amount estimation means.

Distributed-generator power-generation-amount estimation apparatus and method

The output of a photovoltaic power generator is estimated by estimating a solar radiation amount at a point different from solar radiation measurement points and determining an estimation error amount from solar radiation values measured at limited points. A photovoltaic power generator output estimation method estimates an output of a photovoltaic power generator based on a measured solar radiation value. The method includes a first estimation method of estimating a solar radiation amount at a photovoltaic power generator installation point from solar radiation meter installation point information, a value measured by a solar radiation meter, and photovoltaic power generator installation point information; a second estimation method of estimating the solar radiation amount at the photovoltaic power generator installation point in a manner different from that of the first estimation method; an output estimation method of estimating the output of the photovoltaic power generator from an estimated solar radiation amount and a rated capacity of the photovoltaic power generator; and an error estimation method of determining an estimation error of a photovoltaic power generator output from a difference between the first and second estimation methods.

Photovoltaic power generator output estimation method and device, and power system monitoring device using same

A voltage adjustment device, a voltage adjusting method and a power control system for a distribution system are provided, in which the voltage adjustment device and a static var compensator are appropriately operated in a coordinated manner and the sustention of voltage and the enhancement of the operation efficiency are attained. A voltage adjustment device for a distribution system is installed in the distribution system including a static var compensator on an end side and controls a secondary voltage to be within a predetermined limit value by adjusting a tap position. The voltage adjustment device includes a first unit configured to estimate the secondary voltage; a second unit configured to obtain a corrected voltage by correcting the estimated secondary voltage by using a correction amount obtained from an output of the static var compensator; and a third unit configured to compare the corrected voltage with the predetermined limit value and operate the tap position when the corrected voltage deviates from the predetermined limit value.

Voltage adjustment device for power distribution system, voltage adjusting method, and power control system

A load leveling system and a method for a power system are capable of attaining load leveling in a distribution substation unit. The load leveling system is for a power system with a controller having a major customer and lower transforming apparatus, and with a customer connected to the lower transforming apparatus via a low-voltage line. The system also has a communication unit between the customer and its own system, and control use time zones of devices within the customer, as well as an electric demand prediction unit, and a first load leveling processing unit. By employing such a system, it becomes possible to provide a load leveling system for a power system that is capable of realizing load leveling of both a distribution substation unit and a pole transformer unit.

Load leveling system of power system

Growing community of inventors

Sendai, Japan

Katsuhiro Matsuda