Abstract: 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.
Type:
Grant
Filed:
January 14, 2015
Date of Patent:
February 19, 2019
Assignees:
Hitachi, Ltd., Tohoku Electric Power Co., Inc., Tohoku Electric Manufacturing Co., Ltd.
Inventors:
Masahiro Watanabe, Kenichiro Yamane, Takuya Matsumoto, Masatoshi Kumagai, Tsukasa Oonishi, Ryo Egashira, Katsuhiro Matsuda, Jun Murakoshi, Tomoya Sato
Abstract: 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.
Type:
Grant
Filed:
July 24, 2013
Date of Patent:
March 28, 2017
Assignees:
Hitachi, Ltd., Tohoku Electric Power Co., Ltd., Tohoku Electric Manufacturing Co., Ltd.
Abstract: A pair of static induction thyristors, which are coupled in parallel in the opposite bias directions between an AC power source and a load, is turned on by a light signal and is turned off by natural commutation, a light signal or an electric signal. The turn-off light signal is generated within a phase angle of 90.degree. in the time axis around the zero-cross point of the AC voltage from the AC power source.