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Tochigi, Japan

Hishikawa Y.,Japan National Institute of Advanced Industrial Science and Technology | Yamagoe K.,Japan National Institute of Advanced Industrial Science and Technology | Onuma T.,Takaoka Toko Co.
2015 IEEE 42nd Photovoltaic Specialist Conference, PVSC 2015 | Year: 2015

PV module characterization by non-contact electrostatic potential measurement method is investigated. The method can be carried out by a portable equipment under various outdoor operating conditions as well as in laboratories. The electric potential of the cells in various crystalline silicon and thin film PV modules can be determined in a noncontact configuration such as through their cover glass and backsheet. Basic repeatability of the electrostatic voltage measurement was confirmed to be within about ±0.5 V for indoor measurements, which is better than the output voltage of a component cell. The repeatability was typically within the voltage corresponding to 2 to 3 times the component cells even under changeable outdoor conditions. The present study demonstrates that the method is applicable to PV module characterization, such as identifying a hotspot cell in a PV module and determining degraded modules in a PV array, through monitoring the distribution of their electric potential under outdoor conditions without interrupting the grid-connected operation of the system. © 2015 IEEE.


Trademark
Takaoka Toko Co. | Date: 2016-02-09

Ozonisers; electrolysers; electricity meters, namely, energy meters for tracking and monitoring energy usage; circuit breakers; battery chargers for electric vehicles; electric transformers; electric switches; electric circuit closers; electrical power distribution units; electric inverters; electric capacitors; downloadable electronic publications in the nature of manuals in the field of electrical products.


Nagata K.,Takaoka Toko Co. | Ohyama T.,Takaoka Toko Co. | Sato H.,Japan Central Research Institute of Electric Power Industry | Ito T.,Tokyo Electric Power Company | And 2 more authors.
IEEJ Transactions on Power and Energy | Year: 2015

We developed the 550 kV disconnectors that strengthened earthquake proofing by the addition of the damper unit and weight reduction of conductive part based on the damage of the 550 kV disconnectors by the Great East Japanearthquake (March 11, 2011) and inspected the earthquake proofing performance by shake table test. In shake table test, we performed the test by the artificial seismic wave that varied in phase characteristic in addition to the test byresonance method. And, in a high-level earthquake area, we analyzed it about the influence that a phase characteristic of the artificial seismic wave gave to stress to occur in disconnectors. As a result, it is thought that the stress tooccur in disconnectors is decided by a primary natural frequency basically because a bending strain to occur to the disconnectors in the time when the resonance frequency ingredient becomes the big acceleration response value growsbig. But, on a particular phase condition, it was confirmed that the bending strain to occur in disconnectors might grow big conspicuously. As for this, the possibility is thought about by influence of higher natural frequency doingsuperposition. © 2015 The Institute of Electrical Engineers of Japan.


Nagata K.,Takaoka Toko Co. | Ohyama T.,Takaoka Toko Co. | Sato H.,Japan Central Research Institute of Electric Power Industry | Ito T.,Tokyo Electric Power Company | And 2 more authors.
Electrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi) | Year: 2016

We developed the 550-kV disconnectors that strengthened earthquake proofing by the addition of the damper unit and weight reduction of conductive part based on the damage of the 550-kV disconnectors by the Great East Japan earthquake (March 11, 2011) and inspected the earthquake proofing performance by shake table test. In shake table test, we performed the test by the artificial seismic wave that varied in phase characteristic in addition to the test by resonance method. And, in a high-level earthquake area, we analyzed it about the influence that a phase characteristic of the artificial seismic wave gave to stress to occur in disconnectors. As a result, it is thought that the stress to occur in disconnectors is decided by a primary natural frequency basically because a bending strain to occur to the disconnectors in the time when the resonance frequency ingredient becomes the big acceleration response value grows big. But, on a particular phase condition, it was confirmed that the bending strain to occur in disconnectors might grow big conspicuously. As for this, the possibility is thought about by influence of higher natural frequency doing superposition. © 2016 Wiley Periodicals, Inc.


Kikusato H.,Waseda University | Kikusato H.,Japan Science and Technology Agency | Takahashi N.,Waseda University | Takahashi N.,Japan Science and Technology Agency | And 8 more authors.
IEEE PES Innovative Smart Grid Technologies Conference Europe | Year: 2015

A complicated voltage fluctuation in distribution systems and a decline in power quality occur when a large number of photovoltaic (PV) systems are installed. In this paper, the installation of a low-voltage regulator is assumed, and a method for instantly and accurately determining the line drop compensator (LDC) parameters is proposed to perform efficient voltage management, which consists of prediction, operation, and control. In the proposed method, the computational cost to derive the LDC parameters can be reduced by learning the optimality of the parameters in a series of load demands and the PV output using multiple classifiers. We performed numerical simulations to verify the validity of the proposed method. From the results, the classification accuracy is found to improve by considering the majority vote of multiple classifiers. Additionally, the improvement in the voltage control performance is verified. © 2014 IEEE.

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