Ngk Insulators, Inc.

Takashi Isozaki

Toshiyuki Kawaguchi

Hiroyuki Abe

Hiroyuki Katsukawa

Kazumi Nakanishi

Katsuro Shinoda

Yasuhisa Sakurai

Shigeo Yokoi

Ryuta Yamamoto

A system for detecting a fault occurred within a substation and judging a location of the fault including optical current sensors each having a Faraday element arranged on a top of an insulator post of a bus disconnecting switch, a magnetic core arranged to surround a terminal plate of the disconnecting switch to generate a magnetic field corresponding to a current passing through the terminal plate, a laser diode for emitting a laser light beam, an optical fiber for guiding the laser beam to the Faraday element, a photodiode, and an optical fiber for guiding the laser beam transmitted through the Faraday element to the photodiode. The photodiode supplies a signal representing the current passing through the terminal plate to a fault location judging circuit in which the fault location within the substation is judged from the signals from the photodiodes.

System utilizing optical current sensors for detecting fault location in

A system for supervising and guiding workers at various places in a construction such as an underground substation, underground market, building, or tunnel is disclosed which includes a number of receivers arranged in a number of sections of the construction for receiving infrared radiation emitted from workers to produce a detection signal, a detection device arranged in a central control room for processing the detection signals supplied from the receivers to detect positions of workers in the construction, and communication devices provided in each section and the central control room for providing the workers with various kinds of instructions, commands and messages for preventing a disaster and escaping an emergency.

System for supervising and guiding persons in construction

Growing community of inventors

Komaki, Japan

Takashi Isozaki