Hitachi, Ltd.

The Tokyo Electric Power Company, Incorporated

Koji Kondou

Toru Tanimizu

Toshio Horikoshi

Yoshiyasu Watanabe

Ryutaro Yamamoto

Nobuhiro Kuroda

Kazuo Kano

Yasunobu Kanou

A protection apparatus for a spot network substation has a plurality of receiving lines connected between a network bus and a plurality of power sources. Each receiving line is connected to a primary switching device, a network transformer and a protector CB. A detector for detecting a phase of each receiving line voltage and a judging unit for judging the detected phase are provided on the primary side of each network transformer. A previously stored basic phase is compared with the detected phase of the receiving line voltage. If there is a lag in the detected phase of the receiving line voltage, it is judged to be a power-stop of the corresponding power source and the protector CB is tripped.

Protection system for power receiving station

Growing community of inventors

Narita, Japan

Koji Kondou