Kabushiki Kaisha Toshiba

The Tokyo Electric Power Company, Incorporated

Tadayuki Kitahara

Fumio Aoyama

Fumitoshi Ichikawa

Yukio Tokiwa

A power converting apparatus comprises self-commutated converter, fault current restricting device, fault detector, and cutoff circuit. Self-commutated converter converts AC power supplied from an AC power system into DC power and supplying the DC power to a common DC circuit, and for converting DC power supplied from the DC circuit into AC power and supplying the AC power to the AC power system. The fault current restricting device is inserted between the self-commutated converted and the DC circuit, and includes a diode provided to permit a DC circuit current to flow from the self-commutated coverter to the DC circuit, and a series circuit having a reactor and a DC power supply and connected in parallel to the diode. The fault detector detects a fault current generated when self-commutated converter is short-circuited. When the fault detector detects a short circuit occurring in self-commutated converter, the cutoff circuit cuts off power supply to that self-commutated converter. With this structure, the DC power supply supplies a circulating current according to a rated current of the self-commutated converter to the reactor and the diode.

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Tokorozawa, Japan

Tadayuki Kitahara