| 摘要 |
<P>PROBLEM TO BE SOLVED: To discriminate an internal short circuit from a commutation failure which is an abnormality with an external cause, with a simple device configuration. <P>SOLUTION: In a protective device of a power conversion device, an AC side of a first converter is connected to a first AC system, and an AC side of a second converter is connected to a second AC system. A DC reactor is provided to a DC circuit between the first converter and the second converter, and one of the converters is operated as a forward converter while the other converter is operated as a reverse converter. Current of the first AC system and current of the second AC system are compared with a DC current reference value respectively. Based on positiveness or negativeness of its differential current, the abnormality of the power converter is determined as an internal short circuit or as a commutation failure. <P>COPYRIGHT: (C)2012,JPO&INPIT |
