| 摘要 |
PURPOSE: To prevent the damage of a thyristor valve and peripheral equipments by forming constitution, in which preceding protection dependence is prior even when protective devices for converters at both ends simultaneously output protective dependence signals. CONSTITUTION: The protective dependence signal of a converter from a converter controller 17B at an opposed end and a protective dependence signal at the time of the detection of short AC voltage or overvoltage from a protective device 18A at its own end are input to a protective interlocking circuit 15A, the signals are output because a time-limit protective dependence signal is continued when the signals are input to an on-delay circuit 22A, and whether or not the converters are brought to the state of a bypass pair is decided. When there is an output from the on-delay circuit 22A and the converters are not brought to the state of the bypass pair, a flip-flop 26A is set by an output from an AND circuit 21A, and the operation of the bypass pair is conducted. Accordingly, even when protective devices for the converters at both ends simultaneously output the protective dependence signals, both ends are not brought to the state of the operation of the bypass pair at the same time, thus preventing the damage of a thyristor valve and peripheral equipment. |
