| 摘要 |
PURPOSE:To miniaturize a device and reduce production costs by making failure judgment according to the detected value of the current flowing a semiconductor circuit breaker and also extracting the critical breaker conductivity while calcu lating the junction temperature of semiconducting elements constituting the semiconducting circuit breaker based on the current. CONSTITUTION:The AC voltage received through a transformer 1 is converted into DC voltage by a converter 2 and applied to a DC feeder 5 from a positive electrode bus 3 through a GTO circuit breaker 4. DC current is supplied from the DC feeder 5 to an electric vehicle 7 through a pantograph 6. In this case, the forward current and backward current of the GTO circuit breaker 4 are detected through current detectors 11 and 12 and waveform shaping circuits 13 and 14 and are led. On the other hand, the current flow through the GTO circuit breaker 4 is detected by a current detector 16, and based on the resultant current value, failure discrimination is made by a failure selection device 17, and the result of the discrimination is sent to a loading state judging circuit 18. The loading state judging circuit 18 makes a required judgment based on the detected junction temperature and the above failure discrimination result. |
