| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a highly reliable grounging detector capable of surely detecting grounding. SOLUTION: Generation of grounding in high voltage cable ways 81, 82 of an outgoing side and a returning side is made to be surely detected in a high voltage direct current power source circuit connected directly with a pair of rectifiers 71, 72 connected respectively to a pair of secondary coils 61, 62 of a step-up transformer 4, and grounded in an intermediate of the both rectifiers 71, 72. A zero-phase current transformer 13 is provided to output a voltage in response to a deviation between a current flowing in one secondary coil 61 and a current flowing in the other secondary coil 62, and an output voltage from the current transformer 13 is input into a controller 15. When the grounding is generated in the high voltage cable ways 81, 82, balance of currents flowing in the both secondary coils 61, 62 is broken by a grounding current Ig to build up an output voltage of the zero-phase current transformer 13. When the generation of the grounding is detected by the build-up, an electromagnetic breaker 16 is actuated to stop power supply to the step-up transformer 4.</p> |
