Direct current system overhauls voltage detector is including power module, direct current voltage transducer, direct current changer, data processor, display module, button module, air circuit breaker. The repair line sweetgum fruit is crossed air circuit breaker and is connected standby line. First direct current voltage transducer A is used for detecting the repair line way, and second direct current voltage transducer B is used for detecting standby line, first direct current voltage transducer A, second direct current voltage transducer B join conversely detection circuitry through one respectively and connect data processor. Third direct current voltage transducer C connects data processor. Data processor is connected to the direct current changer. The utility model relates to a direct current system overhauls voltage detector during the use, connects can discern one by one behind this detector to detect electric pressure, the line preface that inserts both ends and wait to insert backup power whether have earth fault, can show in real time simultaneously, possess that maintenance efficiency height, work load are little, one -man operation can the advantage.