Development of a Non-contact Direct-voltage Detector

On direct current (DC) sections of JR East conventional lines, trains run on 1,500V DC electricity. The power is supplied to trains from contact wires, and inspection and other work for those wires is conducted with electricity turned off to prevent electric shock. In large-scale station yards into which many tracks enter, however, it is often difficult to turn off electricity to all feeder circuits together. Therefore, work sometimes has to be done with the wires for adjacent tracks kept live. The authors have checked whether power of overhead contact lines in the work area is turned on or off using contact-type detectors up to now, but there still has been the possibility that workers enter areas adjacent to live lines by mistake and receive electric shock. Thus, a means of non-contact checking of DC voltage was demanded. In this study, the authors have developed a non-contact type direct voltage detector with a mechanism for DC voltage detection using liquid crystal, and the authors confirmed that the developed detector can check power of overhead contact lines being turned on or off from the wayside without contacting the line.