SHORTCIRCUITING AND EARTHING TROUBLE DETECTOR

摘要

PURPOSE:To obtain a miniaturized zero phase voltage detector, constituted so that a conductor member is mounted to an insulator pipe at every phase so as to pierce therethrough and an electrode is provided through an insulating layer to form an insulator pipe condenser and the signals of the insulator pipe condensers are collectively taken out at every phase. CONSTITUTION:A conductor member 41 of each phase is mounted to an insulator pipe 42 so as to piece therethrough and an electrode 43 is provided to the insulator pipe 42 through an insulating layer 42a to form an insulator pipe condenser G. A first current sensor 44 for detecting a current flowing at the time of earthing trouble and a second current sensor 45 for detecting an eddy current at the time of shortcircuiting trouble at every phase are provided to the insulator pipe 42. When the radius of the insulator pipe 42 up to the inner peripheral surface thereof is set to (a) and the radius up to the outer peripheral surface is set to (b) and the dielectric constant of a medium is set to epsilon, electrostatic capacity C per the unit length of the insulator pipe condenser G is represented by formula C=2piepsilon/log(b/a). Three phase voltages are divided collectively by the condenser and the sum vectors of phases is taken to enable the detection of voltage corresponding to zero phase voltage. By this constitution, miniaturization and wt. reduction are enabled.