Development of contactless measuring method of transient voltage on cable sheath

This paper proposes a contactless measuring method of a transient voltage on a cable sheath. The proposed method consists of quite simple elements, i.e. detecting and common electrodes and a lumped capacitor, based on capacitive coupling between the electrodes. The sheath voltage is measured as a dividing ratio between the sheath voltage and a voltage across the lumped detecting capacitor. The common electrode, covering the cable at a measuring part can reduce the effect of a stray capacitance. An experiment has been carried out on a scaled-down model of a cross-bonded cable. It has been confirmed from the experimental results that the proposed method has a sufficient accuracy