NONCONTACT VOLTAGE SENSOR AND ELECTRIC POWER MEASUREMENT DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a voltage sensor for measuring the voltage applied to an electric wire with high accuracy without contacting, and an electric power measurement device using this voltage sensor.SOLUTION: Provided is a noncontact voltage sensor capable of measuring the voltage applied to a core wire 1a of an electric wire 1 using a detection probe 2 disposed on the outside of an insulation coating 1b, wherein the detection probe 2 is provided with an electrode 2a included in the insulation coating 1b and facing the core wire 1a, the detection probe 2 having flexibility making it windable around the electric wire 1. A voltage detection circuit 3 is provided with: a modulation circuit 4 for modulating a current flowing via a coupling capacitance Cto a current higher in frequency than an applied voltage by turning switching elements 4a, 4b on and off; a drive circuit 5 for the switching elements 4a, 4b; a transformer 6 for detecting the modulated current; an amplification circuit 8; a demodulation circuit 9 for detecting an original frequency component; a voltage generation circuit 13 for generating a voltage from its output; and measurement means for measuring the voltage applied to the core wire 1a.SELECTED DRAWING: Figure 1