System for reading magnetic sensors for fault location in gas- insulated electrical apparatus

摘要

A fault location system for use with sealed, gas-insulated electrical power apparatus. The system includes a sensor for placement in close proximity to the outer surface of a housing of the apparatus and a detector for in-place reading of the sensor. The detector comprises a first fluxgate magnetometer for detecting magnetization of the sensor. A second fluxgate magnetometer is positioned adjacent and parallel to the first magnetometer to detect only the background magnetic field. An alternating current electrical signal is applied to the magnetometers. A direct current is then automatically generated wherein the direct current is a function of the even harmonics of the ac output of the second magnetometer. The direct current is used to cancel the effects of the background magnetic field detected by the second magnetometer. As such, the direct current is applied to the first magnetometer to cancel the effects of the background magnetic field therefrom.