Sensing principles include changes in the state of the polarisation of the light due to the magnitude of an
electric field(Pockels effect), magnetic field(Faraday effect) , mechanical stress(photoelasticity) and temperature (thermochromic) & Mechanical vibration(changes in the spatial distribution of the light).
Figure shows a schematic diagram of a high voltage gas
blast interrupter indicating various types of optical fibre chromatic sensors which have been deployed. These include sensors for monitoring the gas pressures in the interrupter tank and piston chamber, the contact potential, fault current, temperature of the contact stalk, contact travel, mechanical vibration and arc radiation.
The time variation of the piston chamber pressure (with a Fabry Perot pressure sensor), the contact travel (chromatic linear scale) and the mechanical vibration during circuit breaker operation. Such data taken together provide an insight into the various conditions which occur during the fault current interruption process so that improved understanding of the interrupter operation can be obtained.
