Contactless optical sensors for in situ AC and DC electric field measurement and diagnostics

The possibility of perturbation-free electric-field mapping could give very helpful information concerning possible fault origins in electrotechnical installations during operation or during conception phases. For that purpose, we have developed ultra compact and fully dielectric pigtailed optical sensors for a simultaneous 2-components electric-field measurement. Made of high dielectric strength materials, these millimeter-size sensors can probe the transient temporal profiles of two electric field components inside an electric arc for instance. Their measurement dynamic covers the V/m up to MV/m electric-field strength range. The response of these optical sensors is flat from 30 Hz up to more than 10 MHz, giving a unique opportunity to make in situ diagnostics during a lightning shock wave inside electrotechnical installations. These sensors also exhibit a temperature-dependent free response and can be employed either in gazes or liquids like water or oil. Some electric-field mapping and in situ electric arc measurement will be presented during the conference.