Research and application of a non-contact optical voltage sensor for the monitoring of lightning and switching overvoltage in EHV power grid

In this paper, a type of sensor for the non-contact monitoring of lightning and switching overvoltage in power grid is presented. It is designed based on Pockels effect and stray-capacity coupling theory. Double-crystal structure is utilized to restrain the unwanted influence caused by natural birefringence. The transmission of the data is achieved by optical fibers which are immune to the electromagnetic interference in substation. This type of sensor is applied to an EHV transformer substation for on-line monitoring.