Flexible Noncontact Approach for Fault Location of Transmission Lines Using Electro-Optic Field Sensors

Locating faults in transmission lines is important for the safety and continuous operation of power systems. The existing fault location methods based on traveling waves mostly use current transformers to obtain the transient signals, which requires a direct connection with the live lines and therefore brings inconvenience to the installation, debugging, and maintenance. In this article, we propose a flexible noncontact approach for locating faults in transmission lines based on broadband electro-optic field sensors, where the noncontact fault location system can be easily installed, debugged, and maintained. The approach uses an electric field sensor to directly measure the quasi-static electric field generated by the faults, and then the associated time difference of arrival of the transients at two ends of a transmission line can be obtained. The approach is validated and tested by experiments both in laboratory and real 500 kV transmission lines. The artificial fault experiment shows a location error of approximately 200 m on a 177-km- long 500 kV power transmission line.