Development of open (Broken) conductor detection system for high resistivity areas

In the Kingdom of Saudi Arabia, some distribution lines feed loads that are located in remote desert areas. Such distribution systems, including medium and low voltage networks, face difficulties regarding fault detection and localization as compared with high voltage transmission systems. High impedance fault (HIF) resulting from an open (or broken) conductor in medium voltage (MV) overhead lines represents the most challenging problem in such an environment. The aim of this paper is to report on a new method to detect and locate such high impedance faults generated by downed conductors. These faults usually produce very low fault currents that are usually not detectable by the feeder conventional over-current protection schemes. The proposed Open Conductor Detection (OCD) system is based on distributed voltage measurements performed at low voltage (LV) sides of distribution transformers throughout the distribution network with GSM network communication to locate the faulty line section. The OCD detects the fault by activating all units downstream of the fault. The network operator locates the fault by searching for the last active and the first inactive unit, and then performs the necessary line sectionalizing to prevent incidents and minimize downtime. The OCD has been successfully piloted and has received patents.