Pilot detection and location of broken conductor faults for tapped transmission lines

Abstract

The increasing integration of inverter-based resources (IBR) introduces the need for new protection methods to detect open-circuit faults, such as broken conductor faults. Fast and reliable detection of broken conductor faults is critical, since an undetected fault can lead to wildfire. The presence of tapped lines in a transmission grid introduces further protection challenges since the measured current does not drop significantly compared to a scenario without tapped lines. Moreover, tapped transmission line measurements are not always available, making protection even more challenging. If a fault is located on a tapped line, only the tapped line needs to be disconnected, so locating the fault helps disconnect only the minimal affected area and increase the reliability of the grid. Most previous work does not study broken conductor faults with the presence of IBRs and tapped lines and does not propose ways to locate the fault. This work proposes a communication-based protection algorithm that can detect the broken conductor in a transmission system with tapped lines. The algorithm detects the fault in less than 55 ms and locates the fault accurately. The proposed method is tested under various cases in the modified IEEE 9-bus system with two grid-following IBRs using PSCAD/EMTDC.