Automated fault location system for nonhomogeneous transmission networks

Fault location information is critical for operating and maintaining transmission networks. Some of the challenges in calculating accurate fault location include fault resistance, zero-sequence mutual coupling, load, system nonhomogeneity, and transmission lines composed of multiple sections with considerably different characteristics. This paper presents a fully automated real-time fault location system that provides accurate fault location information for multiple transmission lines and makes the results available to system operators and maintenance personnel. The system is capable of the following: 1) Retrieves all triggered event reports from relays and digital fault recorders (DFRs) automatically. With these reports, the system identifies the faulted transmission line(s) within the transmission network. 2) Determines the fault type and calculates the fault location and fault resistance using multiterminal fault location methods for different types of power lines, including overhead lines, underground cables, and composite lines that include both overhead line and underground cable sections. 3) Uses fault location methods that are accurate under fault resistance, parallel-line mutual coupling, system nonhomogeneity, and load. 4) Supports event reports with a fixed sampling rate or a variable sampling rate that is a multiple of the power system operating frequency. 5) Supports event reports generated by relays and DFRs connected to an IRIG-B time source. This paper compares fault location results calculated from field event reports and reports that are obtained from models of real power systems with actual fault locations.