Current-Limiting Reactors Based Time-Domain Fault Location for High-Voltage DC Systems With Hybrid Transmission Corridors

Accurately locating the fault distance helps in the rapid restoration of the isolated line back into the system. This article proposes a novel time-domain-based algorithm to determine accurate fault location in high-voltage direct current (HVdc) systems with hybrid dc transmission corridors i.e., a combination of underground cables (UGCs) and overhead lines (OHLs). The work gives a fault location method for a two-segment and three-segment hybrid transmission corridor (HTC) and then generalizes the analysis for an n-segment HTC. The algorithm offers flexibility to locate faults ranging from the homogeneous transmission line to n-segment HTC. The algorithm uses a simplified unit resistance-inductance ( RL ) representation of transmission lines along with time-domain-based measurements i.e., terminal voltage, current, and voltage across current-limiting reactors (CLRs). Power systems computer-aided design/electromagnetic transients including dc (PSCAD/EMTDC)-based simulations are used to validate robust performance against variation of key implementation parameters like type of faults, fault resistance, fault location, sampling frequency, and white Gaussian noise (WGN) in measurement. Further, the fault location calculation is analyzed under parameter variation i.e., change in the true value of unit resistance and unit inductance of line or cable and the true value of dc link capacitance.