Zero Sequence Line Parameter Estimation Using PMU Data Considering Uncertainty Factors

Synchronized Measurement Technology has significantly advanced real-time monitoring and control applications for power system control centers. A key component, the Phasor Measurement Unit (PMU), is now widely deployed in transmission systems, enhancing system monitoring and control. PMU-rich systems also enable the refinement of critical modeling parameters, such as transmission line sequence parameters, used in control center applications and substation protection relays. This paper discusses the estimation of zero-sequence parameters of transmission lines, essential for fault analysis in control centers and distance protection relays. Two key factors impacting estimation accuracy are examined, namely the PMU measurement and fault location uncertainties. Their effects on zero sequence line parameter estimation accuracy and consequently on the performance of distance relays are analyzed in the IEEE 9-bus system.