Data Analytics Based on Synchrophasors Captured at Extra-High Voltage Transmission Lines Under Faults and Open Phase Conditions

Synchrophasor measurements were not meant to capture fast transients accompanying short-circuit conditions in a power system. Nonetheless, quite a few research results obtained with both simulated and real-field synchrophasor data arrays clearly show the potential of phasor measurement units (PMUs) not only to capture dynamics pertaining to extra-high voltage faults, but also to ensure reliable fault location (FL) estimates. The FL errors often turn out to be equal to (or even smaller than) those derived through conventional FL hardware and software. Moreover, the high data reporting rate and data quality ensured by the PMU technology can come in handy for an accurate examination of what is happening on the line after isolating a damaged phase and before a subsequent reclosing attempt. At a typical extra-high voltage line, the PMUs are connected to voltage transducers on the line rather than at the bus, which implies their capability of recording a whole range of transient data for a fault, secondary arc conditions, recovery voltage stage, and reclosing. This research carefully examines a set of single phase-to-ground faults recorded by PMUs at three 500 kV transmission lines. In each case, various FL expressions are utilized to show that precise FL results can be derived with real-field synchrophasors. The fault resistance for each dataset is estimated not only for the fault conditions on the line, but also for the subsequent open-pole operation. The calculated fault resistance values are shown to serve as a reliable metric for the fault nature (either permanent or transient). Another criterion based on a “virtual” PMU is examined as well (with “virtual” meaning that line beginning synchrophasors and line passport data are taken to imitate the corresponding line end measurements). Voltage phasor diagrams are drawn to reveal a difference in the phasor orientation between a permanent fault case and various cases with a temporary fault. Finally, the source impedances representing power network components behind the line terminals are also approximated via fault-based synchrophasor measurements. All of the data analytics in this investigation is carried out with real-field phasors only, which implies reliable results and conclusions.