Dynamic characterization of PMUs using step signals

Performance evaluation of PMUs to confirm the consistency of phasor measurements is of a great importance since it promotes the interchangeability among PMUs from different manufacturers. This paper presents a method for evaluating the dynamic performance of PMUs when exposed to a step change of input signals. A phasor estimation scheme is proposed to achieve high accuracy of reference phasors. An interleaving technique applied on output phasors can equivalently increase the reporting rate and can precisely depict the PMU behavior under the step input. Four types of tests with balanced and unbalanced three-phase step signals are performed as reference signals to characterize the step responses. A set of programs are developed to automate step-based tests. Three commercial PMUs are selected to perform step tests using the dynamic test system developed at NIST. The test results are outlined at the end.