Characterizing dynamic behavior of PMUs using step signals

Evaluating performance of PMUs to verify the consistency of phasor measurements is of a great importance since it promotes the interoperability among PMUs from different manufacturers. This paper presents a set of test methodology and tools 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 transient behavior of a PMU 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. Three commercial PMUs are selected to perform step tests using the dynamic test system developed at NIST. A set of programs are developed based the dynamic test system to automate step test procedures. The test results are outlined at the end. Copyright # 2010 John Wiley & Sons, Ltd.