| With the ability to provide synchronized and real-time measurements, Phasor Measurement Unit (PMU) becomes a promising answer to the dynamic security control problem in the complex power system nowadays. It is widely used throughout the world, especially in China, with about 2500 PMUs already implemented in the grid. It creates conditions for studies on WAMS-based monitoring and control of power system, and these applications are greatly subjected to the dynamic features and data quality of PMU. Thus, effective tests and evaluation of PMU dynamic measurement characteristics becomes a key issue that needs to be solved at the moment.This thesis mainly studies assessment methods of PMU measurement quality and the construction of PMU test platform. Typical signal models are abstracted with feature analysis of power system static and dynamic operating situations. Measurement features of PMU under dynamic conditions are preliminarily discussed, and the PMU classification issue is proposed. Based on the study above, comprehensive static-dynamic PMU test schemes with reasonable assessment criteria are put forward. In addition, according to error theory and the properties of DFT algorithm, Normal-distribution Fitting Index (NFI) is proposed to evaluate PMU performances, and Empirical Mode Decomposition (EMD) is applied to analyze and extract the systematic error component due to the estimation algorithm. On the basis above, the automatic static-dynamic PMU test system is built, after solving problems in synchronization compensation, functional integration of the signal generator and off-line data extraction from the DUT. The test system is able to provide flexible and automatic test on the measuring features of PMU devices. With such technical support, a full test is conducted on PMUs from mainstream venders in China, and the results are processed and analyzed using the NFI and EMD methods proposed above, reflecting static and dynamic measurement problems in present devices. |
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