Impact of PMU Measurement Buffer Length on State Estimation and its Optimization

State estimation is applied to process a set of measurements which are assumed to be taken at the same snapshot in time to obtain a best estimate of the states of electric power systems. The beneficial impacts of incorporating phasor measurement unit (PMU) measurements into the state estimator have been studied by many researchers. However, the availability of PMU measurements and many practical implementation issues still need to be resolved. This paper addresses one specific and important issue when integrating PMU measurements into the state estimator, namely, determining the optimal buffer length for PMU data. Due to different reporting rates of the conventional measurements and PMU measurements, a memory buffer of PMU measurements is recommended to be processed ahead of the state estimation. The impact of PMU measurement buffer length on state estimation is discussed. A procedure to determine the optimal buffer length of PMU measurements is presented. Processing a buffer of PMU measurements is also helpful for determining the corresponding weights in state estimation.