Phasor assisted state estimation for NYS transmission system --Implementation & testing

This paper describes the implementation, testing, and performance of phasor measurements in an industrial state estimation at the New York Power Authority (NYPA). Phasor Measurement Units (PMU) with GPS synchronization were incorporated into the data acquisition subsystem of the Energy Management System (EMS). The modified state estimator was subjected to pre- and post-field installation testing. The pre-field installation testing was done to verify the correctness of the solution algorithm, to identify the impact of phasor metering accuracy on the quality of estimator solution, to show the relative effectiveness of phasor measurements with respect to other measurements, to identify the effect of the reference bus selection, to detect the impact of PMUs on the state estimator convergence, and to establish the minimum clock synchronization sampling accuracy required for the PMUs. The post-field installation tests were conducted to identify the effectiveness of the PMUs in the state estimator solution using the real-time data as well as to detect the effect of time skewing and measurement weights on the state estimator solution.