State Estimation Study Based On Phasor Measurement Technology

The phasor measurement technology based on GPS is introduced in this paper, which functions to state estimation is also focused. Following aspects and works are done in this paper:1. The phasor measurement technology based on GPS is introduced briefly. And how to add these phasor measurements into state estimation is analysed from several aspects. The state estimation differences between based on phasor measurements and conventional SCADA are given.2. Models with different measurements precision based on phasor measurements are built. As for measurements with low precision, the voltage phasor of nodes with PMUs are iterated as state variables. As for the measurements with enough precision, the measurements of PMU are regarded as state results directly.3. The placement of measurement points under two conditions are discussed when system measurability could be ensured. One condition is to provide the PMU placements scheme in advance, which can make the system linear observable. The other is to provide PMU numbers in advance. Both can improve the performance of state estimation. Due to former condition, the method that the power equations are resolved directly to decide the placement is applied. The method, Which reduce covariance errors of the measurements, is adopted under the later condition.4. The models and system are simulated by MATLAB in this paper. The results denote that the models of state estimation and the placements of PMUs are efficient.