Possibility of enhancing classical weighted least squares State Estimation with linear PMU measurements

The introduction of phasor measurement unit (PMU) technology is generally expected to significantly improve existing state estimation (SE) algorithms regarding accuracy, observability, convergence. Since PMUs measure current and voltage phasors, in case of complete observability of all the network with PMUs, the PMU based SE will be linear, and consequently the SE algorithm faster and more accurate. Indeed, the complete observability of the network just with PMUs is, for many transmission system operators (TSOs), quite far to be reached; therefore, it becomes necessary to find suitable strategies in order to use all data by PMUs, in the best way in the classical SE. This paper deals with the possibility of using PMUs information in the classical real time least squares SE, with particular attention to the Italian case. Simulations on the complete 380/220 kV Italian transmission system are reported, in order to show the obtained benefits.