Practical experiences on PMU-based linear state estimation in distribution grids

This paper presents the system design and the first practical experiences of a Distribution Area Monitoring System (DAMS) that was practically applied in the German 110 kV network. With regard to the involved components of the larger ICT system, the software architecture - including standardized Smart Grid communication protocols and interfaces - is described. As a main component, a linear state estimator is presented, that uses only phasor measurements to calculate the complex-valued node voltages. Real measurement data provides the necessary input for observing the typical characteristics in distribution systems and for analyzing accuracy and plausibility of the results. A consecutive state assessment is applied in order detect violations of permissible operation limits.