State estimation in Multi-Microgrids

In this paper, a Multi-Microgrid state estimator is proposed, following the concept of distribution state estimators, where a limited number of real-time measurements are available. Since state estimation (SE) solution is impossible with these limited measurements, forecasted values of load injections at buses remote from the substations are needed, for a given period that coincides with the real-time measurements. The proposed state estimator is based on the traditional WLS algorithm and uses few real-time measurements, mainly at the primary (MV) or secondary (LV) substations and DG locations, and pseudo-measurements for the load bus estimates. The impact of the accuracy of distributed generation (DG) voltage magnitude measurements and load pseudo measurements on the bus voltage estimates is also investigated. Grid-connected and islanded modes are simulated and monitored. Topology errors at the main substations and feeders, where there is sufficient measurement redundancy, are also examined. Test results are given for a 55-bus distribution network including DG. Copyright (C) 2010 John Wiley & Sons, Ltd.