A Simplified Microgrid Architecture with Reduced Number of Measurement Units

Abstract

This paper proposes a simplified central-controller based microgrid architecture that eliminates the need for local measurements traditionally required for inverter synchronization and control. This architecture reduces overall number of required measurements in microgrids and consequently the cost of the system. The architecture relies upon state-estimation (performed at the central-controller) and GPS time-synchronization (at the local controller). Local controllers receive voltage/current reference from the central-controller, thus eliminating the need of sensors, analog to digital cards and processors at the inverter level. The proposed architecture is validated through the real time simulations using Typhoon HIL. The results show that the inverters, which operate without the local measurements according to the proposed architecture, have comparatively sluggish response. This represents a trade-off between the cost saving due to eliminated measurements and overall dynamic performance of the microgrid. Further, this indicates that smaller inverters which do not impact the microgrid stability are good candidates to be operated without local measurements.