Estratégias de gerenciamento de energia e de proteção para microrredes de missão crítica: um estudo de caso

Abstract

The research work presented in this document addresses the energy management and the protection of mission critical microgrids, with focus to a case study of a pilot microgrid of this modality recently implemented at the Alcântara Launch Center. Mission critical microgrids mainly serve critical infrastructure applications. Critical infrastructure is every asset, installation, network (physical or virtual) or system considered essential for a country and its economy. Mission critical microgrids differ themselves from other microgrids due to the fact that their main demands are electrical reliability, resilience and security, commonly required by critical infrastructure applications. Although there are several papers published on energy management and protection of microgrids, it is verified in the specialized literature that there are few solutions dedicated to mission critical microgrids. The Alcântara Launch Center mission critical

microgrid, named henceforth CLA- generation source, a battery energy storage system and a dispatchable diesel generation system.

CLA- scenarios predicted for this microgrid. During rocket launch campaigns, off-grid operation is

mandatory and the main goals are electrical resilience and security, including management of N-1 generation contingencies, i.e., loss of one of the local generation or storage resources. On the other hand, during periods when a launch campaign is not taking place (Alcântara Launch Center regular operation), the on-grid operation mode is preferable and the main objectives are reduction of and minimal polluting gas emissions. Black start (i.e., microgrid

restoration in off-grid mode after a blackout) is one of the predicted scenarios for CLA- . Executing this scenario still represents a practical challenge of considerable complexity for microgrids in general. In this context, the research presented in this document aims to propose action strategies for the energy management system (EMS) and also present a philosophy for the protection of mission critical microgrids. This, considering the specificities of these microgrids and taking

the CLA- The main intended contributions are the elaboration of an EMS action strategy and the detailing

of a protection scheme for mission critical microgrids, considering several possibilities of scenarios in steady state and transitions between modes. In addition, a black start methodology for microgrids with an internal medium voltage power grid is also proposed, with the aim of minimizing the effects of transformer magnetization currents (inrush currents) on microgrid protections. This This black start methodology and the other strategies mentioned above were developed considering specific demands of mission critical microgrids, and also the ones of the CLA- . CLA- imulation results and field commissioning experimental tests were used to evaluate the performance of the proposed EMS action strategy, which includes the black start execution methodology. The obtained results evidence the potential of the proposed strategy in contributing for mission critical microgrids goals, and also and also in meeting the specific demands of the CLA- study.