Microrredes despacháveis de baixa tensão : múltiplos serviços ancilares

Abstract

Dispatchable microgrids can support the operations of the electrical distribution networks acting as controllable active entities by interoperability with the microgrid operator. In this context, few published papers have focused on the secondary and tertiary microgrid control levels, their interoperability, and the combination of different ancillary services provided by the same microgrid. Other recent works have addressed single and multiple services applied to distributed generators. This PhD dissertation proposes a multifunctional control of a low-voltage dispatchable microgrid capable of exploiting the microgrid’s battery banks to provide multiple ancillary services depending on the intrinsic microgrid targets and the upstream grid requirements. The microgrid control allows the management of the system considering the following ancillary services: peak shaving, islanded operation, reactive power support and compensation, power reserve, self-consumption, energy time shifting, flat power flow and capacity firming. It is also investigated the aggregate response of a cluster of multifunctional dispatchable microgrids to offer support to the upstream grid under predictable, such as variability of renewable sources and load; and unpredictable events, such as generation, transmission and communication failures, or even overvoltages. For this, the energy management system is devised into a hierarchical architecture comprising the microgrid central controller, microgrid system operator, distribution system operator up to the transmission system operator in a transactive energy system in which microgrids operate as virtual power plants. The simulation results show that the microgrid imports/exports power and manages its net power flow in support to upstream grid (e.g., absence of power generation and support during transients) and inherent targets (e.g., economic interest and enhance the power quality). To achieve such goals, the microgrid is controlled through the power-based control algorithm that allows the microgrid central controller to regulate effectively the active and reactive power flow through the point of common coupling. The available battery capability is partitioned to provide more than one ancillary service concomitantly for the network, while maintaining the state of health and avoiding overcharge risk of the battery banks. The aggregate response alleviates the loading on the upstream grid, whose effects can be perceived locally at the point of common coupling of each microgrid or systemically perceived at the medium and high-voltage levels (i.e., point of common coupling of the microgrid cluster.