Distributed Coordination and Control -- A bottom up design framework for Highly Renewable Grids and

Abstract

The modern power grid is undergoing an inflection point where the role of distributed energy resources (DERs) including renewable energy sources (RESs) has surpassed parity with conventional bulk power generation system as the prevalent source of energy generation. This transition from the conventional to modern power grids is also favored by economies of integrating distributed generation technologies, proliferation of intelligent communication devices such as sensors and data acquisition systems providing a global and persistent view into the state of the power system and, low footprint computational devices that have accelerated the distributed nature of the coordination of these DER units and if desired, to appear as a single aggregated unit to leverage the benefits of scale that a large centralized bulk power system can provide. Most of the design philosophy for the power-electronics interfaced DERs and highly renewable grid has been developed keeping in mind the operation of a conventional power system which is a large inertial system and highly centralized in nature. The existing grid needs to undergo transformations including control design methodologies keeping DERs and RESs at the focus and utilization of distributed communication algorithms at DERs allowing renewable energy resources and battery energy storage systems to participate in grid interactive services that can meet aggressive response timescales to maintain the operation and stability of the power system. This thesis makes several contributions, firstly towards enabling better active and harmonic power sharing in multi-inverter microgrid systems (MMGs) with DERs interfaced with low-inertia voltage source inverters (VSIs) while reducing the complexity of reactive power sharing and control. Secondly, investigations and contributions towards developing a novel aggregation strategy and implementation methodology for smaller DER units for enabling challenging grid interactive services in presence of real-world non-idealities such as time delay in communication channel are also presented and validated by developing a novel end-to-end power-hardware-in-the-loop (PHIL) configuration. The finite-time termination distributed schemes suffer from vulnerability to cyber-attacks that are aimed at manipulating data and control flow. In the final part we develop a novel distributed method for detecting the presence of such intruders for a multi-agent system implementing ratio consensus protocol.