Autonomous Energy Grids

Current frameworks to monitor, control, and optimize large-scale energy systems are becoming increasingly inadequate because of significantly high penetration levels of variable generation and distributed energy resources being integrated into electric power systems; the deluge of data from pervasive metering of energy grids; and a variety of new market mechanisms, including multilevel ancillary services. This paper outlines the concept of autonomous energy grids (AEGs). These systems are supported by a scalable, reconfigurable, and self-organizing information and control infrastructure, are extremely secure and resilient (self-healing), and can self-optimize in real time to ensure economic and reliable performance while systematically integrating energy in all forms. AEGs rely on cellular building blocks that can self-optimize when isolated from a larger grid and participate in optimal operation when interconnected to a larger grid. This paper describes the key concepts and research necessary in the broad domains of optimization theory, control theory, big data analytics, and complex system theory and modeling to realize the AEG vision

A Generic Primary-control Model for Grid-forming Inverters: Towards Interoperable Operation & Control

This paper outlines an architectural vision centered around the notion of interoperability to integrate grid-forming inverter-based resources in large-scale grids. With the underlying principle of interoperability guiding developments, we focus on modeling the characteristics of droop, virtual synchronous machine, and virtual oscillator controls. Emphasis is placed on these three controllers since they are leading grid-forming control candidates and are likely to be commonplace as primary-control schemes in future systems. We show that these controllers can each be considered as instantiations of a more generic model and that all these controllers exhibit similar droop-like relations between pertinent terminal variables in steady state. This commonality between controllers gives interoperability among them such that automatic synchronization, power sharing, and voltage regulation can be achieved. Simulation results validate the models and demonstrate how the steady-state droop characteristics of these control methods can be aligned with the aid of the developed modeling paradigm

Integrating high levels of variable renewable energy into electric power systems

Abstract As more variable renewable energy (VRE) such as wind and solar are integrated into electric power systems, technical challenges arise from the need to maintain the balance between load and generation at all timescales. This paper examines the challenges with integrating ultra-high levels of VRE into electric power system, reviews a range of solutions to these challenges, and provides a description of several examples of ultra-high VRE systems that are in operation today

Advancement of Energy Storage Devices and Applications in Electrical Power System

AbstractOverall structure of electrical power system is inthe process of changing. For incremental growth, it is movingaway from fossil fuel based operations to renewable energyresources that are more environmentally friendly and sustainable.At the same time it has to grow to meet the ever increasing needfor more energy. These changes bring very unique opportunitiesand obstacles. Over the past few decades many new andinnovative ideas have been explored in the broad area of energystorage. They range in size, capacity and complexity in design.Some of the systems are designed for applications in large scalepower and others are performing short term energy storage ridethrough capabilities for critical manufacturing and technologysystems. Energy storage technology has become an enablingtechnology for renewable energy applications and enhancingpower quality in the transmission and distribution powersystems. This paper will summarize all the advancements madeand provide a composite picture of costs and trends in storagetechnologies.8 Halama