Island systems need to be self-sufficient with respect to load-generation balancing, frequency control, system strength, resource adequacy, and other key aspects. The effects of faults and loss-of-generation events on island grids tend to be larger in proportion to the size of the system – for example, a transmission fault is likely to bring voltage very low throughout the entire system, increasing the likelihood of severe stability challenges. Similarly, a trip of the largest generator on an island system may result in the loss of 50% or more of generation, whereas on continental systems the largest contingency tends to be less than 5% of generation. System strength concerns also tend to be more challenging because by adding one or two large inverter-based plants, island systems can find their generation mix dominated by non-synchronous generation during certain hours. The challenges of operating with high levels of wind and solar include lower inertia, inverter/converter control instability, reduced fault current (and varying fault-current characteristics), etc. The ongoing maturation of grid-forming battery inverter controls for grid-connected applications represents a significant step forward relative to the past state-of-the-art, where grid-forming inverter controls were typically only deployed in isolated microgrid applications, and not in larger power systems (10s of megawatts and larger). At the same time, replacement of synchronous generators by grid-fomring inverter-based resources introduces major changes grid operations.

This panel sessions will provide real-world examples of these challenges and some potential solutions from the power systems of Galapagos, Jamaica, and Hawaii.

Speaker Topics:

ElecGalapagos operates the four independent power systems power systems of the Galapagos Islands, all of which have ambitious plans to transition from primarily diesel-based power to primarily renewable power by 2030. Cristian Fernandez, Head of Renewable Energy for ElecGalapagos, will summarize the various technical and economic challenges and opportunities presented by this plan. Technical challenges include integration of large-scale solar and battery plants, integration of microgrid controllers with existing control systems, and management of resource variability.

Rick Case will summarize Jamaica Public Service’s experience integrating over 100 MW of wind generation and over 50 MW of solar PV in its ~700 MW peak load power system. In addition, he will describe JPS’s plans to add 298 MW of additional PV, energy storage, and wind generation in 2025 via an solicitation that closed in late 2023.

KIUC’s 75 MW peak power system operates with 90% inverter-based generation at times, a record for a system of its size. This highly renewable operation is supported by two grid-forming PV-battery plants and one synchronous condenser. Cameron Kruse will summarize KIUC’s operations and the challenges it faces, in particular challenges with protective relay coordination for high-IBR operations.

The final presentation will summarize field and laboratory experience with grid-forming inverter controls in island power systems with very high levels of inverter-based resources. Lessons learned related to grid-forming IBR operations will be described based on simulation studies, MW-scale power hardware-in-the-loop experiments, and field experience with utility partners who plan and operate island power systems.