SPLTRAK Abstract Submission
Operability of a Power System with Synchronous Condensers and Grid-Following Inverters
Marena Trujilo1,2,3, Rick W Kenyon1,2,3, Gemini Yau4, Li Yu4, Andy Hoke3, Bri-Mathias Hodge1,2,3
1Department of Electrical, Computer, and Energy Engineering, University of Colorado of Boulder, Boulder, CO, United States
/2Renewable and Sustainable Energy Institute, University of Colorado of Boulder, Boulder, CO, United States
/3National Renewable Energy Laboratory, Golden, CO, United States
/4Hawaiian Electric Company, Honolulu, HI, United States

Growing shares of inverter-based resources generally correlate with a reduction in power system inertia as synchronous generators are displaced. Power systems operating at these reduced levels of inertia generally exhibit more rapid frequency dynamics; because the presence of inertia bridges the temporal gap between load-generation imbalances and governor response, and the amount of inertia is inversely proportional to the frequency rate of change in synchronous machine dominated systems, relatively less inertia tends to yield larger frequency excursions. Beyond more rapid dynamics, the presence of inertia itself creates a physical link between frequency and the balance of load and generation, which is a critical signal to frequency-responsive devices on the system. Along the path to high shares of inverter-based resources, in particular with only conventional grid-following controls where the inverter tracks a presumed-present sinusoidal voltage waveform at the point of interconnection, a proffered solution is the use of synchronous condensers as a source of inertia to maintain the frequency–power balance relationship. An outstanding question is whether only grid-following inverters and synchronous condensers yield a viable power system, i.e., all frequency response is derived from inverters. Such an operating condition is contemporarily plausible on smaller island systems when a surplus of renewable power is available but minimum output limits of synchronous generators may have been reached. A validated electromagnetic transient model of the Maui system, with all non-linear elements such as load-shedding, relay action, and ride through criteria disabled, is used to investigate the stability of such a system without synchronous generation. Two types of standard perturbations were applied to the system in steady state, a 15% generation loss and a fault event, and it was found that the system remains stable.