ERI: Unveiling Fault Effects on Carrier Waves to Enable New Protection Schemes for Inverter-Based Grids

This NSF ERI project aims to uncover the effects of faults (i.e., short circuits) on High-Frequency (HF) carrier waves traveling through high-voltage Transmission Lines (TLs) to enable the development of source-independent protective devices (relays). Contemporary protection systems often fail to detect faults in grids dominated by Inverter-Based Resources (IBRs). This limits the capacity of electric grids to host large amounts of IBR-based generation units, urging the establishment of new fault detection methods. This research supports national priorities by: i) enhancing the reliability and resilience of the electric grid, ii) accelerating the integration of various energy resources, and iii) promoting energy security that promotes economic competitiveness. The intellectual merits of this project include: 1) advancing the fundamental understanding of wave propagation in flawed and inhomogeneous media (i.e., TLs), 2) discovering fault effects on carrier waves through deterministic mathematics, 3) determining and categorizing the effects of other disturbances (e.g., switching events) on carrier waves, and 4) establishing a foundation for creating innovative source-independent protection schemes premised on the fault effects on carrier waves. Since the proposed project will extend the understanding of wave propagation in inhomogeneous media, the results will serve as a knowledge source for others to build their research. The conclusions of the project will be transformative with potential applications in other fields, including, but not limited to, broadband communication technologies, optics, photonics, acoustics, medical imaging, remote sensing, and non-destructive testing. Broader impacts include: 1) creating educational content for engineering courses, 2) engaging high school students and teachers through outreach events, and 3) preparing a skilled STEM workforce through student involvement. Technically, the hypothesis of this project postulates that, as faults alter the characteristics of TLs, the inception of faults can be effectively detected and distinguished from other sources of disturbance (e.g., noise or switching events) in the receiving carrier waves. To this end, this project will advance deterministic formulations describing the behavior of HF waves in flawed TLs using telegrapher’s equations, boundary conditions at fault locations, partial differential equations, and advanced TL models. If high-frequency waves are transmitted through high-voltage TLs, and receiving waves at the other TL end are analyzed employing signal processing methods, the recognition of fault-induced patterns in receiving carrier waves enables rapid, selective, and sensitive fault detection. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.