Hardware in the Loop Testing of Main and Backup Protection Scheme for Systems with High Penetration of Inverter-Based Resources

- Several challenges arise when designing an adequate protection scheme for transmission systems with inverter-based resources. The communication network plays a vital role in helping the protective relays to overcome the complexities of the architecture and provide a suitable protection technique. This paper presents a co-simulation platform linking the simulated model of the modified IEEE 14 bus transmission system simulated on the RTDS simulator and the commercial SEL-421 protective relays to protect the system. The protection scheme utilizes voltage signals from the buses to identify the faulted section and determine the fault type. Voltages and currents are communicated to the relays by sending SV messages from RTDS to the relays using the GTNETx2 interface, synchronized by the GTSYNC interface card and SEL-2488 Satellite-Synchronized Network Clock. Several cases were simulated to investigate the protection system under breaker and relay failures to provide a suitable backup solution and allow the healthy feeders to serve the system during abnormal conditions. The real-time results show the capability of the suggested protection scheme.