REX615 is a freely configurable all‑in-one protection relay for power generation and distribution applications, representing the next step for ABB’s 615 and 620 series relays. Multiapplication coverage combined with a fully modular and scalable hardware and software ensures maximum flexibility and optimal cost-effectivity throughout the relay life cycle – and supports sustainability. As part of ABB’s Relion® protection and control family of relays, REX615 builds on ABB’s strong heritage of freely configurable multifunctional relays and many proven protection algorithms.