The ABB Relay REF615 4.0 FP1 IEC (HBFFAEAGNEA8BNA11E) ist a distance protection relay designed for the protection of overhead lines and cables in medium voltage networks. It offers extensive protection functions such as overcurrent and earth fault protection and ist standardized in the protection philosophy IEC 61850. The integrated communication protocol supports Modbus RTU/TCP and IEC 60870-5-101, enabling seamless integration into existing systems.