SIPROTEC 7SJ66 is a numerical protection, control and monitoring device. SIPROTEC 7SJ66 is features flexible protection functions. Up to 20 protection functions can be added according to individual requirements. Thus, for example, a rate-of-frequency-change protection or reverse power protection can be implemented. The relay provides control of the circuit-breaker, further switching devices and automation functions. The integrated graphical logic editor (CFC) allows the user to implement its own functions, e. g. for the automation of switchgear (interlocking). The communication interfaces support the easy integration into modern communication networks.