The relay also supports IEC 61850 process bus concept by

sending and receiving sampled values of currents and voltages.

With this functionality the galvanic interpanel wiring can be

replaced with Ethernet communication. The analog values are

transferred as sampled values using the IEC 61850-9-2 LE

protocol. REX640 supports publishing of one and subscribing

of four sampled value streams. The intended application for

sampled values are current-based differential protection

functions or sharing the voltage values with the relays that have

voltage-based protection or supervision functions. The relay

can receive up to four sampled value streams and totally 16

measurements can be connected into the protection relay

application.

The protocols rely on the duplication of all transmitted

information and provide a zero switchover time if the links or

switches fail, thus fulfilling all the stringent real-time

requirements of substation automation.