Check-Synch for Generators: NPRG810
The NPRG810 is a successor to the RG81 (part of the TECHNIREL range).  It is available in two variants:

NPRG810-1G carries out the synchronism check between one generator and the network. Most often, it is used to authorise a closing order to the paralleling Circuit Breaker. 

NPRG810-4G carries out the synchronism check between up to four generators and the network. 

Both variants allow the "Dead Bus" function. 
ANSI function: 25

Do you need an automatic synchronisation function? Consider the NPRG860 / NPRG870.

These relays are part of the NP800 range, offering multi-function protection and communication via Modbus (RS485) or Modbus TCP (Ethernet).  A full brochure is available on the NP800 range page