ReliaGrid™ Autosynchronization Engineered Solution

Ensuring a smooth interconnection of a power source or power networks to each other

This versatile state-of-the-art distributed solution helps to safely connect an incoming power source or a network with a reference power network by controlling the voltage and frequency outputs of the generator(s) participating in the synchronization process, through their respective speed governor and automatic voltage regulator units.

The solution comprises of single or multiple Relion REX640 protection relays utilizing the full potential of the IEC 61850 standard for substation communications.

IEC 61850 GOOSE communication between the REX640 ensures that a reliable exchange of signals required for autosynchronization functionality.

Additionally, IEC 61850-9-2 LE capabilities of the REX640 can be fully utilized to extend voltage signals from switchgear bus section and the incoming source's merging unit SMU615/REF615 and thereby avoiding additional VT wiring.

With some adaptations, the network autosynchronization function can also be applied to regulate an Battery Energy Storage System (BESS) inverter's (PCS100 ESS) voltage and frequency outputs.


  • To connect an ‘incoming’ power source to the bus bar (after generator trip or total power failure)
  • To connect islanded plant power network back with utility grid
  • To reconnect two parts of the plant networks (“left side” and “right side”)
  • Automatic operation for grid incomer and bus coupler synchronization
  • Manual, semi-automatic and fully automatic operation modes 
  • Maximum network configuration: 8 generators,  15 busbars, 17 non-source circuit breakers
  • Can address both single and double busbar arrangements, when it concerns for source or non-source circuit breakers.


  • Eliminates the need of dedicated voltage selection scheme and complexity
  • Ensures complete safety of the switchgear equipment and generators
  • Safeguards customer investment
  • Distributed solution, fully based on IEC 61850 and offers interoperability with REX640

Related offering

REX640 Diesel Generator Monitoring Solution
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