ReliaGrid™ Loop Control Solutions

Ensuring continuity of power in distribution ring networks

Continuity and reliability of power supply is paramount in distribution networks built in urban areas towards transportation, data centers, residential areas, sports arena etc. and in rural residential areas.  

After faults, the loop control solutions restore rings networks to full functional normalcy and in the process ensuring safety, reliability and minimal outage times.

The automated loop control solutions for ring network reconfiguration are developed for network applications with extremely stringent reliability and high-speed post-fault recovery requirements. 

The solution ensures the following:
a) Fault detection in an identified part of the network
b) Isolation of the faulty section of the network 
c) Restoration of power to healthy part of network by reconfiguration
d) Ensures only minimal loads are affected

After fault, these solutions can restore power within 1 second.


  • The loop control solution is applied as different variants in combination with primary and secondary switchgear/RMUs, Unigear ZS1, Unisec, SafeRing, together with voltage and current combi sensors KEVCY_RE in every transformer substation.
    • 2 x Relion RE_615 units in each secondary substation for local protection and control, looking at both sides of the loop and AC800M/ZEE600 SoftPLC as the loop controller. 
    • 1 x RIO600 in each secondary switchgear and 2 x RE_615 units as loop control units.
    • 2 x Relion REX640 units in each secondary substation for local protection and control, looking at both sides of the loop and ZEE600 SoftPLC as the loop controller.
    • 1 x AC500 unit in each substation for local automated actions, 2 x RE_615 units at the start & end sections of the loop and 2 x redundant AC500 units as loop controllers. 
    • Ethernet switches or Arctic ARG600 wireless gateways at loop initiation, termination substations/switchgear and at the intermediate substations/switchgear in the loop.

  • The solutions use various forms of communications such as:
    • IEC 61850 GOOSE based on HSR/PRP using multimode or single mode fiber optic medium
    • Dedicated binary channels using fiber optic medium between RE_615 and REX640 units.
    • IEC 104, Modbus TCP based inter-substation communication, based on wireless networks.

  • Advanced fault location solution with the remote monitoring and control relay REC615 for network management

  • Remote IO unit RIO600 for fault passage indication in a compensated network


  • Continuity of service
  • High performance and reliability
  • State-of-the-art solutions

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