In digital substations, Intelligent Electronic Devices (IEDs) such as Merging Units (MUs) receive analog voltage and current signals from potential transformers (PTs) and current transformers (CTs). These signals are converted into digital form and transmitted over Ethernet using the Sampled Value (SV) protocol defined in IEC 6185092. The communication backbone—known as the process bus—is built on highspeed fiber networks, ensuring reliable and secure data exchange. Our realtime simulation platform, RTSim, enables engineers to test digital substations configurations seamlessly before deployment.

Solution Benefits

  • Futureproof validation for IEC 61850based digital substations.
  • Safe and repeatable testing of protection schemes under fault and extreme scenarios.
  • Interoperability assurance across multivendor IEDs and communication protocols.
  • Reduced commissioning risk by validating schemes virtually before deployment.

Hardware-in-the-Loop (HIL) Testbed for Digital Substations

Our RTSim platform seamlessly integrates with digital substations to enable closedloop testing of protection devices

Simulated Electrical Network - Digital Substation

Digital Substations – Process Bus and Station Bus

Signal Interface

  • RTSim generates analog output signals within a nominal ±10 V peak range.
  • These can be connected directly to IEDs (Merging Units (MU)) if a “lowlevel” interface is available or routed through external power amplifiers to drive MUs at standard secondary voltage and current levels.

IEC 61850 Compliance

  • Protective IEDs under test can directly connect via Ethernet to RTSim using Simulated IEC 61850 GOOSE, SV protocols.
  • SCADA/EMS systems can directly connect via Ethernet to RTSim Station bus using simulated MMS protocol
  • This ensures interoperability with modern digital substation architectures.

ClosedLoop Fault Testing

  • During simulated fault conditions, IEDs generate trip and reclose signals as GOOSE messages.
  • These signals are fed back into RTSim, which updates the state of circuit breakers modeled in the realtime power system simulation.
  • The result is a fully interactive, realtime validation of protection logic under realistic grid conditions.

Why It Matters

  • Implements both process bus and station bus architectures for full IEC 61850 integration
  • Enables seamless communication between IEDs and SCADA systems via the station bus
  • Supports distributed intelligence by decoupling control logic from physical wiring
  • Facilitates centralized monitoring and remote configuration of substation assets
  • Improves scalability and modularity for future upgrades and DER integration
  • Reduces installation complexity through fiber-based digital communication networks
  • Enhances cybersecurity and data integrity with protocol-aware validation and secure messaging
  • Requires rigorous testing of timing, interoperability, and message handling across both buses

Accelerate your transition to digital substations with confidence. Test, validate, and optimize protection schemes using realtime HIL simulation.