A Revolution

in Real Time 


Built to be Real-Time

RTDS® is the Real-Time Digital Simulator of choice of power systems professionals worldwide. Designed and developed from the ground up by RTDS Technologies, it consists of purpose-built parallel processing hardware and software optimized to perform electromagnetic transient simulation in hard real time. Coupled with its full range of high precision I/O capabilities and industry standard communication protocols, RTDS is best suited to meet all your controller hardware-in-loop (CHIL) and power hardware-in-loop (PHIL) testing requirements. It is a design that works, in real-time.

RTDS Applications

The RTDS Simulator was originally developed to model HVDC schemes, and over the last two decades the Simulator has revolutionized the testing process for HVDC controls.
Today, it is the ideal tool for the simulation and testing of HVDC and FACTS devices. RSCAD includes a wide variety of sample cases relating to HVDC and FACTS applications, including MMC (Modular Multilevel Converter) HVDC, SVC MMC, and LCC HVDC schemes, among others.
All of the major manufacturers use the RTDS Simulator to test their HVDC controls during Factory Systems Testing. Systems successfully tested include LCC- and VSC-based HVDC, modular multi-level converters, network and industrial SVCs, STATCOM, TCSC, DVR, UPFC, and more.
Smart Grid and Distributed Generation
The implementation of smart grid technology in the real-time simulation environment requires high-level communication capabilities. Using the GTNET or GTNETx2 card and its available firmwares, the RTDS Simulator is capable of the following smart grid-related communication:
  • IEC 61850 for substation automation applications
  • DNP3 and IEC 60870-5-104 for SCADA systems
  • IEEE C37.118 for PMU applications
The RTDS Simulator also has facilities for simulating distributed generation and renewables. Wind turbines, photovoltaics, fuel cells and various other power sources can be represented by library components, while the corresponding VSC converters can be freely configured in small timestep subnetworks.
Protection Systems Testing
The RTDS Simulator offers the most advanced and effective means available for testing protection systems. Since the simulation runs in real time, the physical protection equipment can be connected in closed-loop with the power system model.
The controlled and flexible environment of the digital simulation allows protection equipment to be subjected to virtually all possible faults and operating conditions. The closed-loop interaction of the protection system with the network model provides insight on both the performance of the relay scheme as well as its effect on the power system.
As is illustrated below, a model of the power system is implemented on the RTDS Simulator that includes the high voltage components (e.g. lines, breakers, instrument transformers, power transformers, generators, etc.) plus the required protection and control functions not included in the equipment under test.
Power Electronics
Power electronics based schemes require small timesteps to properly represent high frequency switching and circuit dynamics. To efficiently include such schemes in larger scale simulations, RTDS Technologies has developed the small timestep VSC subnetwork technique.
The VSC subnetworks operate with timesteps in the range of 1-4 µs and can be interfaced to large scale simulations operating with timesteps in the order of 50 µs.
A key feature of VSC subnetworks is that the circuit and valve topology is user configurable. Two- and three-level converters can be freely configured to provide crow-bar circuits, etc. for PWM switching at greater than 2 kHz. A low-loss, fixed topology two-level converter is also available for operation at PWM switching frequencies in the range of 10 kHz.
Multiple VSC subnetworks can be linked together by traveling wave transmission lines or cables to create entire sytems running with timesteps <4 µs.
Control Systems Testing
The RTDS Simulator is the ideal tool for testing of power system controls where real time closed-loop interaction between the power system simulation and the control hardware is essential.
The real time digital simulation environment provided by the RTDS allows the controls to be subjected to everything from steady state to rare emergency operating conditions. All conditions created can quickly and easily be repeated to investigate, understand and optimize the control behavior.
The RTDS simulator has been used all over the world to test a wide variety of power system controls.
Illustration below shows RTDS testing of inverter controller on a DSP board with the grid and the inverter simulated by RTDS.
Power Hardware In Loop Testing
Power Hardware In Loop (PHIL) simulation involves interfacing the RTDS simulation with power devices such as motors, inverters, generators and transformers via controlled power amplifiers to facilitate exchange of real and reactive power with the amplifier-interface while closing the electric power loop of the RTDS network simulation by feeding back voltage/current measurement signals from the interface back into the RTDS simulation. The following diagram shows a typical PHIL setup.
Closed loop PHIL simulations require more complex circuitry and precision hardware compared to open loop testing of power hardware. The interface between the simulator and the device under test is non-ideal due to time delays, noise and the limited bandwidth of the interface devices including amplifiers and feedback measurement transducers, all of which can significantly impact the stability and accuracy of closed loop simulations and must be carefully considered for any PHIL simulation.

Very often open loop simulation connected to power equipment via amplifiers is misrepresented as PHIL, but strictly speaking it is only a real-time playback setup and can simply be achieved with signal generators or stored waveforms and does not demand a hard-real-time simulation.  So, when you hear about PHIL next time, make sure to ask if it is open loop or closed loop PHIL.

The following document and the video discusses the key factors to be considered for PHIL simulations.

Very valuable ... A must read if you are new to PHIL ...
This 28 page  report discusses all aspects of setting up a PHIL test set up in detail ...

PHIL Video

Distribution System Modeling
RTDS Distribution Mode Example
IEEE 123 Node Test Distribution Feeder with DERs
  • Distribution Mode is a new feature available in RSCAD for modeling large distribution systems for studying distribution automaton, microgrid controller, distribution protection, etc. i
  • This new feature enables simulation of distribution feeders which contain hundreds of single phase nodes
  • Distribution mode library contains average models which require less computational effort making it possible to simulate large systems
  • Standard IEEE test feeder cases are available
  • CYME to RSCAD Conversion tool
  • New drawing mode which allows components to stretch in any direction so that the circuit can closely match the layout of other distribution system drawing packages
  • Reference: M. Dyck and O. Nzimako, 2017, “Real Time Simulation of Large Distribution Networks with Distributed Energy Resources,” in CIRED, Scotland
Distribution Automation
Distribution Automation
HIL Validation of Power Plant Controller (PPC) Model
  • Test communication interface
  • Optimize P, Q, PF and AVR modes

  • Coordinate multiple PPCs at a POI

  • Validate capacitor bank controls

  • Test protective relay settings

There is an increasing requirement to supply Inverter Based Resource (IBR) models compiled using the actual code used in the inverter-controls to allow detailed electro-magnetic transient (emt) studies. Similarly, emt models of Power Plant Controllers (PPC) which are commonly used for managing these utility-scale renewable energy plants are also required by the utilities.  However, validation of
these models against the performance of actual hardware controller is rarely provided. There is an increasing requirement to supply Inverter Based Resource (IBR) models compiled using the actual code used in the inverter-controls to allow detailed electro-magnetic transient (emt) studies. Similarly, emt models of Power Plant Controllers (PPC) which are commonly used for managing these utility-scale renewable energy plants are also required by the utilities.  However, validation of these models against the performance of actual hardware controller is rarely provided.  Validation via field tests is usually narrow in scope. The hardware-in-loop (HIL) validation using RTDS is a well accepted,  flexible, and cost-effective method for a thorough validation. The following articles discuss a unique usecase where the RTDS simulator was used for validating a PSCAD™ model of Nor-Cal Control’s PPC against its General Electric PLC based hardware controller.  In addition, the testbed can also be used as a productivity tool for a wide range of functions from testing a PPC concept in the R&D phase to System Accpetance Test (SAT) of a fully assembled power plant controller and protection system.
Battery Energy Storage System Controls and Protection Testbed
BESS Energy Storage
BESS is becoming a prominent component of renewable energy strategy for utilities worldwide.
A real-time testbed based on RTDS simulator lets the BESS suppliers and the utilities to test the controls, DERMS interface and protection system under all types of grid conditions and BESS operations.
The testbed is also great facility to develop, test and validate a standardized interface so that the utility can specify the interface requirements and verify it before commissioning. The architecture shown here is an example of one such testbed.
Cyber Security Testbed using RTDS
RTDS simulator has been used as the power system simulator in many cyber security research facilities including testbeds at some of the prominent institutions such as Washington State University, Texas A&M University, University of Illinois Urbana Champaign, Iowa State University and Florida State University. Following is a brief overview of the CPS Testbed at FSU & WSU. Please contact us for details about other installations and references.
Smart Grid Demonstration and Research Investigation Lab (SDGRIL) at Washington State University
  • RTDS is used to model IEEE 14 bus system as a part of the physical layer. Software and Hardware PMU’s are used to simulate PMU’s on all the buses
  • Software and hardware PDC’s such as Open PDC and SEL PDC have been interfaced with RTDS
  • CORE, DETERLab, GridStat, and Network Simulator-3 (NS-3) communication system emulators are interfaced with RTDS
  • Communication outage is simulated to observe effects on power system monitoring
  • Wide area voltage stability applications
  • Denial of Service attack, UKRAINE attack and Aurora attack demonstrated by Idaho National Lab have been simulated
  • Remedial Action Schemes (RAS) have been studied and the impact of an attack is observed in real-time
  • Study of coordinated cyber power attack to assess vulnerability is possible and planned
  • The testbed  is used as a Cyber Power Training Simulator
  • Reference:
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