Power electronics-based schemes require small simulation timesteps to properly represent high frequency switching and circuit dynamics. The RTDS Simulator's Substep environment is designed to achieve extremely small timesteps, allowing engineers to flexibly model the behaviour of power electronics (and the AC network) over a large frequency range in real time. Real control hardware can then be connected to the simulated network and tested to significantly reduce risk and improve performance prior to deployment.

The Substep environment contains a selection of fixed-topology converter models that are based on an innovative predictive switching algorithm. These models represent changes in state using a switched resistance (rather than inductance or capacitance, as is the case in L/C switched models). Models using L/C associated discrete circuits may result in unrealistic artificial power loss as well as fictitious current oscillations leading to noise in the simulation results. The Substep environment and its predictive switching feature have been designed to eliminate these issues for the user.

How Substep works:

• Power electronic models (consisting of user-configured individual switching elements or set topology models) are created in the RTDS Simulator's Substep environment, where they run at timesteps a fraction of the size of the main simulation timestep
• Data is exchanged between the Substep subnetwork and the main network every main timestep, allowing the user to study the interactions between power electronics and the AC network

• Multiple Substep networks can be connected to represent large power electronic circuits

Models available in the Substep environment:

• Common converter topologies with resistive switching (2- and 3-level VSCs including T-type and NPC configurations, buck and boost converters).Freely configurable power electronics (individual switching components)
• Point-to-point and back-to-back VSCs
• MMC valve and control models
• Firing pulse and ramp generators
• Lines, machines, transformers, and loads for full circuit simulation
   

About RTDS Technologies Inc.

RTDS Technologies Inc., the exclusive supplier of the RTDS Simulator, has been the world standard of real time digital power system simulation for over 25 years. Leading utilities, equipment manufacturers, research institutes, consultants, and universities around the world use the RTDS Simulator for power system studies and closed loop testing of protection and control equipment.