The increasing penetration of renewables has led to a rapid rise in the amount of power electronics connected to the grid. Renewable energy sources like solar, wind, and tidal power all connect to the grid via inverters. Of course, all the positive changes enabled by power electronics do not come without risk. Since power electronics have closed loop control systems there is potential for resonance to be amplified – and with so many power electronics in the system converting and controlling the flow of electricity, the potential system impact of harmonic resonance has grown dramatically. Making sure all the power electronics on your system work together properly is more important than ever before.
So how do you get everything to play along? Ideally, you need to accurately model all of the equipment that is connected to the grid. A few years ago, this meant off-line computer simulations - modelling traditional generators using simulation time steps around 1 ms, and overall simulation run times in the tens of minutes to simulate a few seconds of real time. However, modelling the fast switching of inverter-connected generation requires simulation time steps around 10 us, and simulation run times of several hours to simulate a few seconds of real time.
While off-line simulation is still widely used in the industry, there is a growing recognition that very long simulation run times tend to make good engineering analysis very difficult. In contrast, real-time simulation (RTS) allows for the timely investigation of the stability and transient responses of the power system and allows system operators to more reliably plan and mitigate the risks presented by the mass integration of new inverter connected energy sources.
There are two major platforms used widely around the world for performing Real Time Simulation:
- Real Time Digital Simulator (RTDS) developed by RTDS Technologies Inc.
- The suite of RTS platforms known as ePHASORSIM, HYPERSIM, eMEGASIM and eFPGASIM, developed by Opal-RT Technologies Inc.
Some of the major applications for RTS are:
- Relay Testing
- Hardware-in-the-Loop (HIL) testing
- Software in the loop (SIL) testing
- Microgrid and DER testing
Only real-time simulation allows you to test and analyze the impact of the real control systems that will be installed. As the power system continues to evolve, the speed and flexibility of simulation tools will become increasingly important. Power system operators should consider the value of real-time simulation to help them evaluate the impact of inverters on their rapidly developing networks.
PSC supports clients with RTS on both major platforms. RTS customers can turn to PSC to develop the power system models in OPAL-RT or RTDS, and perform HIL testing on these platforms. For customers seeking expertise developing models and testing controls in RTS, PSC supports both RTDS and OPAL-RT products.
Other areas you can benefit from RTS support include:
- Developing specifications for factory acceptance and commissioning tests of controls for Inverters, SVC’s, and STATCOM’s
- Modelling in RSCAD/Hypersim (including network modelling)
- Testing in RTDS/Hypersim
- Reviewing and validating factory acceptance and commissioning results
- Model validation between PSS/E (or PSLF or Powerfactory), PSCAD (or EMTP-RV), and RTDS/Hypersim.