Power-Hardware-in-loop test of a Grid-Forming Converter

The transition of the electric power system to a converter-dominant system leaves the grid with low inertia, leading to frequency variations and instabilities. One of the methods to compensate for this inertia is to use virtual inertia, and grid-forming converters can attain the virtual inertia using the swing equation. The grid-forming converters can also mimic the ancillary services provided by the synchronous machine. So, in the future, when converter-based sources replace a significant number of synchronous machines, the grid-forming converter can make the grid more reliable and stable in the absence of synchronous machines. In this paper, the grid-forming converter control is implemented in hardware and connected to a test system. This test system is ideally a simulation model which would run on a real-time simulator and the real-time simulator is connected to hardware using a power amplifier. The bidirectional communication is established between the real-time simulator and the hardware. The power amplifier transfers the power generated by the hardware (grid-forming converter) to the real-time simulator. The effect of transients from the grid-forming converter on the test system in a real-time simulator during the power-hardware-in-loop connection and fault-ride-through tests could be observed. In this paper, the grid-forming converter refers to the hardware and the test system or Kundur 4 machine model refers to the simulation model in a real-time simulator.