Grid forming inverter and its applications to support system strength–A case study

Abstract

With the increasing penetration level of renewable generation, a shortage of system strength becomes a concern for the stable operation of the power system. Most commonly, Inverter Based Resources (IBR) plants are operated with grid following inverters (GFLI). However, a grid forming inverter (GFMI), which work as a voltage source and does not require direct reference and system strength from the grid, is now receiving increased attention. Here, Hardware-in-the-loop (HIL) testing of a GFMI and its capability to actively damp sub-synchronous oscillations and to provide synthetic inertia has been discussed. The improvement to system strength and transient stability have been presented using modelling of the transmission network in the Queensland (Australia). The study shows that with proper tuning and coordination with other generation in the area, the GFMI BESS will not only provide system strength to the grid, but also solve other stability issues.