Estimation of grid-supporting parameters of generation units tested by passive FRT-tester

Internal voltage vector, effective internal impedance and damping behavior are parameters of a Power Generation Unit (PGU) that describe the grid-supporting behavior of a generation unit, as well as their tolerance in terms of their stability and remaining connected to the grid in the event of extreme grid faults. These parameters can be measured well and easily on small PGU’s using a full converter tester. For large units, such tester become rare and expensive. To what extent can these parameters be determined using passive test devices. What properties do passive test devices have to fulfill? The properties of the tester can also be determined during the course of a test.