This presentation introduces a fast simulation method for assessing and proving harmonic compliance of inverter-based-resources (IBR) plants which is necessary for receiving an energization (EON), interim (ION), or finale (FON), operational notification, for grid-connection of the IBR plants to the collective transmission grid.

Usually, the harmonic compliance shall be proven by simulations applying the harmonic impedance polygons ranging from tens ohms up to few thousand ohms with a step by one ohm for each relevant integer harmonic and interharmonic order. The impedance polygons are for representing various operation regimes within the meshed transmission grid and provided by the grid operator. Such studies shall be fully completed and approved by the grid operator prior to granting the operational notifications to the IBR plants.

The harmonic compliance studies involve numerous simulations. Fastest-possible completion of the harmonic compliance studies and high accuracy of the results requiring high resolution within the harmonic impedance polygons are extremely relevant for the IBR plant developers.

The presented method allows expediting the simulation time by omitting slow processes involving many repeated, embedded, load-flow and harmonic load-flow simulations on large harmonic impedance polygons.

Instead, fast arithmetical operations on independent states are applied to simulate the harmonic voltage magnitudes within the impedance polygons. The simulation time has been reduced by approx. 65 times with the largest benefit gained for the largest impedance polygons. This presentation will demonstrate the method by anonymised real-life examples and propose possible areas of further applications.