Posters

Abstract

The rising share of converter-based generation is pushing wind power plants (WPPs) to provide frequency support and voltage support, especially under low-inertia and weak-grid conditions [1,2]. This contribution reports a reproducible simulation on a compact four-bus benchmark. At the point of common coupling (PCC), a 175 MW type-4 WPP in grid-following (GFL) mode, a grid-forming converter (GFM), and a battery energy storage system (BESS) in GFL mode are connected via dedicated transformers. Type-4 turbines (fully rated back-to-back converters) decouple the generator from the grid, enabling flexible active/reactive power control but relying on phase-locked loop (PLL) synchronisation that can constrain performance in weak networks [3,4]. A +100 MW / +30 MVAr load step is applied at the PCC after pre-weakening by opening one of the two circuits that link the external reference to the local subsystem. Three scenarios are assessed: (E1) WPP in GFL; (E2) E1 plus a GFM at the PCC; and (E3) E2 plus a BESS in GFL. The WPP uses PLL-based synchronisation, d/q current control and reactive-power regulation. The GFM acts as a voltage source with active-power droop and a voltage regulator [5-7]. The BESS applies frequency-power droop with dead-band and ramp, state-of-charge (SOC)-dependent charge control, and current limiting. Indicators are frequency nadir, rate of change of frequency (ROCOF), positive-sequence voltage, converter currents and active/reactive power sharing. Results demonstrate that the GFM improves frequency stability, lowers ROCOF and moderates the voltage dip versus purely GFL operation, while the BESS supplies additional active-power support that further strengthens the response [8-10]. The workflow illustrates how GFL WPPs can be complemented by GFMs and co-located storage, and provides guidance for tuning droop slopes, regulator gains and current limits in practice.