The share of wind power has grown drastically in the west coast of Finland in the past. This affects the regional stability, and the Finnish transmission system operator, Fingrid, has seen converter-driven stability issues in both real-life and simulations. One approach to mitigate stability issues is to add STATCOMs or energy storage STATCOMs (ES-STATCOMs) in the area. Therefore, this study assesses the feasibility of the ES-STATCOM compared to the conventional STATCOM without an energy storage from TSO’s perspective. Compensation units’ stabilizing effect is studied by EMT-simulations using SMIB model and semi wide area network model.

Based on the results, both STATCOM and ES-STATCOM stabilized converter-driven stability issues identified by Fingrid. The ES-STATCOMs have wider stabilizing effect due to their active power capacity but even conventional STATCOMs are able to provide a very short burst of active power. This seemed to be enough to mitigate wind power plants’ fault ride through issues. Thus, ES-STATCOM was not found to be superior compared to the STATCOM from Fingrid’s perspective when assessment was done by using these simulation models. However, Fingrid’s other internal studies with larger system models have shown greater advantage of the ES-STATCOM to mitigate wind power plant’s FRT issues.