Impact of Inverter-Based Generation on Voltage Stability in a Modified Nordic Test System

It is well known that an increased share of inverter-based generation has a significant impact on the system dynamics of the electric power grid. Due to this aspect, in this paper the effects of enhanced penetration level of renewable energy sources (RESs) are investigated regarding the system dynamics. The voltage stability is examined in detail based on the Nordic Test System. As a result of the enduring change in power systems, the risk of blackouts caused by voltage instability increases. Therefore, an indispensable need for a test system arises that is capable of simulating such voltage instabilities in the presence of inverter-based generation. Due to the lack of a publicly accessible test system that incorporates inverter-based generation, the well-documented Nordic Test System has been modified to achieve a share of 35% of renewable sources. Various simulation results show that the proposed modified system has a more pronounced voltage gradient compared to the original one. It also has similar long-term dynamics that is depending on the selected current limitation. For complete transparency, all individual modifications are presented and explained in detail.