Maintaining the robustness and stability of the Nordic power systemis an essential task nowadays. The Nordic electricity network has the characteristics of bearing heavy generation in the northern region while supplying large consumption in the southern region through longtransmission lines. Therefore, its operation mightbecomemore complex which infact can lead to operational issues that did not exist in the pastand might lead to major problemsofthe network.The resonance interaction caused by forcing oscillations occurring at frequencies near the inter-area mode frequenciesis such an issue and is studied thoroughly in this thesis project.Small signal stability analysis is the basis for the research of this phenomenon, as the inter-area modes need to be calculated. For verifying this phenomenon, simulations were implemented in DigSilent PowerFactory software. The Nordic 32 test model is utilized, as it reflectsthe original Nordic system. Initially, the modes of the system are calculated,and the inter-area modes of interest are identifiedbased on their frequency and damping ratio value. The observability, controllability and participation factorsof the modes areconsidered for picking the modes of interestfor further analysis. Then, forced oscillations in the formof load variations are implemented to study the resonance impact withthe inter-area modes. As a mean to quantify the resonance impact, the active power flow of tie lines in the system is used.A sensitivity study was performed to study how various factors of the forced oscillations influence the resonance impact. The sensitivity study considered the following aspects of the forced oscillations: frequency, amplitude, location, and type. The amplification of the resulting oscillations seems to be affected by the value of controllability of the mode whose frequency couples with the inter-area frequency. This connection is evaluated in the simulations of this project and interesting results occur for further analysis