Wave energy provides a variable, intermittent source of electrical power with significant power fluctuations occurring over short time scales of seconds. Because of these inherent features, the electricity generated from wave power plants may have a negative impact on the power quality of a local electricity grid. Hence, before large scale wave farms can be allowed to connect to the grid, the impact of these devices on both distribution and transmission networks needs to be well understood. This paper shows a case study performed on the Belmullet region on the west coast of Ireland. Simulations were carried out using DIgSILENT simulation tool " Power Factory ". In this case study, the impact of a wave farm on the distribution network around Belmullet is studied. Static load flow and dynamic analysis for normal and contingency conditions are presented. The analysis was carried out within the framework of the IEA-OES Collaborative Annex III – " Integration of Ocean Energy Plants into Distribution and Transmission Electrical Grids " .