Overview of Technical Studies Conducted for Facilitating Increased Renewable Penetration on the Island of Ireland

As transmission system operators on the island of Ireland, EirGrid and SONI are significantly involved in implementing multiple projects aimed at facilitating the integration of renewable resources in the all-island power system. One such key project is to develop necessary tools and technologies to enable safe and secure operation of the power system with instantaneous non-synchronous renewable penetration (quantified using the System Non-Synchronous Penetration (SNSP) metric) levels of up to 75%. This paper presents key findings of detailed technical studies carried out in the domains of voltage, frequency and rotor angle stability to conclusively establish whether operating the all-island power system at SNSP levels of up to 75% has any adverse impact on relevant operational security standards. The studies are carried out using selected system snapshots from a trial period involving 200 hours of system operations with SNSP levels greater than 70%. Both base case and sensitivity studies are conducted, and detailed discussions are presented to establish the root cause behind insecurities observed, if any. Based on the detailed analyses presented, a recommendation is made for implementing system operations with SNSP levels of up to 75% on an enduring basis.