E-REDES Solution to monitor and analyse underfrequency load shedding performance

Underfrequency Load Shedding (UFLS) is a vital protection scheme to ensure power system stability and integrity, preventing a cascading drop in frequency and potential widespread blackout by automatically disconnecting progressive l oad steps in a timeframe of a few seconds. While UFLS is rarely triggered, the increased penetration of Renewable Energy Sources (RES) has decreased the power system inertia, resulting in the potential for more regular and greater amplitude underfrequency events. Furthermore, the intermittent nature of RES, alongside the fact these generation sources are mainly being integrated in to the distribution grid, creates problems in predicting the load associated with each UFLS step. Considering these challenges, E-REDES designed an algorithm and interface to monitor the UFLS scheme, allowing the simulation of each theoretical step operation for past and future load scenarios. The detailed approach enables a statistical analysis of UFLS scenarios, providing insights into key metrics such as assessing ENTSO-E targets and optimizing each step calculation criteria. This paper details the proposed methodology, the results of UFLS monitoring in Portugal and the major benefits derived from it. The authors believe it allows for a more flexible and proactive monitoring of the UFLS scheme, improving TSO/DSO coordination in this topic.