Proceedings of the 33rd European Safety and Reliability Conference (ESREL 2023) Edited by Mário P. Brito, Terje Aven, Piero Baraldi, Marko Čepin and Enrico Zio ©2023 ESREL2023 Organizers. Published by Research Publishing, Singapore. doi: 10.3850/978-981-18-8071-1_P447-cd Connection Capability of Distributed Generation Units in A Power System under Active Network Management Juan SUN Service de Métrologie Nucléaire, Université libre de Bruxelles, Belgium. E-mail:juan.sun@ulb.be Pierre-Etienne LABEAU Service de Métrologie Nucléaire, Université libre de Bruxelles, Belgium. E-mail:Pierre.Etienne.Labeau@ulb.be In a power system featuring a large share of distributed generations (DGs), the variability of power supply results in various issues in the implementation of more DG units incorporation to the existing distribution networks, particularly, congestion risk. Active Network Management (ANM) could provide (almost) real-time control, by possibly curtailing their production in case of grid congestion so as to allow more DG units integration, while deferring costly and time-consuming network upgrades. This paper provides a methodology for the fast assessment of the connection capability of DG units to a grid in ANM scheme, based on efficient Monte Carlo sampling. Besides, resorting to correlated sampling, it is possible to simultaneously estimate the congestion risk with and without connecting a new DG unit of variable capacity. This significantly reduces the computation burden in assessing the connection capability of a grid. The effectiveness of the proposed method is demonstrated on a test power grid. Keywords: Active Network Management, distributed generation, curtailment, efficient Monte Carlo Sampling, congestion risk, correlated sampling. 1. Introduction Towards the road of energy transition, the amount of decentralized production connected to the Medium-Voltage (MV) power system is significantly increasing. As a consequence, when the power produced is not consumed locally, reverse power flows are injected into the High- Voltage (HV) grid. More frequent line congestions and voltage problems are likely to occur. However, the appearance of Active Network Management (ANM), emerged as (almost) real-time control of power, voltage and frequency within a network (Järventaustac et al. 2010), could provide an effective solution for operating the injection of energy produced by Distributed Generation (DG) units to the grid, by possibly curtailing their production in case of grid congestion. It will help optimize both the use of the present grid infrastructure and the number of connected DG units. These interruptible connections offered to DG customers (also known as Non-Firm Generators, NFGs), combined with a set of rules about the order they are dispatched or curtailed under an ANM scheme, would maximize the use of renewable generation, and allow connection of larger generators. The curtailment rules are actually the Principle of Access (PoA) rules, e.g. Last-In-First-Out (LIFO) and Pro-Rata schemes. The former one means that the first NFG to sign a contract in the ANM scheme is always the last one to be curtailed. It is easily implemented and does not affect existing generators, but might discourage investment in future DG development. When abide by Pro-Rata rule, the required curtailment is shared between all NFG units, proportionally to the rated capacity or actual output of the generators. It also signifies that revenue losses are shared equally. With an ANM arrangement deploying different PoA schemes among the connected units, more DG units are likely to be incorporated into the distribution power system. The impact of an 461