Amid the rising significance of renewable energy sources, Green Hydrogen Plants (GHPs) are emerging as pivotal contributors to sustainable energy solutions. However, efficient and reliable alarm management in such complex systems remains a significant challenge. This paper presents a novel methodology called V-nets Based Alarm Management (VBAM), designed to improve supervision by addressing the intricacies of discrete event management in industrial applications such as Green Hydrogen Plants (GHP). V-nets offer a powerful formalism that integrates visual modeling and using temporal patterns, enabling the precise detection and handling of alarms. The proposed methodology is applied to a case study in a GHP, where critical operational parameters are continuously monitored. By analyzing discrete events and their temporal patterns, V-nets facilitate early fault detection, minimize false positives, and optimize alarm response. The case study demonstrates theoretically the efficacy of V-nets in enhancing system safety, reducing downtime, and improving overall operational efficiency. Furthermore, this paper emphasizes the flexibility and adaptability of the VBAM, as it can be applied to various industrial processes and complex systems beyond Green Hydrogen Plants.