Dynamic Power Tracking Performance and Small Signal Stability Analysis of Integrated Wind-to-Hydrogen System

To achieve the 2050 global climate target, offshore wind will increase to meet the growing demand of direct and indirect electrification (e.g. green hydrogen production for the hard-to-abate sector). To keep up with the rapid increase of offshore wind generation, the energy balancing challenges due to the intermittency nature of wind and the network congestion/capacity challenges resulting from structural network capacity planning latency are to be addressed with system integration technology. In this paper, it is proposed that the hydrogen electrolysis plant be co-located with the wind farm, where the power consumption is controlled to track the wind generation profile accurately to cancel the intermittency of wind generation, reduce the required grid connection capacity, and thereby avoid expensive grid expansion. However, this power tracking controller introduces a cross-plant feedback path from the wind farm to the hydrogen plant, posing challenges for partitioning the power tracking loop completely for stability analysis, which also makes it difficult to make a good trade-off between the tracking performance and stability margins. To address this issue, this paper proposes an equivalent transformation to eliminate the cross-plant feedback path. Then, the criteria for choosing the optimal partition method are proposed and examined for different types of partition methods, which are mathematically proven to be equivalent in terms of stability conditions but provide different insights. An optimal partition method is then proposed in this paper, which not only provides clear insight on the ideal and non-ideal power tracking performances but also can also identify the stability issues of different minor loops individually. Finally, the proposed optimal partition method and its valuable insights into power tracking performance and stability analysis are validated through time-domain simulations of a 180 MW integrated wind-to-hydrogen plant with a realistic complexity.