The objective of this paper is to suggest a suitable design procedure that may be useful for the practical realisation of the bi-layer wide area control (WAC) architecture. The bi-layer WAC architecture indicates the deployment a communication-free supplementary WAC loop in parallel to the conventional WAC loop. The bi-layer WAC system was found to have the potential to counterbalance the communication-related problems that arise in the conventional WAC loop. However, until now, no specific work has been reported in literature for the practical design of the supplementary wide area damping controller (WADC). It is essential to design the supplementary WADC in a way so that it can be practically implemented without the support of any communication network. The particular problem is resolved here by defining a suitable structure of the feedback gain matrix in the supplementary WAC loop. A novel structurally constrained H2 norm optimisation technique is developed to design the particular feedback gain matrix with the proper structure. Here, the structurally constrained H2 norm optimisation is performed for an output feedback loop instead of a state feedback loop. The usefulness of the supplementary WADC design produced is thoroughly verified through real-time (RT) experimentations. © The Institution of Engineering and Technology 2019.