### Virtual Reality for Power Substations Training Programs  
Several projects have been carried out for virtual simulation of substation operations. In a work developed by [42], the implementation of a virtual environment for training in operations of an electric substation is presented. A similar method was developed in the study presented by [48], in which an expert system providing supervision and guidance in the user training process is proposed. In both cases, the simulation was only visible on a computer screen, so it did not allow users to experience total immersion perception, but it allowed the operator to know the main components of the infrastructure [49]. The work of [50] laid out a methodology for the creation of virtual worlds of electrical substations where a high adjustment to reality was proposed, using three-dimensional geometric models of high precision. With this approach, it was possible to achieve realism in the virtual world and in the training process. A similar approach was taken by [10] to generate realistic virtual environments of a power substation. In the study presented by [44], a virtualisation system of a substation is presented, where not only a BIM model is used for the generation of the environment, but the electrical simulation of the equipment and the parameters of the electrical network are also implemented using a dynamic model programmed in MATLAB(r). A software bridge was created between the graphic environment (virtual model) and the dynamic simulator in MATLAB(r). The system simulated both the physical and mechanical world with the graphic engine as well as the electrical behaviour of the network, achieving great realism in training. As previously mentioned, these studies mainly focus on the generation of realistic virtual environments or training tools at a theoretical or preliminary development. However, there have been no assessments in exploring the efficacy of these systems to motivatetechnicians performing real training programs carried out by utility companies. Although there is no unified methodology to evaluate VR applications for training, as explained in the survey developed by [26], most of the works related to performance evaluation identify five key factors that must be considered: user satisfaction, learning rate, skills improvement, immersion and usability. However, this survey also indicated that studies focused on immersion and usability were scarce, although both factors had a direct correlation with a successful experience that could play a pivotal role in the learning and skill-formation process. As mentioned in [51], several studies have demonstrated the learning effectiveness of serious games. However, usability focused on game design, game flow and user interface (UI) suitable for the target audience requires additional efforts. This is a key factor because it is possible that vocational users in training could be users with no affinity to gaming. Consequently, the game interface and functionality must be accurate for a broad audience in order to maintain engagement and contribute to the training process. To answer the RQ, the performance and suitability based on usability and engagement of an immersive serious game were evaluated as a tool to improve vocational training of power substation operations focused on safety in our study. A methodology was utilised to integrate a real power substation BIM model into a game engine, creating a realistic scenario including main power equipment information. The serious game used immersive virtualisation, seizing the advantages of a CAVE room from Pontificia Universidad Javeriana, as well as a six-degree-of-freedom (6 DOF) haptic want device, to play three operator training missions based on common tasks (maintenance, operation and failure) performed in high voltage power substations. The proposed system was validated by executing usability and engagement tests, which are suitable tools to analyse the performance of such applications.