### Virtual Reality and Immersive Technologies  
Virtual reality (VR) is a computer-generated scenario that simulates a realistic experience that can be interacted with in a seemingly real or physical way by a person using special electronic equipment [11; 12]. It has been based mainly on interactive 3D graphics, user interfaces and visual simulation (VS) (graphical representation of objects and systems of interest using graphical languages) to display relevant data and analyses in immersive spaces. VR, in general, is extensively used in the fields of education and training due to its potential in stimulating interactivity and motivation [13]. Different studies about the use of VR and immersive systems were developed to evaluate the performance of this kind of system in a learning scenario [13; 14]. For vocational training aimed at adult workers, VR offers the possibility of moving safely around dangerous places, learning to cope with emotions while experimenting with the best solutions, far away from the real dangers [13] or in those situations that could not be accessed physically, caused by limitations such as time, physical inaccessibility and ethical issues, among others. There is a large portfolio of technologies, including interfaces, portable devices, sensors and 3D graphics, all of which are essential to achieve immersive environments in education and research [13], such as head-mounted displays (HMDs). With this system, the user experiences total immersion in the virtual world [15]. For applications where teamwork was necessary, this system does not allow the user to see the real world (only the virtual reality); therefore, the user cannot interact directly with real people, unless they interact through avatars [16]. In substation operations, tasks are usually performed in teams in response to dangerous situations, large equipment and technical guidelines of the utility maintenance crew chief. Another potential drawback is that it could cause more disorientation and visual fatigue (cyber sickness) with prolonged use compared to large projection systems [17; 18; 19; 20]. Its biggest advantages, as compared to large screen projection systems, are a lower investment cost and the increasing availability of several equipment and tools in the market [21]. Another possible solution is an immersive virtualisation system called cave automatic virtual environment (CAVE) [12], where a physical projection space usually exists in the form of a cube or cylinder, in which various projectors with stereo capability project images to the walls and floor, surrounding several users inside the structure. The users wear active-type stereo glasses, synchronised with the projectors, allowing them to perceive stereo images within the three-dimensional scene [11; 13]. In this type of space, the user can interact with people and objects inside the projection space, as the glasses do not hinder the vision and are only polarised to the images projected on the surfaces. Therefore, virtual or augmented reality applications are possible. The perception of immersion becomes possible by combining multiple projections surrounding the users and using active stereoscopy [12]. CAVE systems require a larger physical space where the projection infrastructure is installedand, usually, their investment is greater than that of HMD systems. However, they allow several users to be present in the same projection area, whereby all can simultaneously visualise the virtual world, while maintaining the ability of interaction among each other, overcoming the disadvantages that HMD has for the specific application, requiring crew chief guidelines [16]. These technologies contribute to improving the user's immersion, presence and interactivity, as mentioned in [22]. Interactivity is the degree to which a user can modify the simulated environment. Presence is the subjective experience (illusion) of being in one place and it is closely related to immersion [23; 24].