## 5 Final Remarks  
Currently, RT simulation technology is available through many companies. Most companies base the hardware engine on Field-Programmable Gate Array (FPGA), Intel processors, or NPX. Nonetheless, despite the differences in hardware engine architectures power electronics, HIL, control, and complex power systems simulations can still be carried out [9]. The most known simulators in the academic environment are OPAL-RT, RTDS, National Instruments, Fuji Electric, and Typhoon among others. The main difference in the implementation of a RT simulator relies on the desired software compatibility and communication interface. The former can vary from MATLAB Simulink, NI Labview, or proprietary software for a specific simulator company, i.e., RT-Lab and HYPERSIM are supported and developed for OPAL-RT hardware by OPAL-RT. Major challenges come with the communication interface and protocols used in RT simulators; depending on the situationm this aspect could become crucial to data exchange fidelity. Some communications interfaces are only suitable for local interconnections, categorized as small-distance systems, meaning that the simulation platforms must be close to each other to ensure RT performance. On the other hand, RT simulation can be also carried out in a long-distance scenario using internet communication protocols that send pieces of data over the internet, in package form, to a specific IP address assigned to a unique simulator. In this case, simulators can be located on separate institutions, or even separate countries. Nonetheless, to ensure RT performance, the interconnected \begin{table}
\begin{tabular}{c c c} \hline \hline
**Competence** & **HIL**[37] & **Co-Simulation**[24] \\ \hline Application and practice of knowledge & & \\ Problem solving and decision making & & \\ Apply science and engineering principles & & \\ Specific engineering discipline domination & & \\ Design and development of experiments & & \\ Independent and autonomous learning & & \\ Quality and Safety operation of equipment & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Competences endorsement by RT simulation strategy. devices need to operate synchronously over the selected communication channel. Table 3 summarises the different communication methods used in a virtual or remote RT co-simulation environment. A major consideration is the corroboratation that the simulators support the same communication interface to avoid third-party linkage points, Programmable Logic Controllers (PLC) and DSP are the most popular simulators, and ensure data exchange fidelity. An important point for long-distance applications is the use of Virtual Private Networks (VPN), since the user establishes a connection to the RT simulators through the internet, meaning that a secure connection is mandatory to protect and improve the data exchange between simulators and the user. In the case of VLS being used as a solution to migrate practical courses to online sessions due to the current global pandemic, the selection of a communication protocol capable of ensuring the long-distance manipulation of equipment is necessary. Fortunately, most of the available RT simulation technologies are built to support remote manipulation through TCP/IP and UDP communication protocols. For power electronics courses oriented for Microgrid and Smartgrid education, many simulation tools can be found in the market; these can be categorized into hardware and software tools. Table 4 shows the most popular RT simulation tools for academic and research purposes. Matlab and National Instruments software tools are commonly used by undergraduates, since these platforms require a lower initial investment, instead of the higher cost of acquiring specialized hardware and software. Table 4 also shows the software compatibility for the different RT simulation tools; most of them are compatible with _Matlab Simulink_, representing an advantage for the bachelor student that is already familiarized with the software environment. Some simulators