# Smart Grid Protection, Automation and Control: Challenges and Opportunities
## 3 Evolution of Substation Architectures and Digital Modernizations for Smart Substations
### Virtualization of Protection, Automation and Control (VPAC)  
VPAC systems for effectiveness and reliability need to be highly technically qualified in such critical environments. Data privacy laws and regulations, industrial standards, and government certifications must therefore be thoroughly studied and considered to ensure availability and high reliability. The design of the VPAC system should be made in such a way that redundancy mechanisms ensure the lowest possibility of a downtime occurrence as is practically possible. Security will be on par with encryption, strong authentication, and threat protection. Interoperability with existing equipment is of the utmost importance, coupled with adherence to open standards. It is essential to maintain lists of detailed hardware and software behavior while monitoring, and auditing should always be present to ensure integrity within a system. Besides this, the management of access control should be restricted, allowing access only to authorized persons. Finally, good backup and disaster recovery plans should be implemented to ensure that a system is resilient, if not fault-tolerant, and can recover from failures with minimum delay. VPAC systems are also deployed based on strict performance requirements, such as those governed by IEC 61850-5, so that they can remain capable of handling the increasing demands of modern power systems [47; 48]. Further, some important technical challenges must be considered in the case of the deployment of VPAC in digital substation environments for achieving better per \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Aspect** & **Characteristics** & **Benefits** \\ \hline Remote Operation & Remote monitoring and control Integration with automation systems & Reduces risk by minimizing personnel exposure to electrical hazards Increases efficiency through quick response without physical intervention \\ \hline Non-Traditional Instrument Transformers & Rogowski current sensors and voltage sensors & Prevents hazards such as high voltages in open CTs and ferro-resonance Easier, safer installation and maintenance \\ \hline Arc Flash Sensors [46] & Rapid detection of arcs via light and heat & Protects personnel and equipment by quickly extinguishing arcs Enhances system reliability and availability through reduced damage \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Key aspects of safety in electrical systems. formance and safety. Aspects include considerations of a virtualization solution, hardware acceleration, network virtualization, time synchronization, and redundancy [6; 49]. The most active associations for promoting the standard-based, open, interoperable, and secure architecture are VPAC Alliance [50] and Edge for Smart Secondary Substation (E4S) [51]. Both indeed support the digitalization of substations to make the grid future-ready, adaptable, resilient, and intelligent. Both organizations offer a solid base for the development of both CPAC and VPAC systems. Additionally, they support having identical requirements on conventional CPAC systems and virtualized systems. However, the VPAC systems include more challenges brought about by themselves due to their virtualized features. Standardization aspects of performance requirements, application architecture, cybersecurity, testing, new firmware deployment, and operation-related considerations stand as some main features of the system [49]. Standardization needs include the capacity for flexibility and scalability in solutions and systems that are deployed, interoperability, and the ability to integrate products from various vendors into a single solution. The systems will have to be designed on the back of widely deployed global standards, such as IEC 61850, to limit vendor lock-in risks; this would ensure hardware-software compatibility. Protection and control entities modeling in conformity with the IEC 61850 standard as discrete logical devices (LD) is the basis of the application architecture.